Antonio.
Am I missing something (I want to make sure that I understand)
from the output below (single router running OSPF)
*Mar 1 00:01:07.091: OSPF: Interface FastEthernet0/0 going Up *(OSPF
interface comes up)*
*Mar 1 00:01:07.595: OSPF: Build router LSA for area 0, router ID
1.1.1.1, seq 0x80000001
*Mar 1 00:01:47.091: OSPF: end of Wait on interface FastEthernet0/0
*(Wait time ended)*
*Mar 1 00:01:47.091: OSPF: DR/BDR election on FastEthernet0/0
*(Election begins)*
Jason Maynard
------------------------------------------------------------------------
*From:* antonio tuozzo <[email protected]>
*To:* Jason Maynard <[email protected]>
*Cc:* David Betz <[email protected]>; [email protected]
*Sent:* Wed, November 24, 2010 2:15:12 PM
*Subject:* Re: [OSL | CCIE_RS] OSPF Election Time
Jason,
wait-timer = 40 sec = 4 x hello-timer (10 sec) = dead-interval on
broadcast (ospf) network type.
regard
antonio
>
> *Mar 1 00:01:07.091: OSPF: Interface FastEthernet0/0 going Up
>
> *Mar 1 00:01:07.595: OSPF: Build router LSA for area 0, router ID
> 1.1.1.1, seq 0x80000001
>
> *Mar 1 00:01:47.091: OSPF: end of Wait on interface FastEthernet0/0
>
> *Mar 1 00:01:47.091: OSPF: DR/BDR election on FastEthernet0/0
>
> Jason Maynard
>
>
> ------------------------------------------------------------------------
> *From:* David Betz <[email protected] <mailto:[email protected]>>
> *To:* [email protected] <mailto:[email protected]>
> *Sent:* Wed, November 24, 2010 9:53:35 AM
> *Subject:* Re: [OSL | CCIE_RS] OSPF Election Time
>
> The results are not in question, the timing is.
>
> My current theory is that election is always from the list of routers
> that a rouer has a two-way relationship with, thus the question has
> nothing to do with that and needs to be pushed back to: "How long does a
> router wait to collect two-way state neighbors before stop waiting and
> starting and election?"
>
> On Wed, Nov 24, 2010 at 5:14 AM, Jason Maynard
<[email protected] <mailto:[email protected]>
> <mailto:[email protected] <mailto:[email protected]>>>
wrote:
>
> I have not read all the comments but I thought I would try this
>
> I configured OSPF on a single router and ran “debug ip ospf adja”
>
> *Mar 1 00:01:07.091: OSPF: Interface FastEthernet0/0 going Up
>
> *Mar 1 00:01:07.595: OSPF: Build router LSA for area 0, router ID
> 1.1.1.1, seq 0x80000001
>
> *Mar 1 00:01:47.091: OSPF: end of Wait on interface FastEthernet0/0
>
> *Mar 1 00:01:47.091: OSPF: DR/BDR election on FastEthernet0/0
>
> *Mar 1 00:01:47.095: OSPF: Elect BDR 1.1.1.1
>
> *Mar 1 00:01:47.095: OSPF: Elect DR 1.1.1.1
>
> *Mar 1 00:01:47.099: OSPF: Elect BDR 0.0.0.0
>
> *Mar 1 00:01:47.099: OSPF: Elect DR 1.1.1.1
>
> *Mar 1 00:01:47.103: DR: 1.1.1.1 (Id)BDR: none
>
> *Mar 1 00:01:47.603: OSPF: No full nbrs to build Net Lsa for
> interface FastEthernet0/0
>
> Does this help?
