There's a need for us to interconnect a third party for interconnecting voice traffic.
For us we have serious problems with the VoIP requirments (99.999% availability, 50ms delay,10^-4 packet loss) in combination with eBGP and its redundancy failover timers.
Even with a VPN interconnection as described in an inter-AS connection as descibed in rfc 2547bis option (b) or option (c) are not capable of archieving the VoIP requirements.
For me now the best we can do in my opinion is running eBGP vpnv4 peering according to rfc 2547b in combination with BFD as a L2 fault detection.
Any comments on this is welcome.