Subject: [rohc] Empty CSRC list issue in IR packet.

From: Remi Pelland <[email-masked]>
Date: Mon, 25 Aug 2003 18:17:17 -0400

Hi,

A couple of weeks ago, there was a discussion about a section in the latest
implementer's guide that corrects RFC 3095 with regards to the handling of
empty CSRC lists: section 5.7.7.6 of the RFC says that an empty generic list
is inserted, while section 4.3.3. of the implementer's guide modifies the
RFC by saying that no generic list should be present.

There seemed to be a concensus among those involved in the discussion to
follow the RFC since this is how interoperability was tested.  That's fine
and I do not want to restart the discussion on this.

Now, it has been a couple of weeks and there hasn't been any final
conclusion on this issue (i.e. officially stating that the RFC method should
be used, anouncing the associated correction to the implementer's guide,
etc...).  

Based on the concensus that existed, I don't think there's a problem for
those who currently receive mailing list messages.  However, it seems to me
like there's a risk that future implementations may use either methods,
leading to interoperability problems.

Thanks,
Remi.

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---

From: Ghyslain Pelletier <[email-masked]>
Date: Wed, 27 Aug 2003 16:05:52 +0200

Hi all,

Does the following summarizes accurately the consensus that Remi is
looking after?

1) Section 4.3.1 and 4.3.2 of the implementer's guide clarifies
   rfc3095, and they should remain as they are.
   
   The text is clear, bring a clarification inline with the
   standard, and this has been interop tested. These two sections
   therefore do not need to be modified. In summary, when an empty
   CSRC list is present, an empty generic list (1-2 octets) must be
   inserted.

   Tommy's mail would then represent the consensus on this:
  
http://www1.ietf.org/mail-archive/working-groups/rohc/current/msg01654.html

2) Section 4.3.3 of the implementer's guide should be removed.

   Section 4.3.3 of the implementer's guide is a "deviation" from the
   standard that proposes an improvement that would remove the need to
   send an empty generic list (1-2 octets) in the presence of an empty
   CSRC list. It is a deviation in the sense that the generic CSRC list
   in rfc3095 is of variable lenght but is not optional (must be
   present), while the text in 4.3.3 is keeping it of variable length
   but makes it optional.

   Section 4.3.3 should thus be removed from the implementer's guide,
   but could later be considered as a proposed improvement when
   bringing rfc3095 to draft standard if the profile gets updated at
   the same time.

   Abigail's mail would then represent the consensus on this:
  
http://www1.ietf.org/mail-archive/working-groups/rohc/current/msg01655.html

Is my understanding of the conclusions/consensus correct?
If so, then we will update the Implementer's guide accordingly.

/Ghyslain

-- 
Ghyslain Pelletier, Dipl. Ing.
Wireless IP Optimizations
AWARE - Advanced Wireless Algorithm Research
Ericsson Research, Corporate Unit

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