Tag Archives: ebgp

Is full meshed iBGP necessary?

Revisit the configuration of the iBGP routers R2#sh run | s r b router bgp 2 bgp log-neighbor-changes neighbor 3.3.3.3 remote-as 2 neighbor 3.3.3.3 update-source Loopback2 neighbor 3.3.3.3 next-hop-self neighbor 4.4.4.4 remote-as 2 neighbor 4.4.4.4 update-source Loopback2 neighbor 4.4.4.4 next-hop-self … Continue reading

Posted in Route | Tagged , , , , | Leave a comment

BGP: Injecting IGP route into BGP without redistribution

The diagram is complicated with an additional link, and instead of full BGP route in AS65000, the BGP route is propagated with the help of OSPF. In previous lab, the BGP full mesh was established by peering both subnets of … Continue reading

Posted in BGP, Route | Tagged , , , , , , | 2 Comments

BGP: Route filter with ip prefix-list

Using the same network diagram, I would want prefix 10.20.0.0 to be filtered from advertisement by the border iBGP routers (r1 and r3). Using prefix-list is a more granular method than using ACL with distribute-list. Hide r2 prefixes from r5 … Continue reading

Posted in BGP, Route | Tagged , , , , , | Leave a comment

BGP: Full mesh BGP without IGP

r1, r2 and r3 have full meshed BGP peering. No IGP was used. BGP synchronization Before a BGP route is advertised and added to the routing table, this route must be known via an IGP. For the case of AS65000, … Continue reading

Posted in BGP, Route | Tagged , , , , | Leave a comment

BGP: Load balancing using ebgp multihop and loopback interface.

1841-1 configuration 1841-1#sh run | s router bgp router bgp 64512 no synchronization bgp log-neighbor-changes network 172.16.1.0 mask 255.255.255.0 neighbor 110.1.1.1 remote-as 64513 neighbor 110.1.1.1 ebgp-multihop 2 neighbor 110.1.1.1 update-source Loopback64512 no auto-summary 1841-1#sh run | i ip route ip … Continue reading

Posted in BGP, Route | Tagged , , , | 1 Comment