RE: OSPF demand-circuit does not work [7:74954]
It will say multicast. Martijn -Oorspronkelijk bericht- Van: Devrim Yener KUCUK [mailto:[EMAIL PROTECTED] Verzonden: maandag 8 september 2003 16:38 Aan: [EMAIL PROTECTED] Onderwerp: Re: OSPF demand-circuit does not work [7:74954] what do you see when you do "sh dialer" on the calling router, as a dial reason? or debug dialer, debug isdn q931 will be telling you regards De - Original Message - From: "Lesly Verdier" To: Sent: Monday, September 08, 2003 2:25 PM Subject: OSPF demand-circuit does not work [7:74954] > Hello All, > > I've configured "ip ospf demand-circuit" on an ISDN connection and this > statement is supposed to supress the calls initiated by the Hello Packets. > Still my router keeps on dialing. > > Does anybody know what the reason might be? > > Thanks, > > Lesly Verdier > **Please support GroupStudy by purchasing from the GroupStudy Store: > http://shop.groupstudy.com > FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html **Please support GroupStudy by purchasing from the GroupStudy Store: http://shop.groupstudy.com FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=75250&t=74954 -- **Please support GroupStudy by purchasing from the GroupStudy Store: http://shop.groupstudy.com FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html
Re: OSPF demand-circuit does not work [7:74954]
Devrim Yener KUCUK wrote: > what do you see when you do "sh dialer" on the calling router, as a dial > reason? > or debug dialer, debug isdn q931 will be telling you And "sh ip ospf stat" will show you activity of OSPF - remember that every change in OSPF topology can trigger dialer. -- EC Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=75038&t=74954 -- **Please support GroupStudy by purchasing from the GroupStudy Store: http://shop.groupstudy.com FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html
Re: OSPF demand-circuit does not work [7:74954]
what do you see when you do "sh dialer" on the calling router, as a dial reason? or debug dialer, debug isdn q931 will be telling you regards De - Original Message - From: "Lesly Verdier" To: Sent: Monday, September 08, 2003 2:25 PM Subject: OSPF demand-circuit does not work [7:74954] > Hello All, > > I've configured "ip ospf demand-circuit" on an ISDN connection and this > statement is supposed to supress the calls initiated by the Hello Packets. > Still my router keeps on dialing. > > Does anybody know what the reason might be? > > Thanks, > > Lesly Verdier > **Please support GroupStudy by purchasing from the GroupStudy Store: > http://shop.groupstudy.com > FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=74967&t=74954 -- **Please support GroupStudy by purchasing from the GroupStudy Store: http://shop.groupstudy.com FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html
OSPF demand-circuit does not work [7:74954]
Hello All, I've configured "ip ospf demand-circuit" on an ISDN connection and this statement is supposed to supress the calls initiated by the Hello Packets. Still my router keeps on dialing. Does anybody know what the reason might be? Thanks, Lesly Verdier Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=74954&t=74954 -- **Please support GroupStudy by purchasing from the GroupStudy Store: http://shop.groupstudy.com FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html
Re: ospf type 5 lsas [7:74699]
someone requested the configs; i'm sorry, i'm not sure who.
and the links are numbered, btw.
7500:
interface atm 0/1/0.101
ip address 192.168.10.1 255.255.255.252
!
!
router ospf 120
network 192.168.10.0 0.0.0.3 area 0
network 10.64.0.0 0.0.0.255 area 14
!
2500:
interface ethernet 0
ip address 172.16.10.5 255.255.255.252
!
interface serial 0/0.101 point-to-point
ip address 192.168.10.2 255.255.255.252
!
!
router ospf 120
network 192.168.10.0 0.0.0.3 area 0
network 172.16.10.4 0.0.0.3 area 15
area 15 nssa no-summary
!
the only other router in area 15 is at 172.16.10.6, and is configured as an
nssa asbr.
the 7500 has all the type 5 lsas in its database, but none entered in its
route table.
eg:
7500#show ip ospf database external 200.88.200.220
OSPF Router with ID (200.55.10.244) (Process ID 20)
Type-5 AS External Link States
LS age: 2576
Options: (No TOS-capability, DC)
LS Type: AS External Link
Link State ID: 200.88.200.220 (External Network Number )
Advertising Router: 200.27.100.154
LS Seq Number: 8008
Checksum: 0x1A8B
Length: 36
Network Mask: /32
Metric Type: 2 (Larger than any link state path)
TOS: 0
Metric: 2
Forward Address: 0.0.0.0
External Route Tag: 3221225472
7500#show ip route | include 200.88.200.220
7500#
thomas
- Original Message -
From: Thomas Salmen
To: [EMAIL PROTECTED]
Sent: Tuesday, September 02, 2003 3:43 PM
Subject: ospf type 5 lsas
i have a problem with ospf that someone may be able to help with.
i have a 2500 connected to a 7500 via a frame (2500 end) to atm (7500 end)
link. the 2500 is an abr for area 15 (serial area 0, ethernet area 15); the
7500 is an abr for area 14 (atm area 0, other interfaces area 14).
area 15 is configured as an nssa, as it is attached to another router which
is
redistributing static routes. area 14 is a standard ospf area, not stub or
nssa.
the 2500 (abr) is recieving type 7 lsas and converting them to type 5 and
flooding them into area 0, no problems. the 7500 has them in its lsa
database.
the problem is that none of the type 5 lsas are being entered in the 7500s
route table.
i have run through everything i can think of, and i'm a bit stuck. the
forwarding address of each lsa is 0.0.0.0. the network type is correct (ptp).
the 7500 can reach the abr and the asbr. subnet masks are all correct. i'm
not
sure what to look for next...
anyone?
thomas
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Message Posted at:
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Re: ospf type 5 lsas [7:74699]
Looks like you have two OSPF processes on the 7500. Typical case of "less would be more"... :) Thanks, Zsombor Thomas Salmen wrote: > > someone requested the configs; i'm sorry, i'm not sure who. > > and the links are numbered, btw. > > > 7500: > > interface atm 0/1/0.101 > ip address 192.168.10.1 255.255.255.252 > > ! > > ! > router ospf 120 > network 192.168.10.0 0.0.0.3 area 0 > network 10.64.0.0 0.0.0.255 area 14 > > ! > > > > 2500: > > interface ethernet 0 > ip address 172.16.10.5 255.255.255.252 > ! > interface serial 0/0.101 point-to-point > ip address 192.168.10.2 255.255.255.252 > > ! > > ! > router ospf 120 > network 192.168.10.0 0.0.0.3 area 0 > network 172.16.10.4 0.0.0.3 area 15 > area 15 nssa no-summary > ! > > the only other router in area 15 is at 172.16.10.6, and is > configured as an > nssa asbr. > > the 7500 has all the type 5 lsas in its database, but none > entered in its > route table. > > eg: > > 7500#show ip ospf database external 200.88.200.220 > > OSPF Router with ID (200.55.10.244) (Process ID 20) > > Type-5 AS External Link States > > LS age: 2576 > Options: (No TOS-capability, DC) > LS Type: AS External Link > Link State ID: 200.88.200.220 (External Network Number ) > Advertising Router: 200.27.100.154 > LS Seq Number: 8008 > Checksum: 0x1A8B > Length: 36 > Network Mask: /32 > Metric Type: 2 (Larger than any link state path) > TOS: 0 > Metric: 2 > Forward Address: 0.0.0.0 > External Route Tag: 3221225472 > > 7500#show ip route | include 200.88.200.220 > > 7500# > > > > > thomas > > > > - Original Message - > From: Thomas Salmen > To: [EMAIL PROTECTED] > Sent: Tuesday, September 02, 2003 3:43 PM > Subject: ospf type 5 lsas > > > i have a problem with ospf that someone may be able to help > with. > > i have a 2500 connected to a 7500 via a frame (2500 end) to atm > (7500 end) > link. the 2500 is an abr for area 15 (serial area 0, ethernet > area 15); the > 7500 is an abr for area 14 (atm area 0, other interfaces area > 14). > > area 15 is configured as an nssa, as it is attached to another > router which is > redistributing static routes. area 14 is a standard ospf area, > not stub or > nssa. > > the 2500 (abr) is recieving type 7 lsas and converting them to > type 5 and > flooding them into area 0, no problems. the 7500 has them in > its lsa database. > the problem is that none of the type 5 lsas are being entered > in the 7500s > route table. > > i have run through everything i can think of, and i'm a bit > stuck. the > forwarding address of each lsa is 0.0.0.0. the network type is > correct (ptp). > the 7500 can reach the abr and the asbr. subnet masks are all > correct. i'm not > sure what to look for next... > > anyone? > > thomas > > Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=74751&t=74699 -- **Please support GroupStudy by purchasing from the GroupStudy Store: http://shop.groupstudy.com FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html
Re: ospf type 5 lsas [7:74699]
Mmm, looks like you have area 15 configured as a Not so stubby totally stubby area (NSSTSA) rather than as a not so stubby area (NSSA)...some slight differences as noted below; also, note how type 5 and 7 are (and are not) supportedLSA type 5 routes will not be used in a NSSA or NSSTSA; however, the same information conveyed by type 7 will (comes from ABR for the area). NSSA: If there is an ABR configured into this area (to area 0), it will convert the LSA type 7 to an LSA type 5. The LSA type 5 that was a LSA type 7 gets passed to the backbone area, where it gets distributed as a normal LSA type 5 to the rest of the OSPF routing domain. This LSA type 5 does not get sent into the NSSA because the NSSA does not allow LSA type 5 into the area.not to mention that the NSSA routers already have this information via the LSA type 7. By default, type 5 LSAs cannot be summarized at an ASBR or ABR, though Type 7 can. An area is configured as a NSSA with the following command in OSPF configuration mode. This command must be entered on all routers in the area in order for them to become neighbors. area 1 nssa About NSSTSA... The Not So Stubby Totally Stubby Area (NSSTSA) is a special definition of the NSSA. It is more restrictive regarding what it allows into the area. The NSSTSA is similar to the NSSA, except that it does not allow LSA type 3 and 4 into the area. Otherwise, the NSSTSA is just like a NSSA. The NSSTSA ASBR creates LSA type 7 for the routes that it is redistributing from another routing protocol into the NSSTSA. The NSSTSA ABR converts the 7 into a 5 for propagation to the rest of the OSPF domain. A default route, sent as a LSA type 3 summary, is the only exception to NSSTSA rule that no 3 or 4 is allowed into the area. To configure a NSSTSA, enter the following command on the NSSTSA ABR only. This configures the ABR not to send LSA type 3 and 4 into the NSSTSA. All routers will be configured with the NSSA command, as previously discussed. On the NSSTSA ABR only: area 1 nssa no-summary On all other NSSTSA routers: area 1 nssa HTH, Charles ""Thomas Salmen"" wrote in message news:[EMAIL PROTECTED] > someone requested the configs; i'm sorry, i'm not sure who. > > and the links are numbered, btw. > > > 7500: > > interface atm 0/1/0.101 > ip address 192.168.10.1 255.255.255.252 > > ! > > ! > router ospf 120 > network 192.168.10.0 0.0.0.3 area 0 > network 10.64.0.0 0.0.0.255 area 14 > > ! > > > > 2500: > > interface ethernet 0 > ip address 172.16.10.5 255.255.255.252 > ! > interface serial 0/0.101 point-to-point > ip address 192.168.10.2 255.255.255.252 > > ! > > ! > router ospf 120 > network 192.168.10.0 0.0.0.3 area 0 > network 172.16.10.4 0.0.0.3 area 15 > area 15 nssa no-summary > ! > > the only other router in area 15 is at 172.16.10.6, and is configured as an > nssa asbr. > > the 7500 has all the type 5 lsas in its database, but none entered in its > route table. > > eg: > > 7500#show ip ospf database external 200.88.200.220 > > OSPF Router with ID (200.55.10.244) (Process ID 20) > > Type-5 AS External Link States > > LS age: 2576 > Options: (No TOS-capability, DC) > LS Type: AS External Link > Link State ID: 200.88.200.220 (External Network Number ) > Advertising Router: 200.27.100.154 > LS Seq Number: 8008 > Checksum: 0x1A8B > Length: 36 > Network Mask: /32 > Metric Type: 2 (Larger than any link state path) > TOS: 0 > Metric: 2 > Forward Address: 0.0.0.0 > External Route Tag: 3221225472 > > 7500#show ip route | include 200.88.200.220 > > 7500# > > > > > thomas > > > > - Original Message - > From: Thomas Salmen > To: [EMAIL PROTECTED] > Sent: Tuesday, September 02, 2003 3:43 PM > Subject: ospf type 5 lsas > > > i have a problem with ospf that someone may be able to help with. > > i have a 2500 connected to a 7500 via a frame (2500 end) to atm (7500 end) > link. the 2500 is an abr for area 15 (serial area 0, ethernet area 15); the > 7500 is an abr for area 14 (atm area 0, other interfaces area 14). > > area 15 is configured as an nssa, as it is attached to another router which > is > redistributing static routes. area 14 is a standard ospf area, not stub or > nssa. > > the 2500 (abr) is recieving type 7 lsas and converting them to type 5 and > flooding them into area 0, no problems. the 7500 has them in its lsa > database. > the problem is that none of the type 5 lsas are being entered in the 7500s > route table. > > i have run through everything i can think of, and i'm a bit stuck. the > forwarding address of each lsa is 0.0.0.0. t
Re: ospf type 5 lsas [7:74699]
someone requested the configs; i'm sorry, i'm not sure who.
and the links are numbered, btw.
7500:
interface atm 0/1/0.101
ip address 192.168.10.1 255.255.255.252
!
!
router ospf 120
network 192.168.10.0 0.0.0.3 area 0
network 10.64.0.0 0.0.0.255 area 14
!
2500:
interface ethernet 0
ip address 172.16.10.5 255.255.255.252
!
interface serial 0/0.101 point-to-point
ip address 192.168.10.2 255.255.255.252
!
!
router ospf 120
network 192.168.10.0 0.0.0.3 area 0
network 172.16.10.4 0.0.0.3 area 15
area 15 nssa no-summary
!
the only other router in area 15 is at 172.16.10.6, and is configured as an
nssa asbr.
the 7500 has all the type 5 lsas in its database, but none entered in its
route table.
eg:
7500#show ip ospf database external 200.88.200.220
OSPF Router with ID (200.55.10.244) (Process ID 20)
Type-5 AS External Link States
LS age: 2576
Options: (No TOS-capability, DC)
LS Type: AS External Link
Link State ID: 200.88.200.220 (External Network Number )
Advertising Router: 200.27.100.154
LS Seq Number: 8008
Checksum: 0x1A8B
Length: 36
Network Mask: /32
Metric Type: 2 (Larger than any link state path)
TOS: 0
Metric: 2
Forward Address: 0.0.0.0
External Route Tag: 3221225472
7500#show ip route | include 200.88.200.220
7500#
thomas
- Original Message -
From: Thomas Salmen
To: [EMAIL PROTECTED]
Sent: Tuesday, September 02, 2003 3:43 PM
Subject: ospf type 5 lsas
i have a problem with ospf that someone may be able to help with.
i have a 2500 connected to a 7500 via a frame (2500 end) to atm (7500 end)
link. the 2500 is an abr for area 15 (serial area 0, ethernet area 15); the
7500 is an abr for area 14 (atm area 0, other interfaces area 14).
area 15 is configured as an nssa, as it is attached to another router which
is
redistributing static routes. area 14 is a standard ospf area, not stub or
nssa.
the 2500 (abr) is recieving type 7 lsas and converting them to type 5 and
flooding them into area 0, no problems. the 7500 has them in its lsa
database.
the problem is that none of the type 5 lsas are being entered in the 7500s
route table.
i have run through everything i can think of, and i'm a bit stuck. the
forwarding address of each lsa is 0.0.0.0. the network type is correct (ptp).
the 7500 can reach the abr and the asbr. subnet masks are all correct. i'm
not
sure what to look for next...
anyone?
