© 2006 Cisco Systems, Inc. All rights reserved.IP6FD v IPv6 Services Implementing Multicasting in an IPv6 Network

© 2006 Cisco Systems, Inc. All rights reserved.IP6FD v Describe MLDv1 in IPv6 networks Describe MLDv2 in IPv6 networks Describe IPv6 multicast scoping Describe MAC address mapping in IPv6 networks Describe PIMv6 in IPv6 networks Describe MPBGP in IPv6 networks Describe static RP in IPv6 networks Describe embedded RP in IPv6 networks Describe RP redundancy in IPv6 networks Objectives

© 2006 Cisco Systems, Inc. All rights reserved.IP6FD v Generic Multicast Address Scoping IPv6 Multicast Addressing Group ID 112 bits 128 bits 1111 FF Flags PTScope 8 bits Flags = T lifetime, 0 if permanent, 1 if temporary P proposed for unicast-based assignments Scope = 1 = interface-local 2 = link-local 4 = admin-local 5 = site-local 8 = organization-local E = global

© 2006 Cisco Systems, Inc. All rights reserved.IP6FD v Multicast Example Using NTP IPv6 Multicast Addressing (Cont.) Permanently assigned multicast addresses may have multiple scopes. For example, the NTP servers group is assigned a multicast address with a group ID of 101 (hexadecimal): FF01:0:0:0:0:0:0:101 means all NTP servers on the same node are the sender. FF02:0:0:0:0:0:0:101 means all NTP servers on the same link are the sender. FF05:0:0:0:0:0:0:101 means all NTP servers at the same site are the sender. FF0E:0:0:0:0:0:0:101 means all NTP servers in the Internet.

© 2006 Cisco Systems, Inc. All rights reserved.IP6FD v IPv4 vs. IPv6 Multicast IP ServiceIPv4 SolutionIPv6 Solution Address Range32-bit, Class D128-bit Routing Protocol Independent, All IGPs and BGP4+ Protocol Independent, All IGPs and BGP4+ with v6 mcast SAFI Forwarding PIM-DM, PIM-SM, PIM-SSM, PIM-bidir Group ManagementIGMPv1, v2, v3MLDv1, v2 Domain ControlBoundary/BorderScope Identifier Interdomain Solutions MSDP Across Independent PIM Domains Single RP Within Globally Shared Domains

© 2006 Cisco Systems, Inc. All rights reserved.IP6FD v Multicast Listener DiscoveryMLDv1 MLDv1 is equivalent to IGMP in IPv4. MLDv1 messages are transported over ICMPv6. MLDv1 uses link-local source addresses. MLDv1 packets use the Router Alert option in IPv6 header (RFC 2711). There is some version number confusion: –MLDv1 (RFC 2710) is similar to IGMPv2 (RFC 2236). –MLDv2 (draft-vida-mld-v2-07) is similar to IGMPv3 (RFC 3376) SSM support. MLD snooping is discussed in RFC CGMP for IPv6 is under consideration.

© 2006 Cisco Systems, Inc. All rights reserved.IP6FD v Message Types Multicast Listener DiscoveryMLDv1 (Cont.) What multicast addresses are you listening to? General Query Are any of your nodes listening to FF0E::107 (Audionews)? Address-Specific Query Im listening to FF0E::102 (SGI-Dogfight) Report Im finished listening to FF0E::102 (SGI-Dogfight) Done Designated Router Listener

© 2006 Cisco Systems, Inc. All rights reserved.IP6FD v Joining a Group (REPORT) Multicast Listener DiscoveryMLDv1 (Cont.) Destination: FF3E:40:2001:DB8:100:E:1111:1111 ICMPv6 Type 131 Host 1 FE80::209:5BFF:FE08:A674 Host 1 sends a REPORT for the group Group:FF3E:40:2001:DB8:100:E:1111:1111 RTR-A Source Host 2

© 2006 Cisco Systems, Inc. All rights reserved.IP6FD v Joining a Group (REPORT) Multicast Listener DiscoveryMLDv1 (Cont.) FE80::250:8BFF:FE55:78DE Host 2 also listening; report suppressed Destination: FF3E:40:2001:DB8:100:E:1111:1111 ICMPv6 Type 131 Host 1 Group:FF3E:40:2001:DB8:100:E:1111:1111 RTR-A Source Host 2