>
> *From:*[email protected]
<mailto:[email protected]>
> <mailto:[email protected]
<mailto:[email protected]>>
> [mailto:[email protected]
<mailto:[email protected]>
> <mailto:[email protected]
<mailto:[email protected]>>] *On Behalf Of *David Betz
> *Sent:* November-24-10 3:37 AM
>
>
> *To:* [email protected]
<mailto:[email protected]> <mailto:[email protected]
<mailto:[email protected]>>
> *Subject:* Re: [OSL | CCIE_RS] OSPF Election Time
>
> That's my current theory. However, this really shouldn't be a
> theory, but scientific fact. I've looked at the RFC and still
> haven't found anything. Granted, it was a skim. I'd need to scan it
> to be sure of it's absence or presence.
>
> On Wed, Nov 24, 2010 at 2:10 AM, antonio <[email protected]
<mailto:[email protected]>
> <mailto:[email protected]
<mailto:[email protected]>>> wrote:
>
> Maybe you have to look at wait timer (by default equals to
> dead-interval)
>
> regards
> antonio
>
> Il 24/11/2010 03:43, David Betz ha scritto:
>
> Upon closer examination of the process, it seems that DR/BDR election is
> based on the candidates that are adjacencies (neighbor routers with
> priority > 0). Thus, the question is pushed backed a step: when does a
> router say "I've 2-way with n-number of routers on this broadcast
> segment, let's begin election."? Even then, multiple routers are doing
> this, but given that that is per-segment, the election results should be
> the same all over. So, that part shouldn't be an issue.
>
> On Tue, Nov 23, 2010 at 7:58 PM, David Betz <[email protected]
<mailto:[email protected]>
> <mailto:[email protected] <mailto:[email protected]>>
>
> <mailto:[email protected] <mailto:[email protected]> <mailto:[email protected]
<mailto:[email protected]>>>> wrote:
>
> Yes?
>
> I've done this experiment myriad times and looked over the data for
> a long time. What is your personal analysis of this data? Any
> conclusion? I've not been any to come up with with anything based
> on this data. If we are going to do our work off empirical data, we
> need to have a series of tests with a specified baseline. However,
> I'm more looking for an axiom from the [seemingly non-existent]
> documentation. Normally I'd look at the RFC, but do not any any
> reason to think that Cisco is following it at this point.
>
>
> On Tue, Nov 23, 2010 at 7:49 PM, Jason Maynard
>
> <[email protected] <mailto:[email protected]>
<mailto:[email protected] <mailto:[email protected]>>
> <mailto:[email protected] <mailto:[email protected]>
<mailto:[email protected] <mailto:[email protected]>>>>
> wrote:
>
> Have a look at the times below. Between two routers in a
> broadcast network
>
> *Mar 1 00:09:00.215: OSPF: end of Wait on interface FastEthernet0/0
>
> *Mar 1 00:09:00.215: OSPF: DR/BDR election on FastEthernet0/0
>
> *Mar 1 00:09:00.219: OSPF: Elect BDR 222.222.222.222
>
> *Mar 1 00:09:00.219: OSPF: Elect DR 222.222.222.222
>
> *Mar 1 00:09:00.223: OSPF: Elect BDR 0.0.0.0
>
> *Mar 1 00:09:00.223: OSPF: Elect DR 222.222.222.222
>
> *Mar 1 00:09:00.227: DR: 222.222.222.222 (Id) BDR: none
>
> *Mar 1 00:09:00.323: OSPF: 2 Way Communication to 1.1.1.1 on
> FastEthernet0/0, state 2WAY
>
