The Research on VPN Route Control Mechanism with Route Distinguisher Granularity in Intra-AS and Inter-AS Scenarios

Virtual Private Network (VPN) is widely used in intranet communication of customer sites in different Autonomous Systems (AS). The existing VPN route control mechanisms cannot filter VPN routes with Route Distinguisher (RD) granularity. This paper defines a RD-based routing control mechanism-VPN Prefix Outbound Route Filter (ORF) mechanism. The encoding format of VPN Prefix ORF entry is given, including the length and meaning of every field. The trigger of this mechanism on the sender of VPN Prefix ORF entry is described in detail to ensure that normal VRF will not be influenced due to the rejection of some VPN routes. Besides, this paper describes the operation processes of VPN Prefix ORF in inter-AS option B/AB/C scenario, intra-AS scenario and VPN routes shared on one PE scenario.