Adam Thompson(athom...@athompso.net) on 2013.10.29 15:20:04 -0500: > I've got two border gateways that peer (eBGP) with the same external AS; > they also peer with each other (iBGP) as per normal BGP design. > > Naturally, the BGP RIB contains two copies of every route; one learned > from the external peer and one learned from the internal peer. > > However, when I run "bgpctl show", both routes are marked with origin > "i" (i.e. IGP). > > Do I have to use "set origin egp" in the external neighbour's stanza in > /etc/bgpd.conf? Doing so works, and produces the expected output, but > should it be necessary?
The origin attribute doesn't mean what you think it does! It is a information added by the originating router of that route: "i" stands for "IGP" (not "iBGP") and means the route was redistributed from an IGP (e.g. OSPF) into BGP. "e" means EGP, meaning the route was learned by an EGP. and "?" or incomplete is used for everything else (for example static routes being redistributed). The origin is used in step 5 of the decision process in bgpd (see bgpd(8)), and the "set origin" option can be used to change the origin of routes to manipulate the process of selecting routes. But you should never just use "set origin" on all your bgp sessions to other ASes just because they are "eBGP" sessions. /Benno