thomas
Message Posted at:
http://www.groupstudy.com/form/read.php?f=7&i=74699&t=74699
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Re: ospf type 5 lsas [7:74632]
Can we see the configuration for the 2500 and 7500 (just the OSPF part). Also, is this route in the table at all? That is, is another protocol (like EIGRP) also advertising this route?? Thanks, Charles ""Thomas Salmen"" wrote in message news:[EMAIL PROTECTED] > i have a problem with ospf that someone may be able to help with. > > i have a 2500 connected to a 7500 via a frame (2500 end) to atm (7500 end) > link. the 2500 is an abr for area 15 (serial area 0, ethernet area 15); the > 7500 is an abr for area 14 (atm area 0, other interfaces area 14). > > area 15 is configured as an nssa, as it is attached to another router which > is > redistributing static routes. area 14 is a standard ospf area, not stub or > nssa. > > the 2500 (abr) is recieving type 7 lsas and converting them to type 5 and > flooding them into area 0, no problems. the 7500 has them in its lsa > database. > the problem is that none of the type 5 lsas are being entered in the 7500s > route table. > > i have run through everything i can think of, and i'm a bit stuck. the > forwarding address of each lsa is 0.0.0.0. the network type is correct (ptp). > the 7500 can reach the abr and the asbr. subnet masks are all correct. i'm > not > sure what to look for next... > > anyone? > > thomas > **Please support GroupStudy by purchasing from the GroupStudy Store: > http://shop.groupstudy.com > FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=74658&t=74632 -- **Please support GroupStudy by purchasing from the GroupStudy Store: http://shop.groupstudy.com FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html
RE: ospf type 5 lsas [7:74632]
Are you using unnumbered on your serial interface? Try using an assigned IP address and see if that makes a difference. Fred Reimer - CCNA Eclipsys Corporation, 200 Ashford Center North, Atlanta, GA 30338 Phone: 404-847-5177 Cell: 770-490-3071 Pager: 888-260-2050 NOTICE; This email contains confidential or proprietary information which may be legally privileged. It is intended only for the named recipient(s). If an addressing or transmission error has misdirected the email, please notify the author by replying to this message. If you are not the named recipient, you are not authorized to use, disclose, distribute, copy, print or rely on this email, and should immediately delete it from your computer. -Original Message- From: Thomas Salmen [mailto:[EMAIL PROTECTED] Sent: Monday, September 01, 2003 11:44 PM To: [EMAIL PROTECTED] Subject: ospf type 5 lsas [7:74632] i have a problem with ospf that someone may be able to help with. i have a 2500 connected to a 7500 via a frame (2500 end) to atm (7500 end) link. the 2500 is an abr for area 15 (serial area 0, ethernet area 15); the 7500 is an abr for area 14 (atm area 0, other interfaces area 14). area 15 is configured as an nssa, as it is attached to another router which is redistributing static routes. area 14 is a standard ospf area, not stub or nssa. the 2500 (abr) is recieving type 7 lsas and converting them to type 5 and flooding them into area 0, no problems. the 7500 has them in its lsa database. the problem is that none of the type 5 lsas are being entered in the 7500s route table. i have run through everything i can think of, and i'm a bit stuck. the forwarding address of each lsa is 0.0.0.0. the network type is correct (ptp). the 7500 can reach the abr and the asbr. subnet masks are all correct. i'm not sure what to look for next... anyone? thomas **Please support GroupStudy by purchasing from the GroupStudy Store: http://shop.groupstudy.com FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=74657&t=74632 -- **Please support GroupStudy by purchasing from the GroupStudy Store: http://shop.groupstudy.com FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html
ospf type 5 lsas [7:74632]
i have a problem with ospf that someone may be able to help with. i have a 2500 connected to a 7500 via a frame (2500 end) to atm (7500 end) link. the 2500 is an abr for area 15 (serial area 0, ethernet area 15); the 7500 is an abr for area 14 (atm area 0, other interfaces area 14). area 15 is configured as an nssa, as it is attached to another router which is redistributing static routes. area 14 is a standard ospf area, not stub or nssa. the 2500 (abr) is recieving type 7 lsas and converting them to type 5 and flooding them into area 0, no problems. the 7500 has them in its lsa database. the problem is that none of the type 5 lsas are being entered in the 7500s route table. i have run through everything i can think of, and i'm a bit stuck. the forwarding address of each lsa is 0.0.0.0. the network type is correct (ptp). the 7500 can reach the abr and the asbr. subnet masks are all correct. i'm not sure what to look for next... anyone? thomas Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=74632&t=74632 -- **Please support GroupStudy by purchasing from the GroupStudy Store: http://shop.groupstudy.com FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html
RE: ospf type 5 lsas [7:74632]
May be something related to default-originate. > -Original Message- > From: Thomas Salmen [SMTP:[EMAIL PROTECTED] > Sent: 02 September 2003 04:44 > To: [EMAIL PROTECTED] > Subject: ospf type 5 lsas [7:74632] > > i have a problem with ospf that someone may be able to help with. > > i have a 2500 connected to a 7500 via a frame (2500 end) to atm (7500 end) > link. the 2500 is an abr for area 15 (serial area 0, ethernet area 15); > the > 7500 is an abr for area 14 (atm area 0, other interfaces area 14). > > area 15 is configured as an nssa, as it is attached to another router > which > is > redistributing static routes. area 14 is a standard ospf area, not stub or > nssa. > > the 2500 (abr) is recieving type 7 lsas and converting them to type 5 and > flooding them into area 0, no problems. the 7500 has them in its lsa > database. > the problem is that none of the type 5 lsas are being entered in the 7500s > route table. > > i have run through everything i can think of, and i'm a bit stuck. the > forwarding address of each lsa is 0.0.0.0. the network type is correct > (ptp). > the 7500 can reach the abr and the asbr. subnet masks are all correct. i'm > not > sure what to look for next... > > anyone? > > thomas > **Please support GroupStudy by purchasing from the GroupStudy Store: > http://shop.groupstudy.com > FAQ, list archives, and subscription info: > http://www.groupstudy.com/list/cisco.html ** This email and any files transmitted with it are confidential and intended solely for the use of the individual or entity to whom they are addressed. If you have received this email in error please notify the system manager. This footnote also confirms that this email message has been swept by MIMEsweeper for the presence of computer viruses. www.UlsterBank.com ** This e-mail is for use by the addressee only. If the message is received by anyone other than the addressee, please return the message to the sender by replying to it and then delete the message from your computer. Internet e-mail messages are not necessarily secure. The Royal Bank of Scotland and each of its Group companies does not accept responsibility for changes made to this message after it was sent. Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=74640&t=74632 -- **Please support GroupStudy by purchasing from the GroupStudy Store: http://shop.groupstudy.com FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html
RE: Metric of OSPF Summary Routes [7:74361]
Hi, A guy from Cisco confirmed that it is a version approach. 11.2 uses the lowest metric (RFC RFC1583). 12.0 and later uses the highest metric (RFC2328). Thanks Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=74431&t=74361 -- **Please support GroupStudy by purchasing from the GroupStudy Store: http://shop.groupstudy.com FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html
RE: Metric of OSPF Summary Routes [7:74361]
Please show us the topology database, that should tell us all. Martijn -Oorspronkelijk bericht- Van: alaerte Vidali [mailto:[EMAIL PROTECTED] Verzonden: dinsdag 26 augustus 2003 0:10 Aan: [EMAIL PROTECTED] Onderwerp: Metric of OSPF Summary Routes [7:74361] Is there a way to define the metric of a OSPF summary route? This is strange, but two routers with the same IOS (and similar commands) are using different approaches: one router is using the highest metric of more specific routes, while the other router is using the lower metric. This one is using the higher metric: LS age: 1405 Options: (No TOS-capability, DC, Upward) LS Type: Summary Links(Network) Link State ID: 100.7.0.0 (summary Network Number) Advertising Router: rta LS Seq Number: 80016DE5 Checksum: 0x6A95 Length: 28 Network Mask: /16 TOS: 0 Metric: 1603 This one is using the lower metric: Routing Bit Set on this LSA LS age: 946 Options: (No TOS-capability, DC, Upward) LS Type: Summary Links(Network) Link State ID: 100.7.0.0 (summary Network Number) Advertising Router: rtb LS Seq Number: 80008D8C Checksum: 0x3E53 Length: 28 Network Mask: /16 TOS: 0 Metric: 0 The only difference is the platform: one is 7507 and the other 4700. **Please support GroupStudy by purchasing from the GroupStudy Store: http://shop.groupstudy.com FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=74398&t=74361 -- **Please support GroupStudy by purchasing from the GroupStudy Store: http://shop.groupstudy.com FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html
Metric of OSPF Summary Routes [7:74361]
Is there a way to define the metric of a OSPF summary route? This is strange, but two routers with the same IOS (and similar commands) are using different approaches: one router is using the highest metric of more specific routes, while the other router is using the lower metric. This one is using the higher metric: LS age: 1405 Options: (No TOS-capability, DC, Upward) LS Type: Summary Links(Network) Link State ID: 100.7.0.0 (summary Network Number) Advertising Router: rta LS Seq Number: 80016DE5 Checksum: 0x6A95 Length: 28 Network Mask: /16 TOS: 0 Metric: 1603 This one is using the lower metric: Routing Bit Set on this LSA LS age: 946 Options: (No TOS-capability, DC, Upward) LS Type: Summary Links(Network) Link State ID: 100.7.0.0 (summary Network Number) Advertising Router: rtb LS Seq Number: 80008D8C Checksum: 0x3E53 Length: 28 Network Mask: /16 TOS: 0 Metric: 0 The only difference is the platform: one is 7507 and the other 4700. Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=74361&t=74361 -- **Please support GroupStudy by purchasing from the GroupStudy Store: http://shop.groupstudy.com FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html
Re: OSPF Cost [7:74098]
I think you got it wrong. 10^8 bites/second has cost 1. That means that cost 1 is 100 Mb/s. If you have higher bandwiths in you environment, you should set 'ospf auto-cost reference-bandwidth' to correct reference bandwith (if I get it right, this will then be cost 1 and all other costs will use this as a reference instead of 10^8). Be careful with this, especially with older IOSes and in multi-vendor env. Marko. - Original Message - From: To: Sent: Monday, August 18, 2003 9:31 AM Subject: OSPF Cost [7:74098] > Guys, > > Just to confirm that this is the correct costing default for OSPF :- > > 10*8 (1,,) \ bandwidth in kbps > > BW 1000 Kbit - 10Gig = OSPF Cost 10 > BW 100 Kbit - 1Gig= OSPF Cost 100 > BW 10 Kbit - 100Meg = OSPF Cost 1000 > BW1 Kbit - 10Meg = OSPF Cost 1 > BW 1544 Kbit - T1= OSPF Cost 64767 (rounded up) > BW 64 kbit - DS0 = OSPF Cost 1562500 Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=74099&t=74098 -- **Please support GroupStudy by purchasing from the GroupStudy Store: http://shop.groupstudy.com FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html
OSPF Cost [7:74098]
Guys, Just to confirm that this is the correct costing default for OSPF :- 10*8 (1,,) \ bandwidth in kbps BW 1000 Kbit - 10Gig = OSPF Cost 10 BW 100 Kbit - 1Gig= OSPF Cost 100 BW 10 Kbit - 100Meg = OSPF Cost 1000 BW1 Kbit - 10Meg = OSPF Cost 1 BW 1544 Kbit - T1 = OSPF Cost 64767 (rounded up) BW 64 kbit - DS0 = OSPF Cost 1562500 Many thx indeed. Ken For more information about Barclays Capital, please visit our web site at http://www.barcap.com. Internet communications are not secure and therefore the Barclays Group does not accept legal responsibility for the contents of this message. Although the Barclays Group operates anti-virus programmes, it does not accept responsibility for any damage whatsoever that is caused by viruses being passed. Any views or opinions presented are solely those of the author and do not necessarily represent those of the Barclays Group. Replies to this email may be monitored by the Barclays Group for operational or business reasons. Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=74098&t=74098 -- **Please support GroupStudy by purchasing from the GroupStudy Store: http://shop.groupstudy.com FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html
RE: hsrp default route in ospf [7:74017]
That makes sense. I managed to find the same answer after doing some reading on Cisco's site. I appreciate the info. Thanks Zsombor! Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=74026&t=74017 -- **Please support GroupStudy by purchasing from the GroupStudy Store: http://shop.groupstudy.com FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html
RE: hsrp default route in ospf [7:74017]
Because the HSRP virtual IP address is used only by the directly connected hosts (as a gateway), not by the remote devices that learn the routes via OSPF. Thanks, Zsombor Robert Kimble wrote: > > Why would that not make sense? Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=74025&t=74017 -- **Please support GroupStudy by purchasing from the GroupStudy Store: http://shop.groupstudy.com FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html
RE: hsrp default route in ospf [7:74017]
No, that would not make sense. Fred Reimer - CCNA Eclipsys Corporation, 200 Ashford Center North, Atlanta, GA 30338 Phone: 404-847-5177 Cell: 770-490-3071 Pager: 888-260-2050 NOTICE; This email contains confidential or proprietary information which may be legally privileged. It is intended only for the named recipient(s). If an addressing or transmission error has misdirected the email, please notify the author by replying to this message. If you are not the named recipient, you are not authorized to use, disclose, distribute, copy, print or rely on this email, and should immediately delete it from your computer. -Original Message- From: Robert Kimble [mailto:[EMAIL PROTECTED] Sent: Friday, August 15, 2003 9:43 AM To: [EMAIL PROTECTED] Subject: hsrp default route in ospf [7:74017] Howdy all, I have two 6509's with hsrp running between their msfc's. OSPF is advertising the ip addresses of interfaces of the routers instead of the virtual ip that I set up in hsrp. Since hsrp fails over faster than ospf, I was wondering if there is a way to have ospf advertise the virtual ip address instead of the interface addresses? Any suggestions are much appreciated ;-) **Please support GroupStudy by purchasing from the GroupStudy Store: http://shop.groupstudy.com FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=74022&t=74017 -- **Please support GroupStudy by purchasing from the GroupStudy Store: http://shop.groupstudy.com FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html
RE: hsrp default route in ospf [7:74017]
Why would that not make sense? Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=74023&t=74017 -- **Please support GroupStudy by purchasing from the GroupStudy Store: http://shop.groupstudy.com FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html
hsrp default route in ospf [7:74017]
Howdy all, I have two 6509's with hsrp running between their msfc's. OSPF is advertising the ip addresses of interfaces of the routers instead of the virtual ip that I set up in hsrp. Since hsrp fails over faster than ospf, I was wondering if there is a way to have ospf advertise the virtual ip address instead of the interface addresses? Any suggestions are much appreciated ;-) Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=74017&t=74017 -- **Please support GroupStudy by purchasing from the GroupStudy Store: http://shop.groupstudy.com FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html
RE: OSPF DR and BDR elections [7:73504]
If I am understanding this correctly. There are no routers up in the network. I turn on 3 routers simultaneously at the same time. The routers will first select the BDR. They will then look for the DR. Since none exist, the BDR will be promoted to DR. Then another election will be held to find a new BDR. Is this correct? -Original Message- From: Zsombor Papp [mailto:[EMAIL PROTECTED] Sent: Tuesday, August 05, 2003 11:01 AM To: [EMAIL PROTECTED] Subject: RE: OSPF DR and BDR elections [7:73504] The DR is not chosen from the "remaining list." The DR is chosen from the list of routers that declared themselves designated routers (this is why a high-priority router that comes up late won't take over the DR role from an existing DR), or if no router declared itself DR, then the BDR will become DR (this is why a high-priority router that came up late won't necessarily become DR even if the existing DR dies). See RFC2328, Page 75 for more details. Thanks, Zsombor DeVoe, Charles (PKI) wrote: > > I am reading the CCNP/CCIP BSCI Study Guide by Todd Lammle > from Sybex. In > the OSPF section under the discussion of DR and BDR (page 171) > he says that > the BDR is chosen first and that the DR is chosen from the > reaming list. > That seems illogical and backwards. Can someone please confirm > or deny and > explain it. Thanks **Please support GroupStudy by purchasing from the GroupStudy Store: http://shop.groupstudy.com FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=73557&t=73504 -- **Please support GroupStudy by purchasing from the GroupStudy Store: http://shop.groupstudy.com FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html
RE: OSPF summary address with Null 0 [7:73500]
OSPF installs that summary route pointing to Null0 automatically. Thanks, Zsombor Shab Hanon wrote: > > Hi everybody > The case .. OSPF summary address with Null 0 > > In all the case studies for CCIE R & S we told don't use static > routes! . > While we need to have a static route to Null 0 with address > summarization. > "Page 548 Routing TCP/IP Vol. 1 > > The catch J > What we do? What is the best? > > Any idea??? > > > > Cheers, > Shab. > > Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=73519&t=73500 -- **Please support GroupStudy by purchasing from the GroupStudy Store: http://shop.groupstudy.com FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html
Re: OSPF summary address with Null 0 [7:73500]
It is easy to block other routes by using ACL with distribution-list FROM appearing in the routing table "in other word you can remove them from the routing table :)" No way to remove LSA from the ospf database. Soon I will try "no default-information originate always" :) Cheers, Shab. ""Zsombor Papp"" wrote in message news:[EMAIL PROTECTED] > Shab Hanon wrote: > > > > Can any one tell us how to block a default route? > > > > it is easy to block other routes by using ACL with > > distribution-list > > But > > how to remove the default route which is being advertised by " > > default-information originate always " command. > > 'no default-information originate always' :) > > Once it is in the OSPF database, you can't take it out. This is the same for > other routes as well, btw, so I am not quite sure I understand why you say > it's easy to block other routes. > > Thanks, > > Zsombor > **Please support GroupStudy by purchasing from the GroupStudy Store: > http://shop.groupstudy.com > FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=73625&t=73500 -- **Please support GroupStudy by purchasing from the GroupStudy Store: http://shop.groupstudy.com FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html
RE: multiple ospf processes & route insertion [7:73727]
I haven't read the rest of the replies to this yet, but I think there is some confusion (probably on my part reading the post I replied to). The post I replied to talked about "putting into the [OSPF] routing table." If there is a static and a BGP route, the router should put both into the active router table, right? Now, what route the router chooses when actually routing packets is of course the most specific first, and then the one with the lowest administrative distance. That's what I said in my reply, that the router would put both static and BGP route in the routing table. I didn't make any statement on what route a router should choose when routing packets... I guess I got thrown because the original post was talking about multiple OSPF processes and what route would get inserted into the routing table, and then the subject was changed mid-way to what route in the routing table a router should choose. Fred Reimer - CCNA Eclipsys Corporation, 200 Ashford Center North, Atlanta, GA 30338 Phone: 404-847-5177 Cell: 770-490-3071 Pager: 888-260-2050 NOTICE; This email contains confidential or proprietary information which may be legally privileged. It is intended only for the named recipient(s). If an addressing or transmission error has misdirected the email, please notify the author by replying to this message. If you are not the named recipient, you are not authorized to use, disclose, distribute, copy, print or rely on this email, and should immediately delete it from your computer. -Original Message- From: Jason J [mailto:[EMAIL PROTECTED] Sent: Saturday, August 09, 2003 10:36 AM To: [EMAIL PROTECTED] Subject: RE: multiple ospf processes & route insertion [7:73727] Dear Fred in fact, 192.168.0.0/18 does include 192.168.0.0/19 and 192.168.32.0/19.wherenever router choose route, it will always pick the most concrete one so even 192.168.0.0/18 is static, it will choose the one from EBGP, 192.168.0.0/19. when the route from EBG is 192.168.0.0/18 and there is static route 192.168.0.0/18, sure the router will choose the static one. Jasong.J CCNP P.R.C **Please support GroupStudy by purchasing from the GroupStudy Store: http://shop.groupstudy.com FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=73790&t=73727 -- **Please support GroupStudy by purchasing from the GroupStudy Store: http://shop.groupstudy.com FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html
