Inter-Autonomous System MPLS VPN---L3 VPN.pptVIP

INTER-AUTONOMOUS SYSTEM MPLS VPN December 2003 Agenda Inter-AS MPLS VPN is a scalable mechanism for exchanging prefix and label information between two Service Provider networks. It is an extension of the basic MPLS VPN architecture (RFC 2547bis). Why Inter-AS? Enables communication between networks under separate autonomous systems Provides traffic separation and maintain end-to-end privacy while traffic traverses multiple MPLS VPN backbones in a scalable manner Allows VPN information to pass between MPLS VPN Service Providers so that they can successfully route traffic for a particular VPN Extends MPLS VPN services across geographical boundaries, so Service Providers can support their customer base in geographical locations that do not have POPs Allows a single Service Provider to partition its network into multiple domains for scalability and inter-departmental privacy Uses MPLS to forward the traffic end-to-end and across the systems Inter-AS Deployment More than ten Service Providers globally Hardware Cisco 7200 and 7500 Series Routers Cisco 10000 and 12000 Series Internet Routers Popular Inter-AS connectivity models Back-to-Back VRF( option A) MP-eBGP between ASBRs(option B) eBGP between ASBRs and MP-eBGP between RRs(option C) Defined in RFC2547bit Inter-AS Topology Overview Inter-AS Functionality Routing For Each Service Provider Domain Each AS operates under different administrative control and runs different IGP No IGP routing information exchange between the domains All routing information exchange between the domains is via Exterior Routing Protocol Routing policies may differ between the exchange points Customer VPN routes are distributed into VRFs at the ingress PE of the ISP Each PE assigns labels for the routes to establish connections Inter-AS Control Plane Establishes EBGP session between the PE-ASBRs Distribute IPv4 routes for the VPNs in the form of VPNv4 addresses PE-ASBRs re-write Next-hop and labels when a route is distributed to a neighb