© 2006 Cisco Systems, Inc. All rights reserved.IP6FD v IPv6-Enabled Routing Protocols Understanding Support for IPv6 in MPLS

© 2006 Cisco Systems, Inc. All rights reserved.IP6FD v MPLS Operations MPLS combines Layer 3 routing with label swapping and forwarding, as follows: Labels are imposed at the ingress router. Generally, all forwarding decisions made within the core of the MPLS network are made using only the label. Label table lookups are used instead of routing table lookups. Labels are stripped at the egress router.

© 2006 Cisco Systems, Inc. All rights reserved.IP6FD v Label Distribution Protocol (LDP/TDP, RSVP, BGP) At Edge (ingress): Classify packets Label them In Core: Forward using labels (as opposed to IP addr) Label indicates service class and destination Label Edge Router (LER/PE) At Edge (egress): Remove label Label Switch Router (LSR/P)

© 2006 Cisco Systems, Inc. All rights reserved.IP6FD v MPLS Packet Forwarding Process Step 1: Existing routing protocols establish reachability to destination networks Step 2: LDP establishes an initial label to be prepended to IP packets destined for a given network, as well as populating the label lookup table on all MPLS routers for passing labeled packets to their nexthop

© 2006 Cisco Systems, Inc. All rights reserved.IP6FD v MPLS Packet Forwarding Process (Cont.) L5 Step 3: Ingress edge label switch router (LSR) receives the packet, performs Layer 3 value-added services, and labels the packets

© 2006 Cisco Systems, Inc. All rights reserved.IP6FD v MPLS Packet Forwarding Process (Cont.) L6L7 Step 4: LSR switches packets using label swapping

© 2006 Cisco Systems, Inc. All rights reserved.IP6FD v MPLS Packet Forwarding Process (Cont.) Step 5: Edge LSR at egress removes the label and delivers the packet

© 2006 Cisco Systems, Inc. All rights reserved.IP6FD v IPv6 over MPLS Deployment Scenarios There are a number of methods to provision IPv6 over an MPLS network IPv6 tunnels configured on the CE IPv6 over AToM Cisco 6PE

© 2006 Cisco Systems, Inc. All rights reserved.IP6FD v IPv6 Tunnels Configured on CE Dual Stack IPv4-IPv6 CE Routers OC48/192 P PE IPv6 IPv4 P PE IPv4 IPv6 IPv4 P P PE IPv6 in IPv4 Tunnels IPv6 Dual Stack IPv4-IPv6 CE Routers IPv4 IPv6

© 2006 Cisco Systems, Inc. All rights reserved.IP6FD v IPv6 Over AToM Circuit IPv4 AToM IPv6 P IPv4 AToM P PP IPv6 IPv4 AToM IPv6 Circuit over MPLS (e.g., ATM VC, FR PVC, Ethernet) IPv6

© 2006 Cisco Systems, Inc. All rights reserved.IP6FD v PE Topology 2001:db8:0002:: IPv6 IPv4 IPv6 CE IPv4 CE 2001:db8:0003:: IPv6 IPv4 IPv6 CE IPv4 CE PP 6PE PP 2001:db8:0004:: IPv6 CE IPv6 CE 2001:db8:0005:: IPv4 CE MP-iBGP sessions

© 2006 Cisco Systems, Inc. All rights reserved.IP6FD v IPv6 unaware No core upgrade 6PE Topology (Cont.) 2001:db8:0002:: IPv6 IPv4 IPv6 CE IPv4 CE 2001:db8:0003:: IPv6 IPv4 IPv6 CE IPv4 CE PP 6PE PP 2001:db8:0004:: IPv6 CE IPv6 CE 2001:db8:0005:: IPv4 CE MP-iBGP sessions

© 2006 Cisco Systems, Inc. All rights reserved.IP6FD v IPv6 Network Running IGP Loop 0: Step 1: IGPv4 advertises reachability of :db8:0002:: CE-1 P1 6PE :db8:4:: CE-2 Loop 0: PE-1 P2