RE: multiple ospf processes & route insertion [7:73727]
O.K., no problem, everyone makes mistakes, and that was a pretty easy one to make. Fred Reimer - CCNA Eclipsys Corporation, 200 Ashford Center North, Atlanta, GA 30338 Phone: 404-847-5177 Cell: 770-490-3071 Pager: 888-260-2050 NOTICE; This email contains confidential or proprietary information which may be legally privileged. It is intended only for the named recipient(s). If an addressing or transmission error has misdirected the email, please notify the author by replying to this message. If you are not the named recipient, you are not authorized to use, disclose, distribute, copy, print or rely on this email, and should immediately delete it from your computer. -Original Message- From: Jason J [mailto:[EMAIL PROTECTED] Sent: Sunday, August 10, 2003 3:04 AM To: [EMAIL PROTECTED] Subject: RE: multiple ospf processes & route insertion [7:73727] er.Sorry about that! I Think i make a mistake, I did no see two same routes from two different routing protocols. in fact, one is "61.168.0.0",another is" 161.168.0.0" . really sorry for put so much trouble on you. everything comes from my experiments's wrong result. the wrong result comes to the wrong conclusion. so ,really thanks a lot , Zomber and Fred. for pointing out my mistake, so i can get a chance to learn more. Jason.J CCNP P.R.C **Please support GroupStudy by purchasing from the GroupStudy Store: http://shop.groupstudy.com FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html **Please support GroupStudy by purchasing from the GroupStudy Store: http://shop.groupstudy.com FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=73824&t=73727 -- **Please support GroupStudy by purchasing from the GroupStudy Store: http://shop.groupstudy.com FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html
RE: multiple ospf processes & route insertion [7:73727]
O.K., no problem, everyone makes mistakes, and that was a pretty easy one to make. Fred Reimer - CCNA Eclipsys Corporation, 200 Ashford Center North, Atlanta, GA 30338 Phone: 404-847-5177 Cell: 770-490-3071 Pager: 888-260-2050 NOTICE; This email contains confidential or proprietary information which may be legally privileged. It is intended only for the named recipient(s). If an addressing or transmission error has misdirected the email, please notify the author by replying to this message. If you are not the named recipient, you are not authorized to use, disclose, distribute, copy, print or rely on this email, and should immediately delete it from your computer. -Original Message- From: Jason J [mailto:[EMAIL PROTECTED] Sent: Sunday, August 10, 2003 3:04 AM To: [EMAIL PROTECTED] Subject: RE: multiple ospf processes & route insertion [7:73727] er.Sorry about that! I Think i make a mistake, I did no see two same routes from two different routing protocols. in fact, one is "61.168.0.0",another is" 161.168.0.0" . really sorry for put so much trouble on you. everything comes from my experiments's wrong result. the wrong result comes to the wrong conclusion. so ,really thanks a lot , Zomber and Fred. for pointing out my mistake, so i can get a chance to learn more. Jason.J CCNP P.R.C **Please support GroupStudy by purchasing from the GroupStudy Store: http://shop.groupstudy.com FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=73805&t=73727 -- **Please support GroupStudy by purchasing from the GroupStudy Store: http://shop.groupstudy.com FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html
RE: multiple ospf processes & route insertion [7:73727]
Dear Zsombor: "You can't put the same interface into multiple OSPF processes but that doesn't mean that the two processes can't learn about the same network." if you can't learn put one interface into multiple OSPF processes, then except you redistribute the direct donnected and static, how could they learn the same address ,learn from each other? i think the same condition exist on other routes ,how could a network link's status be share with other ospf process without put the sme interface into multiple OSPF processes? best regards Jason J CCNP P.R.C **Please support GroupStudy by purchasing from the GroupStudy Store: http://shop.groupstudy.com FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=73845&t=73727 -- **Please support GroupStudy by purchasing from the GroupStudy Store: http://shop.groupstudy.com FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html
RE: multiple ospf processes & route insertion [7:73727]
No, I don't think there will be any load balancing even in the same ospf processes. thanks Jason J CCNP P.R.C Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=73784&t=73727 -- **Please support GroupStudy by purchasing from the GroupStudy Store: http://shop.groupstudy.com FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html
RE: multiple ospf processes & route insertion [7:73727]
Jason J wrote: > > Fred is right > all routes from different routing protocals will be put > into route table ,but!! even if they are the same ! Would be surprising. IMHO one route (meaning a prefix+mask combo) can be installed only by one routing process. Can you post some 'show ip route' output that shows otherwise? > and what i mean in the last article is the "ospf routing > table", not route table.even there can be more same network > link in its ospf database. > > the router will choose which protocol's route/routes to use. > but i do not think the same ospf process will load balanc > inside it. So what do you suppose would happen if there are multiple equal cost routes to the same destination? Every reasonable routing protocol can do load-balancing, I am surprised that anyone would doubt that OSPF can do it, too. > what if the EIGRP load balance,but the router decide to use the > static or ospf route ?? If the router decided to use the static or OSPF route, then obviously the EIGRP route(s) won't play any role. > and what if different ospf processes learn the same routes to > the same destination i mean what the router will do then??(the > concrete operations) See my first post in this thread. > what will the IOS do ? maybe at the time when we start the > OSPF processes it will not permit us to overlap the same > network address > at all !! i am not sure about that. You can't put the same interface into multiple OSPF processes but that doesn't mean that the two processes can't learn about the same network. Thanks, Zsombor Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=73787&t=73727 -- **Please support GroupStudy by purchasing from the GroupStudy Store: http://shop.groupstudy.com FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html
RE: multiple ospf processes & route insertion [7:73727]
Since you say you want to run one OSPF process for each traffic type, I assume the type of the traffic is defined by destination IP address. If this is not correct, then I would be curious to know what a "traffic type" is and how you will associate a traffic type with an OSPF process. If however my assumption is correct, then I can see several ways to solve the problem you cited as an example, with BGP or with a single OSPF process. Let me restate the problem for N=1: suppose there are 3 routers, R1, R2, R3, connected in a triangle. Both traffic A and B usually go directly from R1 to R2, but when that link fails, traffic A should go from R1 to R3 to R2, and traffic B should be dropped at R1. Solution with BGP: run BGP between R1-R2 and R1-R3, make the routes coming from R2 preferred, and filter out the routes corresponding to traffic B from the advertisements R3 sends to R1. Solution with single OSPF process: configure an access list on the link between R1-R3 that drops traffic B. :) Of course I might be missing something, so feel free to point out why these wouldn't work in your case. Thanks, Zsombor p b wrote: > > > Using multiple processes might provide a way to implement > policy at the link level. Typically, when one thinks of > policy, > one thinks of BGP. But what if your policy requires the ability > to control what traffic can or can't go over a particular > link? For example, consider two routers, that are > interconnected > by a direct link and a N-hop L3 path. Suppose traffic types > A and B should typically go over the direct link but, if the > direct link fails, traffic type A should be routed over the > N-hop L3 path and traffic type B should not be forwarded. > > I don't believe there's a way to get this level of policy from > a single OSPF process or a single OSPF process coupled with BGP. > > However, if you run multiple OSPF processes, say one for each > interesting traffic type, and if you use BGP to set a network's > next-hop to match the right OSPF RID, and for each link define > a sub-interface (or not) for each OSPF process, then I think the > above routing requirements might be supported. > > MPLS might work here, but I'm not sure. > > > > > > Suppose you have certain types > of traffic that > > Zsombor Papp wrote: > > > > What are you trying to achieve with these ~3 OSPF routing > > processes? > > > > Thanks, > > > > Zsombor > > > > p b wrote: > > > > > > > > > I'm considering a routing architecture where devices in the > > > network would run ~3 OSPF routing processes. > > > > > > I think each routing process will be handling the routing > > > of non-overlapping address blocks and thus the routes they > > > give to the forwarding table should be disjoint. > > > > > > However, I'd like to understand what happens if two > processes > > > each were to provide the same prefix to the forwarding > table. > > > Specifically, what are the rules to determine which prefix > > > is put into the routing table? > > > > > > Also be interested in any learnings folks might have had > when > > > they've run multiple OSPF processes. > > > > > > Thanks > > > > > Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=73794&t=73727 -- **Please support GroupStudy by purchasing from the GroupStudy Store: http://shop.groupstudy.com FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html
RE: multiple ospf processes & route insertion [7:73727]
Lets go down another layer in your proposed BGP solution. The core topology will be along the lines of 5-10 routers in a ring. Lets say 7 routers, R1, R2, R3, R4, R5, R6 and R7 are connected in a p2p ring topology. Assume that there's one or more direct connections between R1 and R4. R4 has 3 other interfaces for networks A, B, and C. Each is a different service. Assume that R1 is connected to another cloud of routers and that traffic to networks A, B, and C will originate from this other cloud. The service routing requirements are as follows (from R1's perspective): * traffic to A should go follow the R1-R2-R3-R4 and/or the R1-R7-R6-R5-R4 path. * traffic to B and C should follow the R1-R4 path * when the link between R1 and R4 fails, B should be routed over the R1-R2-R3-R4 and/or R1-R7-R6-R5-R4 path. Traffic to C should stop. Provide some sample configs snipets for R1, R4 and an intermediate router which demonstrates how the proposed BGP solution would support the policy requirements. Thanks Zsombor Papp wrote: > > I am not sure what's the significance of the existing routing > setup. Is there a desire to preserve any part of it? > > Your new example is pretty much the same as I described the > problem, isn't it? So running BGP over I1 and I2 (just directly > to the neighbor routers) would still work. > > Or is the requirement to be able to make such a decision at > every single hop, not only at the end point? If so, using MPLS > and Traffic Engineering might really be a better option, > depending on how flexible your solution needs to be (ie. if > there are thousands of possible paths and you want to allow > only a few hundred, then that will be a nightmare even with TE). > > But let's consider a non-MPLS solution first. That would be > what you call the "BGP as IGP" approach (although I assume you > would still want to keep OSPF running to provide connectivity > between the routers). The most important issue here is how you > will make sure that the BGP sessions go up and down together > with the links they correspond to. With eBGP, this is easy as > you have direct control over the TTL of the BGP packets. With > iBGP, you would probably have to use the physical interfaces' > IP addresses for the BGP sessions (instead of the loopbacks, as > it probably is currently). Unless you can limit the TTL of the > iBGP packets (I don't remember if there is a way to do this in > IOS). > > Another issue with iBGP is that routes learned from an iBGP > peer are not advertised to another iBGP peer unless the local > router is a route-reflector, so you would probably end up > configuring every router except the end-points as a > route-reflector. On a second thought, this is probably not a > big issue, but I'll mention it anyway, maybe it rings an alarm > bell in someone else's mind. :) > > I am not sure if setting the next-hop at every router would be > necessary. The fact that in case of a link failure -- thanks to > the filters applied to the BGP sessions corresponding to the > still functional links -- there simply wouldn't be any routes > advertised, seems to be sufficient. If so, the advantage of > using iBGP would be that you could still rely on OSPF to select > the path for the services that are still functioning. Of > course, if a certain type of traffic is allowed on multiple > links, then you will have to make sure that the OSPF metric is > set so that the preferred link will be picked in case multiple > links are available. > > Yes, maintaining the filters won't be great fun, but I suspect > that it would be easier to comprehend than a per-serivce OSPF > topology. > > The "one AS per router" requirement for eBGP doesn't seem to be > very scary. An AS number is just a number, like the RID in > OSPF, which you have one per router, so unless you expect to > have 65000+ routers in this network, I don't see a problem with > that. Also, you can prepend AS numbers to emulate the IGP cost. > The bottle-neck of this approach might be the max allowed > length for AS_PATH attribute. I seem to remember that it's 128, > which is not a lot, but it's still better than old-style > metrics in ISIS... > > Speaking of scaling, do you think that one OSPF process per > service will scale? Since you will probably want to run all the > OSPF processes on almost every link and pretty much every > router, the load of running OSPF will be proportional to the > number of services. Will the routers be able to keep up? What > if they decide to add yet another service? Or three more? > > As for the ACLs, technically speaking, they do satisfify the > requirement that the end-points need to be notified. Ther
RE: multiple ospf processes & route insertion [7:73727]
What is "advertising router" and what are "those same prefixes"? And where does it learn them from? Otherwise it's clear... :) Thanks, Zsombor amer kulaif wrote: > > hi > > guys, how about if the advertising router has received an > update to one of those same prefixes, how does it know which > is which. > > thanx Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=73905&t=73727 -- **Please support GroupStudy by purchasing from the GroupStudy Store: http://shop.groupstudy.com FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html
RE: multiple ospf processes & route insertion [7:73727]
hi guys, how about if the advertising router has received an update to one of those same prefixes, how does it know which is which. thanx Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=73881&t=73727 -- **Please support GroupStudy by purchasing from the GroupStudy Store: http://shop.groupstudy.com FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html
RE: multiple ospf processes & route insertion [7:73727]
I freely admit that I've lost the sense of the problem that actually needs to be solved, with all the discussion of the various tables. Before my brain started to reboot, however, it sounded like it was a traffic engineering problem. Has anyone looked at the OSPF Traffic Engineering extensions here? Also, I got an impression that people didn't want to use MPLS for a TE problem. Why? That's essentially what it's for. Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=73928&t=73727 -- **Please support GroupStudy by purchasing from the GroupStudy Store: http://shop.groupstudy.com FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html
RE: Distribution Router and OSPF [7:73933]
One concern would be that area 50 will be separated from the rest of the network if any one of R1, R2, or the link between R1-R2 fails. This is not related to R2 being or not being connected to area 0 though. Thanks, Zsombor alaerte Vidali wrote: > > R1 is a ABR router; it connects to the backbone area and to > area 50. > R2 is a distribution router connected to router R1 through area > 50. > > R2 connects to 4 other routers in area 50. > > I am wondering if there are concerns about R2 being a > distribution router without connecting to area 0. > > area 0 (R1)--area 50 ---(R2)--area 50(R3,R4,R5,R6) Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=73939&t=73933 -- **Please support GroupStudy by purchasing from the GroupStudy Store: http://shop.groupstudy.com FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html
RE: multiple ospf processes & route insertion [7:73727]
At 6:49 PM + 8/12/03, Zsombor Papp wrote: >So you want to solve a traffic engineering problem with MPLS/TE, huh? How >boring... :) Hey, if you can't take a joke in this business... > >Howard C. Berkowitz wrote: >> >> I freely admit that I've lost the sense of the problem that >> actually >> needs to be solved, with all the discussion of the various >> tables. >> Before my brain started to reboot, however, it sounded like it >> was a >> traffic engineering problem. Has anyone looked at the OSPF >> Traffic >> Engineering extensions here? >> >> Also, I got an impression that people didn't want to use MPLS >> for a > > TE problem. Why? That's essentially what it's for. Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=73946&t=73727 -- **Please support GroupStudy by purchasing from the GroupStudy Store: http://shop.groupstudy.com FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html
RE: multiple ospf processes & route insertion [7:73727]
