Subject: [rohc] SigComp clarifications

From: "Surtees, Abigail" <[email-masked]>
Date: Wed, 12 May 2004 10:19:46 +0100

Hi Folks,

A couple of minor ambiguities in SigComp have come to light.  If we can
agree on the outcome, then I'll write some text for the implementer's guide.
I believe it was also agreed that the DAP specification used for SIPit
should be put as an annex to the implementer's guide.  I'll do this in the
same update.

Byte copying rules:

Section 8.4 of 3320 does not list CRC but 9.3.5 does say byte-copying rules
apply.  Presumably byte copying rules do apply?

The SHA-1 instruction uses byte-copying rules to write the computed hash to
UDVM 
memory.  Should byte copying rules be used for reading a partial state
identifier provided by a STATE-FREE instruction?

The STATE-FREE instruction doesn't say so, nor is it listed in section 8.4.
However, if the byte-copying rules don't apply, then if you were do a SHA-1
instruction and write the identifier into the circular buffer, (though I
can't currently see any reason for wanting to do so) and then free some
state using STATE-FREE and that identifier, the identifier would be read
incorrectly.

A similar question applies to the feedback items and whether they should
obey byte-copying rules - the requested feedback could be the result of a
SHA-1 instruction which obeys byte-copying rules.

The END-MESSAGE description uses the term 'byte-copy' when referring to the 
partial state id but does not explicitly reference 8.4 (though it is
mentioned there).

Any thoughts welcome.

Best regards,

Abbie

Abbie Surtees
Senior Engineer
Networks
Roke Manor Research Ltd
Old Salisbury Lane
Romsey, SO51 0ZN
Tel:   +44 (0) 1794 833131

_______________________________________________
Rohc mailing list
[email-masked]
https://www1.ietf.org/mailman/listinfo/rohc