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BGP confederations PEER command

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

2 ACCEPTED SOLUTIONS

Accepted Solutions
Purple

Re: BGP confederations PEER command

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

Purple

Re: BGP confederations PEER command

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.

4 REPLIES
Purple

Re: BGP confederations PEER command

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

Purple

Re: BGP confederations PEER command

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

Re: BGP confederations PEER command

Paresh,

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

Patrick

Purple

Re: BGP confederations PEER command

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.

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