I am not sure what's the significance of the existing routing setup. Is there a desire to preserve any part of it? Your new example is pretty much the same as I described the problem, isn't it? So running BGP over I1 and I2 (just directly to the neighbor routers) would still work. Or is the requirement to be able to make such a decision at every single hop, not only at the end point? If so, using MPLS and Traffic Engineering might really be a better option, depending on how flexible your solution needs to be (ie. if there are thousands of possible paths and you want to allow only a few hundred, then that will be a nightmare even with TE). But let's consider a non-MPLS solution first. That would be what you call the "BGP as IGP" approach (although I assume you would still want to keep OSPF running to provide connectivity between the routers). The most important issue here is how you will make sure that the BGP sessions go up and down together with the links they correspond to. With eBGP, this is easy as you have direct control over the TTL of the BGP packets. With iBGP, you would probably have to use the physical interfaces' IP addresses for the BGP sessions (instead of the loopbacks, as it probably is currently). Unless you can limit the TTL of the iBGP packets (I don't remember if there is a way to do this in IOS). Another issue with iBGP is that routes learned from an iBGP peer are not advertised to another iBGP peer unless the local router is a route-reflector, so you would probably end up configuring every router except the end-points as a route-reflector. On a second thought, this is probably not a big issue, but I'll mention it anyway, maybe it rings an alarm bell in someone else's mind. :) I am not sure if setting the next-hop at every router would be necessary. The fact that in case of a link failure -- thanks to the filters applied to the BGP sessions corresponding to the still functional links -- there simply wouldn't be any routes advertised, seems to be sufficient. If so, the advantage of using iBGP would be that you could still rely on OSPF to select the path for the services that are still functioning. Of course, if a certain type of traffic is allowed on multiple links, then you will have to make sure that the OSPF metric is set so that the preferred link will be picked in case multiple links are available. Yes, maintaining the filters won't be great fun, but I suspect that it would be easier to comprehend than a per-serivce OSPF topology. The "one AS per router" requirement for eBGP doesn't seem to be very scary. An AS number is just a number, like the RID in OSPF, which you have one per router, so unless you expect to have 65000+ routers in this network, I don't see a problem with that. Also, you can prepend AS numbers to emulate the IGP cost. The bottle-neck of this approach might be the max allowed length for AS_PATH attribute. I seem to remember that it's 128, which is not a lot, but it's still better than old-style metrics in ISIS... Speaking of scaling, do you think that one OSPF process per service will scale? Since you will probably want to run all the OSPF processes on almost every link and pretty much every router, the load of running OSPF will be proportional to the number of services. Will the routers be able to keep up? What if they decide to add yet another service? Or three more? As for the ACLs, technically speaking, they do satisfify the requirement that the end-points need to be notified. There will be ICMP messages to this effect. You could extend the application to look for those (or write a separate small application). This might sound a bit crazy, but looking at the other options, I am not sure this is the worst one... :) Thanks, Zsombor p b wrote: > > > Here's some more detail. > > Yes, assume the destination address (networks) represent > the corresponding service. > > This is an existing production network where OSPF and iBGP are > already in use for the existing (single) service. OSPF carries > p2p and loopbacks; iBGP carries customer end-point networks. > > We want to overlay two other services. The paths the packets > take to their destination, even if hosted on the same router, > will be different. Further, when there's a failure in the > network, the manner in which traffic gets re-routed will be > specific to each service. > > An example might help. Consider some router R1 in this network. > It has several connections to other routers in the network. It > also has three interfaces each with a network assigned to it. > Lets call these networks A, B and C and each is for a different > service. Under normal conditions, traffic to A comes in via > interface I1 and traffic to B and C comes in via interface I2. > Now assume I2 fails. Traffic for A and B should come in o
RE: multiple ospf processes & route insertion [7:73727]
Am I missing something here? 192.168.0.0/18 and 192.168.0.19/19 are two different routes. It should put both of them in the routing table, not choose between them based on administrative distance. Fred Reimer - CCNA Eclipsys Corporation, 200 Ashford Center North, Atlanta, GA 30338 Phone: 404-847-5177 Cell: 770-490-3071 Pager: 888-260-2050 NOTICE; This email contains confidential or proprietary information which may be legally privileged. It is intended only for the named recipient(s). If an addressing or transmission error has misdirected the email, please notify the author by replying to this message. If you are not the named recipient, you are not authorized to use, disclose, distribute, copy, print or rely on this email, and should immediately delete it from your computer. -Original Message- From: Jason J [mailto:[EMAIL PROTECTED] Sent: Friday, August 08, 2003 8:43 PM To: [EMAIL PROTECTED] Subject: RE: multiple ospf processes & route insertion [7:73727] well, in my thoughts, there is no loading balance in ospf. it will choose only one route and put it into its ospf routing table. also i got a case: when there is a route from EBGP peer which is 192.168.0.0/19 and also a route comes from static input which is 192.168.0.0/18, which one do you think the router will pick ?? the answer is : the route from EBGP! Jason G.F CCNP **Please support GroupStudy by purchasing from the GroupStudy Store: http://shop.groupstudy.com FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=73772&t=73727 -- **Please support GroupStudy by purchasing from the GroupStudy Store: http://shop.groupstudy.com FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html
RE: multiple ospf processes & route insertion [7:73727]
Jason J wrote: > > well, in my thoughts, there is no loading balance in ospf. There is, just not between processes. > it > will choose only one route and put it into its ospf routing > table. > also i got a case: when there is a route from EBGP peer which > is 192.168.0.0/19 and also a route comes from static input > which is 192.168.0.0/18, which one do you think > the router will pick ?? > the answer is : the route from EBGP! The answer is "both routes will be in the routing table and it depends on the destination address of the packet which one will be used for forwarding." Obviously, you can't forward a packet to 192.168.32.x based on a route to 192.168.0.0/19. Thanks, Zsombor > > Jason G.F CCNP > Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=73781&t=73727 -- **Please support GroupStudy by purchasing from the GroupStudy Store: http://shop.groupstudy.com FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html
RE: multiple ospf processes & route insertion [7:73727]
So you want to solve a traffic engineering problem with MPLS/TE, huh? How boring... :) Howard C. Berkowitz wrote: > > I freely admit that I've lost the sense of the problem that > actually > needs to be solved, with all the discussion of the various > tables. > Before my brain started to reboot, however, it sounded like it > was a > traffic engineering problem. Has anyone looked at the OSPF > Traffic > Engineering extensions here? > > Also, I got an impression that people didn't want to use MPLS > for a > TE problem. Why? That's essentially what it's for. > > Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=73938&t=73727 -- **Please support GroupStudy by purchasing from the GroupStudy Store: http://shop.groupstudy.com FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html
RE: multiple ospf processes & route insertion [7:73727]
Yup, it is a traffic engineering (service specific routing) problem. MPLS TE might be one way to solve this.I've honestly not looked at what it would take to get MPLS to run in this environment.However, enabling MPLS on the network would be a major undertaking so I've been looking at what other options might be possible. Zsomber has suggested using eBGP in order to enforce the policy (thanks). As the proposed network evolves, and direct links are built to many of the other ring routers, the eBGP solution would require running eBGP each link. This doesn't seem like the right path to take. An approach with using 3 OSPF processes and corresponding sub-interfaces leverages features we enable today. Granted we don't run 3 OSPF processes, but we do run one, so it may not be as big a deployment and operation stretch to go this route. As I surfed the net looking for other options, I ran across the concept of logical routers available in JUNOS (6.0?). I just glanced at the web site, and the multiple OSPF process concept seems similar to Juniper's logical router concept. I've attached the Juniper link for those interested. Apologies in advance for doing this on the cisco list... http://www.juniper.net/techpubs/software/junos/junos60/feature-guide-60/html/fg-logical-routers.html Howard C. Berkowitz wrote: > > I freely admit that I've lost the sense of the problem that > actually > needs to be solved, with all the discussion of the various > tables. > Before my brain started to reboot, however, it sounded like it > was a > traffic engineering problem. Has anyone looked at the OSPF > Traffic > Engineering extensions here? > > Also, I got an impression that people didn't want to use MPLS > for a > TE problem. Why? That's essentially what it's for. > > Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=73943&t=73727 -- **Please support GroupStudy by purchasing from the GroupStudy Store: http://shop.groupstudy.com FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html
RE: OSPF DR and BDR elections [7:73504]
That is the point I needed clarification on. Just seemed odd that the DR would not be established first, followed by the BDR. For a brief moment when the routers are first started, there is no DR, but there is a BDR. I wonder what the logic for that is. -Original Message- From: Zsombor Papp [mailto:[EMAIL PROTECTED] Sent: Tuesday, August 05, 2003 8:20 PM To: [EMAIL PROTECTED] Subject: RE: OSPF DR and BDR elections [7:73504] Technically, the BDR is elected first. If no router is claiming to be a DR, then the BDR will be immediately promoted to DR. Nonetheless, the end result is pretty much what the web page referenced below describes. Thanks, Zsombor mccloud mike wrote: > > The DR is elected first by highest priority, the tie breaker is > highest RID. Then the process is repeated for the BDR. > > http://www.cisco.com/warp/customer/104/2.html#10.1 > > My understanding is that if the DR goes down then the BDR is > promoted to DR and an election is held for the new BDR. This > means that when the original DR comes back up it can not become > DR until both of the current DR and BDR go offline. > > Cheers, Mike > > DeVoe, Charles (PKI) wrote: > > > > If I am understanding this correctly. There are no routers up > > in the > > network. I turn on 3 routers simultaneously at the same > time. > > The routers > > will first select the BDR. They will then look for the DR. > > Since none > > exist, the BDR will be promoted to DR. Then another election > > will be held > > to find a new BDR. Is this correct? > > > > -Original Message- > > From: Zsombor Papp [mailto:[EMAIL PROTECTED] > > Sent: Tuesday, August 05, 2003 11:01 AM > > To: [EMAIL PROTECTED] > > Subject: RE: OSPF DR and BDR elections [7:73504] > > > > > > The DR is not chosen from the "remaining list." The DR is > > chosen from the > > list of routers that declared themselves designated routers > > (this is why a > > high-priority router that comes up late won't take over the DR > > role from an > > existing DR), or if no router declared itself DR, then the BDR > > will become > > DR (this is why a high-priority router that came up late won't > > necessarily > > become DR even if the existing DR dies). > > > > See RFC2328, Page 75 for more details. > > > > Thanks, > > > > Zsombor > > > > DeVoe, Charles (PKI) wrote: > > > > > > I am reading the CCNP/CCIP BSCI Study Guide by Todd Lammle > > > from Sybex. In > > > the OSPF section under the discussion of DR and BDR (page > > 171) > > > he says that > > > the BDR is chosen first and that the DR is chosen from the > > > reaming list. > > > That seems illogical and backwards. Can someone please > > confirm > > > or deny and > > > explain it. Thanks > > **Please support GroupStudy by purchasing from the GroupStudy > > Store: > > http://shop.groupstudy.com > > FAQ, list archives, and subscription info: > > http://www.groupstudy.com/list/cisco.html **Please support GroupStudy by purchasing from the GroupStudy Store: http://shop.groupstudy.com FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=73597&t=73504 -- **Please support GroupStudy by purchasing from the GroupStudy Store: http://shop.groupstudy.com FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html
Re: OSPF DR and BDR elections [7:73504]
The OSPF interface priority is the parameter that controls DR election. Its default value is 1. When OSPF interface priority is 0, the router is not eligible to become a DR. If a router comes up on a network segment and there are no other routers there already, it will become a DR. If there is an existing DR (or BDR), the new router will NOT attempt to preempt them. If several routers come up at roughly the same time (or the DR fails), a new DR election process will be triggered. The router with the highest priority value then will become a DR. In short, the DR/BDR election process is not deterministic and depends on the sequence of events. Therefore it is important to be able to prevent routers from EVER becoming DR/BDR, when that is appropriate for the topology in which they are connected. This si accomplished by setting their OSPF interface priority to 0: ospf set interface priority 0 So there has to be a DR first and after that there will be an BDR If you start an router on itsself not yet connected to the network it will start as an BDR. Quoting "DeVoe, Charles (PKI)" : > I am reading the CCNP/CCIP BSCI Study Guide by Todd Lammle from Sybex. In > the OSPF section under the discussion of DR and BDR (page 171) he says that > the BDR is chosen first and that the DR is chosen from the reaming list. > That seems illogical and backwards. Can someone please confirm or deny and > explain it. Thanks > **Please support GroupStudy by purchasing from the GroupStudy Store: > http://shop.groupstudy.com > FAQ, list archives, and subscription info: > http://www.groupstudy.com/list/cisco.html > > Iwan Hoogendoorn Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=73510&t=73504 -- **Please support GroupStudy by purchasing from the GroupStudy Store: http://shop.groupstudy.com FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html
RE: multiple ospf processes & route insertion [7:73727]
Dear Fred "Wow, um, err, no offense, but you're a CCNP? And confused about the concept of a route table? " everyone could get confused about anything :). especially in some 2 or 3 am morning. first sorry about that. "There can't be the same route for BGP and a static in the active routing table concurrently. That is unless you do something weird like set the administrative distance of the static route equal to that of the BGP route, but I'm not even sure about that. " yes, i do saw two same routes ,one from EBGP ,one from static. both them are 192.168.0.0/17. one AD is 20 another is 110. best regards. Jason J. CCNP P.R.C Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=73796&t=73727 -- **Please support GroupStudy by purchasing from the GroupStudy Store: http://shop.groupstudy.com FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html
RE: multiple ospf processes & route insertion [7:73727]
Fred is right all routes from different routing protocals will be put into route table ,but!! even if they are the same ! and what i mean in the last article is the "ospf routing table", not route table.even there can be more same network link in its ospf database. the router will choose which protocol's route/routes to use. but i do not think the same ospf process will load balanc inside it. what if the EIGRP load balance,but the router decide to use the static or ospf route ?? and what if different ospf processes learn the same routes to the same destination i mean what the router will do then??(the concrete operations) what will the IOS do ? maybe at the time when we start the OSPF processes it will not permit us to overlap the same network address at all !! i am not sure about that. thanks Jason. J CCNP P.R.C Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=73785&t=73727 -- **Please support GroupStudy by purchasing from the GroupStudy Store: http://shop.groupstudy.com FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html
Re: OSPF summary address with Null 0 [7:73500]
Can any one tell us how to block a default route? it is easy to block other routes by using ACL with distribution-list But how to remove the default route which is being advertised by " default-information originate always " command. ""Reimer, Fred"" wrote in message news:[EMAIL PROTECTED] > From the CCIE Power Session: > > "Unless a question says so, you are not permitted to use**: > > Static routes (of any kind) > > Default routes > > **Dynamic routes to null are permitted" > > Floating statics are also allowed: > > "ip route 2.2.2.0 255.255.255.0 1.1.1.2 240 > > * Uses a higher administrative distance so that dynamic protocols will take > precedence > > * Use only if explicitly allowed in a test question > > * Make sure the dynamic route actually exists when DDR is not active" > > HTH, > > Fred Reimer - CCNA > > > Eclipsys Corporation, 200 Ashford Center North, Atlanta, GA 30338 > Phone: 404-847-5177 Cell: 770-490-3071 Pager: 888-260-2050 > > > NOTICE; This email contains confidential or proprietary information which > may be legally privileged. It is intended only for the named recipient(s). > If an addressing or transmission error has misdirected the email, please > notify the author by replying to this message. If you are not the named > recipient, you are not authorized to use, disclose, distribute, copy, print > or rely on this email, and should immediately delete it from your computer. > > > -Original Message- > From: Shab Hanon [mailto:[EMAIL PROTECTED] > Sent: Tuesday, August 05, 2003 5:30 AM > To: [EMAIL PROTECTED] > Subject: OSPF summary address with Null 0 [7:73500] > > Hi everybody > The case .. OSPF summary address with Null 0 > > In all the case studies for CCIE R & S we told don't use static routes! **Please support GroupStudy by purchasing from the GroupStudy Store: http://shop.groupstudy.com FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html
Re: OSPF DR and BDR elections [7:73504]
> > I wonder what the logic for that is. > > I wonder, too. :) The reason could be as simple as the possibility to reuse the code (or function-call). For that brief moment when there is BDR, but no DR, exactly the same code base can be used as if router has realized that DR just failed miserably :-). I just realized that my logic above actually makes sense. Of course, someone will correct me if I'm horribly wrong. Marko. Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=73628&t=73504 -- **Please support GroupStudy by purchasing from the GroupStudy Store: http://shop.groupstudy.com FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html
Distribution Router and OSPF [7:73933]
R1 is a ABR router; it connects to the backbone area and to area 50. R2 is a distribution router connected to router R1 through area 50. R2 connects to 4 other routers in area 50. I am wondering if there are concerns about R2 being a distribution router without connecting to area 0. area 0 (R1)--area 50 ---(R2)--area 50(R3,R4,R5,R6) Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=73933&t=73933 -- **Please support GroupStudy by purchasing from the GroupStudy Store: http://shop.groupstudy.com FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html
RE: Distribution Router and OSPF [7:73933]
Why would there be? Not unless R3-R6 are in a different area, in which case they would need to create a Virtual Link to R1. Fred Reimer - CCNA Eclipsys Corporation, 200 Ashford Center North, Atlanta, GA 30338 Phone: 404-847-5177 Cell: 770-490-3071 Pager: 888-260-2050 NOTICE; This email contains confidential or proprietary information which may be legally privileged. It is intended only for the named recipient(s). If an addressing or transmission error has misdirected the email, please notify the author by replying to this message. If you are not the named recipient, you are not authorized to use, disclose, distribute, copy, print or rely on this email, and should immediately delete it from your computer. -Original Message- From: alaerte Vidali [mailto:[EMAIL PROTECTED] Sent: Tuesday, August 12, 2003 1:42 PM To: [EMAIL PROTECTED] Subject: Distribution Router and OSPF [7:73933] R1 is a ABR router; it connects to the backbone area and to area 50. R2 is a distribution router connected to router R1 through area 50. R2 connects to 4 other routers in area 50. I am wondering if there are concerns about R2 being a distribution router without connecting to area 0. area 0 (R1)--area 50 ---(R2)--area 50(R3,R4,R5,R6) **Please support GroupStudy by purchasing from the GroupStudy Store: http://shop.groupstudy.com FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=73941&t=73933 -- **Please support GroupStudy by purchasing from the GroupStudy Store: http://shop.groupstudy.com FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html
RE: multiple ospf processes & route insertion [7:73727]
