Inter-AS VPLS
Inter-AS VPLS refers to the application of the VPLS across multiple ASs. The switch supports only inter-AS Option A.
When using inter-AS VPLS, you do not need to consider the learning or forwarding functions of VSIs. Only establishment of PWs between PEs is important. Inter-AS VPLS therefore has the same principle and implementation methods as those of inter-AS L2VPN.
In Option A, configuration is eas. There is no need to run MPLS between ASBRs or perform particular configurations for inter-AS communications. However, Option A has poor expansion capacity and higher requirements for PEs. It is suitable for use in the early servicing stage when the number of inter-AS VPNs is small.
Inter-AS Kompella VPLS (Option A)
Figure 1 shows an example implementation of the inter-AS Kompella VPLS (Option A).
The inter-AS Kompella VPLS (Option A) is implemented as follows:
An IGP protocol is configured on the backbone network to allow communication between ASBRs and PEs. Tunnels are set up between PEs.
MP-IBGP peer relationships are established between the PE and ASBR in each same AS.
VSIs are configured on PE1, PE2, ASBR1, and ASBR2. The VSIs are bound to the AC interfaces.
Inter-AS Martini VPLS (Option A)
Figure 2 shows an example implementation of the inter-AS Martini VPLS (Option A).
The inter-AS Martini VPLS (Option A) is implemented as follows:
An IGP protocol is configured on the backbone network to allow communications between devices in the same AS.
Basic MPLS functions are enabled on the backbone network. A dynamic LSP is set up between the PE and ASBR in each AS. A remote LDP session is set up between the PE and ASBR if they are not directly connected.
A VPLS connection is set up between the PE and ASBR in each AS.