BGP confederations PEER command

[Patrick Laidlaw]

Hello,

Needed some clarification on the following command

bgp confederation peer blah

So when I define confederation peers do I only need to put the bgp confederation peer command on router's bordering other confederation peers or do I have to put the command on all my routers that is in that confederation?

Patrick

[pkhatri · Accepted solution]

Hi Patrick,

You have to configure this command on every router within the confederation that has BGP sessions to routers within other (real, external) ASs or other sub-ASs within the confederation. This tells the router whether to use confederation-type processing on the EBGP session or whether to use standard EBGP processing. If a router only has iBGP sessions, this command is not required because IBGP processing within a confederation sub-AS is not different to IBGP processing within a standard AS.

Hope that helps - pls rate the post if it does.

Paresh

[pkhatri]

Just a clarification,

If a router has an EBGP session to an external AS but no EBGP sessions to any routers in any other sub-ASs, the command is not required. The router will invoke standard EBGP processing with all EBGP peers that are not explicitly listed using the 'bgp confederation peer' command.

Paresh

[Patrick Laidlaw]

Paresh,

Thanks thats what I thought but I wasn't sure.

Patrick

[pkhatri · Accepted solution]

Yeah, that's a strange one, Patrick.

In fact, I think you can even get away without configuring the 'bgp confederation identifier' command on routers that don't have any external BGP sessions...

Paresh.