5. VPN BGP/MPLS IPv6 inter-AS

Customer sites for BGP/MPLS VPN solutions in the same virtual private network may not all be covered by the same network operator, meaning in particular that the VPN is supported by different stand-alone systems. In this case, the exchange of VPN routes between two PEs from different routing domains cannot take place via MP-iBGP. To offer end-to-end VPN solutions, the two networks interconnect via gateways called ASBRs, using one or more of the inter-domain methods listed in this section.