rfc2894.txt

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   The use of authentication for Router Renumbering Result messages is
   RECOMMENDED.








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3.1.  Router Renumbering Header

    0                   1                   2                   3
    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |     Type      |     Code      |            Checksum           |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                        SequenceNumber                         |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   | SegmentNumber |     Flags     |            MaxDelay           |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                           reserved                            |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   Fields:

   Type        138 (decimal), the ICMPv6 type value assigned to Router
               Renumbering

   Code          0 for a Router Renumbering Command
                 1 for a Router Renumbering Result
               255 for a Sequence Number Reset.
               The Sequence Number Reset is described in section 5.

   Checksum    The ICMPv6 checksum, as specified in [ICMPV6].  The
               checksum covers the IPv6 pseudo-header and all fields of
               the RR message from the Type field onward.

   SequenceNumber
               An unsigned 32-bit sequence number.  The sequence number
               MUST be non-decreasing between Sequence Number Resets.

   SegmentNumber
               An unsigned 8-bit field which enumerates different valid
               RR messages having the same SequenceNumber.  No ordering
               among RR messages is imposed by the SegmentNumber.

   Flags       A combination of one-bit flags.  Five are defined and
               three bits are reserved.

                                  +-+-+-+-+-+-+-+-+
                                  |T|R|A|S|P| res |
                                  +-+-+-+-+-+-+-+-+








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              The flags T, R, A and S have defined meanings in an RR
              Command message.  In a Result message they MUST be
              copied from the corresponding Command.  The P flag is
              meaningful only in a Result message and MUST be zero in
              a transmitted Command and ignored in a received Command.

              T   Test command --
                  0 indicates that the router configuration is to be
                    modified;
                  1 indicates a "Test" message: processing is to be
                    simulated and no configuration changes are to be
                    made.

              R   Result requested --
                  0 indicates that a Result message MUST NOT be sent
                    (but other forms of logging are not precluded);
                  1 indicates that the router MUST send a Result
                    message upon completion of processing the Command
                    message;

              A   All interfaces --
                  0 indicates that the Command MUST NOT be applied to
                    interfaces which are administratively shut down;
                  1 indicates that the Command MUST be applied to all
                    interfaces regardless of administrative shutdown
                    status.

              S   Site-specific -- This flag MUST be ignored unless
                  the router treats interfaces as belonging to
                  different "sites".
                  0 indicates that the Command MUST be applied to
                    interfaces regardless of which site they belong
                    to;
                  1 indicates that the Command MUST be applied only to
                    interfaces which belong to the same site as the
                    interface to which the Command is addressed.  If
                    the destination address is appropriate for
                    interfaces belonging to more than one site, then
                    the Command MUST be applied only to interfaces
                    belonging to the same site as the interface on
                    which the Command was received.

              P   Processed previously --
                  0 indicates that the Result message contains the
                    complete report of processing the Command;






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                  1 indicates that the Command message was previously
                    processed (and is not a Test) and the responding
                    router is not processing it again.  This Result
                    message MAY have an empty body.

   MaxDelay   An unsigned 16-bit field specifying the maximum time, in
              milliseconds, by which a router MUST delay sending any
              reply to this Command.  Implementations MAY generate the
              random delay between 0 and MaxDelay milliseconds with a
              finer granularity than 1ms.

3.2.  Message Body -- Command Message

   The body of an RR Command message is a sequence of zero or more
   Prefix Control Operations, each of variable length.  The end of the
   sequence MAY be inferred from the IPv6 length and the lengths of
   extension headers which precede the ICMPv6 header.

3.2.1.  Prefix Control Operation

   A Prefix Control Operation has one Match-Prefix Part of 24 octets,
   followed by zero or more Use-Prefix Parts of 32 octets each.

