Re: ISIS and OSPF redistribution Weirdness - Update
Craig, Firstly, all protocols that allow for redistribution have default metrics to which external routes are identified. For ex... 1 - OSPF assigns the metric of 20 as you pointed out earlier and also identifies external routes using the default External type 2(E2) when no specific type is used. 2 - EIGRP of course stands out above most as the protocol has a totally separate AD of 170 assigned to external routes. Although there are default values given to the BW, DLY,REL,LOAD,and MTU variables the AD of 170 would automatically tag these routes as external to the routing domain. 3 - ISIS being much the same as OSPF it too defaults to the level-2 on any routes redistributed. Of course what must also be noted is that in basic ISIS configuration cisco defaults to L!/L2 so currently in this scenario all the ISIS routers are L1/L2. Before migrating to various level types I was hoping to figure out what that specific router represents. Off to see if this happens in frame relay Also, why do you believe there's no need to summarize..? In large networks this would be "good practice" smaller routing tables which means I should be able to do it here. Trying to tie up this part of my studying on this topic soon... Thoughts.. Nigel.. - Original Message - From: Thounda Craig, Jr. <[EMAIL PROTECTED]> To: 'Nigel Taylor' <[EMAIL PROTECTED]> Sent: Wednesday, January 10, 2001 9:41 AM Subject: RE: ISIS and OSPF redistribution Weirdness - Update > Look at Jeff Doyle's book "Routing TCP/IP" (p. 730-732) > It explains how to redistribute IS-IS into other protocols. > > Note: You need to specific "level" with the "summary" and "redistribute" > command. > No need to summarize as the book will probably provide more info. > > I think this explains your question. > > -Original Message- > From: Nigel Taylor [mailto:[EMAIL PROTECTED]] > Sent: Wednesday, January 10, 2001 7:50 AM > To: [EMAIL PROTECTED] > Subject: Re: ISIS and OSPF redistribution Weirdness - Update > > Craig, > If you look again at the example I do have a metric defined for > the ISIS routes being redistributed into the OSPF domain. The problem that > I'm looking at is the advertisement of the summarized router into the ISIS > domain that shows up in the ASBR as; > > i su 172.16.0.0/16 [115/30] via 0.0.0.0, Null0 > > Thoughts > > Nigel.. > > > > ----- Original Message - > From: Thounda Craig, Jr. <[EMAIL PROTECTED]> > To: 'Nigel Taylor' <[EMAIL PROTECTED]> > Sent: Wednesday, January 10, 2001 7:39 AM > Subject: RE: ISIS and OSPF redistribution Weirdness - Update > > > > If I understand your question correctly, you are getting a metric of 20 > b/c > > that's the default for OSPF when the administrator does not assign one > > during the redistribution process. > > > > brgds, > > Craig > > > > -Original Message- > > From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]] On Behalf Of > > Nigel Taylor > > Sent: Wednesday, January 10, 2001 7:26 AM > > To: Cisco Group Study; CCIE_Lab Group Study > > Subject: ISIS and OSPF redistribution Weirdness - Update > > > > Hi All, > > I was working with redistribution between OSPF and IS-IS domains and got = > > this=20 > > route in the table and wondered if anyone have seen this and could = > > explain. I'm=20 > > using the example from Slattery/Burton pg. 297 (ex. #10). I've replace = > > the EIGRP=20 > > process with Isis and in summarizing the ospf routes into isis I get the = > > following=20 > > route in the RIB of the router doing the redistribution/summarization... > > > > Relevant configs...on the router performing redistribution. > > > > ! > > router ospf 200 > > log-adjacency-changes > > summary-address 182.18.0.0 255.255.0.0 > > redistribute isis metric 300 