[Softwires] MAP Open issues: Interface-id

[Ole Troan <[e-mail]>]

all,

what should the interface-id in MAP IPv6 addresses be?
the interface-id is used both for creating a local source address, and for mapping an IPv4 address + port into an IPv6 destination address.

requirements:
 - MUST be possible for CE's in the domain to calculate with an algorithm based on destination IPv4 address + port
 - MUST encode the destination IPv4 address for out of domain traffic (for translation)
 - MUST be possible to use to configure an IPv6 address on the MAP node
 - MAY be globally unique
 - SHOULD be simple to read (by human or machine) for troubleshooting

possibilities:
1) RFC6052
2) IANA-ish:
   Not globally unique:
                  |   32 bits        |    32 bits       |
                  +------------------+------------------+
                  | 00-00-5E-FE      |  IPv4 address    |
                  +------------------+------------------+
3) IANA type:

   Globally unique, with max sharing ratio of 256:

                  |   24 bits  |    32 bits     | 8 bits|
                  +------------+----------------+-------+
                  | 02-00-5E-FE|  IPv4 address  | PSID  |
                  +------------+----------------+-------+

4)
   Globally unique with "Length" field to allow parsing of interface id (in case of full IPv4 address or IPv4 prefix)

                  <-8-><-------- L>=32 -------><48-L><8->
                  +---+----------------+------+-----+---+
                  | u |  IPv4 address  | PSID |  0  | L |
                  +---+----------------+------+-----+---+

5) New IANA assigned with V flag to allow 'identification' of MAP traffic versus native:

                  <-8-><-------- L>=32 -------><48-L><8->
                  +---+----------------+------+-----+---+
                  | V |  IPv4 address  | PSID |  0  | L |
                  +---+----------------+------+-----+---+


6) Right aligned:

                  <-8-><--0-16->     < 5><--  32  ------>
                  +---+--------+----+---+---------------+
                  | u |  PSID  | 0  | L | IPv4 address  |
                  +---+--------+----+---+---------------+