> *Mar 1 00:09:00.323: OSPF: Neighbor change Event on interface
> FastEthernet0/0
>
> *Mar 1 00:09:00.327: OSPF: DR/BDR election on FastEthernet0/0
>
> *Mar 1 00:09:00.327: OSPF: Elect BDR 1.1.1.1
>
> *Mar 1 00:09:00.331: OSPF: Elect DR 222.222.222.222
>
> *Mar 1 00:09:00.331: DR: 222.222.222.222 (Id) BDR:
> 1.1.1.1 (Id)
>
> *Mar 1 00:09:00.331: OSPF: Send DBD to 1.1.1.1 on
> FastEthernet0/0 seq 0xA62 opt 0x52 flag 0x7 len 32
>
> *Mar 1 00:09:00.331: OSPF: Neighbor change Event on interface
> FastEthernet0/0
>
> *Mar 1 00:09:00.331: OSPF: DR/BDR election on FastEthernet0/0
>
> *Mar 1 00:09:00.331: OSPF: Elect BDR 1.1.1.1
>
> *Mar 1 00:09:00.331: OSPF: Elect DR 222.222.222.222
>
> *Mar 1 00:09:00.331: DR: 222.222.222.222 (Id) BDR:
> 1.1.1.1 (Id)
>
> *Mar 1 00:09:00.331: OSPF: Neighbor change Event on interface
> FastEthernet0/0
>
> *Mar 1 00:09:00.331: OSPF: DR/BDR election on FastEthernet0/0
>
> *Mar 1 00:09:00.331: OSPF: Elect BDR 1.1.1.1
>
> *Mar 1 00:09:00.331: OSPF: Elect DR 222.222.222.222
>
> *Mar 1 00:09:00.331: DR: 222.222.222.222 (Id) BDR:
> 1.1.1.1 (Id)
>
> *Mar 1 00:09:00.331: OSPF: Rcv DBD from 1.1.1.1 on
> FastEthernet0/0 seq 0x1376 opt 0x52 flag 0x7 len 32 mtu 1500
> state EXSTART
>
> *Mar 1 00:09:00.331: OSPF: First DBD and we are not SLAVE
>
> *Mar 1 00:09:00.379: OSPF: Rcv DBD from 1.1.1.1 on
> FastEthernet0/0 seq 0xA62 opt 0x52 flag 0x2 len 52 mtu 1500
> state EXSTART
>
> *Mar 1 00:09:00.383: OSPF: NBR Negotiation Done. We are the MASTER
>
> *Mar 1 00:09:00.387: OSPF: Send DBD to 1.1.1.1 on
> FastEthernet0/0 seq 0xA63 opt 0x52 flag 0x3 len 52
>
> *Mar 1 00:09:00.475: OSPF: Rcv DBD from 1.1.1.1 on
> FastEthernet0/0 seq 0xA63 opt 0x52 flag 0x0 len 32 mtu 1500
> state EXCHANGE
>
> *Mar 1 00:09:00.479: OSPF: Send DBD to 1.1.1.1 on
> FastEthernet0/0 seq 0xA64 opt 0x52 flag 0x1 len 32
>
> *Mar 1 00:09:00.483: OSPF: Send LS REQ to 1.1.1.1 length 12 LSA
> count 1
>
> *Mar 1 00:09:00.567: OSPF: Rcv LS REQ from 1.1.1.1 on
> FastEthernet0/0 length 36 LSA count 1
>
> *Mar 1 00:09:00.571: OSPF: Send UPD to 10.0.0.2 on
> FastEthernet0/0 length 40 LSA count 1
>
> *Mar 1 00:09:00.619: OSPF: Rcv DBD from 1.1.1.1 on
> FastEthernet0/0 seq 0xA64 opt 0x52 flag 0x0 len 32 mtu 1500
> state EXCHANGE
>
> *Mar 1 00:09:00.623: OSPF: Exchange Done with 1.1.1.1 on
> FastEthernet0/0
>
> *Mar 1 00:09:00.623: OSPF: Rcv LS UPD from 1.1.1.1 on
> FastEthernet0/0 length 64 LSA count 1
>
> *Mar 1 00:09:00.627: OSPF: Synchronized with 1.1.1.1 on
> FastEthernet0/0, state FULL
>
> *Mar 1 00:09:00.631: %OSPF-5-ADJCHG: Process 1, Nbr 1.1.1.1 on
> FastEthernet0/0 from LOADING to FULL, Loading Done
>
> *Mar 1 00:09:00.727: OSPF: Build network LSA for
> FastEthernet0/0, router ID 222.222.222.222
>
> *Mar 1 00:09:00.731: OSPF: Build network LSA for
> FastEthernet0/0, router ID 222.222.222.222
>
> *Mar 1 00:09:00.735: OSPF: Build router LSA for area 0, router
> ID 222.222.222.222, seq 0x80000004
>
> *Mar 1 00:09:03.439: OSPF: Rcv LS UPD from 1.1.1.1 on
> FastEthernet0/0 length 64 LSA count 1
>
> *From:*Jason Maynard [mailto:[email protected]
<mailto:[email protected]>
> <mailto:[email protected] <mailto:[email protected]>>
> <mailto:[email protected] <mailto:[email protected]>