metric-type 1 subnets > > network 172.16.253.4 0.0.0.3 area 0 > > network 172.16.254.0 0.0.0.255 area 0 > > distribute-list 4 out > > ! > > router isis=20 > > summary-address 172.16.0.0 255.255.0.0 =20 > > redistribute ospf 200 =20 > > net 48.0001...0001.00 > > > > > > > > r2_01#sh ip ro > > 172.16.0.0/16 is variably subnetted, 9 subnets, 5 masks > > O IA 172.16.2.252/30 [110/139] via 172.16.254.1, 02:35:35, Ethernet0 > > C 172.16.254.0/24 is directly connected, Ethernet0 > > C 172.16.253.4/30 is directly connected, Loopback0 > > O 172.16.253.9/32 [110/11] via 172.16.254.1, 02:35:35, Ethernet0 > > O IA 172.16.2.32/27 [110/144] via 172.16.254.1, 0
RE: ISIS and OSPF redistribution Weirdness - Update
Nigel, question #1, can you ping from domain to domain? Particularly from IS-IS to OSPF? Question #2, isn't the creation of the route to null 0 established behaviour on Cisco routers when summarization is invoked, no matter what the protocol involved? I was planning on doing a couple of the Slattery exercises later this week. I like your idea of substituting IS-IS in there. When I have completed the exercises, I will try what you did and report back. I do wish Mentor allowed the saving of multiple sets of configurations from their pods. I use the 6 router open lab for the complex scenarios, but can only save a singe set of configs. So I have to choose wisely. Chuck -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]] On Behalf Of Nigel Taylor Sent: Wednesday, January 10, 2001 4:26 AM To: Cisco Group Study; CCIE_Lab Group Study Subject:ISIS and OSPF redistribution Weirdness - Update Hi All, I was working with redistribution between OSPF and IS-IS domains and got = this=20 route in the table and wondered if anyone have seen this and could = explain. I'm=20 using the example from Slattery/Burton pg. 297 (ex. #10). I've replace = the EIGRP=20 process with Isis and in summarizing the ospf routes into isis I get the = following=20 route in the RIB of the router doing the redistribution/summarization... Relevant configs...on the router performing redistribution. ! router ospf 200 log-adjacency-changes summary-address 182.18.0.0 255.255.0.0 redistribute isis metric 300 metric-type 1 subnets network 172.16.253.4 0.0.0.3 area 0 network 172.16.254.0 0.0.0.255 area 0 distribute-list 4 out ! router isis=20 summary-address 172.16.0.0 255.255.0.0 =20 redistribute ospf 200 =20 net 48.0001...0001.00 r2_01#sh ip ro 172.16.0.0/16 is variably subnetted, 9 subnets, 5 masks O IA 172.16.2.252/30 [110/139] via 172.16.254.1, 02:35:35, Ethernet0 C 172.16.254.0/24 is directly connected, Ethernet0 C 172.16.253.4/30 is directly connected, Loopback0 O 172.16.253.9/32 [110/11] via 172.16.254.1, 02:35:35, Ethernet0 O IA 172.16.2.32/27 [110/144] via 172.16.254.1, 02:35:35, Ethernet0 O IA 172.16.2.4/30 [110/202] via 172.16.254.1, 02:35:35, Ethernet0 i su 172.16.0.0/16 [115/30] via 0.0.0.0, Null0 O IA 172.16.1.0/24 [110/74] via 172.16.254.1, 02:35:36, Ethernet0 O IA 172.16.2.0/24 [110/138] via 172.16.254.1, 02:35:36, Ethernet0 182.18.0.0/16 is variably subnetted, 6 subnets, 2 masks i L1 182.18.4.0/24 [115/20] via 182.18.1.1, Serial1 i L1 182.18.5.0/24 [115/20] via 182.18.2.2, Serial0 O 182.18.0.0/16 is a summary, 02:21:02, Null0 C 182.18.1.0/24 is directly connected, Serial1 C 182.18.2.0/24 is directly connected, Serial0 i L1 182.18.3.0/24 [115/20] via 182.18.2.2, Serial0 [115/20] via 182.18.1.1, Serial1 Connected ISIS router which sees the summarized route... r4_02c#sh ip ro Codes: C - connected, S - static, I - IGRP, R - RIP, M - mobile, B - BGP D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area=20 N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2 E1 - OSPF external type 1, E2 - OSPF external type 2, E - EGP i - IS-IS, L1 - IS-IS level-1, L2 - IS-IS level-2, * - candidate default U - per-user static route, o - ODR Gateway of last resort is not set i L2 172.16.0.0/16 [115/40] via 182.18.1.2, Serial0 182.18.0.0/16 is variably subnetted, 6 subnets, 2 masks C 182.18.4.0/24 is directly connected, TokenRing0 i L1 182.18.5.0/24 [115/20] via 182.18.3.1, Serial1 i L2 182.18.0.0/16 [115/40] via 182.18.1.2, Serial0 C 182.18.1.0/24 is directly connected, Serial0 i L1 182.18.2.0/24 [115/20] via 182.18.3.1, Serial1 [115/20] via 182.18.1.2, Serial0 C 182.18.3.0/24 is directly connected, Serial i su 172.16.0.0/16 [115/30] via 0.0.0.0, Null0 I'm thinking that this route is being suppressed but on the connected = isis=20 routers within it's routing domain I get this summarized route to the = ospf networks.=20 What does the "su" represent in the table. And if this is being = suppressed why is=20 it showing up in the RIB at all. I know BGP allows the suppression of = routes and=20 was unaware that IGP's did this as well. Is this only specific to = isis..? Has anyone encountered this and knows what it means. Off to check the = RFC's. =20 Nigel.. ___ To unsubscribe from the CCIELAB list, send a message to [EMAIL PROTECTED] with the body containing: unsubscribe ccielab _ FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
Re: ISIS and OSPF redistribution Weirdness - Update
Chuck, Null 0 creation is not automatic for OSPF, you must manually enter it. Question #2, isn't the creation of the route to null 0 established behaviour > on Cisco routers when summarization is invoked, no matter what the protocol > involved? - Original Message - From: "Chuck Larrieu" <[EMAIL PROTECTED]> To: "Nigel Taylor" <[EMAIL PROTECTED]>; "Cisco Group Study" <[EMAIL PROTECTED]>; "CCIE_Lab Group Study" <[EMAIL PROTECTED]> Sent: Wednesday, January 10, 2001 12:28 PM Subject: RE: ISIS and OSPF redistribution Weirdness - Update > Nigel, question #1, can you ping from domain to domain? Particularly from > IS-IS to OSPF? > > Question #2, isn't the creation of the route to null 0 established behaviour > on Cisco routers when summarization is invoked, no matter what the protocol > involved? > > I was planning on doing a couple of the Slattery exercises later this week. > I like your idea of substituting IS-IS in there. When I have completed the > exercises, I will try what you did and report back. I do wish Mentor allowed > the saving of multiple sets of configurations from their pods. I use the 6 > router open lab for the complex scenarios, but can only save a singe set of > configs. So I have to choose wisely. > > Chuck > > -Original Message- > From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]] On Behalf Of > Nigel Taylor > Sent: Wednesday, January 10, 2001 4:26 AM > To: Cisco Group Study; CCIE_Lab Group Study > Subject: ISIS and OSPF redistribution Weirdness - Update > > Hi All, > I was working with redistribution between OSPF and IS-IS domains and got = > this=20 > route in the table and wondered if anyone have seen this and could = > explain. I'm=20 > using the example from Slattery/Burton pg. 297 (ex. #10). I've replace = > the EIGRP=20 > process with Isis and in summarizing the ospf routes into isis I get the = > following=20 > route in the RIB of the router doing the redistribution/summarization... > > Relevant configs...on the router performing redistribution. > > ! > router ospf 200 > log-adjacency-changes > summary-address 182.18.0.0 255.255.0.0 > redistribute isis metric 300 metric-type 1 subnets > network 172.16.253.4 0.0.0.3 area 0 > network 172.16.254.0 0.0.0.255 area 0 > distribute-list 4 out > ! > router isis=20 > summary-address 172.16.0.0 255.255.0.0 =20 > redistribute ospf 200 =20 > net 48.0001...0001.00 > > > > r2_01#sh ip ro > 172.16.0.0/16 