Inter-as vpn Analysis

Inter-as vpn analysis RFC2547bisOption 10A: Back to Back VRFOption 10B: MP-eBGP between ASBRsOption 10C: multihop MP-eBGP between Route-ReflectorsOption AB: an enhanced mix from option A and B and developed by CiscoOption 10A: Back to Back VRF when the number of VPN connections and the number of VPN routes are small, you can use the cross-origin VPN-OptionA solution. The cross-origin VPN-OptionA scheme is used. ASBR, The AS border device, must support VPN instances and be able to manage VPN routes. In addition, a dedicated interface (subinterface, physical interface, and bundled logical interface) must be prepared for each cross-domain VPN on the ASBR ). Therefore, this scheme has high requirements on the Performance of ASBR, but there is no need to make any special configuration for cross-origin on ASBR. 1. ASBR peer-to-peer: each sub-interface is bound to a VRF through the drag-down interface to ensure the private nature of Inter-Domain route propagation. 2. ASBR peers only run common BGP, do not run LDP, and exchange IPv4 routes. 3. Each PE-ASBR treats the other PE-ASBR as CE. 4. It is suitable for scenarios where the number of interactive VPNs between AS domains is small, but the scalability is poor. Cross-origin VPN-Option B (ASBR and do PE) configuration across two AS VPNs, where ASBR publishes a label MP-EBGP route through the VPN-IPv4, and ASBR also do PE. If the ASBR can manage VPN routes, but does not have enough interfaces dedicated for each cross-domain VPN, and the ASBR itself acts as a PE device, there is CE access. You can select cross-origin VPN-OptionB (ASBR and PE ). This scheme requires the ASBR device to publish and maintain the VPNv4 route of other VPNs, and also maintain and publish the route of the VPN instance connected to it.