Connecting Ipv6 Islands Across Ipv4 Clouds With Bgp; Figure 110: Ipv6 Tunneled Over Mpls-Ipv4 - Juniper BGP - CONFIGURATION GUIDE V 11.1.X Configuration Manual

JUNOSe 11.1.x BGP and MPLS Configuration Guide

Connecting IPv6 Islands Across IPv4 Clouds with BGP

If you have not upgraded your core to IPv6, you can still provide IPv6 services to
customers by connecting remote IPv6 islands across IPv4 clouds by means of MP-BGP
and MPLS. An IPv6 island is a network employing IPv6 addressing, such as a customer
site. The IPv4 cloud consists of the PE–P–PE core.
NOTE: You must configure an IPv6 interface in the parent VR for this feature to work.
Consider Figure 110 on page 476. Each customer site is connected by means of a CE
router to a PE router. The PE routers in this implementation are referred to as
dual-stack BGP (DS-BGP) routers because they run both the IPv6 and IPv4 protocol
stack.

Figure 110: IPv6 Tunneled over MPLS-IPv4

The PE routers learn IPv6 routes using MP-BGP over TCPv4 or TCPv6 from the CE
devices. Alternatively, you can configure IPv6 static routes on the PE routers to reach
the customer IPv6 networks through the CE IPv6 link. You can use any IPv6-enabled
routing protocol to access the CE routers.
Use any MPLS signaling protocol to establish an MPLS base tunnel in the IPv4 core
network. Each PE router runs MP-BGP over an IPv4 stack (MP-BGP/TCP/IPv4). MP-BGP
advertises the customer IPv6 routes by exchanging IPv6 NLRI reachability information
across the IPv4 cloud.
Each PE router announces the IPv4 address of its core-facing interface (the tunnel
endpoint) to its PE peers as the BGP next hop. Because MP-BGP requires the next
hop to be in the same address family as the NLRI, the IPv4 next-hop address must
be embedded in an IPv6 format. The PE router advertises the IPv6 routes as labeled
routes and an IPv6 next hop.
In the topology shown in Figure 110 on page 476, OSPF advertises reachability of the
loopback (10.1.1.1/32 and 10.2.2.1/32) and core-facing (10.10.10.1/32 and
10.20.20.2/32) interfaces of the PE routers. LDP binds label L1 to 10.1.1.1/32 on the
P router.
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Connecting IPv6 Islands Across IPv4 Clouds with BGP