is variably subnetted, 9 subnets, 5 masks > O IA 172.16.2.252/30 [110/139] via 172.16.254.1, 02:35:35, Ethernet0 > C 172.16.254.0/24 is directly connected, Ethernet0 > C 172.16.253.4/30 is directly connected, Loopback0 > O 172.16.253.9/32 [110/11] via 172.16.254.1, 02:35:35, Ethernet0 > O IA 172.16.2.32/27 [110/144] via 172.16.254.1, 02:35:35, Ethernet0 > O IA 172.16.2.4/30 [110/202] via 172.16.254.1, 02:35:35, Ethernet0 > i su 172.16.0.0/16 [115/30] via 0.0.0.0, Null0 > O IA 172.16.1.0/24 [110/74] via 172.16.254.1, 02:35:36, Ethernet0 > O IA 172.16.2.0/24 [110/138] via 172.16.254.1, 02:35:36, Ethernet0 > 182.18.0.0/16 is variably subnetted, 6 subnets, 2 masks > i L1 182.18.4.0/24 [115/20] via 182.18.1.1, Serial1 > i L1 182.18.5.0/24 [115/20] via 182.18.2.2, Serial0 > O 182.18.0.0/16 is a summary, 02:21:02, Null0 > C 182.18.1.0/24 is directly connected, Serial1 > C 182.18.2.0/24 is directly connected, Serial0 > i L1 182.18.3.0/24 [115/20] via 182.18.2.2, Serial0 > [115/20] via 182.18.1.1, Serial1 > > > Connected ISIS router which sees the summarized route... > > r4_02c#sh ip ro > Codes: C - connected, S - static, I - IGRP, R - RIP, M - mobile, B - BGP > D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area=20 > N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2 > E1 - OSPF external type 1, E2 - OSPF external type 2, E - EGP > i - IS-IS, L1 - IS-IS level-1, L2 - IS-IS level-2, * - candidate default > U - per-user static route, o - ODR > > Gateway of last resort is not set > > i L2 172.16.0.0/16 [115/40] via 182.18.1.2, Serial0 > 182.18.0.0/16 is variably subnetted, 6 subnets, 2 masks > C 182.18.4.0/24 is directly connected, TokenRing0 > i L1 182.18.5.0/24 [115/20] via 182.18.3.1, Serial1 > i L2 182.18.0.0/16 [115/40] via 182.18.1.2, Serial0 > C 182.18.1.0/24 is directly connected, Serial0 > i L1 182.18.2.0/24 [115/20] via 182.18.3.1, Serial1 >[115/20] via 182.18.1.2, Serial0 > C 182.18.3.0/24 is directly connected, Serial > > > > i su 172.16.0.0/16 [115/30] via 0.0.0.0, Null0 > > I'm thinking that this route is being suppressed but on the connected = > isis=20 >
RE: ISIS and OSPF redistribution Weirdness - Update
Hey Chuck, See Inline >From: "Chuck Larrieu" <[EMAIL PROTECTED]> >To: "Nigel Taylor" <[EMAIL PROTECTED]>,"Cisco Group Study" ><[EMAIL PROTECTED]>, "CCIE_Lab Group Study" ><[EMAIL PROTECTED]> >Subject: RE: ISIS and OSPF redistribution Weirdness - Update >Date: Wed, 10 Jan 2001 09:28:46 -0800 > >Nigel, question #1, can you ping from domain to domain? Particularly from >IS-IS to OSPF? Yep, I can ping from both domains no problem. > >Question #2, isn't the creation of the route to null 0 established >behaviour >on Cisco routers when summarization is invoked, no matter what the protocol >involved? Yes, the creation of the null 0 route is expected behaviour but what I'm trying to figure out is what does the tag on this specific route mean. i.eThe "su" to be specific. i su 172.16.0.0/16 [115/30] via 0.0.0.0, Null0 > >I was planning on doing a couple of the Slattery exercises later this week. >I like your idea of substituting IS-IS in there. When I have completed the >exercises, I will try what you did and report back. I do wish Mentor >allowed >the saving of multiple sets of configurations from their pods. I use the 6 >router open lab for the complex scenarios, but can only save a singe set of >configs. So I have to choose wisely. Everything works fine and all the routers in the ISIS domain recieve the summarized route it's just that I've never seen this happen in any other summarized route and was hoping to find out what caused it. Nigel >Chuck > >-Original Message- >From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]] On Behalf Of >Nigel Taylor >Sent: Wednesday, January 