[c-nsp] Cisco BGP AIGP

Saku Ytti saku at ytti.fi
Mon Jun 8 08:53:13 EDT 2015

On (2015-06-08 09:30 +0000), Adam Vitkovsky wrote:


> I think there's no need for VPNv4 and VPNv6 AF to carry this attribute (unless in CsC scenario where customer-carrier is doing RFC3107 over provider-carrier and customer-carrier would like to use AIGP). 
> My understanding is that this feature is intended for Inter-AS hierarchical MPLS solutions to carry accumulated IGP metric towards the VPN prefix NHs in remote AS-es.

Does not have to be InterAS, can be seamless MPLS.

> Though use with care as when enabled it will turn your BGP-LU basically into RIP as the AIGP metric comparison is done before any of the standard BGP best path decision steps.

Which is desirable for lookbacks, when they are distributed by BGP instead of

But I can't immediately think of why you'd want it on VPNv4.


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