Here's some more detail. Yes, assume the destination address (networks) represent the corresponding service. This is an existing production network where OSPF and iBGP are already in use for the existing (single) service. OSPF carries p2p and loopbacks; iBGP carries customer end-point networks. We want to overlay two other services. The paths the packets take to their destination, even if hosted on the same router, will be different. Further, when there's a failure in the network, the manner in which traffic gets re-routed will be specific to each service. An example might help. Consider some router R1 in this network. It has several connections to other routers in the network. It also has three interfaces each with a network assigned to it. Lets call these networks A, B and C and each is for a different service. Under normal conditions, traffic to A comes in via interface I1 and traffic to B and C comes in via interface I2. Now assume I2 fails. Traffic for A and B should come in over I1 and traffic to C stops being delivered. ACLs won't work in this situation for a number of reasons. Besides the configuration and operational issues, another requirement is that the end-points generating traffic to destinations in C will want to know when C is unavailable via I2. They'll want to know this so they can stop generating traffic or leverage some higher level (service specific) mechanism to address the failure. Running BGP as the IGP might work, but I'm not sure. I think it might need to operate in iBGP mode and I think it would require lots of policy filters on all outgoing advertisements and would probably require setting the next hop at each router. These are both typically not done when operating in iBGP mode. Further, I think one would lose the concept of IGP cost; the iBGP mechanism might allow one to construct a path between two end-points which satisfies the service policy, but if multiple paths exist, the concept of link cost would not be available.I guess running eBGP as the IGP could also work, but now we're talking configuring a unique AS for each router (which doesn't scale). One could see the path selected through the network via the AS_PATH attribute, but there still would be no concept of IGP cost. I've not come up with a way to solve this without moving to a model where theres an IGP and thus SPT for each service, which implies multiple OSPF processes. But I'm interested in other thoughts or options on this... Zsombor Papp wrote: > > Since you say you want to run one OSPF process for each traffic > type, I assume the type of the traffic is defined by > destination IP address. If this is not correct, then I would be > curious to know what a "traffic type" is and how you will > associate a traffic type with an OSPF process. > > If however my assumption is correct, then I can see several > ways to solve the problem you cited as an example, with BGP or > with a single OSPF process. > > Let me restate the problem for N=1: suppose there are 3 > routers, R1, R2, R3, connected in a triangle. Both traffic A > and B usually go directly from R1 to R2, but when that link > fails, traffic A should go from R1 to R3 to R2, and traffic B > should be dropped at R1. > > Solution with BGP: run BGP between R1-R2 and R1-R3, make the > routes coming from R2 preferred, and filter out the routes > corresponding to traffic B from the advertisements R3 sends to > R1. > > Solution with single OSPF process: configure an access list on > the link between R1-R3 that drops traffic B. :) > > Of course I might be missing something, so feel free to point > out why these wouldn't work in your case. > > Thanks, > > Zsombor > > p b wrote: > > > > > > Using multiple processes might provide a way to implement > > policy at the link level. Typically, when one thinks of > > policy, > > one thinks of BGP. But what if your policy requires the > ability > > to control what traffic can or can't go over a particular > > link? For example, consider two routers, that are > > interconnected > > by a direct link and a N-hop L3 path. Suppose traffic types > > A and B should typically go over the direct link but, if the > > direct link fails, traffic type A should be routed over the > > N-hop L3 path and traffic type B should not be forwarded. > > > > I don't believe there's a way to get this level of policy from > > a single OSPF process or a single OSPF process coupled with > BGP. > > > > However, if you run multiple OSPF processes, say one for each > > interesting traffic type, and if you use BGP to set a > network's > > next-hop to match the right OSPF RID, and for each link define
RE: multiple ospf processes & route insertion [7:73727]
"OSPF process" is a per-router thing. You can have two processes on one router talking to a single process on another router (over two separate links), for example. Thanks, Zsombor Jason J wrote: > > Dear Zsombor: > "You can't put the same interface into multiple OSPF processes > but that doesn't mean that the two processes can't learn about > the same network." > if you can't learn put one interface into multiple OSPF > processes, > then except you redistribute the direct donnected and static, > how > could they learn the same address ,learn from each other? > i think the same condition exist on other routes ,how could a > network link's status be share with other ospf process without > put > the sme interface into multiple OSPF processes? > > best regards > > Jason J CCNP P.R.C > Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=73817&t=73727 -- **Please support GroupStudy by purchasing from the GroupStudy Store: http://shop.groupstudy.com FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html
Re: OSPF summary address with Null 0 [7:73500]
Can you please give us the link to the CCIE power session. Cheers. ""Reimer, Fred"" wrote in message news:[EMAIL PROTECTED] > From the CCIE Power Session: > > "Unless a question says so, you are not permitted to use**: > > Static routes (of any kind) > > Default routes > > **Dynamic routes to null are permitted" > > Floating statics are also allowed: > > "ip route 2.2.2.0 255.255.255.0 1.1.1.2 240 > > * Uses a higher administrative distance so that dynamic protocols will take > precedence > > * Use only if explicitly allowed in a test question > > * Make sure the dynamic route actually exists when DDR is not active" > > HTH, > > Fred Reimer - CCNA > > > Eclipsys Corporation, 200 Ashford Center North, Atlanta, GA 30338 > Phone: 404-847-5177 Cell: 770-490-3071 Pager: 888-260-2050 > > > NOTICE; This email contains confidential or proprietary information which > may be legally privileged. It is intended only for the named recipient(s). > If an addressing or transmission error has misdirected the email, please > notify the author by replying to this message. If you are not the named > recipient, you are not authorized to use, disclose, distribute, copy, print > or rely on this email, and should immediately delete it from your computer. > > > -Original Message- > From: Shab Hanon [mailto:[EMAIL PROTECTED] > Sent: Tuesday, August 05, 2003 5:30 AM > To: [EMAIL PROTECTED] > Subject: OSPF summary address with Null 0 [7:73500] > > Hi everybody > The case .. OSPF summary address with Null 0 > > In all the case studies for CCIE R & S we told don't use static routes! **Please support GroupStudy by purchasing from the GroupStudy Store: http://shop.groupstudy.com FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html
multiple ospf processes & route insertion [7:73727]
I'm considering a routing architecture where devices in the network would run ~3 OSPF routing processes. I think each routing process will be handling the routing of non-overlapping address blocks and thus the routes they give to the forwarding table should be disjoint. However, I'd like to understand what happens if two processes each were to provide the same prefix to the forwarding table. Specifically, what are the rules to determine which prefix is put into the routing table? Also be interested in any learnings folks might have had when they've run multiple OSPF processes. Thanks Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=73727&t=73727 -- **Please support GroupStudy by purchasing from the GroupStudy Store: http://shop.groupstudy.com FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html
RE: OSPF DR and BDR elections [7:73504]
It may be stated that way in the RFC, I have not checked, but the logic of it is il, as in illogical. ;-) Fred Reimer - CCNA Eclipsys Corporation, 200 Ashford Center North, Atlanta, GA 30338 Phone: 404-847-5177 Cell: 770-490-3071 Pager: 888-260-2050 NOTICE; This email contains confidential or proprietary information which may be legally privileged. It is intended only for the named recipient(s). If an addressing or transmission error has misdirected the email, please notify the author by replying to this message. If you are not the named recipient, you are not authorized to use, disclose, distribute, copy, print or rely on this email, and should immediately delete it from your computer. -Original Message- From: DeVoe, Charles (PKI) [mailto:[EMAIL PROTECTED] Sent: Wednesday, August 06, 2003 7:34 AM To: [EMAIL PROTECTED] Subject: RE: OSPF DR and BDR elections [7:73504] That is the point I needed clarification on. Just seemed odd that the DR would not be established first, followed by the BDR. For a brief moment when the routers are first started, there is no DR, but there is a BDR. I wonder what the logic for that is. -Original Message- From: Zsombor Papp [mailto:[EMAIL PROTECTED] Sent: Tuesday, August 05, 2003 8:20 PM To: [EMAIL PROTECTED] Subject: RE: OSPF DR and BDR elections [7:73504] Technically, the BDR is elected first. If no router is claiming to be a DR, then the BDR will be immediately promoted to DR. Nonetheless, the end result is pretty much what the web page referenced below describes. Thanks, Zsombor mccloud mike wrote: > > The DR is elected first by highest priority, the tie breaker is > highest RID. Then the process is repeated for the BDR. > > http://www.cisco.com/warp/customer/104/2.html#10.1 > > My understanding is that if the DR goes down then the BDR is > promoted to DR and an election is held for the new BDR. This > means that when the original DR comes back up it can not become > DR until both of the current DR and BDR go offline. > > Cheers, Mike > > DeVoe, Charles (PKI) wrote: > > > > If I am understanding this correctly. There are no routers up > > in the > > network. I turn on 3 routers simultaneously at the same > time. > > The routers > > will first select the BDR. They will then look for the DR. > > Since none > > exist, the BDR will be promoted to DR. Then another election > > will be held > > to find a new BDR. Is this correct? > > > > -Original Message- > > From: Zsombor Papp [mailto:[EMAIL PROTECTED] > > Sent: Tuesday, August 05, 2003 11:01 AM > > To: [EMAIL PROTECTED] > > Subject: RE: OSPF DR and BDR elections [7:73504] > > > > > > The DR is not chosen from the "remaining list." The DR is > > chosen from the > > list of routers that declared themselves designated routers > > (this is why a > > high-priority router that comes up late won't take over the DR > > role from an > > existing DR), or if no router declared itself DR, then the BDR > > will become > > DR (this is why a high-priority router that came up late won't > > necessarily > > become DR even if the existing DR dies). > > > > See RFC2328, Page 75 for more details. > > > > Thanks, > > > > Zsombor > > > > DeVoe, Charles (PKI) wrote: > > > > > > I am reading the CCNP/CCIP BSCI Study Guide by Todd Lammle > > > from Sybex. In > > > the OSPF section under the discussion of DR and BDR (page > > 171) > > > he says that > > > the BDR is chosen first and that the DR is chosen from the > > > reaming list. > > > That seems illogical and backwards. Can someone please > > confirm > > > or deny and > > > explain it. Thanks > > **Please support GroupStudy by purchasing from the GroupStudy > > Store: > > http://shop.groupstudy.com > > FAQ, list archives, and subscription info: > > http://www.groupstudy.com/list/cisco.html **Please support GroupStudy by purchasing from the GroupStudy Store: http://shop.groupstudy.com FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html **Please support GroupStudy by purchasing from the GroupStudy Store: http://shop.groupstudy.com FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=73602&t=73504 -- **Please support GroupStudy by purchasing from the GroupStudy Store: http://shop.groupstudy.com FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html
Re: OSPF DR and BDR elections [7:73504]
At 8:08 PM + 8/6/03, Marko Milivojevic wrote: > > > I wonder what the logic for that is. >> >> I wonder, too. :) > > The reason could be as simple as the possibility to reuse the code (or >function-call). For that brief moment when there is BDR, but no DR, exactly >the same code base can be used as if router has realized that DR just failed >miserably :-). > > I just realized that my logic above actually makes sense. Of course, >someone will correct me if I'm horribly wrong. > That's the exact reason it's done that way. I think it's documented in the code in Moy's second book on implementation, but it might be the first. Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=73636&t=73504 -- **Please support GroupStudy by purchasing from the GroupStudy Store: http://shop.groupstudy.com FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html
RE: OSPF DR and BDR elections [7:73504]
The DR is not chosen from the "remaining list." The DR is chosen from the list of routers that declared themselves designated routers (this is why a high-priority router that comes up late won't take over the DR role from an existing DR), or if no router declared itself DR, then the BDR will become DR (this is why a high-priority router that came up late won't necessarily become DR even if the existing DR dies). See RFC2328, Page 75 for more details. Thanks, Zsombor DeVoe, Charles (PKI) wrote: > > I am reading the CCNP/CCIP BSCI Study Guide by Todd Lammle > from Sybex. In > the OSPF section under the discussion of DR and BDR (page 171) > he says that > the BDR is chosen first and that the DR is chosen from the > reaming list. > That seems illogical and backwards. Can someone please confirm > or deny and > explain it. Thanks > > Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=73524&t=73504 -- **Please support GroupStudy by purchasing from the GroupStudy Store: http://shop.groupstudy.com FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html
RE: multiple ospf processes & route insertion [7:73727]
sorry , i think what i've said is totally wrong!.god damn. i'am a little dizzy. confused about the concept of route table. i'am just doing experiments on routers. dizzy. since the same routes from different protocols can not be present on the route table , but why do i saw there are the same route from BGP and Static?? :( Jason J CCNP P.R.C Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=73786&t=73727 -- **Please support GroupStudy by purchasing from the GroupStudy Store: http://shop.groupstudy.com FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html
RE: multiple ospf processes & route insertion [7:73727]
The process with the lower administrative distance will install the prefix into the routing table. If the administrative distances are the same (and they are by default), then the process that "comes first" will install the route. In other words, it is not deterministic unless you change the default admin distance. What are you trying to achieve with these ~3 OSPF routing processes? Thanks, Zsombor p b wrote: > > > I'm considering a routing architecture where devices in the > network would run ~3 OSPF routing processes. > > I think each routing process will be handling the routing > of non-overlapping address blocks and thus the routes they > give to the forwarding table should be disjoint. > > However, I'd like to understand what happens if two processes > each were to provide the same prefix to the forwarding table. > Specifically, what are the rules to determine which prefix > is put into the routing table? > > Also be interested in any learnings folks might have had when > they've run multiple OSPF processes. > > Thanks > Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=73741&t=73727 -- **Please support GroupStudy by purchasing from the GroupStudy Store: http://shop.groupstudy.com FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html
RE: multiple ospf processes & route insertion [7:73727]
Dear Zsombor: "You can't put the same interface into multiple OSPF processes but that doesn't mean that the two processes can't learn about the same network." if you can't learn put one interface into multiple OSPF processes, then except you redistribute the direct donnected and static, how could they learn the same address ,learn from each other? i think the same condition exist on other routes ,how could a network link's status be share with other ospf process without put the sme interface into multiple OSPF processes? best regards Jason J CCNP P.R.C Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=73797&t=73727 -- **Please support GroupStudy by purchasing from the GroupStudy Store: http://shop.groupstudy.com FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html
RE: multiple ospf processes & route insertion [7:73727]
er.Sorry about that! I Think i make a mistake, I did no see two same routes from two different routing protocols. in fact, one is "61.168.0.0",another is" 161.168.0.0" . really sorry for put so much trouble on you. everything comes from my experiments's wrong result. the wrong result comes to the wrong conclusion. so ,really thanks a lot , Zomber and Fred. for pointing out my mistake, so i can get a chance to learn more. Jason.J CCNP P.R.C **Please support GroupStudy by purchasing from the GroupStudy Store: http://shop.groupstudy.com FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html **Please support GroupStudy by purchasing from the GroupStudy Store: http://shop.groupstudy.com FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=73818&t=73727 -- **Please support GroupStudy by purchasing from the GroupStudy Store: http://shop.groupstudy.com FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html
RE: multiple ospf processes & route insertion [7:73727]
Dear Fred "Wow, um, err, no offense, but you're a CCNP? And confused about the concept of a route table? " everyone could get confused about anything :). especially in some 2 or 3 am morning. first sorry about that. "There can't be the same route for BGP and a static in the active routing table concurrently. That is unless you do something weird like set the administrative distance of the static route equal to that of the BGP route, but I'm not even sure about that. " yes, i do saw two same routes ,one from EBGP ,one from static. both them are 192.168.0.0/17. one AD is 20 another is 110. best regards. Jason J. CCNP P.R.C **Please support GroupStudy by purchasing from the GroupStudy Store: http://shop.groupstudy.com FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=73843&t=73727 -- **Please support GroupStudy by purchasing from the GroupStudy Store: http://shop.groupstudy.com FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html
RE: multiple ospf processes & route insertion [7:73727]
Yeh, you are righ, Zsombor. in fact, i just want to say that .for 192.168.0.0/24---192.168.31.0/24 ,the router will use 192.168.0.0/19 from EBGP,not the static one "192.168.0.0/18". also if you tyep" show ip route 192.168.0.0 " , the router show u the 192.168.0.0/19. By the way ,i just understand what p b was interested in. i'm also interest in it too! If two ospf processes learn the same network route,what will happen then ?? :) Jason J CCNP P.R.C Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=73783&t=73727 -- **Please support GroupStudy by purchasing from the GroupStudy Store: http://shop.groupstudy.com FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html
Re: OSPF summary address with Null 0 [7:73500]
Good question. Null0 will only be used if it can't find a particular address. It's used to prevent routing loops essentially. ""Shab Hanon"" wrote in message news:[EMAIL PROTECTED] > Hi everybody > The case .. OSPF summary address with Null 0 > > In all the case studies for CCIE R & S we told don't use static routes! **Please support GroupStudy by purchasing from the GroupStudy Store: http://shop.groupstudy.com FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html
RE: multiple ospf processes & route insertion [7:73727]