10, 2001 4:26 AM >To:Cisco Group Study; CCIE_Lab Group Study >Subject: ISIS and OSPF redistribution Weirdness - Update > >Hi All, >I was working with redistribution between OSPF and IS-IS domains and got = >this=20 >route in the table and wondered if anyone have seen this and could = >explain. I'm=20 >using the example from Slattery/Burton pg. 297 (ex. #10). I've replace = >the EIGRP=20 >process with Isis and in summarizing the ospf routes into isis I get the = >following=20 >route in the RIB of the router doing the redistribution/summarization... > >Relevant configs...on the router performing redistribution. > >! >router ospf 200 > log-adjacency-changes > summary-address 182.18.0.0 255.255.0.0 > redistribute isis metric 300 metric-type 1 subnets > network 172.16.253.4 0.0.0.3 area 0 > network 172.16.254.0 0.0.0.255 area 0 > distribute-list 4 out >! >router isis=20 > summary-address 172.16.0.0 255.255.0.0 =20 > redistribute ospf 200 =20 > net 48.0001...0001.00 > > > >r2_01#sh ip ro >172.16.0.0/16 is variably subnetted, 9 subnets, 5 masks >O IA 172.16.2.252/30 [110/139] via 172.16.254.1, 02:35:35, Ethernet0 >C 172.16.254.0/24 is directly connected, Ethernet0 >C 172.16.253.4/30 is directly connected, Loopback0 >O 172.16.253.9/32 [110/11] via 172.16.254.1, 02:35:35, Ethernet0 >O IA 172.16.2.32/27 [110/144] via 172.16.254.1, 02:35:35, Ethernet0 >O IA 172.16.2.4/30 [110/202] via 172.16.254.1, 02:35:35, Ethernet0 >i su 172.16.0.0/16 [115/30] via 0.0.0.0, Null0 >O IA 172.16.1.0/24 [110/74] via 172.16.254.1, 02:35:36, Ethernet0 >O IA 172.16.2.0/24 [110/138] via 172.16.254.1, 02:35:36, Ethernet0 >182.18.0.0/16 is variably subnetted, 6 subnets, 2 masks >i L1 182.18.4.0/24 [115/20] via 182.18.1.1, Serial1 >i L1 182.18.5.0/24 [115/20] via 182.18.2.2, Serial0 >O 182.18.0.0/16 is a summary, 02:21:02, Null0 >C 182.18.1.0/24 is directly connected, Serial1 >C 182.18.2.0/24 is directly connected, Serial0 >i L1 182.18.3.0/24 [115/20] via 182.18.2.2, Serial0 >[115/20] via 182.18.1.1, Serial1 > > >Connected ISIS router which sees the summarized route... > >r4_02c#sh ip ro >Codes: C - connected, S - static, I - IGRP, R - RIP, M - mobile, B - BGP >D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area=20 >N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2 >E1 - OSPF external type 1, E2 - OSPF external type 2, E - EGP >i - IS-IS, L1 - IS-IS level-1, L2 - IS-IS level-2, * - candidate default >U - per-user static route, o - ODR > >Gateway of last resort is not set > >i L2 172.16.0.0/16 [115/40] via 182.18.1.2, Serial0 > 182.18.0.0/16 is variably subnetted, 6 subnets, 2 masks >C 182.18.4.0/24 is directly connected, TokenRing0 >i L1 182.18.5.0/24 [115/20] via 182.18.3.1, Serial1 >i L2 182.18.0.0/16 [115/40] via 182.18.1.2, Serial0 >C 182.18.1.0/24 is directly connected, Serial0 >i L1 182.18.2.0/24 [115/20] via 182.18.3.1, Serial1 >
RE: ISIS and OSPF redistribution Weirdness - Update
i su 172.16.0.0/16 [115/30] via 0.0.0.0, Null0 Nigel, the other interesting thing about this route as I see it, is the last part of the line. The source is IS-IS, the su maybe we are guessing it is short for summary, but we don't know, and then we get to that route via 0.0.0.0 comma null0 Without looking at some router output, this looks a bit unusual as well. Want to call it one of those Cisco things? I did not see a route to 0.0.0.0 in either of your show ip route outputs. IS-IS level one routers, if my recollection is correct, are analogous to OSPF stub area. In fact, it seems to me that on one of tests, I actually saw a 0.0.0.0 route generated by a level 1 router. did you spot anything like this on any of your level 1's? I will certainly keep an eye out when I set up next time. Chuck _ FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