© 2006 Cisco Systems, Inc. All rights reserved.IP6FD v Multicast Listener DiscoveryMLDv1 (Cont.) Host Management (Group-Specific Query) Destination: FF02::2 ICMPv6 Type 132 Host 1 FE80::209:5BFF:FE08:A674 Host 1 sends MLD DONE to the group Group:FF3E:40:2001:DB8:100:E:1111:1111 Source Host 2 RTR-A

© 2006 Cisco Systems, Inc. All rights reserved.IP6FD v Multicast Listener DiscoveryMLDv1 (Cont.) Host Management (Group-Specific Query) Destination: FF3E:40:2001:DB8:100:E:1111:1111 ICMPv6 Type 131 Host 1 Group:FF3E:40:2001:DB8:100:E:1111:1111 Source Host 2 rtr-a sends Group-Specific Query RTR-A

© 2006 Cisco Systems, Inc. All rights reserved.IP6FD v Multicast Listener DiscoveryMLDv1 (Cont.) Host Management (Group-Specific Query) Host 2 sends a REPORT for the group FF80:250:2001:8BFF:FE55:78DE Destination: FF3E:40:2001:DB8:100:E:1111:1111 ICMPv6 Type 131 Host 1 Group:FF3E:40:2001:DB8:100:E:1111:1111 Source Host 2 RTR-A

© 2006 Cisco Systems, Inc. All rights reserved.IP6FD v MLD uses a straightforward process to obtain a consolidated list of multicast groups needed on the LAN. Multicast Listener DiscoveryMLDv1 (Cont.) General MLDv1 Process General Query Designated Router Listener

© 2006 Cisco Systems, Inc. All rights reserved.IP6FD v MLD uses a straightforward process to obtain a consolidated list of multicast groups needed on the LAN. Multicast Listener DiscoveryMLDv1 (Cont.) General MLDv1 Process Designated Router Listener List of addresses

© 2006 Cisco Systems, Inc. All rights reserved.IP6FD v MLD uses a straightforward process to obtain a consolidated list of multicast groups needed on the LAN. Multicast Listener DiscoveryMLDv1 (Cont.) General MLDv1 Process Designated Router Listener New address

© 2006 Cisco Systems, Inc. All rights reserved.IP6FD v MLD uses a straightforward process to obtain a consolidated list of multicast groups needed on the LAN. Multicast Listener DiscoveryMLDv1 (Cont.) General MLDv1 Process Designated Router Listener Multicast streams

© 2006 Cisco Systems, Inc. All rights reserved.IP6FD v MLD uses a straightforward process to obtain a consolidated list of multicast groups needed on the LAN. Multicast Listener DiscoveryMLDv1 (Cont.) General MLDv1 Process Designated Router Listener Message: Done Not listening Listener

© 2006 Cisco Systems, Inc. All rights reserved.IP6FD v MLD uses a straightforward process to obtain a consolidated list of multicast groups needed on the LAN. Multicast Listener DiscoveryMLDv1 (Cont.) General MLDv1 Process Designated Router Listener Address- specific Query

© 2006 Cisco Systems, Inc. All rights reserved.IP6FD v Multicast Listener DiscoveryMLDv1 (Cont.) Querier MLD A Router Listener General Query MLD B Router

© 2006 Cisco Systems, Inc. All rights reserved.IP6FD v Multicast Listener DiscoveryMLDv2 Additional Features With source filtering, MLDv2 only requests desired sources for traffic. DR (first-hop) Source 1 Multicast Router Multicast Router RP: Not Used for SSM Multicast Router DR (first-hop) Receiver Source 2

© 2006 Cisco Systems, Inc. All rights reserved.IP6FD v Additional Features (Cont.) Multicast Listener DiscoveryMLDv2 (Cont.) Introduces all MLDv2-capable router link-local multicast address Provides optional ability for the designated router (forwarder) to store state on individual link-local listeners Changes report messages for enhanced efficiency

