Re: Interface Identifier in ASPTM message in M2UA

Supreet Jain <[email protected]> Tue, 30 Aug 2011 03:24:15 -0700 (PDT)
Newsgroups gmane.ietf.sigtran
Message-ID <[email protected]>
Hi Brain,
 
Thank you for giving insights on this matter.  It is now very clear that the length field should be equal to 8 for MAUP messages. 
 
I would request you to throw some light for messages other than MAUP (such as ASPAC). 
 
RFC 3331, section 3.2 states that:
-----
“The Tag value for the Integer-based Interface Identifier is 0x1.  The  length is always set to a value of 8.”
 
 “The M2UA specific message header will   immediately follow the common message header, but will “only” be used   with “MAUP” messages.”
----
 
As per RFC 3331, "The M2UA specific message header will immediately follow the common message header, but will only be used with MAUP messages".
 
For ASPTM (such as ASPAC) messages it is not very clear on what should be the value of length field. 
 
As per RFC section 3.3.2.7, from the ASPAC message format it appears that multiple interface identifiers values can be used along with a single tag (0x1)….
 
 
 
   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
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |           Tag (0xb)           |            Length = 8         |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                     Traffic Mode Type                         |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |     Tag (0x1=integer)         |            Length             |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   /                                                               \
   \                     Interface Identifiers*                    /
   /                                                               \
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 
It would be great if you could confirm if length can be greater than 8 for ASPAC messages or it has to be always set to 8 for ASPAC as well.
 
Thank you in advance for your views on this matter.
 
Thanks and Regards
Supreet Jain
 

From: Brian F. G. Bidulock <[email protected]>
To: Rajesh Makhija <[email protected]>
Cc: "[email protected]" <[email protected]>; "[email protected]" <[email protected]>; "[email protected]" <[email protected]>
Sent: Tuesday, August 30, 2011 8:47 AM
Subject: Re: [Sigtran] Interface Identifier in ASPTM message in M2UA

Rajesh,

Read RFC 3331/Page 22:

  The Tag value for the Integer-based Interface Identifier is 0x1.  The
  length is always set to a value of 8.

--brian

-- 
Brian F. G. Bidulock
[email protected]
http://www.openss7.org/

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