2. PE-CE relationship in IPv6 MPLS VPNs

Several interconnection solutions exist between the PE and the CE, as illustrated in figure 5 .

This method uses the same concept of route exchange between PEs and CEs as for the BGP/MPLS IPv4 VPN model: CE routers announce their routes to the parent PE routers, with the PEs distributing to all CEs in a given VPN the IPv6 routes received by other CEs in the same VPN.

In this model, the CEs don't exchange routes directly, or in other words, the VPN routing algorithm is not aware of any IPv6 overlay network.

PE-CE interconnection can be pure IPv6 or dual-stack:

• it is said to be dual-stack when the – interface or the – PE-CE sub-interface activates both an IPv4 and an IPv6 stack....