BGP Multipath load sharing iBGP and eBGP

[ReneMolenaar]

Hi Stefanita,

@staut_stefanita

At eBGP Same AS example “R1 will will have paths” should be replaced with “R1 will have 2 paths”. R2 configuration also needs the mask for “network 192.168.23.0” under bgp 23.

At the conclusion there is a note “the hidden bgp bestpath asp-path multipath-relax command”.
I guess the command is bgp bestpath as-path multipath-relax .

Thanks for this, I just fixed these errors.

@staut_stefanita

Shouldn’t R1#show ip route bgp at the end of iBGP example also include the 192.168.123.0/24 network?

192.168.123.0/24 is a directly connected network for R1. It’s in the routing table, but as directly connected.

@staut_stefanita

A (perhaps stupid) question would be if you could trick a router to bypass the as-path length also using the prepending mechanism.

BGP multipath requires the same AS number and the same AS path length. With the bgp bestpath as-path multipath-relax command you tell BGP to ignore the AS number so that only the AS path length is left. If you end up with two options where one path has a longer AS path length then you could use prepending to fix this, making the two paths equal.

Rene