From: Ned (ccie2004@excite.com)
Date: Thu Dec 23 2004 - 11:00:25 GMT-3
Hi All, I apologize but looking back at all my questions I guess I haven't been quite clear about what I am trying to find out. I do understand that if a route is redistributed on the same router that won't be chosen and also if the route is not in the routing table as an eigrp route than it won't be advertised to its neighbor. However, I am trying to find out something different. Apologize since I don't actually have a practical lab layout at the moment hence cannot try it out and provide the relevant tables. Hopefully the scenario below can convey what I am trying to find out. R1 and R6 are at different locations and are running EBGP with other routers not mentioned. They receive a prefix say 1.1.1.0/8 and that gets redistributed into EIGRP. EIGRP Admin distance is 170 on R1 and R6. The route in the routing table is showing up as a BGP learned route. R2,R5 are internal routers running only EIGRP. The route does get propogated to them and does show up in the EIGRP table b!
ut notice that its getting redistributed at 2 locations and is going to be learned via R1 and R6. Based on the metric 1 of those 2 routes is going to be chosen and installed in the Routing Table and will be sent to R3 and R4. What I am trying to find out is will the other(2nd) route get propogated via EIGRP to the other routers R3 and R4 which are the neighbors of R2 and R5 or will only the route that is chosen get advertised and will show ip int the EIGRP Topology table. Thanks for all your help.--- On Wed 12/22, Adebola Adegbonmire [ MTN - UBA ] < AdebolaA@mtnnigeria.net > wrote:From: Adebola Adegbonmire [ MTN - UBA ] [mailto: AdebolaA@mtnnigeria.net]To: bmcgahan@internetworkexpert.com, Vijaybhasker.Vuppala2@ge.com, ccie2004@excite.com, ccielab@groupstudy.comDate: Wed, 22 Dec 2004 08:46:17 +0100Subject: RE: EIGRP Topology TableBrian,Thanks for the very illustrative explanation. Truth is I knew in scenarioslike this BGP route or better AD will be installed, but I nev!
er went tocheck what happened to EIGRP routes FD in such cases!
. Tells
me I can knowthe result of a scenario and still fail to know the related events involvedin when that scenario plays out.Thanks ManBola-----Original Message-----From: Brian McGahan [mailto:bmcgahan@internetworkexpert.com]Sent: 21 December 2004 17:46To: Adebola Adegbonmire [ MTN - UBA ]; Vijaybhasker.Vuppala2@ge.com;ccie2004@excite.com; ccielab@groupstudy.comSubject: RE: EIGRP Topology TableBola,Take the below example. R1 and R2 run EIGRP and peer via EBGP.A prefix is first injected into EIGRP, then the same prefix is injectedinto BGP.Before route is injected into BGP:R1#show ip routeCodes: C - connected, S - static, R - RIP, M - mobile, B - BGPD - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter areaN1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2E1 - OSPF external type 1, E2 - OSPF external type 2i - IS-IS, L1 - IS-IS level-1, L2 - IS-IS level-2, ia - IS-ISinter area* - candidate default, U - per-user static route, o - ODRP - periodic downloaded static rou!
teGateway of last resort is not set2.0.0.0/32 is subnetted, 1 subnetsD 2.2.2.2 [90/409600] via 12.0.0.2, 00:00:04, Ethernet0/0C 12.0.0.0/8 is directly connected, Ethernet0/0R1#show ip eigrp topology IP-EIGRP Topology Table for AS(1)/ID(12.0.0.1)Codes: P - Passive, A - Active, U - Update, Q - Query, R - Reply,r - reply Status, s - sia StatusP 2.2.2.2/32, 1 successors, FD is 409600via 12.0.0.2 (409600/128256), Ethernet0/0P 12.0.0.0/8, 1 successors, FD is 281600via Connected, Ethernet0/0R1#In the above output we can see the prefix 2.2.2.2/32 is learned viaEIGRP and has a feasible distance of 409600. Now the prefix is injectedinto BGP on R2, and the administrative distance of 20 vs 90 will causethe BGP route to be installed on R1 instead of EIGRP.R1#show ip routeCodes: C - connected, S - static, R - RIP, M - mobile, B - BGPD - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter areaN1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2E1 - OSPF external type 1, E2 - O!
