Alcatel-Lucent 7750 SR OS - Manual (Page 31)

IP Router Configuration
7750 SR OS Router Configuration Guide Page 31
IPv6 Provider Edge Router over MPLS (6PE)
6PE allows IPv6 domains to communicate with each other over an IPv4 MPLS core network. This
architecture requires no backbone infrastructure upgrades and no reconfiguration of core routers,
because forwarding is purely based on MPLS labels. 6PE is a cost effective solution for IPv6
deployment.
Figure 7: Example of a 6PE Topology within One AS
6PE Control Plane Support
The 6PE MP-BGP routers support:
• IPv4/IPv6 dual-stack
• MP-BGP can be used between 6PE routers to exchange IPv6 reachability information.
→ The 6PE routers exchange IPv6 prefixes over MP-BGP sessions running over IPv4
transport. The MP-BGP AFI used is IPv6 (value 2).
→ An IPv4 address of the 6PE router is encoded as an IPv4-mapped IPv6 address in the
BGP next-hop field of the IPv6 NLRI. By default, the IPv4 address that is used for
peering is used. It is configurable through the route policies.
→ The 6PE router binds MPLS labels to the IPv6 prefixes it advertises. The SAFI used in
MP-BGP is the SAFI (value 4) label. The 7750 SR-Series router uses the IPv6 Explicit
Null (value 2) label for all the IPv6 prefixes that it advertises and can accept an
arbitrary label from its peers.