IPv6 Multicast Address 整理(草稿)

rfc 4291

Reserved Multicast Addresses:
  FF0X::0

All Nodes Addresses:  
  FF01:0:0:0:0:0:0:1
  FF02:0:0:0:0:0:0:1

All Routers Addresses:  
  FF01:0:0:0:0:0:0:2
  FF02:0:0:0:0:0:0:2
  FF05:0:0:0:0:0:0:2

Solicited-Node Address:
  FF02:0:0:0:0:1:FFXX:XXXX

   +--------+----+----+---------------------------------------------+
   |   8    |  4 |  4 |                  112 bits                   |
   +------ -+----+----+---------------------------------------------+
   |11111111|flgs|scop|                  group ID                   |
   +--------+----+----+---------------------------------------------+

flags:
                                    +-+-+-+-+
      flgs is a set of 4 flags:     |0|R|P|T|
                                    +-+-+-+-+

  T = 0 indicates a permanently-assigned ("well-known") multicast
  address, assigned by the Internet Assigned Numbers Authority
  (IANA).

  T = 1 indicates a non-permanently-assigned ("transient" or
  "dynamically" assigned) multicast address.

  P flag, RFC3306, Unicast-Prefix-based IPv6 Multicast Addresses
      +--------+----+----+--------+--------+----------------+----------+
      |   8    |  4 |  4 |   8    |    8   |       64       |    32    |
      +--------+----+----+--------+--------+----------------+----------+
      |11111111|flgs|scop|reserved|  plen  | network prefix | group ID |
      +--------+----+----+--------+--------+----------------+----------+
     
      example: A network with a unicast prefix of 3FFE:FFFF:1::/48 would also
               have a unicast prefix-based multicast prefix of
               FF3x:0030:3FFE:FFFF:0001::/96


  R flag, RFC3956, Embedding the Rendezvous Point (RP) Address in an IPv6 Multicast Address
      It can also be used as an automatic RP discovery mechanism in those
      deployment scenarios that would have previously used the Bootstrap
      Router protocol (BSR)

      +--------+----+----+----+----+----+----------------+----------+
      |   8    |  4 |  4 |  4 |  4 | 8  |       64       |    32    |
      +--------+----+----+----+----+----+----------------+----------+
      |11111111|flgs|scop|rsvd|RIID|plen| network prefix | group ID |
      +--------+----+----+----+----+----+----------------+----------+

    When the highest-order bit is 0, R = 1 indicates a multicast address
     that embeds the address on the RP.  Then P MUST be set to 1, and
     consequently T MUST be set to 1, as specified in [RFC3306]

    R = 0 indicates a multicast address that does not embed the address
       of the RP and follows the semantics defined i

scop:
         0  reserved
         1  Interface-Local scope
         2  Link-Local scope
         3  reserved
         4  Admin-Local scope
         5  Site-Local scope
         6  (unassigned)
         7  (unassigned)
         8  Organization-Local scope
         9  (unassigned)
         A  (unassigned)
         B  (unassigned)
         C  (unassigned)
         D  (unassigned)
         E  Global scope
         F  reserved

RFC 4541
2.  IGMP Snooping Recommendations
2.1.  Forwarding rules
2.1.2.  Data Forwarding Rules

   1) Packets with a destination IP address outside 224.0.0.X which are
      not IGMP should be forwarded according to group-based port
      membership tables and must also be forwarded on router ports.

   2) Packets with a destination IP (DIP) address in the 224.0.0.X range
      which are not IGMP must be forwarded on all ports.

3.  IPv6 Considerations
   In IPv6, the data forwarding rules are more straight forward because
   MLD is mandated for addresses with scope 2 (link-scope) or greater.
   The only exception is the address FF02::1 which is the all hosts
   link-scope address for which MLD messages are never sent.  Packets
   with the all hosts link-scope address should be forwarded on all
   ports.