© 2006 Cisco Systems, Inc. All rights reserved.IP6FD v IPv6 Network Running IGP (Cont.) Loop 0: Step 2: LDPv4 binds label to :db8:0002:: CE-1 P1 6PE :db8:4:: CE-2 Loop 0: PE-1 P2

© 2006 Cisco Systems, Inc. All rights reserved.IP6FD v IPv6 Network Running IGP (Cont.) Loop 0: Step 3: MP-BGP advertises 2001:db8:4:: and binds a (second-level) label. IPv6 next hop is an IPv4 mapped IPv6 address built from :db8:0002:: CE-1 P1 6PE :db8:4:: CE-2 Loop 0: PE-1 P2

© 2006 Cisco Systems, Inc. All rights reserved.IP6FD v IPv6 Network Running IGP (Cont.) Loop 0: :db8:0002:: CE-1 P1 6PE :db8:4:: CE-2 Loop 0: PE-1 P2 Translation of v6 BGP Next_Hop into v4addresses Recursion of this address via IGPv4

© 2006 Cisco Systems, Inc. All rights reserved.IP6FD v Forwarding Process IPv6 packet to 2001:db8:4:: Loop 0: :db8:0002:: CE-1 P1 6PE :db8:4:: CE-2 Loop 0: PE-1 P2

© 2006 Cisco Systems, Inc. All rights reserved.IP6FD v Forwarding Process (Cont.) IPv6 Forwarding and Label Imposition: 6PE-1 receives an IPv6 packet. Lookup is done on the IPv6 prefix. The result is the following: Label binded by MP-BGP to 2001:db8:4:: Label1 binded by LDP/IGPv4 to the IPv4 address of BGP next hop (6PE-2) IPv6 packet to 2001:db8:4:: Loop 0: :db8:0002:: CE-1 P1 6PE :db8:4:: CE-2 Loop 0: PE-1 P2 LDP/IGPv4 label1 to 6PE-2 MP-BGP label to 2001:db8:4:: IPv6 packet 2001:db8:4::

© 2006 Cisco Systems, Inc. All rights reserved.IP6FD v Forwarding (P1) IPv6-unaware MPLS label switching: P1 receives an MPLS packet. Lookup is done on label1. The result is label2. IPv6 packet to 2001:db8:4:: Loop 0: :db8:0002:: CE-1 P1 6PE-2 Loop 0: PE-1 P2 LDP/IGPv4 label1 to 6PE-2 MP-BGP label to 2001:db8:4:: IPv6 packet 2001:db8:4:: LDP/IGPv4 label1 to 6PE-2 MP-BGP label to 2001:db8:4:: IPv6 packet 2001:db8:4:: 2001:db8:4:: CE-2

© 2006 Cisco Systems, Inc. All rights reserved.IP6FD v Forwarding (P1) (Cont.) IPv6-unaware MPLS label switching: P2 receives an MPLS packet. Lookup is done on label2. The result includes POP label (PHP). IPv6 packet to 2001:db8:4:: Loop 0: :db8:0002:: CE-1 P1 6PE-2 Loop 0: PE-1 P2 LDP/IGPv4 label1 to 6PE-2 MP-BGP label to 2001:db8:4:: IPv6 packet 2001:db8:4:: LDP/IGPv4 label1 to 6PE-2 MP-BGP label to 2001:db8:4:: IPv6 packet 2001:db8:4:: MP-BGP label to 2001:db8:4:: IPv6 packet 2001:db8:4:: 2001:db8:4:: CE-2

