MPLS-Enabled Applications: Emerging Developments and New Technologies

8.9. IPv6 VPNs

The discussion in the previous chapter assumed that the customer of the L3VPN service uses IPv4. There is increasing interest in being able to support IPv6 customers using the L3VPN model. One driver for this is the fact that the US Government has mandated the use of IPv6 in all of the networks belonging to US Federal Agencies [OMB]. Because some US Government departments buy L3VPN services from service providers, those service providers need to support IPv6 transport over the L3VPN service. There is also interest in the scheme from operators of mobile telephony networks. Increasingly, the transport infrastructure is based on MPLS with VPNs being used to provide separation between the different traffic types. This, coupled with the likely introduction of IPv6 addressing in the future for parts of the mobile infrastructure, including the handsets, makes IPv6 L3VPN a useful internal infrastructure tool for these networks.

The IPv6 L3VPN scheme [RFC 4659] was designed to be very similar to the IPv4 L3VPN scheme in terms of mechanisms and operational model. The following mechanisms are common to both schemes:

• A PE achieves separation between different customers by storing their routes in separate VRFs.

• Route targets are used to achieve constrained route distribution.

• Route distinguishers are used to disambiguate overlapping addresses.

• Multiprotocol BGP is used to carry labeled routes between PE routers.

• Route Target Filtering can be used to ensure that a PE only receives ...