© 2006 Cisco Systems, Inc. All rights reserved.IP6FD v Global Multicast Address Scoping IPv6 Scoping This method solves the old IPv4 address assignment problem of obtaining global IPv4 multicast addresses. In IPv6, if you own an IPv6 unicast address prefix, you implicitly own an IPv6 multicast address prefix. FFRsvdFlagsScopePlenNetwork-PrefixGroup-ID FF3E:0040:2001:DB8:100:E:0000: hex Uni-pfx E hex Global Prefix Length Flags = 00PT, P = 1, T = 1=> Unicast-based address

© 2006 Cisco Systems, Inc. All rights reserved.IP6FD v More than one IPv6 multicast address will map to the same MAC address (80 bits lost). MAC Address Mapping FFHigh-OrderFlagsScopeLow-Order bits 80 Bits Lost xx-xx-xx-xx Bits Ethernet MAC Address Example: FF05::1: IPv6 Multicast Address

© 2006 Cisco Systems, Inc. All rights reserved.IP6FD v PIM provides communications between designated routers and RPs. PIMv6 Multicast Router DR (last-hop) PIM MLD Multicast Source Multicast Listener Multicast RP DR (first-hop) Multicast Router DR (last-hop) Multicast Listener MLD

© 2006 Cisco Systems, Inc. All rights reserved.IP6FD v PIMv6 (Stage 1) Stage 1: DR and RP routers are configured. Multicast Router DR (Forward) PIM MLD Multicast Source Multicast Listener Multicast RP DR (first-hop) Multicast Router DR (Forward) Multicast Listener MLD

© 2006 Cisco Systems, Inc. All rights reserved.IP6FD v PIMv6 (Stage 2) Stage 2: Packets are sent to multicast destinations. Multicast Router DR (Forward) PIM MLD Multicast Source Multicast Listener Multicast RP Multicast Router DR (Forward) Multicast Listener MLD DR (first-hop)

© 2006 Cisco Systems, Inc. All rights reserved.IP6FD v PIMv6 (Stage 3) Stage 3: DR sends a PIM message. Multicast Router DR (Forward) PIM MLD Multicast Source Multicast Listener Multicast RP Multicast Router DR (Forward) Multicast Listener MLD DR (first-hop)

© 2006 Cisco Systems, Inc. All rights reserved.IP6FD v PIMv6 (Stage 4) Stage 4: RP joins the multicast source. Multicast Router DR (Forward) PIM MLD Multicast Source Multicast Listener Multicast RP Multicast Router DR (Forward) Multicast Listener MLD DR (first-hop)

© 2006 Cisco Systems, Inc. All rights reserved.IP6FD v PIMv6 (Stage 5) Stage 5: The DR (last hop) receives multicast traffic directly. Multicast Router DR (Forward) PIM MLD Multicast Source Multicast Listener Multicast RP Multicast Router DR (Forward) Multicast Listener MLD DR (first-hop)

© 2006 Cisco Systems, Inc. All rights reserved.IP6FD v MP-BGP Can carry routing information for IPv6 unicast and IPv6 multicast Can also carry multicast routing information Contains route tables that can be divergent, allowing traffic to be managed explicitly

© 2006 Cisco Systems, Inc. All rights reserved.IP6FD v RP and last-hop routers are statically configured with a single RP IPv6 address. Static RP L0 ipv6 multicast-routing ! interface Loopback0 description IPV6 IPmc RP no ip address ipv6 address 2001:DB8:300:AB::40/64 ipv6 pim rp-address 2001:DB8:300:AB::40 ipv6 multicast-routing ! ipv6 pim rp-address 2001:DB8:300:AB::40 Corporate Network IP WAN RPDR

© 2006 Cisco Systems, Inc. All rights reserved.IP6FD v Embedded RP 8 FF 4 Rsvd 4 Flags 4 Scope 8 Plen 64 Network-Prefix 32 Group-ID 4 RPadr Flags = 0RPT, R = 1, P = 1, T = 1 = RP address embedded Embeds the RP address into multicast group Redefines what was 8-bit reserved field into 4-bit reserved and 4-bit R field: –R field allows provision of 16 RPs on embedded address. –32-bit group ID field provides for 2 32 multicast groups per RP.

