Hi Hunt, A little cut and past here. For those reading along, it page 150 of version 1.
Router A (SJ) has only 1 physical connection which is to router B with an IGP next hop of 3.3.3.3. In this example, Halabi is describing the relationship between IGP and BGP next Hops. 2.2.2.0/24 is likely learned via the IGP and is reachable through via 3.3.3.3 which is the IGP next hop toward router C. The same goes for 1.1.1.0/24 which again is reachable via router C. Indeed, router A has only one path out of the network. In reality, the network looks like this: A----B----C---EBGP--D A,B, and C are fully meshed with IBGP. Hence, A will only ever have one IGP next hop since it has only one path toward other networks and must transit router B. Keep in mind that you are looking at the Routing Table, not the BGP table. These are quite different which is what Sam is trying to point out. What may be confusing you is that at first glance it looks like SF has a direct link to SJ (A to C) when in fact it doesn't, and the line in the diagram is really an arrow describing the logical IBGP connection. Hope that helps? Pete What I am confused it's the Routing Table of Router A, >Destination 192.212.1.0 /24 Next-hop 2.2.2.2 (Best Route inserted >from BGP table) - cool > >Destination 128.213.1.0 /24 Next-hop: 1.1.1.1 (Best Route inserted >from BGP table) - cool > >Destination 3.3.3.0 /24 Next-hop: Directly Connected via Serial >0 - cool > >Destination 2.2.2.0 /24 Next-hop: 3.3.3.3 (why?? isn't this >directly connected via IBGP, shouldn't it be directly connected?) > >Destination 1.1.1.0 /24 Next-hop: 3.3.3.3 (why?? shouldn't >this have 2 routes, one via 3.3.3.3, and the other via 2.2.2.2?) > > >Also, I thought that in such a scenario, one would want to make sure that >every BGP Next-Hop can be reached via either IGP or static routes - However, >Halabi says it's only needed for IBGP Next-hop, is it correct? > >Thanks, >Hunt Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=39714&t=39704 -------------------------------------------------- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
