[c-nsp] Cisco BGP AIGP

[Adam Vitkovsky]

Hi Tim,

> Tim Durack
> Sent: 05 June 2015 19:40
> 
> BGP AIGP has been added to some versions of IOS/IOS-XE/IOS-XR. Looks like
> this feature is restricted to IPv4 and IPv6 AF though. Anyone know if AIGP
> for VPNv4 and VPNv6 is supported or on the roadmap?
> 

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.
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.

adam