BGP: Difference between revisions

* If any of the neighbors in below command output shows as in 'Active' state, it means some issue with the neighbor:

show ip bgp summary

* Use Loopback interface for forming peers in router having multiple links.

When using eBGP, peers will not come up when using loopback as they need to be directly connected and should not have a Hop.

Use ebgp-multihop command to resovle this issue:

# neighbor 1.1.1.1 ebgp-multihop 2

* There are 2 ways to advertise networks into BGP:

Network Command

Redistribution

* When using Network command:

Below command will advertize 50.0.0.0/8 into BGP

network 50.0.0.0

Therefore advertize exact subnet only:

network 50.1.1.0 mask 255.255.255.0

* If the carot sign '>' is missing, the route is not the best one, so not installed in routing table:

<pre>

* valid, > best, i - internal, r RIB-failure

Network Next Hop Metric LocPrf Weight Path

*> 10.1.1.1/32 0.0.0.0 0 32768 i

*>i10.2.2.2/32 172.16.1.2 0 100 0 i

</pre>