RE: ISIS and OSPF redistribution Weirdness - Update
This is a generated summary route for the class which as a summary is routed via null0. Remember a route only gets entered into the table or advertised if it exists so all summaries get routed to null0 which is the bit bucket interface and that way the 'route' is active. If this is a problem turn off classful routing and/or remove auto-summary. This behaviour also occurs in EIGRP and you have to turn off auto-aummary or you'll advertise a summary route to other networks not part of the summary range. You can also see the same behaviour by manually configuring summarization such as 'ip summary-address eigrp 1 1.1.1.0 255.255.252.0' then look at the summary route as it it appears in the routing table. Darren On Wed, 10 Jan 2001, Chuck Larrieu wrote: > i su 172.16.0.0/16 [115/30] via 0.0.0.0, Null0 > > > Nigel, the other interesting thing about this route as I see it, is the last > part of the line. > > The source is IS-IS, the su maybe we are guessing it is short for summary, > but we don't know, and then we get to that route via 0.0.0.0 comma null0 > Without looking at some router output, this looks a bit unusual as well. > Want to call it one of those Cisco things? > > I did not see a route to 0.0.0.0 in either of your show ip route outputs. > IS-IS level one routers, if my recollection is correct, are analogous to > OSPF stub area. In fact, it seems to me that on one of tests, I actually saw > a 0.0.0.0 route generated by a level 1 router. did you spot anything like > this on any of your level 1's? > > I will certainly keep an eye out when I set up next time. > > > Chuck > > _ > FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html > Report misconduct and Nondisclosure violations to [EMAIL PROTECTED] > _ FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
RE: ISIS and OSPF redistribution Weirdness - Update
I'm making changes to the isis router types as we speak to see if it changes anything. i looked into the possibility of this being a possible summary route and can't say for sure. In the same route table there is a summary for for the OSPF domain . O 182.18.0.0/16 is a summary, 10:01:24, Null0 comapred to the isis summary route of i su172.16.0.0/16 [115/0] via 0.0.0.0, Null0 this could be one of those cisco things. The funny thing is this keeps comming back even after I make changes. You also made a good point in that the 0.0.0.0 defined by the summary route is strange as well. As far as the 0.0.0.0 generated by the L1 router in doinf some checking in Doyle's Routing TCP/IP pg. 656-660, he mentions that there's are two ways for the L1 router to get the default route 1. through the use of the CLNS function which knows how to interpret the ATT bit. 2. the use of a ststic default route to 0.0.0.0 and he command "default-information originate" on a L2 conneted device. Nigel. >From: "Chuck Larrieu" <[EMAIL PROTECTED]> >Reply-To: "Chuck Larrieu" <[EMAIL PROTECTED]> >To: "Nigel Taylor" <[EMAIL PROTECTED]>, <[EMAIL PROTECTED]>, > <[EMAIL PROTECTED]> >Subject: RE: ISIS and OSPF redistribution Weirdness - Update >Date: Wed, 10 Jan 2001 16:44:24 -0800 > >i su 172.16.0.0/16 [115/30] via 0.0.0.0, Null0 > > >Nigel, the other interesting thing about this route as I see it, is the >last >part of the line. > >The source is IS-IS, the su maybe we are guessing it is short for summary, >but we don't know, and then we get to that route via 0.0.0.0 comma null0 >Without looking at some router output, this looks a bit unusual as well. >Want to call it one of those Cisco things? > >I did not see a route to 0.0.0.0 in either of your show ip route outputs. >IS-IS level one routers, if my recollection is correct, are analogous to >OSPF stub area. In fact, it seems to me that on one of tests, I actually >saw >a 0.0.0.0 route generated by a level 1 router. did you spot anything like >this on any of your level 1's? > >I will certainly keep an eye out when I set up next time. > > >Chuck > >___ >To unsubscribe from the CCIELAB list, send a message to >[EMAIL PROTECTED] with the body containing: >unsubscribe ccielab _ Get your FREE download of MSN Explorer at http://explorer.msn.com _ FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
