BGP ?

richard.m.gilbert · ‎01-02-2009

Hello,

I am studying for the CCNP and I am setting up a simple BGP connection between two routers but can't get it to work.

Here are the configs.

<RTR_A>-------<switch>------<RTR_B>

Router A

int lo0

ip add 10.10.10.10 255.255.255.255

int fa0/0

ip add 192.168.0.1 255.255.255.252

router bgp 1

neighbor 192.168.0.2 remote-as 2

Router B

int lo0

ip add 20.20.20.20 255.255.255.255

int fa0/0

ip add 192.168.0.2 255.255.255.252

router bgp 2

neighbor 192.168.0.1 remote-as 1

Any reason why this isn't connecting? Physical layer is good as I can ping connected interfaces from both sides.

Thanks,

Richard

richard.m.gilbert · ‎01-02-2009

Ahh ... figured it out. Have to advertise networks as well as name neighbors in router bgp

Giuseppe Larosa · ‎01-03-2009

Hello Richard,

a useful command is

sh ip bgp summary

as you have just discovered is possible to build a BGP session without advertising nothing.

in this case you see 0 as the number of prefixes received.

If you use sh ip route bgp you don't see nothing but the BGP session is up.

Think of BGP session as a communication channel between two devices

Hope to help

Giuseppe