Here's some more detail. Yes, assume the destination address (networks) represent the corresponding service. This is an existing production network where OSPF and iBGP are already in use for the existing (single) service. OSPF carries p2p and loopbacks; iBGP carries customer end-point networks. We want to overlay two other services. The paths the packets take to their destination, even if hosted on the same router, will be different. Further, when there's a failure in the network, the manner in which traffic gets re-routed will be specific to each service. An example might help. Consider some router R1 in this network. It has several connections to other routers in the network. It also has three interfaces each with a network assigned to it. Lets call these networks A, B and C and each is for a different service. Under normal conditions, traffic to A comes in via interface I1 and traffic to B and C comes in via interface I2. Now assume I2 fails. Traffic for A and B should come in over I1 and traffic to C stops being delivered. ACLs won't work in this situation for a number of reasons. Besides the configuration and operational issues, another requirement is that the end-points generating traffic to destinations in C will want to know when C is unavailable via I2. They'll want to know this so they can stop generating traffic or leverage some higher level (service specific) mechanism to address the failure. Running BGP as the IGP might work, but I'm not sure. I think it might need to operate in iBGP mode and I think it would require lots of policy filters on all outgoing advertisements and would probably require setting the next hop at each router. These are both typically not done when operating in iBGP mode. Further, I think one would lose the concept of IGP cost; the iBGP mechanism might allow one to construct a path between two end-points which satisfies the service policy, but if multiple paths exist, the concept of link cost would not be available.I guess running eBGP as the IGP could also work, but now we're talking configuring a unique AS for each router (which doesn't scale). One could see the path selected through the network via the AS_PATH attribute, but there still would be no concept of IGP cost. I've not come up with a way to solve this without moving to a model where theres an IGP and thus SPT for each service, which implies multiple OSPF processes. But I'm interested in other thoughts or options on this... Zsombor Papp wrote: > > Since you say you want to run one OSPF process for each traffic > type, I assume the type of the traffic is defined by > destination IP address. If this is not correct, then I would be > curious to know what a "traffic type" is and how you will > associate a traffic type with an OSPF process. > > If however my assumption is correct, then I can see several > ways to solve the problem you cited as an example, with BGP or > with a single OSPF process. > > Let me restate the problem for N=1: suppose there are 3 > routers, R1, R2, R3, connected in a triangle. Both traffic A > and B usually go directly from R1 to R2, but when that link > fails, traffic A should go from R1 to R3 to R2, and traffic B > should be dropped at R1. > > Solution with BGP: run BGP between R1-R2 and R1-R3, make the > routes coming from R2 preferred, and filter out the routes > corresponding to traffic B from the advertisements R3 sends to > R1. > > Solution with single OSPF process: configure an access list on > the link between R1-R3 that drops traffic B. :) > > Of course I might be missing something, so feel free to point > out why these wouldn't work in your case. > > Thanks, > > Zsombor > > p b wrote: > > > > > > Using multiple processes might provide a way to implement > > policy at the link level. Typically, when one thinks of > > policy, > > one thinks of BGP. But what if your policy requires the > ability > > to control what traffic can or can't go over a particular > > link? For example, consider two routers, that are > > interconnected > > by a direct link and a N-hop L3 path. Suppose traffic types > > A and B should typically go over the direct link but, if the > > direct link fails, traffic type A should be routed over the > > N-hop L3 path and traffic type B should not be forwarded. > > > > I don't believe there's a way to get this level of policy from > > a single OSPF process or a single OSPF process coupled with > BGP. > > > > However, if you run multiple OSPF processes, say one for each > > interesting traffic type, and if you use BGP to set a > network's > > next-hop to match the right OSPF RID, and for each link define
RE: multiple ospf processes & route insertion [7:73727]
Here's some more detail. Yes, assume the destination address (networks) represent the corresponding service. This is an existing production network where OSPF and iBGP are already in use for the existing (single) service. OSPF carries p2p and loopbacks; iBGP carries customer end-point networks. We want to overlay two other services. The paths the packets take to their destination, even if hosted on the same router, will be different. Further, when there's a failure in the network, the manner in which traffic gets re-routed will be specific to each service. An example might help. Consider some router R1 in this network. It has several connections to other routers in the network. It also has three interfaces each with a network assigned to it. Lets call these networks A, B and C and each is for a different service. Under normal conditions, traffic to A comes in via interface I1 and traffic to B and C comes in via interface I2. Now assume I2 fails. Traffic for A and B should come in over I1 and traffic to C stops being delivered. ACLs won't work in this situation for a number of reasons. Besides the configuration and operational issues, another requirement is that the end-points generating traffic to destinations in C will want to know when C is unavailable via I2. They'll want to know this so they can stop generating traffic or leverage some higher level (service specific) mechanism to address the failure. Running BGP as the IGP might work, but I'm not sure. I think it might need to operate in iBGP mode and I think it would require lots of policy filters on all outgoing advertisements and would probably require setting the next hop at each router. These are both typically not done when operating in iBGP mode. Further, I think one would lose the concept of IGP cost; the iBGP mechanism might allow one to construct a path between two end-points which satisfies the service policy, but if multiple paths exist, the concept of link cost would not be available.I guess running eBGP as the IGP could also work, but now we're talking configuring a unique AS for each router (which doesn't scale). One could see the path selected through the network via the AS_PATH attribute, but there still would be no concept of IGP cost. I've not come up with a way to solve this without moving to a model where theres an IGP and thus SPT for each service, which implies multiple OSPF processes. But I'm interested in other thoughts or options on this... Zsombor Papp wrote: > > Since you say you want to run one OSPF process for each traffic > type, I assume the type of the traffic is defined by > destination IP address. If this is not correct, then I would be > curious to know what a "traffic type" is and how you will > associate a traffic type with an OSPF process. > > If however my assumption is correct, then I can see several > ways to solve the problem you cited as an example, with BGP or > with a single OSPF process. > > Let me restate the problem for N=1: suppose there are 3 > routers, R1, R2, R3, connected in a triangle. Both traffic A > and B usually go directly from R1 to R2, but when that link > fails, traffic A should go from R1 to R3 to R2, and traffic B > should be dropped at R1. > > Solution with BGP: run BGP between R1-R2 and R1-R3, make the > routes coming from R2 preferred, and filter out the routes > corresponding to traffic B from the advertisements R3 sends to > R1. > > Solution with single OSPF process: configure an access list on > the link between R1-R3 that drops traffic B. :) > > Of course I might be missing something, so feel free to point > out why these wouldn't work in your case. > > Thanks, > > Zsombor > > p b wrote: > > > > > > Using multiple processes might provide a way to implement > > policy at the link level. Typically, when one thinks of > > policy, > > one thinks of BGP. But what if your policy requires the > ability > > to control what traffic can or can't go over a particular > > link? For example, consider two routers, that are > > interconnected > > by a direct link and a N-hop L3 path. Suppose traffic types > > A and B should typically go over the direct link but, if the > > direct link fails, traffic type A should be routed over the > > N-hop L3 path and traffic type B should not be forwarded. > > > > I don't believe there's a way to get this level of policy from > > a single OSPF process or a single OSPF process coupled with > BGP. > > > > However, if you run multiple OSPF processes, say one for each > > interesting traffic type, and if you use BGP to set a > network's > > next-hop to match the right OSPF RID, and for each link define
RE: multiple ospf processes & route insertion [7:73727]
er.Sorry about that! I Think i make a mistake, I did no see two same routes from two different routing protocols. in fact, one is "61.168.0.0",another is" 161.168.0.0" . really sorry for put so much trouble on you. everything comes from my experiments's wrong result. the wrong result comes to the wrong conclusion. so ,really thanks a lot , Zomber and Fred. for pointing out my mistake, so i can get a chance to learn more. Jason.J CCNP P.R.C **Please support GroupStudy by purchasing from the GroupStudy Store: http://shop.groupstudy.com FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html **Please support GroupStudy by purchasing from the GroupStudy Store: http://shop.groupstudy.com FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=73831&t=73727 -- **Please support GroupStudy by purchasing from the GroupStudy Store: http://shop.groupstudy.com FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html
RE: multiple ospf processes & route insertion [7:73727]
O.K., no problem, everyone makes mistakes, and that was a pretty easy one to make. Fred Reimer - CCNA Eclipsys Corporation, 200 Ashford Center North, Atlanta, GA 30338 Phone: 404-847-5177 Cell: 770-490-3071 Pager: 888-260-2050 NOTICE; This email contains confidential or proprietary information which may be legally privileged. It is intended only for the named recipient(s). If an addressing or transmission error has misdirected the email, please notify the author by replying to this message. If you are not the named recipient, you are not authorized to use, disclose, distribute, copy, print or rely on this email, and should immediately delete it from your computer. -Original Message- From: Jason J [mailto:[EMAIL PROTECTED] Sent: Sunday, August 10, 2003 3:04 AM To: [EMAIL PROTECTED] Subject: RE: multiple ospf processes & route insertion [7:73727] er.Sorry about that! I Think i make a mistake, I did no see two same routes from two different routing protocols. in fact, one is "61.168.0.0",another is" 161.168.0.0" . really sorry for put so much trouble on you. everything comes from my experiments's wrong result. the wrong result comes to the wrong conclusion. so ,really thanks a lot , Zomber and Fred. for pointing out my mistake, so i can get a chance to learn more. Jason.J CCNP P.R.C **Please support GroupStudy by purchasing from the GroupStudy Store: http://shop.groupstudy.com FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html **Please support GroupStudy by purchasing from the GroupStudy Store: http://shop.groupstudy.com FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=73838&t=73727 -- **Please support GroupStudy by purchasing from the GroupStudy Store: http://shop.groupstudy.com FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html
RE: multiple ospf processes & route insertion [7:73727]
er.Sorry about that! I Think i make a mistake, I did no see two same routes from two different routing protocols. in fact, one is "61.168.0.0",another is" 161.168.0.0" . really sorry for put so much trouble on you. everything comes from my experiments's wrong result. the wrong result comes to the wrong conclusion. so ,really thanks a lot , Zomber and Fred. for pointing out my mistake, so i can get a chance to learn more. Jason.J CCNP P.R.C **Please support GroupStudy by purchasing from the GroupStudy Store: http://shop.groupstudy.com FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=73814&t=73727 -- **Please support GroupStudy by purchasing from the GroupStudy Store: http://shop.groupstudy.com FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html
RE: multiple ospf processes & route insertion [7:73727]
I assume you meant R4 not R1 here: > Assume that R1 is connected to another cloud of routers and > that traffic to networks A, B, and C will originate from this > other cloud. And you didn't say what should happen if both the R1-R2-R3-R4 and R1-R7-R6-R5-R4 path are unavailable, so I will assume only traffic B and C are supposed to go through via the R1-R4 link. (Though it wouldn't make a big difference if traffic A needed to go through there, too.) I am also a bit uncertain why the routing requirements are stated "from R1's perspective", if they refer to the traffic that goes *to* R1. I'll assume this is just an oversight and you are not interested in how traffic *from* R1 will be routed. Having said that, my suggestion would be to run eBGP between - R4-R1 and filter out network A and increase the weight of network B, - R4-R3 and filter out network C, and - R4-R5 and filter out network C. R4 should run OSPF only on the interface towards the cloud, ie. R4 would talk only BGP towards R1, R3 and R5, and you would redistribute BGP into OSPF on R4. R3 and R5 could learn A, B and C via OSPF, I don't see why they would have to run BGP towards R1/R2/R6 (but they can if you want that). I think the above description pretty much nails down the configuration. If you really want specific configs, then tell me which part you are not clear about. Thanks, Zsombor p b wrote: > > > Lets go down another layer in your proposed BGP solution. > > The core topology will be along the lines of 5-10 routers > in a ring. Lets say 7 routers, R1, R2, R3, R4, R5, R6 and > R7 are connected in a p2p ring topology. Assume that there's > one or more direct connections between R1 and R4. > > R4 has 3 other interfaces for networks A, B, and C. Each is > a different service. > > Assume that R1 is connected to another cloud of routers and > that traffic to networks A, B, and C will originate from this > other cloud. > > The service routing requirements are as follows (from R1's > perspective): > > * traffic to A should go follow the R1-R2-R3-R4 and/or the > R1-R7-R6-R5-R4 path. > * traffic to B and C should follow the R1-R4 path > * when the link between R1 and R4 fails, B should be routed over > the R1-R2-R3-R4 and/or R1-R7-R6-R5-R4 path. Traffic to C should > stop. > > Provide some sample configs snipets for R1, R4 and an > intermediate > router which demonstrates how the proposed BGP solution would > support the policy requirements. > > Thanks > Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=73849&t=73727 -- **Please support GroupStudy by purchasing from the GroupStudy Store: http://shop.groupstudy.com FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html
RE: multiple ospf processes & route insertion [7:73727]
er.Sorry about that! I Think i make a mistake, I did no see two same routes from two different routing protocols. in fact, one is "61.168.0.0",another is" 161.168.0.0" . really sorry for put so much trouble on you. everything comes from my experiments's wrong result. the wrong result comes to the wrong conclusion. so ,really thanks a lot , Zomber and Fred. for pointing out my mistake, so i can get a chance to learn more. Jason.J CCNP P.R.C Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=73798&t=73727 -- **Please support GroupStudy by purchasing from the GroupStudy Store: http://shop.groupstudy.com FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html
RE: OSPF DR and BDR elections [7:73504]
> I wonder what the logic for that is. I wonder, too. :) Without answering your question, I would like to point out though that the "moment" for which there is BDR but no DR is *really* brief. The election process is not something that the routers need to discuss among themselves; every router elects the DR/BDR independently. This is a point that folks miss sometimes. So if there is no DR, then the router that eventually becomes the DR will know *immediately* that it needs to be the DR, because the DR selection is just a function call away from the BDR selection. It's not like the routers have a chit-chat to discuss who will be the BDR, and then they have a rest, and subsequently they discuss who will be the DR... :) In other words, there is no OSPF information exchange between the routers during the process described on Page 75 in RFC2328. Another slightly related thing is that, in the scenario you described below, ie. when all the routers on the same segment are booting up at the same time, then for a relatively long time (ie. the Dead interval) all of them will go into a Waiting state so there won't be any election process for long-long seconds to start with. Compared to this, I guess it is pretty insignificant whether the election process selects the DR a few microseconds sooner or later. Thanks, Zsombor DeVoe, Charles (PKI) wrote: > > That is the point I needed clarification on. Just seemed odd > that the DR > would not be established first, followed by the BDR. For a > brief moment > when the routers are first started, there is no DR, but there > is a BDR. I > wonder what the logic for that is. > > -Original Message- > From: Zsombor Papp [mailto:[EMAIL PROTECTED] > Sent: Tuesday, August 05, 2003 8:20 PM > To: [EMAIL PROTECTED] > Subject: RE: OSPF DR and BDR elections [7:73504] > > > Technically, the BDR is elected first. If no router is claiming > to be a DR, > then the BDR will be immediately promoted to DR. Nonetheless, > the end result > is pretty much what the web page referenced below describes. > > Thanks, > > Zsombor > > mccloud mike wrote: > > > > The DR is elected first by highest priority, the tie breaker > is > > highest RID. Then the process is repeated for the BDR. > > > > http://www.cisco.com/warp/customer/104/2.html#10.1 > > > > My understanding is that if the DR goes down then the BDR is > > promoted to DR and an election is held for the new BDR. This > > means that when the original DR comes back up it can not > become > > DR until both of the current DR and BDR go offline. > > > > Cheers, Mike > > > > DeVoe, Charles (PKI) wrote: > > > > > > If I am understanding this correctly. There are no routers > up > > > in the > > > network. I turn on 3 routers simultaneously at the same > > time. > > > The routers > > > will first select the BDR. They will then look for the DR. > > > Since none > > > exist, the BDR will be promoted to DR. Then another > election > > > will be held > > > to find a new BDR. Is this correct? > > > > > > -Original Message- > > > From: Zsombor Papp [mailto:[EMAIL PROTECTED] > > > Sent: Tuesday, August 05, 2003 11:01 AM > > > To: [EMAIL PROTECTED] > > > Subject: RE: OSPF DR and BDR elections [7:73504] > > > > > > > > > The DR is not chosen from the "remaining list." The DR is > > > chosen from the > > > list of routers that declared themselves designated routers > > > (this is why a > > > high-priority router that comes up late won't take over the > DR > > > role from an > > > existing DR), or if no router declared itself DR, then the > BDR > > > will become > > > DR (this is why a high-priority router that came up late > won't > > > necessarily > > > become DR even if the existing DR dies). > > > > > > See RFC2328, Page 75 for more details. > > > > > > Thanks, > > > > > > Zsombor > > > > > > DeVoe, Charles (PKI) wrote: > > > > > > > > I am reading the CCNP/CCIP BSCI Study Guide by Todd > Lammle > > > > from Sybex. In > > > > the OSPF section under the discussion of DR and BDR (page > > > 171) > > > > he says that > > > > the BDR is chosen first and that the DR is chosen from the > > > > reaming list. > > > > That seems illogical and backwards. Can someone please > > > confirm > > > > or deny and > > > &
RE: multiple ospf processes & route insertion [7:73727]
Dear Fred in fact, 192.168.0.0/18 does include 192.168.0.0/19 and 192.168.32.0/19.wherenever router choose route, it will always pick the most concrete one so even 192.168.0.0/18 is static, it will choose the one from EBGP, 192.168.0.0/19. when the route from EBG is 192.168.0.0/18 and there is static route 192.168.0.0/18, sure the router will choose the static one. Jasong.J CCNP P.R.C Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=73776&t=73727 -- **Please support GroupStudy by purchasing from the GroupStudy Store: http://shop.groupstudy.com FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html
RE: multiple ospf processes & route insertion [7:73727]
Using multiple processes might provide a way to implement policy at the link level. Typically, when one thinks of policy, one thinks of BGP. But what if your policy requires the ability to control what traffic can or can't go over a particular link? For example, consider two routers, that are interconnected by a direct link and a N-hop L3 path. Suppose traffic types A and B should typically go over the direct link but, if the direct link fails, traffic type A should be routed over the N-hop L3 path and traffic type B should not be forwarded. I don't believe there's a way to get this level of policy from a single OSPF process or a single OSPF process coupled with BGP. However, if you run multiple OSPF processes, say one for each interesting traffic type, and if you use BGP to set a network's next-hop to match the right OSPF RID, and for each link define a sub-interface (or not) for each OSPF process, then I think the above routing requirements might be supported. MPLS might work here, but I'm not sure. Suppose you have certain types of traffic that Zsombor Papp wrote: > > What are you trying to achieve with these ~3 OSPF routing > processes? > > Thanks, > > Zsombor > > p b wrote: > > > > > > I'm considering a routing architecture where devices in the > > network would run ~3 OSPF routing processes. > > > > I think each routing process will be handling the routing > > of non-overlapping address blocks and thus the routes they > > give to the forwarding table should be disjoint. > > > > However, I'd like to understand what happens if two processes > > each were to provide the same prefix to the forwarding table. > > Specifically, what are the rules to determine which prefix > > is put into the routing table? > > > > Also be interested in any learnings folks might have had when > > they've run multiple OSPF processes. > > > > Thanks > > Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=73789&t=73727 -- **Please support GroupStudy by purchasing from the GroupStudy Store: http://shop.groupstudy.com FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html
RE: multiple ospf processes & route insertion [7:73727]