RE: ISIS and OSPF redistribution Weirdness - Update
Darren, I understand what a summary route is and what it does, as well the configuration commands required however, the question still stands as to what is the meaning of the route that is in the table. i su 172.16.0.0/16 [115/30] via 0.0.0.0, Null0 comapred to the average summary route... O 182.18.0.0/16 is a summary, 10:01:24, Null0 Do you not see the difference...! Now this is working as far as I can tell because all the routers in the ISIS domain get the summarized route to the OSPF domain and can effectively ping and trace to all point therein. Could this just simply be the way ISIS defines a summary route..? Not a whole lot of examples to reference...:-) Nigel.. It's seems quite logical that I move on to the next problem... Noted by some of our newly minted CCIE's. Pratice makes perfect...:-) >From: [EMAIL PROTECTED] >Reply-To: [EMAIL PROTECTED] >To: Chuck Larrieu <[EMAIL PROTECTED]> >CC: Nigel Taylor <[EMAIL PROTECTED]>, [EMAIL PROTECTED], >[EMAIL PROTECTED] >Subject: RE: ISIS and OSPF redistribution Weirdness - Update >Date: Thu, 11 Jan 2001 11:29:07 +1100 (EST) > >This is a generated summary route for the class which as a summary is >routed via null0. > >Remember a route only gets entered into the table or advertised if it >exists so all summaries get routed to null0 which is the bit bucket >interface and that way the 'route' is active. > >If this is a problem turn off classful routing and/or remove auto-summary. > >This behaviour also occurs in EIGRP and you have to turn off auto-aummary >or you'll advertise a summary route to other networks not part of the >summary range. > >You can also see the same behaviour by manually configuring summarization >such as 'ip summary-address eigrp 1 1.1.1.0 255.255.252.0' >then look at the summary route as it it appears in the routing table. > >Darren > >On Wed, 10 Jan 2001, Chuck Larrieu wrote: > > > i su 172.16.0.0/16 [115/30] via 0.0.0.0, Null0 > > > > > > Nigel, the other interesting thing about this route as I see it, is the >last > > part of the line. > > > > The source is IS-IS, the su maybe we are guessing it is short for >summary, > > but we don't know, and then we get to that route via 0.0.0.0 comma null0 > > Without looking at some router output, this looks a bit unusual as well. > > Want to call it one of those Cisco things? > > > > I did not see a route to 0.0.0.0 in either of your show ip route >outputs. > > IS-IS level one routers, if my recollection is correct, are analogous to > > OSPF stub area. In fact, it seems to me that on one of tests, I actually >saw > > a 0.0.0.0 route generated by a level 1 router. did you spot anything >like > > this on any of your level 1's? > > > > I will certainly keep an eye out when I set up next time. > > > > > > Chuck > > > > _ > > FAQ, list archives, and subscription info: >http://www.groupstudy.com/list/cisco.html > > Report misconduct and Nondisclosure violations to [EMAIL PROTECTED] > > > >_ >FAQ, list archives, and subscription info: >http://www.groupstudy.com/list/cisco.html >Report misconduct and Nondisclosure violations to [EMAIL PROTECTED] _ Get your FREE download of MSN Explorer at http://explorer.msn.com _ FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
