1974_chp9ONLa.fm Page 731 Tuesday, November 14, 2006 10:06 AM 1974_chp9ONLa.fm Page 732 Tuesday, November 14, 2006 10:06 AM CHAPTER SUPPLEMENT IPv6 over MPLS This online supplement of Chapter gives you a brief overview of how to deploy 6VPE across more than one autonomous system that is running MPLS You can deploy 6VPE over multiple autonomous systems in the same way as described in Chapter 7, “MPLS VPN”: InterAutonomous MPLS VPN or Carrier’s Carrier Inter-Autonomous Systems 6VPE Spanning the 6VPE solution across multiple autonomous systems is specified in RFC 4364 You can use three methods that are discussed in Chapter to provide inter-as support for 6VPE: ■ Virtual routing/forwarding (VRF)-to-VRF connections between autonomous system (AS) border routers ■ MP-eBGP exchanging vpnv6 prefixes + label between AS border routers ■ MP-eBGP exchanging vpnv6 prefixes + label between PE routers or route reflectors (RR) and exchanging IPv4 prefixes + label for the PE IPv4/32 prefixes In the first option, you can have AS border routers (ASBR) from different autonomous systems exchange the IPv6 prefixes directly over VRF interfaces The two ASBRs must have one link in common between them for each VPN for which they are exchanging prefixes These links can be (sub)interfaces with vrf forwarding configured on them The packets that cross the links between the two ASBRs are unlabeled IPv6 packets The second option is to have ASBRs from different autonomous systems exchange vpnv6 prefixes and labels The packets that cross the links between the ASBRs are labeled packets The third option is to have the vpnv6 prefixes and labels exchanged between PE routers or RRs from different autonomous systems However, a labeled IPv4 path needs to exist between the PE routers or RRs from the different autonomous systems Therefore, an IPv4 prefixes + label exchange must take place between the ASBRs for the PE IPv4/32 prefixes These PE IPv4/32 prefixes + label can be advertised via MP-eBGP or via an Interior Gateway Protocol (IGP) and Label Distribution Protocol (LDP) If the RRs from different autonomous systems exchange the vpnv6 prefixes, they must leave the BGP next-hop field unchanged 1974_chp9ONLa.fm Page 733 Tuesday, November 14, 2006 10:06 AM Chapter 9: IPv6 over MPLS Carrier’s Carrier Through 6VPE Because LDP for IPv6 is not available, Carrier’s Carrier (CsC) for IPv6 is a bit different from CsC for IPv4 You learned from Chapter that CsC involves sending labeled packets over a VRF interface of the PE router The same is true for CsC for IPv6 Two scenarios are possible for transporting IPv6 with a CsC solution: ■ 6VPE over IPv4 MPLS network ■ CsC network is MPLS VPN for IPv4 In the first scenario, 6VPE over IPv4 MPLS network, you have a regular 6VPE network running over an IPv4 MPLS backbone The IPv6 packets switched between the PE and CE routers are now labeled Because LDP for IPv6 is not available, the only option is to run MP-eBGP for IPv6 + label between the PE and CE routers You this by configuring the send-label keyword for the eBGP neighbor on the PE and CE router Figure 9-1 shows the CsC 6VPE over IPv4 MPLS network scenario in a schematic form Figure 9-1 6VPE over IPv4 MPLS Network MP-iBGP for vpnv6 + Label VPN Red VPN Red MPLS for IPv4 MP-eBGP for IPv6 + Label MP-eBGP for IPv6 + Label CsC-PE VRF VRF Site CsC-PE Site 733 IPv4 MPLS Backbone The second scenario, CsC network is MPLS VPN for IPv4, is a regular CsC MPLS VPN for the IPv4 network, meaning that the CsC is running MPLS VPN for IPv4 with IPv4 prefixes + label exchange between the CsC PE and the carrier’s CE routers The carrier network is running MPLS IPv4 end to end in its network and has 6VPE configured on the PEs only The PE IPv4/32 prefixes are the prefixes from the carrier’s network that must be labeled On the PE routers of the carrier’s network is MP-eBGP for IPv6 + label configured toward the CE routers to carry the customer prefixes Figure 9-2 shows the second scenario in a schematic form 1974_chp9ONLa.fm Page 734 Tuesday, November 14, 2006 10:06 AM Carrier’s Carrier Through 6VPE Figure 9-2 734 CsC Network Is MPLS VPN for IPv4 MP-iBGP for vpnv6 + Label MPLS VPN for IPv4 IPv4 + Label MP-eBGP for IPv6 + Label IPv4 + Label VPN Red CsC-PE VRF VRF Carrier Network Site Customer Network Site VPN Red CsC-PE PE CE MP-eBGP for IPv6 + Label PE VRF MPLS VPN for IPv4 Network Carrier’s Carrier Network CE VRF Carrier Network Site Customer Network Site NOTE To better understand the operation of CsC, refer to the section “Carrier’s Carrier” in Chapter ...1974_chp9ONLa.fm Page 732 Tuesday, November 14, 2006 10:06 AM CHAPTER SUPPLEMENT IPv6 over MPLS This... autonomous systems exchange the vpnv6 prefixes, they must leave the BGP next-hop field unchanged 1974_chp9ONLa.fm Page 733 Tuesday, November 14, 2006 10:06 AM Chapter 9: IPv6 over MPLS Carrier’s Carrier... routers to carry the customer prefixes Figure 9-2 shows the second scenario in a schematic form 1974_chp9ONLa.fm Page 734 Tuesday, November 14, 2006 10:06 AM Carrier’s Carrier Through 6VPE Figure 9-2