SPF external type 2i - IS-IS, L1 - IS-IS level-1, L2 - IS-IS l!
evel-2,
ia
- IS-ISinter area* - candidate default, U - per-user static route, o - ODRP - periodic downloaded static routeGateway of last resort is not set2.0.0.0/32 is subnetted, 1 subnetsB 2.2.2.2 [20/0] via 12.0.0.2, 00:00:18C 12.0.0.0/8 is directly connected, Ethernet0/0R1#show ip eigrp topologyIP-EIGRP Topology Table for AS(1)/ID(12.0.0.1)Codes: P - Passive, A - Active, U - Update, Q - Query, R - Reply,r - reply Status, s - sia StatusP 2.2.2.2/32, 0 successors, FD is Inaccessiblevia 12.0.0.2 (409600/128256), Ethernet0/0P 12.0.0.0/8, 1 successors, FD is 281600via Connected, Ethernet0/0Now 2.2.2.2/32 is installed via BGP. Since the route is not installedvia EIGRP the feasible distance is now Inaccessible (infinite metric).HTH,Brian McGahan, CCIE #8593bmcgahan@internetworkexpert.comInternetwork Expert, Inc.http://www.InternetworkExpert.comToll Free: 877-224-8987 x 705Outside US: 775-826-4344 x 70524/7 Support: http://forum.internetworkexpert.comLive Chat: http://www.internetworkexpe!
rt.com/chat/> -----Original Message-----> From: Adebola Adegbonmire [ MTN - UBA ][mailto:AdebolaA@mtnnigeria.net]> Sent: Tuesday, December 21, 2004 4:58 AM> To: Brian McGahan; Vijaybhasker.Vuppala2@ge.com; ccie2004@excite.com;> ccielab@groupstudy.com> Subject: RE: EIGRP Topology Table>> Brian,> You say ". Routes in the EIGRP topology that are not installed in> the IP routing table have a feasible distance of inaccessible"> But if I have a route for same route in the table via BGP it won't be> advertised to neighbour I understand, what I do not understand is your> referring to all routes not installed in table as having aninaccessible> feasible distance is that so?>> Bola>>> -----Original Message-----> From: nobody@groupstudy.com [mailto:nobody@groupstudy.com]On Behalf Of> Brian> McGahan> Sent: 21 December 2004 04:54> To: Vijaybhasker.Vuppala2@ge.com; ccie2004@excite.com;> ccielab@groupstudy.com> S!
ubject: RE: EIGRP Topology Table>> This is correct. Rout!
es in th
e EIGRP topology that are not installedin> the IP routing table have a feasible distance of inaccessible> (infinite). This means, like a metric of 16 in RIP, that the route is> not used nor is it advertised onto other neighbors.>> Brian McGahan, CCIE #8593> bmcgahan@internetworkexpert.com>> Internetwork Expert, Inc.> http://www.InternetworkExpert.com>; Toll Free: 877-224-8987 x 705> Outside US: 775-826-4344 x 705> 24/7 Support: http://forum.internetworkexpert.com>; Live Chat: http://www.internetworkexpert.com/chat/>>>; > -----Original Message-----> > From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf> Of> > Vijaybhasker.Vuppala2@ge.com> > Sent: Monday, December 20, 2004 9:11 PM> > To: ccie2004@excite.com; ccielab@groupstudy.com> > Subject: RE: EIGRP Topology Table> >> > If a route to a subnet is available in the topology table but is not> > installed in routin!
g table for some reason (Eg: router has another> route> > to> > the same subnet with better admin distance like static route) it> doesn't> > propogate/advertise the EIGRP route to it's neighbour...> >> > Others group members....correct me if i'm wrong....> >> > -----Original Message-----> > From: Ned [mailto:ccie2004@excite.com]> > Sent: Monday, December 20, 2004 8:44 PM> > To: ccielab@groupstudy.com> > Subject: EIGRP Topology Table> >> >> > Hi, was just reading up on some eigrp and had a doubt which I amsure> > most> > of you know the answers too. When viewing the show ip eigrp topology> table> > on a router what routes will I see in the table?Will all routes thatI> see> > in a neighboring routers topology table show up in this routers> topology> > table even though the neighbor might not be using that route in the> > routing> > table!
.So I think my question goes back to where if the route is not!
> bei
ng
> > used by a router will it advertise that route to its neighbors?Thnks> for> > your help.> >> > _______________________________________________> > Join Excite! - http://www.excite.com>; > The most personalized portal on the Web!> >> >>_______________________________________________________________________> > Subscription information may be found at:> > http://www.groupstudy.com/list/CCIELab.html>; >> >>_______________________________________________________________________> > Subscription information may be found at:> > http://www.groupstudy.com/list/CCIELab.html>>_______________________________________________________________________>; Subscription information may be found at:> http://www.groupstudy.com/list/CCIELab.html>; NOTE: This e-mail message is subject to the MTN Nigeria disclaimer see> http://www.mtnonline.com/contact/disclaimer.aspNOTE: This e-mail message !
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