© 2006 Cisco Systems, Inc. All rights reserved.IP6FD v RP addresses per network prefix 2 32 multicast groups per RP Guaranteed unique because enterprise-assigned /64 network used in address Address Example Embedded RP (Cont.) FFRsvdFlagsScopePlenNetwork-PrefixGroup-IDRPadr FF76:0130:2001:0db8:9abc:: :5678:9abc::1 Resulting RP Address

© 2006 Cisco Systems, Inc. All rights reserved.IP6FD v Use of Embedded RP Embedded RP (Cont.) Embedded RP can be considered an automatic replacement to static RP configuration. Unsupported routers can be configured statically or via BSR for embedded RPs. Embedded RP does not provide RP redundancy as BSR or MSDP or anycast RP can.

© 2006 Cisco Systems, Inc. All rights reserved.IP6FD v Example Embedded RP (Cont.) Multicast Group corpRP Branch DR Receiver Sends Report corpRP#show ipv6 pim group FF7E:140:2001:DB8:45A:31::/96* RP : 2001:DB8:45a:31::1 Protocol: SM Client : Embedded Groups : 1 Info : RPF: Se0/0.1,FE80::210:7FF:FEDD:40 IP WAN

© 2006 Cisco Systems, Inc. All rights reserved.IP6FD v If RP fails, the multicast session fails. RP Redundancy Flooding Building State Flooding DR (first-hop) Multicast Router RP Multicast Router DR (last-hop) Receiver Source Multicast Router

© 2006 Cisco Systems, Inc. All rights reserved.IP6FD v Mechanisms and Issues RP Redundancy (Cont.) IPv4 RP redundancy solutions for IPv6 implementation: –Static RP configuration cannot provide for redundancy by itself. –MSDP (for anycast RP redundancy) is not defined for IPv6. –BSR and autoRP in IPv4 are considered inferior solutions to anycast: Worse convergence times Active protocol operations required in all routers Today, BSR is the only available RP redundancy solution for IPv6.

© 2006 Cisco Systems, Inc. All rights reserved.IP6FD v Potential Anycast RP Alternatives RP Redundancy (Cont.) MSDP for IPv6 –Perfectly well-suited to support anycast RP (one mesh group) –Complex protocol (only small subset of MSDP functions required for anycast RP function) –A temporary solution because of intrinsic (not anycast RP- related) restrictions; many think reviving it for IPv6 counter- productive draft-ietf-pim-anycast-rp-07.txt: Most simple protocol, does exactly what MSDP needs to do in one mesh group, unicast forwarding PIM SM register messages between redundant RPs Prefix length/anycast-RP is a Cisco internal idea –Solution without any new protocol (like embedded RP); most simple solution? –Could support PIM-SM and bidirectional PIM, IPv4, and IPv6

© 2006 Cisco Systems, Inc. All rights reserved.IP6FD v RP Redundancy (Cont.) Proposed RP Redundancy Solution Loopback :DB8:9AB0::1/64 Primary RP Designate a primary and a secondary RP (add more if necessary) for the anycast group. NEW: Configure primary RP with the longest prefix on the loopback; secondary RP has shorter prefix, and so on. DR 1 Secondary RP DR 2 Loopback :DB8:9AB0::1/63

© 2006 Cisco Systems, Inc. All rights reserved.IP6FD v Simple multicast environments require network configuration of MLD, PIM, and multicast support for intermediate routers. How to Implement Multicasting in an IPv6 Network Multicast Source Multicast Listener DR Multicast RPMulticast Router DR Multicast Listener

© 2006 Cisco Systems, Inc. All rights reserved.IP6FD v Summary The four major components in multicasting are designated routers, multicast receivers and sources, and rendezvous points. MLDv2 provides additional features over MLDv1, including source filtering and more efficient handling of reports based on multiple report types. PIM allows DRs and RPs to discover the best forwarding paths for multicast control and data packets. Embedded RPs eliminate the need for static configuration of RPs on the first-hop and last-hop routers. RP redundancy can be achieved via BSR today, and possibly in the future with embedded anycast-RP (still in draft), and prefix-length/anycast-RP (still conceptual).

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