I'm not exactly sure what your scenario is, so I will give you a new one and walk you through it.
Scenario: You have 4 routers: R1, R2, R3, R4. R1 is in AS100, R2 and R3 are in AS200, and R4 is in AS300. R1's interface S0 is connected to R2's interface S0. R2's interface S1 is connected to R3's interface S1. R3's interface S0 is connected to R4's interface S0. The devices are configured with the following addressing: R1 interface S0 - 10.10.10.1 255.255.255.0 R2 interface S0 - 10.10.10.2 255.255.255.0 R2 interface S1 - 10.10.20.1 255.255.255.0 R3 interface S1 - 10.10.20.2 255.255.255.0 R3 interface S0 - 10.10.30.1 255.255.255.0 R4 interface S0 - 10.10.30.2 255.255.255.0 1. Configure IBGP for R2 and R3. Make sure the IGP routing table and the BGP routing table do not need to be in synch for the BGP routes to appear in the routers routing table. 2. Configure EBGP for R2 and R1. 3. Configure EBGP for R3 and R4. Answer for question 1: R2#conf t R2(config)#router bgp 200 R2(config-router)#no synch R2(config-router)#neighbor 10.10.20.2 remote-as 200 R2(config-router)#exit R2(config)#exit R2# R3#conf t R3(config)#router bgp 200 R3(config-router)#no synch R3(config-router)#neighbor 10.10.20.1 remote-as 200 R3(config-router)#exit R3(config)#exit R3# Explination for question 1: The router bgp 200 command creates BGP AS200 on the device. The no synch command turns off synchronization between the IGP routing table and the BGP routing table. The neighbor 10.10.20.2 remote-as 200 command configures R2 as an IBGP neighbor of R3 since the remote AS number is the same as it's AS number. The neighbor 10.10.20.1 remote-as 200 command configures R3 as an IBGP neighbor of R2 since the remote AS number is the same as it's AS number. Answer to question 2: R1#conf t R1(config)#router bgp 100 R1(config-router)#neighbor 10.10.10.2 remote-as 200 R1(config-router)#exit R1(config)#exit R1# R2#conf t R2(config)#router bgp 200 R2(config-router)#neighbor 10.10.10.1 remote-as 100 R2(config-router)#exit R2(config)#exit R2# Explination to answer 2: In these configurations EBGP is configured because the remote AS # is different than the devices AS #. Answer to question 3: R3#conf t R3(config)#router bgp 200 R3(config-router)#neighbor 10.10.30.2 remote-as 300 R3(config-router)#exit R3(config)#exit R3# R4#conf t R4(config)#router bgp 300 R4(config-router)#neighbor 10.10.30.1 remote-as 200 R4(config-router)#exit R4(config)#exit R4# Explination to answer 3: Same as explination to answer 2. The final configs would look like this: R1#conf t R1(config)#router bgp 100 R1(config-router)#neighbor 10.10.10.2 remote-as 200 R1(config-router)#exit R1(config)#exit R1# R2#conf t R2(config)#router bgp 200 R2(config-router)#no synch R2(config-router)#neighbor 10.10.20.2 remote-as 200 R2(config-router)#neighbor 10.10.10.1 remote-as 100 R2(config-router)#exit R2(config)#exit R2# R3#conf t R3(config)#router bgp 200 R3(config-router)#no synch R3(config-router)#neighbor 10.10.20.1 remote-as 200 R3(config-router)#neighbor 10.10.30.2 remote-as 300 R3(config-router)#exit R3(config)#exit R3# R4#conf t R4(config)#router bgp 300 R4(config-router)#neighbor 10.10.30.1 remote-as 200 R4(config-router)#exit R4(config)#exit R4# I hope this answers what you were looking for. Carl Timm, CCIE #7149 Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=54755&t=54737 -------------------------------------------------- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
