BGP Route Selection Question

dppagc

I have a question on this statement:

Choose routes that this router originated.

What does it mean?
Does it include loopback addresses?
Does it include directly connected links?

EdTheLad

It means routes that were originated into bgp on the local device. i.e using the network command, redistribution or the aggregate command. So as an example R1 and R2 form an iBGP peer, both have an interface lo100 with ip 100.100.100.100/32; both install into the bgp table using the network command.
Looking at R1 bgp table i can see two paths for 100.100.100.100/32; one from R1 and one from R2; the path via R1 is preferred on R1 because it's been originated locally, if i increase the local preference for the route on R2 and look again at R1's bgp table, the path via R2 will be preferred as local preference is higher than originated in the bgp best path algorithm.

dppagc

Interesting question to ponder.
Can loopback addresses and directly connected routes be advertised into bgp although people don't do it.

deth1k

Well, route will be preferred based on weight as local routes have weight of 32768 by default

zeetskeet

Yes they can.

dppagc

Ok I got the answer from INE. There are 4 ways to originate a route into bgp
network command
redistribute connected
aggregate command
conditional advertisement.