Wow, um, err, no offense, but you're a CCNP? And confused about the concept of a route table? There can't be the same route for BGP and a static in the active routing table concurrently. That is unless you do something weird like set the administrative distance of the static route equal to that of the BGP route, but I'm not even sure about that. From your past posts, you are probably seeing two different routes, with the same prefix but different masks, in the routing table. 192.168.0.0/18 and 192.168.0.0/19 are not the same route. It might make it easier to follow if you quoted at least the post you are replying to... Fred Reimer - CCNA Eclipsys Corporation, 200 Ashford Center North, Atlanta, GA 30338 Phone: 404-847-5177 Cell: 770-490-3071 Pager: 888-260-2050 NOTICE; This email contains confidential or proprietary information which may be legally privileged. It is intended only for the named recipient(s). If an addressing or transmission error has misdirected the email, please notify the author by replying to this message. If you are not the named recipient, you are not authorized to use, disclose, distribute, copy, print or rely on this email, and should immediately delete it from your computer. -Original Message- From: Jason J [mailto:[EMAIL PROTECTED] Sent: Saturday, August 09, 2003 3:32 PM To: [EMAIL PROTECTED] Subject: RE: multiple ospf processes & route insertion [7:73727] sorry , i think what i've said is totally wrong!.god damn. i'am a little dizzy. confused about the concept of route table. i'am just doing experiments on routers. dizzy. since the same routes from different protocols can not be present on the route table , but why do i saw there are the same route from BGP and Static?? :( Jason J CCNP P.R.C **Please support GroupStudy by purchasing from the GroupStudy Store: http://shop.groupstudy.com FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=73791&t=73727 -- **Please support GroupStudy by purchasing from the GroupStudy Store: http://shop.groupstudy.com FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html
RE: multiple ospf processes & route insertion [7:73727]
well, in my thoughts, there is no loading balance in ospf. it will choose only one route and put it into its ospf routing table. also i got a case: when there is a route from EBGP peer which is 192.168.0.0/19 and also a route comes from static input which is 192.168.0.0/18, which one do you think the router will pick ?? the answer is : the route from EBGP! Jason G.F CCNP Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=73764&t=73727 -- **Please support GroupStudy by purchasing from the GroupStudy Store: http://shop.groupstudy.com FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html
Re: multiple ospf processes & route insertion [7:73727]
Is this correct? Off the cuff, I would think that the route with the lowest cost would be inserted into the table, and if they both have the same cost, wouldn't both routes be inserted and then load balancing occur? Again this is not lab tested, but just my initial thoughts... Mark - Original Message - From: "Zsombor Papp" To: Sent: Friday, August 08, 2003 12:44 PM Subject: RE: multiple ospf processes & route insertion [7:73727] > The process with the lower administrative distance will install the prefix > into the routing table. If the administrative distances are the same (and > they are by default), then the process that "comes first" will install the > route. In other words, it is not deterministic unless you change the default > admin distance. > > What are you trying to achieve with these ~3 OSPF routing processes? > > Thanks, > > Zsombor > > p b wrote: > > > > > > I'm considering a routing architecture where devices in the > > network would run ~3 OSPF routing processes. > > > > I think each routing process will be handling the routing > > of non-overlapping address blocks and thus the routes they > > give to the forwarding table should be disjoint. > > > > However, I'd like to understand what happens if two processes > > each were to provide the same prefix to the forwarding table. > > Specifically, what are the rules to determine which prefix > > is put into the routing table? > > > > Also be interested in any learnings folks might have had when > > they've run multiple OSPF processes. > > > > Thanks > **Please support GroupStudy by purchasing from the GroupStudy Store: > http://shop.groupstudy.com > FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=73751&t=73727 -- **Please support GroupStudy by purchasing from the GroupStudy Store: http://shop.groupstudy.com FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html
RE: OSPF DR and BDR elections [7:73504]
Technically, the BDR is elected first. If no router is claiming to be a DR, then the BDR will be immediately promoted to DR. Nonetheless, the end result is pretty much what the web page referenced below describes. Thanks, Zsombor mccloud mike wrote: > > The DR is elected first by highest priority, the tie breaker is > highest RID. Then the process is repeated for the BDR. > > http://www.cisco.com/warp/customer/104/2.html#10.1 > > My understanding is that if the DR goes down then the BDR is > promoted to DR and an election is held for the new BDR. This > means that when the original DR comes back up it can not become > DR until both of the current DR and BDR go offline. > > Cheers, Mike > > DeVoe, Charles (PKI) wrote: > > > > If I am understanding this correctly. There are no routers up > > in the > > network. I turn on 3 routers simultaneously at the same > time. > > The routers > > will first select the BDR. They will then look for the DR. > > Since none > > exist, the BDR will be promoted to DR. Then another election > > will be held > > to find a new BDR. Is this correct? > > > > -Original Message- > > From: Zsombor Papp [mailto:[EMAIL PROTECTED] > > Sent: Tuesday, August 05, 2003 11:01 AM > > To: [EMAIL PROTECTED] > > Subject: RE: OSPF DR and BDR elections [7:73504] > > > > > > The DR is not chosen from the "remaining list." The DR is > > chosen from the > > list of routers that declared themselves designated routers > > (this is why a > > high-priority router that comes up late won't take over the DR > > role from an > > existing DR), or if no router declared itself DR, then the BDR > > will become > > DR (this is why a high-priority router that came up late won't > > necessarily > > become DR even if the existing DR dies). > > > > See RFC2328, Page 75 for more details. > > > > Thanks, > > > > Zsombor > > > > DeVoe, Charles (PKI) wrote: > > > > > > I am reading the CCNP/CCIP BSCI Study Guide by Todd Lammle > > > from Sybex. In > > > the OSPF section under the discussion of DR and BDR (page > > 171) > > > he says that > > > the BDR is chosen first and that the DR is chosen from the > > > reaming list. > > > That seems illogical and backwards. Can someone please > > confirm > > > or deny and > > > explain it. Thanks > > **Please support GroupStudy by purchasing from the GroupStudy > > Store: > > http://shop.groupstudy.com > > FAQ, list archives, and subscription info: > > http://www.groupstudy.com/list/cisco.html > > > > > > Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=73575&t=73504 -- **Please support GroupStudy by purchasing from the GroupStudy Store: http://shop.groupstudy.com FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html
Re: OSPF summary address with Null 0 [7:73500]
Shab Hanon wrote: > > Can any one tell us how to block a default route? > > it is easy to block other routes by using ACL with > distribution-list > But > how to remove the default route which is being advertised by " > default-information originate always " command. 'no default-information originate always' :) Once it is in the OSPF database, you can't take it out. This is the same for other routes as well, btw, so I am not quite sure I understand why you say it's easy to block other routes. Thanks, Zsombor Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=73556&t=73500 -- **Please support GroupStudy by purchasing from the GroupStudy Store: http://shop.groupstudy.com FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html
RE: OSPF DR and BDR elections [7:73504]
The DR is elected first by highest priority, the tie breaker is highest RID. Then the process is repeated for the BDR. http://www.cisco.com/warp/customer/104/2.html#10.1 My understanding is that if the DR goes down then the BDR is promoted to DR and an election is held for the new BDR. This means that when the original DR comes back up it can not become DR until both of the current DR and BDR go offline. Cheers, Mike DeVoe, Charles (PKI) wrote: > > If I am understanding this correctly. There are no routers up > in the > network. I turn on 3 routers simultaneously at the same time. > The routers > will first select the BDR. They will then look for the DR. > Since none > exist, the BDR will be promoted to DR. Then another election > will be held > to find a new BDR. Is this correct? > > -Original Message- > From: Zsombor Papp [mailto:[EMAIL PROTECTED] > Sent: Tuesday, August 05, 2003 11:01 AM > To: [EMAIL PROTECTED] > Subject: RE: OSPF DR and BDR elections [7:73504] > > > The DR is not chosen from the "remaining list." The DR is > chosen from the > list of routers that declared themselves designated routers > (this is why a > high-priority router that comes up late won't take over the DR > role from an > existing DR), or if no router declared itself DR, then the BDR > will become > DR (this is why a high-priority router that came up late won't > necessarily > become DR even if the existing DR dies). > > See RFC2328, Page 75 for more details. > > Thanks, > > Zsombor > > DeVoe, Charles (PKI) wrote: > > > > I am reading the CCNP/CCIP BSCI Study Guide by Todd Lammle > > from Sybex. In > > the OSPF section under the discussion of DR and BDR (page > 171) > > he says that > > the BDR is chosen first and that the DR is chosen from the > > reaming list. > > That seems illogical and backwards. Can someone please > confirm > > or deny and > > explain it. Thanks > **Please support GroupStudy by purchasing from the GroupStudy > Store: > http://shop.groupstudy.com > FAQ, list archives, and subscription info: > http://www.groupstudy.com/list/cisco.html > > Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=73558&t=73504 -- **Please support GroupStudy by purchasing from the GroupStudy Store: http://shop.groupstudy.com FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html
Re: OSPF summary address with Null 0 [7:73500]
under ospf no discard route internal (does not install the Null0 route in routing table) no discard route external (used whey you use the summary address command) Ronnie ""Shab Hanon"" wrote in message news:[EMAIL PROTECTED] > Hi everybody > The case .. OSPF summary address with Null 0 > > In all the case studies for CCIE R & S we told don't use static routes! **Please support GroupStudy by purchasing from the GroupStudy Store: http://shop.groupstudy.com FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html
OSPF summary address with Null 0 [7:73500]
Hi everybody The case .. OSPF summary address with Null 0 In all the case studies for CCIE R & S we told don't use static routes! . While we need to have a static route to Null 0 with address summarization. "Page 548 Routing TCP/IP Vol. 1 The catch J What we do? What is the best? Any idea??? Cheers, Shab. Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=73500&t=73500 -- **Please support GroupStudy by purchasing from the GroupStudy Store: http://shop.groupstudy.com FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html
OSPF DR and BDR elections [7:73504]
I am reading the CCNP/CCIP BSCI Study Guide by Todd Lammle from Sybex. In the OSPF section under the discussion of DR and BDR (page 171) he says that the BDR is chosen first and that the DR is chosen from the reaming list. That seems illogical and backwards. Can someone please confirm or deny and explain it. Thanks Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=73504&t=73504 -- **Please support GroupStudy by purchasing from the GroupStudy Store: http://shop.groupstudy.com FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html
RE: OSPF summary address with Null 0 [7:73500]
As far as I know, there isn't one. I consider it fair use to quote a small section of the handouts they provided, but it was a separate charge to attend at Networkers, so I don't believe it would be ethical to just type the whole thing (and I don't really feel like typing the whole thing ;-) If you have a specific question I'll try to answer it. Fred Reimer - CCNA Eclipsys Corporation, 200 Ashford Center North, Atlanta, GA 30338 Phone: 404-847-5177 Cell: 770-490-3071 Pager: 888-260-2050 NOTICE; This email contains confidential or proprietary information which may be legally privileged. It is intended only for the named recipient(s). If an addressing or transmission error has misdirected the email, please notify the author by replying to this message. If you are not the named recipient, you are not authorized to use, disclose, distribute, copy, print or rely on this email, and should immediately delete it from your computer. -Original Message- From: Shab Hanon [mailto:[EMAIL PROTECTED] Sent: Tuesday, August 05, 2003 8:55 AM To: [EMAIL PROTECTED] Subject: Re: OSPF summary address with Null 0 [7:73500] Can you please give us the link to the CCIE power session. Cheers. ""Reimer, Fred"" wrote in message news:[EMAIL PROTECTED] > From the CCIE Power Session: > > "Unless a question says so, you are not permitted to use**: > > Static routes (of any kind) > > Default routes > > **Dynamic routes to null are permitted" > > Floating statics are also allowed: > > "ip route 2.2.2.0 255.255.255.0 1.1.1.2 240 > > * Uses a higher administrative distance so that dynamic protocols will take > precedence > > * Use only if explicitly allowed in a test question > > * Make sure the dynamic route actually exists when DDR is not active" > > HTH, > > Fred Reimer - CCNA > > > Eclipsys Corporation, 200 Ashford Center North, Atlanta, GA 30338 > Phone: 404-847-5177 Cell: 770-490-3071 Pager: 888-260-2050 > > > NOTICE; This email contains confidential or proprietary information which > may be legally privileged. It is intended only for the named recipient(s). > If an addressing or transmission error has misdirected the email, please > notify the author by replying to this message. If you are not the named > recipient, you are not authorized to use, disclose, distribute, copy, print > or rely on this email, and should immediately delete it from your computer. > > > -Original Message- > From: Shab Hanon [mailto:[EMAIL PROTECTED] > Sent: Tuesday, August 05, 2003 5:30 AM > To: [EMAIL PROTECTED] > Subject: OSPF summary address with Null 0 [7:73500] > > Hi everybody > The case .. OSPF summary address with Null 0 > > In all the case studies for CCIE R & S we told don't use static routes! **Please support GroupStudy by purchasing from the GroupStudy Store: http://shop.groupstudy.com FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=73530&t=73500 -- **Please support GroupStudy by purchasing from the GroupStudy Store: http://shop.groupstudy.com FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html
RE: OSPF summary address with Null 0 [7:73500]
>From the CCIE Power Session: "Unless a question says so, you are not permitted to use**: Static routes (of any kind) Default routes **Dynamic routes to null are permitted" Floating statics are also allowed: "ip route 2.2.2.0 255.255.255.0 1.1.1.2 240 * Uses a higher administrative distance so that dynamic protocols will take precedence * Use only if explicitly allowed in a test question * Make sure the dynamic route actually exists when DDR is not active" HTH, Fred Reimer - CCNA Eclipsys Corporation, 200 Ashford Center North, Atlanta, GA 30338 Phone: 404-847-5177 Cell: 770-490-3071 Pager: 888-260-2050 NOTICE; This email contains confidential or proprietary information which may be legally privileged. It is intended only for the named recipient(s). If an addressing or transmission error has misdirected the email, please notify the author by replying to this message. If you are not the named recipient, you are not authorized to use, disclose, distribute, copy, print or rely on this email, and should immediately delete it from your computer. -Original Message- From: Shab Hanon [mailto:[EMAIL PROTECTED] Sent: Tuesday, August 05, 2003 5:30 AM To: [EMAIL PROTECTED] Subject: OSPF summary address with Null 0 [7:73500] Hi everybody The case .. OSPF summary address with Null 0 In all the case studies for CCIE R & S we told don't use static routes! . While we need to have a static route to Null 0 with address summarization. "Page 548 Routing TCP/IP Vol. 1 The catch J What we do? What is the best? Any idea??? Cheers, Shab. **Please support GroupStudy by purchasing from the GroupStudy Store: http://shop.groupstudy.com FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=73507&t=73500 -- **Please support GroupStudy by purchasing from the GroupStudy Store: http://shop.groupstudy.com FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html
RE: OSPF Book - Tom Thomas 2nd Edition [7:73318]
Tried Amazon? Martijn -Oorspronkelijk bericht- Van: Daniel Cotts [mailto:[EMAIL PROTECTED] Verzonden: donderdag 31 juli 2003 23:14 Aan: [EMAIL PROTECTED] Onderwerp: OSPF Book - Tom Thomas 2nd Edition [7:73318] I'm looking for an evaluation of the second edition of Tom Thomas' "OSPF Network Design Solutions". I have the first edition and am wondering if there are major differences/improvements between the editions. Thanks in advance. Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=73330&t=73318 -- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
OSPF Book - Tom Thomas 2nd Edition [7:73318]
I'm looking for an evaluation of the second edition of Tom Thomas' "OSPF Network Design Solutions". I have the first edition and am wondering if there are major differences/improvements between the editions. Thanks in advance. Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=73318&t=73318 -- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
RE: OSPF through PIX [7:72938]
OSPF doesn't generate broadcast packets. It genereates multicast packets; the ones addressed to 224.0.0.5 are received by all OSPF routers, and the ones addressed to 224.0.0.6 are received by all DRs. I suppose you should allow transport protocol number 89 - if you only allow TCP (6) and UDP (17), OSPF information just won't get through. That's my $0.02. Take my advice with a grain of salt, however, because I've only recently started to prepare for my Routing exam. Georger Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=72953&t=72938 -- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
Re: OSPF through PIX [7:72938]
Get PIXOS 6.3, enable OSPF on the firewall, and let it participate in OSPF routing...voila! OSPF "through" the firewall... Also, how about using neighbor statements (with no translation) which converts the OSPF multicasts to unicasts? Just a thoughtobviously, would need an ACL applied at key points. ""Robertson, Douglas"" wrote in message news:[EMAIL PROTECTED] > OSPF through a PIX firewall is not supported. There are two ways to > configure routing through a PIX. > 1) Configure a GRE tunnel between the two routers. > 2) Configure BGP between the two routers. > The two choices have different implications depending on your specific > network. > > Thanks Doug > > -Original Message- > From: Massucco Emanuele [mailto:[EMAIL PROTECTED] > Sent: Thursday, July 24, 2003 11:28 AM > To: [EMAIL PROTECTED] > Subject: OSPF through PIX [7:72938] > > > Does anyone know if there are any problems configuring OSPF trhough PIX > interfaces? > I know PIX should block broadcast, so which is the way to make it work? > > thanks > LEle Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=72958&t=72938 -- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
RE: OSPF through PIX [7:72938]
Only possible way would be to have a tunnel interface through the PIX, and run OSPF over that. I think. Fred Reimer - CCNA Eclipsys Corporation, 200 Ashford Center North, Atlanta, GA 30338 Phone: 404-847-5177 Cell: 770-490-3071 Pager: 888-260-2050 NOTICE; This email contains confidential or proprietary information which may be legally privileged. It is intended only for the named recipient(s). If an addressing or transmission error has misdirected the email, please notify the author by replying to this message. If you are not the named recipient, you are not authorized to use, disclose, distribute, copy, print or rely on this email, and should immediately delete it from your computer. -Original Message- From: Massucco Emanuele [mailto:[EMAIL PROTECTED] Sent: Thursday, July 24, 2003 11:28 AM To: [EMAIL PROTECTED] Subject: OSPF through PIX [7:72938] Does anyone know if there are any problems configuring OSPF trhough PIX interfaces? I know PIX should block broadcast, so which is the way to make it work? thanks LEle Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=72947&t=72938 -- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
RE: OSPF through PIX [7:72938]
OSPF through a PIX firewall is not supported. There are two ways to configure routing through a PIX. 1) Configure a GRE tunnel between the two routers. 2) Configure BGP between the two routers. The two choices have different implications depending on your specific network. Thanks Doug -Original Message- From: Massucco Emanuele [mailto:[EMAIL PROTECTED] Sent: Thursday, July 24, 2003 11:28 AM To: [EMAIL PROTECTED] Subject: OSPF through PIX [7:72938] Does anyone know if there are any problems configuring OSPF trhough PIX interfaces? I know PIX should block broadcast, so which is the way to make it work? thanks LEle Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=72952&t=72938 -- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