© 2006 Cisco Systems, Inc. All rights reserved.IP6FD v Forwarding (P1) (Cont.) MPLS label POP and IPv6 forwarding: 6PE-2 receives an MPLS packet. Lookup is done on label. The result is the following: POP label & IPv6 lookup on IPv6 destination IPv6 packet to 2001:db8:4:: Loop 0: :db8:0002:: CE-1 P1 6PE-2 Loop 0: PE-1 P2 LDP/IGPv4 label1 to 6PE-2 MP-BGP label to 2001:db8:4:: IPv6 packet 2001:db8:4:: LDP/IGPv4 label1 to 6PE-2 MP-BGP label to 2001:db8:4:: IPv6 packet 2001:db8:4:: MP-BGP label to 2001:db8:4:: IPv6 packet 2001:db8:4:: 2001:db8:4:: CE-2 IPv6 packet 2001:db8:4::

© 2006 Cisco Systems, Inc. All rights reserved.IP6FD v PE for IPv6 Integration IPv6 IPv4 IPv6 IPv4 IPv6 IPv4 IPv6 IPv4 PP 6PE PP IPv6 IPv4 MP-iBGP Sessions IPv6 IGP MP-BGP

© 2006 Cisco Systems, Inc. All rights reserved.IP6FD v PE for IPv6 Integration (Cont.) IPv6 IPv4 PP 6PE PP IPv6 CE IPv4 CE MP-iBGP Sessions IPv4 CE 6PE IPv6

© 2006 Cisco Systems, Inc. All rights reserved.IP6FD v Topology 2001:db8:0620:: IPv6 CE1 2001:db8:0621:: IPv6 IPv4 CE PP 6VPE PP 2001:db8:0420:: IPv4 CE MP-iBGP Sessions CE IPv6/ IPv4 CE IPv6/ IPv CE IPv6/ IPv4 2001:db8:0421::

© 2006 Cisco Systems, Inc. All rights reserved.IP6FD v Forwarding 2001:db8:0620:: Ethernet0 IPv6 CE1 2001:db8:0621:: IPv6 IPv4 CE PP 6VPE PP 2001:db8:0420:: IPv4 CE MP-iBGP Sessions CE IPv6/ IPv4 CE IPv6/ IPv CE IPv6/ IPv4 2001:db8:0421:: interface Ethernet0 ip vrf forwarding green-v4 ip address // (ipv4 installed in VRF green-v4)

© 2006 Cisco Systems, Inc. All rights reserved.IP6FD v VRF Forwarding 2001:db8:0620:: Ethernet0 IPv6 CE1 2001:db8:0621:: IPv6 IPv4 CE PP 6VPE PP 2001:db8:0420:: IPv4 CE MP-iBGP Sessions CE IPv6/ IPv4 CE IPv6/ IPv CE IPv6/ IPv4 2001:db8:0421:: interface Ethernet0 ip vrf forwarding green-v4 ip address // ipv4 installed in VRF green-v4 ipv6 vrf forwarding green-v6 ipv6 address 2001:db8:0620::1/64 // ipv6 installed in VRF green-v6

© 2006 Cisco Systems, Inc. All rights reserved.IP6FD v Deploy 6PE over MPLS Networks 2001:dbf:0620:: CE1 2001:dbf:0421:: CE2 P1 6PE1 6PE2

© 2006 Cisco Systems, Inc. All rights reserved.IP6FD v Deploy 6PE over MPLS Networks (Cont.) 2001:dbf:0620:: CE1 2001:dbf:0421:: CE2 P1 6PE1 6PE2

© 2006 Cisco Systems, Inc. All rights reserved.IP6FD v Summary MPLS combines Layer 3 routing with label swapping and forwarding. IPv6 over MPLS backbones allow isolated IPv6 domains to communicate over an MPLS IPv4 core network. Deployment strategies include IPv6 tunnels configured on CE, IPv6 over AToM or Circuit, Cisco 6PE, and native MPLS support of IPv6 (future). Cisco 6PE and Cisco 6VPE are approaches adding IPv6 global reachability and IPv6 VPN services with marginal cost and risk, with IPv6 VPM over MPLS available in future. IPv6 and IPv6 VPN are treated as just another service that can be added on the edge over the stable multiservice IPv4 MPLS core.

© 2006 Cisco Systems, Inc. All rights reserved.IP6FD v