3.2.1.1.  Match-Prefix Part

    0                   1                   2                   3
    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |    OpCode     |   OpLength    |    Ordinal    |   MatchLen    |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |    MinLen     |    MaxLen     |           reserved            |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                                                               |
   +-                                                             -+
   |                                                               |
   +-                         MatchPrefix                         -+
   |                                                               |
   +-                                                             -+
   |                                                               |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   Fields:

   OpCode      An unsigned 8-bit field specifying the operation to be
               performed when the associated MatchPrefix matches an
               interface's prefix or address.  Values are:

               1    the ADD operation



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               2    the CHANGE operation

               3    the SET-GLOBAL operation

   OpLength    The total length of this Prefix Control Operation, in
               units of 8 octets.  A valid OpLength will always be of
               the form 4N+3, with N equal to the number of UsePrefix
               parts (possibly zero).

   Ordinal     An 8-bit field which MUST have a different value in each
               Prefix Control Operation contained in a given RR Command
               message.  The value is otherwise unconstrained.

   MatchLen    An 8-bit unsigned integer between 0 and 128 inclusive
               specifying the number of initial bits of MatchPrefix
               which are significant in matching.

   MinLen      An 8-bit unsigned integer specifying the minimum length
               which any configured prefix must have in order to be
               eligible for testing against the MatchPrefix.

   MaxLen      An 8-bit unsigned integer specifying the maximum length
               which any configured prefix may have in order to be
               eligible for testing against the MatchPrefix.

   MatchPrefix The 128-bit prefix to be compared with each interface's
               prefix or address.
























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3.2.1.2.  Use-Prefix Part

    0                   1                   2                   3
    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |    UseLen     |    KeepLen    |   FlagMask    |    RAFlags    |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                        Valid Lifetime                         |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                      Preferred Lifetime                       |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |V|P|                         reserved                          |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                                                               |
   +-                                                             -+
   |                                                               |
   +-                          UsePrefix                          -+
   |                                                               |
   +-                                                             -+
   |                                                               |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   Fields:

   UseLen      An 8-bit unsigned integer less than or equal to 128
               specifying the number of initial bits of UsePrefix to
               use in creating a new prefix for an interface.

   KeepLen     An 8-bit unsigned integer less than or equal to (128-
               UseLen) specifying the number of bits of the prefix or
               address which matched the associated Match-Prefix which
               should be retained in the new prefix.  The retained bits
               are those at positions UseLen through (UseLen+KeepLen-1)
               in the matched address or prefix, and they are copied to
               the same positions in the New Prefix.

   FlagMask    An 8-bit mask.  A 1 bit in any position means that the
               corresponding flag bit in a Router Advertisement (RA)
               Prefix Information Option for the New Prefix should be
               set from the RAFlags field in this Use-Prefix Part.  A 0
               bit in the FlagMask means that the RA flag bit for the
               New Prefix should be copied from the corresponding RA
               flag bit of the Matched Prefix.

   RAFlags     An 8 bit field which, under control of the FlagMask
               field, may be used to initialize the flags in Router
               Advertisement Prefix Information Options [ND] which
               advertise the New Prefix.  Note that only two flags have



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               defined meanings to date: the L (on-link) and A
               (autonomous configuration) flags.  These flags occupy
               the two leftmost bit positions in the RAFlags field,
               corresponding to their position in the Prefix
               Information Option.

   Valid Lifetime
               A 32-bit unsigned integer which is the number of seconds
               for which the New Prefix will be valid [ND, SAA].

   Preferred Lifetime
               A 32-bit unsigned integer which is the number of seconds
               for which the New Prefix will be preferred [ND, SAA].

   V           A 1-bit flag indicating that the valid lifetime of the
               New Prefix MUST be effectively decremented in real time.

   P           A 1-bit flag indicating that the preferred lifetime of
               the New Prefix MUST be effectively decremented in real
               time.

   UsePrefix   The 128-bit Use-prefix which either becomes or is used
               in forming (if KeepLen is nonzero) the New Prefix.  It
               MUST NOT have the form of a multicast or link-local
               address [AARCH].

3.3.  Message Body -- Result Message

   The body of an RR Result message is a sequence of zero or more Match
   Reports of 24 octets.  An RR Command message with the "R" flag set
   will elicit an RR Result message containing one Match Report for each
   Prefix Control Operation, for each different prefix it matches on