Re: [Softwires] MAP Open issues: Interface-id

Ole,

1. Checksum neutrality being an open question, it is relevant here.
2. It is useful AFAIK to distinguish CE addresses from BR addresses.

The best proposal I know so far is as follows (with CNP = Checksum neutrality preserver) 

CE ADDRESS

<- - - - - - IPv6 Unformatted  address (104 bits) - - - ->
+-------------------+----------+----------+---------------+
| Rule IPv6 prefix  |IPv4 suff.| Max PSID |  Padding = 0  |
+-------------------+----------+----------+---------------+
:
:<- - - - - - - - - 64  - - - - - >:<- - - - 40 - - - - ->:
:                                  :\                      \ 
:                                  <8>                      :<- 16 ->
:                                  : :                      :        :
+----------------------------------'-'----------------------+--------+
| IPv6 unformatted address (part 1)|V|                      |   CNP  |        
+----------------------------------+-+----------------------+--------+
<- - - - - - - - - - -  IPv6 address (108 bits)  - - - - - - - - - - >                

BR ADDRESS

+------------------------------------+-+-----------------+-+-------+
|              BR IPv6 prefix        |V|   IPv4 address  |0|  CNP  |
+------------------------------------+-+-----------------+-+-------+
< - - - - - - - - - 64  - - - - - - ><8><- - -  32 - - -><8><  16  > 

Cheers,
RD

Le 4 nov. 2011 à 14:45, Ole Troan a écrit :

> 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  |
>                 +---+--------+----+---+---------------+
> 
> 
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