Summary

IPv6 can be added to an existing MPLS network with some simple changes without changing the network core or changing the core routing protocols. An IETF draft, "Scenarios and Analysis for Introducing IPv6 into ISP Networks," (draft-ietf-v6ops-isp-scenarios-analysis-03.txt) describes the various migration scenarios in detail and specifies which tunneling and translational techniques are available. IPv6 does not change the fundamental operational model of an MPLS network, and all the currently available techniques can be leveraged in building the IPv6 services to end users. IPv6 VPNs and 6PE are simple extensions to the MPLS VPN model and are designed to accommodate the forwarding of IPv6 frames to IPv4 BGP next hop. In other words, MPLS forms an efficient encapsulation technique to deliver the v6 frames without any 6-to-4 translation or tunneling. IPv6 can also be transparently tunneled across the VPNs or MPLS network as another overlay option with relative ease.

Network operators today have started assigning IPv6 addresses for broadband users or mobile users. Especially in countries such as China and Japan, where the government provides incentives to deploy IPv6, providers are deploying IPv6 services at the edge and using techniques such as 6PE or 6VPE to deliver IPv6 services across an IPv4 core. The U.S. federal government has provided a mandate to its agencies that by June, 2008, all networks must be capable of running IPv6 services. Certainly, IPv4 is here to stay and is unlikely to be phased out in the next decade, but new and upcoming services of the next decade certainly will have a strong IPv6 flavor to them.