<mailto:[email protected] <mailto:[email protected]>>>]
> *Sent:* November-23-10 8:25 PM
> *To:* 'David Betz'; '[email protected]
<mailto:[email protected]>
> <mailto:[email protected] <mailto:[email protected]>>
>
> <mailto:[email protected] <mailto:[email protected]>
> <mailto:[email protected]
<mailto:[email protected]>>>'
>
>
> *Subject:* RE: [OSL | CCIE_RS] OSPF Election Time
>
> Well that depends
>
> How long does the device take to boot up compared to other devices
>
> When is the device ready to participate in the OSPF election
> process (running more services on a device may take it longer to
> start participating compared to a router with less services)
>
> DR and BDR election is done via the Hello protocol –
>
> OSPF Network Type | Hello | DR/BDR |
> _________________________________________
> Broadcast | 10sec | Elects DR/BDR|
> _________________________________________
> NonBroadcast | 30sec | Elects DR/BDR|
> _________________________________________
> P2MP | 30sec | No DR/BDR |
> _________________________________________
> P2MP NonBroadcast | 30sec | No DR/BDR |
> _________________________________________
> P2P | 10sec | No DR/BDR |
>
> If you want to control which devices become the DR/BDR you can
> use “*ip ospf priority” and set all devices that you do not want
> to be DR/BDR to “0” ***
>
> Not sure exactly how may hellos before the DR/BDR election takes
> place, perhaps I will lab it up to see -
>
> HTH
>
> *From:*[email protected]
<mailto:[email protected]>
> <mailto:[email protected]
<mailto:[email protected]>>
> <mailto:[email protected]
<mailto:[email protected]>
> <mailto:[email protected]
<mailto:[email protected]>>>
> [mailto:[email protected]
<mailto:[email protected]>
> <mailto:[email protected]
<mailto:[email protected]>>
> <mailto:[email protected]
<mailto:[email protected]>
> <mailto:[email protected]
<mailto:[email protected]>>>] *On Behalf Of
> *David Betz
> *Sent:* November-23-10 7:32 PM
> *To:* [email protected]
<mailto:[email protected]> <mailto:[email protected]
<mailto:[email protected]>>
>
> <mailto:[email protected] <mailto:[email protected]>
> <mailto:[email protected]
<mailto:[email protected]>>>
>
>
> *Subject:* [OSL | CCIE_RS] OSPF Election Time
>
> I've not been able to figure this out nor can I find any
> documentation for this: how long does OSPF wait for others to
> cast their vote before doing the DR/BDR election?
>
> If R1, R2, and R3 come online with 10.1.1.X/25 (X=RX) ip
> addresses, and R1 and R2 see each other's messages, they will
> start an election. If R3 is there, it wins... if it's too late,
> R2 wins.
>
> When is "too late"?
>
>
>
>
> _______________________________________________
> For more information regarding industry leading CCIE Lab training,
please visit www.ipexpert.com <http://www.ipexpert.com>
<http://www.ipexpert.com>
>
> _______________________________________________
> For more information regarding industry leading CCIE Lab training,
please visit www.ipexpert.com <http://www.ipexpert.com>
<http://www.ipexpert.com>
>
>
>
>
> _______________________________________________
For more information regarding industry leading CCIE Lab training,
please visit www.ipexpert.com <http://www.ipexpert.com>
