Inter-AS VPN Notes
Inter-AS VPN
– VNPv4 communication between 2 ASs to exchange client routes
Problem
– Each client would require a separate L3 interface for the separate VRFs
-> Subinterfaces are commonly used to solve this
Client-to-client over multiple ASs must be a Labeled Switched Path (LSP), unless a VRF is being used somewhere in an AS
Thee are three was to enable inter-AS communication
– Inter-AS Option (10) A
-> Back-to-back VRF
– Inter-AS Option (10) B
-> ASBR VPNv4 MP-eBGP
– Inter-AS Option (10) C
-> Multihop MP-BGP
Cisco Docs:
MPLS VPN Inter-AS IPv4 BGP Label Distribution
http://www.cisco.com/c/en/us/td/docs/ios/12_2s/feature/guide/fsiaslbl.pdf