GroupStudy.com GroupStudy.com - A virtual community of network engineers
 Home  BookStore  StudyNotes  Links  Archives  StudyRooms  HelpWanted  Discounts  Login
IBGP neighbors over F/R posted 08/05/2003
[Chronological Index] [Thread Index] [Top] [Date Prev][Date Next] [Thread Prev][Thread Next]


Hi,

BGP wouldn't form peers between 2 spokes on a F/R hub and spoke topology.

Here are the details:

       R3---------R2----------R1
     spoke       hub         spoke


All routers are running OSPF and the F/R is in subnet 172.16.100.0/24 and the
f/r interfaces were all left at their default ospf network types -
non-broadcast.  The neighbor command was configured on R2 to allow it to form
ospf adjacencies with R1 and R3.  R1 can ping R2 but not R3 and R3 can ping R2
but not R1.

R1's loopback interface = 192.168.1.1 and R2's loopback = 192.168.2.2 and R3's
loopback = 192.168.3.3

The route table of each router shows all 3 loopbacks.

R1's BGP config:

router bgp 123
nei 192.168.2.2 remote-as 123
nei 192.168.2.2 update-source lo0
nei 192.168.3.3 remote-as 123
nei 192.168.3.3 update-source lo0


R2's config:

router bgp 123
nei 192.168.1.1 remote-as 123
nei 192.168.1.1 update-source lo0
nei 192.168.3.3 remote-as 123
nei 192.168.3.3 update-source lo0

R3's config:

router bgp 123
nei 192.168.1.1 remote-as 123
nei 192.168.1.1 update-source lo0
nei 192.168.2.2 remote-as 123
nei 192.168.2.2 update-source lo0


R1 and R3 can both peer with R2 but they don't peer with each other.  I
thought that as long as there was a TCP path ( the ip addr was in the route
table),  R3 and R1 could peer.  But this isn't working.  Can someone explain
why not?

Thanks, Raj