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IPv6 Multicast Routing Introduction

IPv6 multicast address

  1. IPv6 multicast address starts with 1111 1111.
  2. Hexadecimal notation is FF00::/8.
  3. next 4 bit: Flag
  4. next 4 bit: Scope
  5. last 112 bit: Group ID
  6. Flag
    1. persisted assign by IANA: 0
    2. temporariry assign: 1
  7. Scope
    1. 2: Link Local
    2. 5: Site Local
    3. 8: Organization Local
    4. E: Global
  8. If Cisco router IPv6 configured, automatically join 3 multicast group.
    1. FF02::1: Same link all nodes
    2. FF02::2: Same link all routers
    3. FF02::1:FF00:0/104(FF02::1:FFxx:xxxx): solicited-node multicast address
  9. IPv6 enabled host automatically join 2 multicast group.
    1. FF02::1: Same link all nodes
    2. FF02::1:FF00:0/104(FF02::1:FFxx:xxxx): solicited-node multicast address
  10. Reserverd IPv6 multicast address examples
    1. FF02::1: Same link all nodes
    2. FF02::2: Same link all routers
    3. FF02::1:FF00:0/104(FF02::1:FFxx:xxxx = FF02::1:FF00:0000 ~ FF02::1:FFFF:FFFF): solicited-node multicast address
    4. FF02::5: Same link all OSPFv3 routers
    5. FF02::6: Smae link all OSPFv3 Designated Routers(DR) or BDR
    6. FF02::9: Same link all RIPng routers (ref. IPv4 multicast is
    7. FF02::A: Same link all EIGRP routers (ref. IPv4 multicast is
    8. FF02::D: Same link all PIM routers (ref. IPv4 multicast is
    9. FF02::1:2: All DHCP Agent
    10. FF05::1:3: All DHCP Server (site local)
    11. FF02::101: Same link all NTP servers
    12. FF05::101: Site local all NTP servers (ref. IPv4 multicast is

Ref. IPv6 / IPv4 multicast address assignment

Scope consideration

  1. 4 bit Scope field can control multicast packet reachability area.
  2. e.g. all node multicast address (Group ID is identical)
    1. FF02::1: send to same link all nodes
    2. FF05::1: send to same site all nodes
    3. FF08::1: send to same organization all nodes
    4. FF0E::1: send to internet everything node(LOL)

MAC address

  1. Starts with 33:33
  2. Under 32 bit is same as IPv6 multicast address under 32 bit.
  3. e.g.
    1. IPv6 multicast address FF00::1:FF22:2222, MAC address is 33:33:FF:22:22:22.
    2. IPv6 multicast address FF00::1, MAC address is 33:33:00:00:00:01.

solicited-node multicast address

  1. solicited-node multicast address used to resolve data link layer address resolution for IPv6.
  2. IPv6 solicited-node multicast corresponds to IPv4 ARP.
  3. FF02::1:FF00:0/104
  4. Under 24 bit mapped under 24 bit of IPv6 unicast or anycast address.
  5. e.g.
    1. IPv6 address is 2037::1:800:200D:8C6C.
    2. solicited-node multicast address is FF02::1:FF0D:8C6C.
  6. IPv6 MAC address resolution: ICMPv6 Type 135: Neighbor Solicitation Message.
  7. Send ICMPv6 Type 135 to solicited-node multicast address.
  8. e.g.
    1. If destination address is FE80::1A3B:5C7E.
    2. solicited-node multicast address is FF02::1:FF3B:5C7E.
    3. IPv6 node send to the solicited-node multicast address and resolve MAC address resolution.
  9. This is why solicited-node multicast address used Neighbor Discovery.

IPv6 Multicast Routing

  1. IPv6 multicast routing assume IPv6 unicast routing successful inter IPv6 routers.
  2. Fundamental strategy is almost same as IPv4 multicast routing.
  3. IGMP for IPv4 correspond to MLD(Multicast Listener Discover) for IPv6.
  4. PIMv2 for IPv4 correspond to “IPv6 PIM” for IPv6. “IPv6 PIM” also called “PIMv6”.
  5. IGMP Snooping for IPv4 correspond to MLD Snooping for IPv6.

What is MLD?

  1. MLD: Multicast Listener Discovery
  2. MLD used by between IPv6 LHR(Last Hop Router) and Receiver.
  3. LHR manages multicast groups by MLD.
  4. MLD version
    1. MLDv1: correspond to IGMPv2
    2. MLDv2: correspond to IGMPv3
  5. FF05::3333

What is IPv6 PIM?

  1. IPv6 PIM is IPv6 multicast routing protocol between IPv6 multicast router.
  2. IPv6 PIM behavior is almost same as IPv4 PIMv2.
  3. However, IPv6 PIM does not have PIM Dense Mode.
  4. So, IPv6 PIM always uses RP for distribution tree.


tech/network/cisco/multicast/routing/pim/ipv6/introduction/introduction.txt · Last modified: 2021/07/16 08:06 by wnoguchi