OSPF through PIX [7:72938]
Does anyone know if there are any problems configuring OSPF trhough PIX interfaces? I know PIX should block broadcast, so which is the way to make it work? thanks LEle Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=72938&t=72938 -- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
OSPF Neighbor State is "Flapping" [7:72874]
Hi all, I have 3 devices on an ethernet segment where all ethernet interfaces are in the same vlan and ospf area 0 catalyst 3550priority 0rid 1.1.1.1 router5priority 2 rid 55.55.55.55BDR router1priority 3 rid 11.11.11.11DR The problem is that the switch keeps changing it's state. For example, from the router 1 perspective I get the following: ( sh ip ospf nei command ) Neighbor ID Pri State Dead Time Address Interface 1.1.1.1 0 DOWN/DROTHER -150.50.15.8 Ethernet0 55.55.55.55 2 FULL/BDR00:00:35150.50.15.5 Ethernet0 Neighbor ID Pri State Dead Time Address Interface 1.1.1.1 0 EXSTART/DROTHER 00:00:35150.50.15.8 Ethernet0 55.55.55.55 2 FULL/BDR00:00:38150.50.15.5 Ethernet0 ..and on and on, back and forth etc. router 5 perspective: Neighbor ID Pri State Dead Time Address Interface 1.1.1.1 0 EXSTART/DROTHER 00:00:38150.50.15.8 Ethernet0/0 11.11.11.11 3 FULL/DR 00:00:30150.50.15.1 Ethernet0/0 Neighbor ID Pri State Dead Time Address Interface 1.1.1.1 0 DOWN/DROTHER -150.50.15.8 Ethernet0/0 11.11.11.11 3 FULL/DR 00:00:32150.50.15.1 Ethernet0/0 .switch perspective: Neighbor ID Pri State Dead Time Address Interface 55.55.55.55 2 INIT/DROTHER00:00:33150.50.15.5 Vlan15 11.11.11.11 3 INIT/DROTHER00:00:39150.50.15.1 Vlan15 Neighbor ID Pri State Dead Time Address Interface 55.55.55.55 2 INIT/DROTHER00:00:37150.50.15.5 Vlan15 11.11.11.11 3 EXCHANGE/DR 00:00:36150.50.15.1 Vlan15 Neighbor ID Pri State Dead Time Address Interface 55.55.55.55 2 EXCHANGE/BDR00:00:39150.50.15.5 Vlan15 11.11.11.11 3 EXCHANGE/DR 00:00:39150.50.15.1 Vlan15 So...it seems as though r1 and r5 are recognizing eachother's roles as dr and bdr correctly. But they see the switch as down or init or exchange DROTHER. The switch however, sees itelf as DROTHER and r1/r5 as DROTHER or init/exchange dr and bdr. Here is the output from "sh ip ospf int vlan15" on the switch: Vlan15 is up, line protocol is up Internet Address 150.50.15.8/24, Area 0 Process ID 100, Router ID 1.1.1.1, Network Type BROADCAST, Cost: 1 Transmit Delay is 1 sec, State DROTHER, Priority 0 No designated router on this network No backup designated router on this network Timer intervals configured, Hello 10, Dead 40, Wait 40, Retransmit 5 Hello due in 00:00:07 Index 1/1, flood queue length 0 Next 0x0(0)/0x0(0) Last flood scan length is 0, maximum is 0 Last flood scan time is 0 msec, maximum is 0 msec Neighbor Count is 2, Adjacent neighbor count is 0 Suppress hello for 0 neighbor(s) Then two seconds laterit changes... Vlan15 is up, line protocol is up Internet Address 150.50.15.8/24, Area 0 Process ID 100, Router ID 1.1.1.1, Network Type BROADCAST, Cost: 1 Transmit Delay is 1 sec, State DROTHER, Priority 0 Designated Router (ID) 11.11.11.11, Interface address 150.50.15.1 Backup Designated router (ID) 55.55.55.55, Interface address 150.50.15.5 Timer intervals configured, Hello 10, Dead 40, Wait 40, Retransmit 5 Hello due in 00:00:05 Index 1/1, flood queue length 0 Next 0x0(0)/0x0(0) Last flood scan length is 0, maximum is 0 Last flood scan time is 0 msec, maximum is 0 msec Neighbor Count is 2, Adjacent neighbor count is 0 Suppress hello for 0 neighbor(s) Any ideas? Thanks, -- Dain Deutschman CCNP, CSS-1, MCP, CNA Data Communications Manager New Star Sales and Service, Inc. -- Dain Deutschman CCNP, CSS-1, MCP, CNA Data Communications Manager New Star Sales and Service, Inc. 800.261.0475 [EMAIL PROTECTED] Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=72913&t=72874 -- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
RE: OSPF Neighbor State is "Flapping" [7:72874]
do the mtus all match? do big packets get through? /thomas > > > Hi all, > > I have 3 devices on an ethernet segment where all ethernet > interfaces are in > the same vlan and ospf area 0 > > catalyst 3550priority 0rid 1.1.1.1 > router5priority 2 rid 55.55.55.55BDR > router1priority 3 rid 11.11.11.11DR > > The problem is that the switch keeps changing it's state. For > example, from > the router 1 perspective I get the following: > ( sh ip ospf nei command ) > > > Neighbor ID Pri State Dead Time Address > Interface > 1.1.1.1 0 DOWN/DROTHER -150.50.15.8 > Ethernet0 > 55.55.55.55 2 FULL/BDR00:00:35150.50.15.5 > Ethernet0 > > Neighbor ID Pri State Dead Time Address > Interface > 1.1.1.1 0 EXSTART/DROTHER 00:00:35150.50.15.8 > Ethernet0 > 55.55.55.55 2 FULL/BDR00:00:38150.50.15.5 > Ethernet0 > > and on and on, back and forth etc. > > router 5 perspective: > > > Neighbor ID Pri State Dead Time Address > Interface > 1.1.1.1 0 EXSTART/DROTHER 00:00:38150.50.15.8 > Ethernet0/0 > 11.11.11.11 3 FULL/DR 00:00:30150.50.15.1 > Ethernet0/0 > > Neighbor ID Pri State Dead Time Address > Interface > 1.1.1.1 0 DOWN/DROTHER -150.50.15.8 > Ethernet0/0 > 11.11.11.11 3 FULL/DR 00:00:32150.50.15.1 > Ethernet0/0 > > ..switch perspective: > > Neighbor ID Pri State Dead Time Address > Interface > 55.55.55.55 2 INIT/DROTHER00:00:33150.50.15.5 > Vlan15 > 11.11.11.11 3 INIT/DROTHER00:00:39150.50.15.1 > Vlan15 > > Neighbor ID Pri State Dead Time Address > Interface > 55.55.55.55 2 INIT/DROTHER00:00:37150.50.15.5 > Vlan15 > 11.11.11.11 3 EXCHANGE/DR 00:00:36150.50.15.1 > Vlan15 > > Neighbor ID Pri State Dead Time Address > Interface > 55.55.55.55 2 EXCHANGE/BDR00:00:39150.50.15.5 > Vlan15 > 11.11.11.11 3 EXCHANGE/DR 00:00:39150.50.15.1 > Vlan15 > > So...it seems as though r1 and r5 are recognizing eachother's > roles as dr > and bdr correctly. But they see the switch as down or init or exchange > DROTHER. > The switch however, sees itelf as DROTHER and r1/r5 as DROTHER or > init/exchange dr and bdr. Here is the output from "sh ip ospf > int vlan15" on > the switch: > > Vlan15 is up, line protocol is up > Internet Address 150.50.15.8/24, Area 0 > Process ID 100, Router ID 1.1.1.1, Network Type BROADCAST, Cost: 1 > Transmit Delay is 1 sec, State DROTHER, Priority 0 > No designated router on this network > No backup designated router on this network > Timer intervals configured, Hello 10, Dead 40, Wait 40, Retransmit 5 > Hello due in 00:00:07 > Index 1/1, flood queue length 0 > Next 0x0(0)/0x0(0) > Last flood scan length is 0, maximum is 0 > Last flood scan time is 0 msec, maximum is 0 msec > Neighbor Count is 2, Adjacent neighbor count is 0 > Suppress hello for 0 neighbor(s) > > Then two seconds laterit changes... > > Vlan15 is up, line protocol is up > Internet Address 150.50.15.8/24, Area 0 > Process ID 100, Router ID 1.1.1.1, Network Type BROADCAST, Cost: 1 > Transmit Delay is 1 sec, State DROTHER, Priority 0 > Designated Router (ID) 11.11.11.11, Interface address 150.50.15.1 > Backup Designated router (ID) 55.55.55.55, Interface > address 150.50.15.5 > Timer intervals configured, Hello 10, Dead 40, Wait 40, Retransmit 5 > Hello due in 00:00:05 > Index 1/1, flood queue length 0 > Next 0x0(0)/0x0(0) > Last flood scan length is 0, maximum is 0 > Last flood scan time is 0 msec, maximum is 0 msec > Neighbor Count is 2, Adjacent neighbor count is 0 > Suppress hello for 0 neighbor(s) > > > Any ideas? > > Thanks, > > > -- > Dain Deutschman > CCNP, CSS-1, MCP, CNA > Data Communications Manager > New Star Sales and Service, Inc. > > > > > > > -- > Dain Deutschman > CCNP, CSS-1, MCP, CNA > Data Communications Manager > New Star Sales and Service, Inc. > 800.261.0475 > [EMAIL PROTECTED] Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=72881&t=72874 -- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
Re: OSPF Neighbor State is "Flapping" [7:72874]
Figured it out... It was an mtu mismatch ( router e0 mtu 1500, cat vlan15 mtu 1518 ). A "deb ip ospf adj" on r1 revealed the problem. Since changing mtu on lan interface is not possible in IOS...the interface command "ip ospf mtu-ignore" allowed OSPF to deal with the mismatch and just form the adjacency. The cisco url is:www.cisco.com/warp/public/104/12.pdf Thanks anyway! Dain ""Dain Deutschman"" wrote in message news:[EMAIL PROTECTED] > Hi all, > > I have 3 devices on an ethernet segment where all ethernet interfaces are in > the same vlan and ospf area 0 > > catalyst 3550priority 0rid 1.1.1.1 > router5priority 2 rid 55.55.55.55BDR > router1priority 3 rid 11.11.11.11DR > > The problem is that the switch keeps changing it's state. For example, from > the router 1 perspective I get the following: > ( sh ip ospf nei command ) > > > Neighbor ID Pri State Dead Time Address Interface > 1.1.1.1 0 DOWN/DROTHER -150.50.15.8 Ethernet0 > 55.55.55.55 2 FULL/BDR00:00:35150.50.15.5 Ethernet0 > > Neighbor ID Pri State Dead Time Address Interface > 1.1.1.1 0 EXSTART/DROTHER 00:00:35150.50.15.8 Ethernet0 > 55.55.55.55 2 FULL/BDR00:00:38150.50.15.5 Ethernet0 > > and on and on, back and forth etc. > > router 5 perspective: > > > Neighbor ID Pri State Dead Time Address Interface > 1.1.1.1 0 EXSTART/DROTHER 00:00:38150.50.15.8 > Ethernet0/0 > 11.11.11.11 3 FULL/DR 00:00:30150.50.15.1 > Ethernet0/0 > > Neighbor ID Pri State Dead Time Address Interface > 1.1.1.1 0 DOWN/DROTHER -150.50.15.8 > Ethernet0/0 > 11.11.11.11 3 FULL/DR 00:00:32150.50.15.1 > Ethernet0/0 > > ..switch perspective: > > Neighbor ID Pri State Dead Time Address Interface > 55.55.55.55 2 INIT/DROTHER00:00:33150.50.15.5 Vlan15 > 11.11.11.11 3 INIT/DROTHER00:00:39150.50.15.1 Vlan15 > > Neighbor ID Pri State Dead Time Address Interface > 55.55.55.55 2 INIT/DROTHER00:00:37150.50.15.5 Vlan15 > 11.11.11.11 3 EXCHANGE/DR 00:00:36150.50.15.1 Vlan15 > > Neighbor ID Pri State Dead Time Address Interface > 55.55.55.55 2 EXCHANGE/BDR00:00:39150.50.15.5 Vlan15 > 11.11.11.11 3 EXCHANGE/DR 00:00:39150.50.15.1 Vlan15 > > So...it seems as though r1 and r5 are recognizing eachother's roles as dr > and bdr correctly. But they see the switch as down or init or exchange > DROTHER. > The switch however, sees itelf as DROTHER and r1/r5 as DROTHER or > init/exchange dr and bdr. Here is the output from "sh ip ospf int vlan15" on > the switch: > > Vlan15 is up, line protocol is up > Internet Address 150.50.15.8/24, Area 0 > Process ID 100, Router ID 1.1.1.1, Network Type BROADCAST, Cost: 1 > Transmit Delay is 1 sec, State DROTHER, Priority 0 > No designated router on this network > No backup designated router on this network > Timer intervals configured, Hello 10, Dead 40, Wait 40, Retransmit 5 > Hello due in 00:00:07 > Index 1/1, flood queue length 0 > Next 0x0(0)/0x0(0) > Last flood scan length is 0, maximum is 0 > Last flood scan time is 0 msec, maximum is 0 msec > Neighbor Count is 2, Adjacent neighbor count is 0 > Suppress hello for 0 neighbor(s) > > Then two seconds laterit changes... > > Vlan15 is up, line protocol is up > Internet Address 150.50.15.8/24, Area 0 > Process ID 100, Router ID 1.1.1.1, Network Type BROADCAST, Cost: 1 > Transmit Delay is 1 sec, State DROTHER, Priority 0 > Designated Router (ID) 11.11.11.11, Interface address 150.50.15.1 > Backup Designated router (ID) 55.55.55.55, Interface address 150.50.15.5 > Timer intervals configured, Hello 10, Dead 40, Wait 40, Retransmit 5 > Hello due in 00:00:05 > Index 1/1, flood queue length 0 > Next 0x0(0)/0x0(0) > Last flood scan length is 0, maximum is 0 > Last flood scan time is 0 msec, maximum is 0 msec > Neighbor Count is 2, Adjacent neighbor count is 0 > Suppress hello for 0 neighbor(s) > > > Any ideas? > > Thanks, > > > -- > Dain Deutschman > CCNP, CSS-1, MCP, CNA > Data Communications Manager > New Star Sales and Service, Inc. > > > > > > > -- > Dain Deutschman > CCNP, CSS-1, MCP, CNA > Data Communications Manager > New Star Sales and Service, Inc. > 800.261.0475 > [EMAIL PROTECTED] Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=72877&t=72874 -- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
OSPF Neighbor State is "Flapping" [7:72874]
Hi all, I have 3 devices on an ethernet segment where all ethernet interfaces are in the same vlan and ospf area 0 catalyst 3550priority 0rid 1.1.1.1 router5priority 2 rid 55.55.55.55BDR router1priority 3 rid 11.11.11.11DR The problem is that the switch keeps changing it's state. For example, from the router 1 perspective I get the following: ( sh ip ospf nei command ) Neighbor ID Pri State Dead Time Address Interface 1.1.1.1 0 DOWN/DROTHER -150.50.15.8 Ethernet0 55.55.55.55 2 FULL/BDR00:00:35150.50.15.5 Ethernet0 Neighbor ID Pri State Dead Time Address Interface 1.1.1.1 0 EXSTART/DROTHER 00:00:35150.50.15.8 Ethernet0 55.55.55.55 2 FULL/BDR00:00:38150.50.15.5 Ethernet0 and on and on, back and forth etc. router 5 perspective: Neighbor ID Pri State Dead Time Address Interface 1.1.1.1 0 EXSTART/DROTHER 00:00:38150.50.15.8 Ethernet0/0 11.11.11.11 3 FULL/DR 00:00:30150.50.15.1 Ethernet0/0 Neighbor ID Pri State Dead Time Address Interface 1.1.1.1 0 DOWN/DROTHER -150.50.15.8 Ethernet0/0 11.11.11.11 3 FULL/DR 00:00:32150.50.15.1 Ethernet0/0 ..switch perspective: Neighbor ID Pri State Dead Time Address Interface 55.55.55.55 2 INIT/DROTHER00:00:33150.50.15.5 Vlan15 11.11.11.11 3 INIT/DROTHER00:00:39150.50.15.1 Vlan15 Neighbor ID Pri State Dead Time Address Interface 55.55.55.55 2 INIT/DROTHER00:00:37150.50.15.5 Vlan15 11.11.11.11 3 EXCHANGE/DR 00:00:36150.50.15.1 Vlan15 Neighbor ID Pri State Dead Time Address Interface 55.55.55.55 2 EXCHANGE/BDR00:00:39150.50.15.5 Vlan15 11.11.11.11 3 EXCHANGE/DR 00:00:39150.50.15.1 Vlan15 So...it seems as though r1 and r5 are recognizing eachother's roles as dr and bdr correctly. But they see the switch as down or init or exchange DROTHER. The switch however, sees itelf as DROTHER and r1/r5 as DROTHER or init/exchange dr and bdr. Here is the output from "sh ip ospf int vlan15" on the switch: Vlan15 is up, line protocol is up Internet Address 150.50.15.8/24, Area 0 Process ID 100, Router ID 1.1.1.1, Network Type BROADCAST, Cost: 1 Transmit Delay is 1 sec, State DROTHER, Priority 0 No designated router on this network No backup designated router on this network Timer intervals configured, Hello 10, Dead 40, Wait 40, Retransmit 5 Hello due in 00:00:07 Index 1/1, flood queue length 0 Next 0x0(0)/0x0(0) Last flood scan length is 0, maximum is 0 Last flood scan time is 0 msec, maximum is 0 msec Neighbor Count is 2, Adjacent neighbor count is 0 Suppress hello for 0 neighbor(s) Then two seconds laterit changes... Vlan15 is up, line protocol is up Internet Address 150.50.15.8/24, Area 0 Process ID 100, Router ID 1.1.1.1, Network Type BROADCAST, Cost: 1 Transmit Delay is 1 sec, State DROTHER, Priority 0 Designated Router (ID) 11.11.11.11, Interface address 150.50.15.1 Backup Designated router (ID) 55.55.55.55, Interface address 150.50.15.5 Timer intervals configured, Hello 10, Dead 40, Wait 40, Retransmit 5 Hello due in 00:00:05 Index 1/1, flood queue length 0 Next 0x0(0)/0x0(0) Last flood scan length is 0, maximum is 0 Last flood scan time is 0 msec, maximum is 0 msec Neighbor Count is 2, Adjacent neighbor count is 0 Suppress hello for 0 neighbor(s) Any ideas? Thanks, -- Dain Deutschman CCNP, CSS-1, MCP, CNA Data Communications Manager New Star Sales and Service, Inc. -- Dain Deutschman CCNP, CSS-1, MCP, CNA Data Communications Manager New Star Sales and Service, Inc. 800.261.0475 [EMAIL PROTECTED] Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=72874&t=72874 -- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
OSPF over IPSec [7:72606]
Hey would like to run something by the ospf-geeks here. For a little bit I've been mulling over OSPF over an IPSec vpn tunnel. I know it can be done with routers and a GRE tunnel but what about the two actual end devices. Im currently tinkering with a PIX506 and a VPN Concentrator 3000. Both devices are OSPF aware. But, they don't seem to accept the concept of a vpn int being . an interface and really don't like to think about forming adjencies over that. I was just wondering if anyone had any ideas about this or if they've experianced ospf between two separate networks with just these devices on the edges. google turns up only GRE methods as well it seems as CCO. Thus it probably wont work but I figured Cisco might hack a way into it since after all they implemented ospf on the pix and concentrators. Thanks in advance for any ideas or thoughts. Dave Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=72606&t=72606 -- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
OSPF summarisation when to use? [7:72443]
Hello everybody, Assume there is no expilicit question to summarise a particular subnet, is it really necessary to include "area range" or "summary-address" command in specific routers? In the practice labs we see the final goal is to see all networks in all the routers. Even without the summarisation commands I am able to see the routes in the routing tables, but the solutions for the lab includes them as well. Can somebody point me to any guidelines of when to use. Also if there is a need to use, do we need to include "area range" command in all the ABR's in the network? I would appreciate any help in regard to this. Thanks, rajesh Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=72443&t=72443 -- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
Re[3]: OSPF max Router-LSA links [7:72024]
MTU is not an OSPF specific value. It would be rather strange if OSPF could adjust it dynamically to its liking. >"However, a vendor could choose to implement >something that, after getting no response to DD packets, would decrease the >packet size, How do you know you don't receive response due to packet size? > even sending a really tiny DD packet to continue negotiations >and receive DD from the other router, learning its MTU, then adjusting to >that. I *think* that would work." Sorry, which problem are you trying to solve here? If the MTUs are different on the two routers, then OSPF won't work as per the RFC. So the solution to the MTU mismatch problem IMHO is to make sure that the MTUs match. :) That (ie. that a router doesn't send a packet larger than what its neighbor can digest) sounds like a pretty basic requirement to me. Thanks, Zsombor At 11:34 AM 7/16/2003 +, Karen E Young wrote: >Sorry, accidentally sent the message before I finished my response and DNS >problems to boot... > > >If the Interface MTU field is larger than can be accepted without >fragmentation, then the packet is rejected. No acknowledgement is sent and >the behavior after that is dependent on the vendor. Usually it results in >neighbors getting stuck in Exchange or ExStart. In any case, the adjacency >will never form. Even if the MTU is smaller than the receiving interface the >exchange will fail. There's always one side that's larger and one that's >smaller, so one or the other of them will hang. > >This particular little hole is (unfortunately) due to a fault in OSPF itself >since no acknowledgement and situational handling was specified. > >As a CCIE friend of mine said, "However, a vendor could choose to implement >something that, after getting no response to DD packets, would decrease the >packet size, even sending a really tiny DD packet to continue negotiations >and receive DD from the other router, learning its MTU, then adjusting to >that. I *think* that would work." - I personally am not aware of any >vendors that implement anything like this but I could be wrong... > >Here's a good discussion of it: >http://www.riverstonenet.com/support/ospf/stuckexstart.htm#_Toc515894155 > >There's also a doc on Cisco about it: >http://www.cisco.com/en/US/tech/tk365/tk480/technologies_tech_note09186a0080093f0d.shtml > > >Here's an interesting thought... what if the router with the larger MTU >checked the MTU size of its neighbor, and dynamically adjusted? No guessing >involved, just match the smaller MTU and deal with the mismatch? The MTUs >could remain mismatched, which might cause frame fragmentation, but the OSPF >multicast traffic would be sent with matching MTU sizes. Basically after >being hung in ExStart for x seconds, it would send its first DD packet using >the same size received by the adjacent router. > >Just a thought... > > >HTH, >Karen > >"A rose by any other name is Cisco specific terminology..." > >*** REPLY SEPARATOR *** > >On 7/15/2003 at 7:29 AM Zsombor Papp wrote: > > >At 09:48 AM 7/15/2003 +, Karen E Young wrote: > >>KY: According to the RFC (page 99) "If the Interface MTU field in the > >>Database Description packet indicates an IP datagram size that is larger > >>than the router can accept on the receiving interface without > >fragmentation, > >>the Database Description packet is rejected." > >> > >>With this in mind the only time fragmentation should occur is when a > >virtual > >>link is used since the MTU of a virtual link is set to "0". > > > >The "Interface MTU" field describes the MTU of the sending interface, not > >the size of the DD packet. Just because the MTU of the sending router is > >smaller than or equal to that of the receiving router, it doesn't follow > >that fragmentation can't occur. Fragmentation occurs because the data (ie. > >the DD packet) to be sent is larger than the MTU of the *sending* router. > > > >Thanks, > > > >Zsombor Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=72395&t=72024 -- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
