Re: [AVT] Comments on draft-ietf-avt-hc-mpls-reqs-00.txt

On 29 Apr 2004, at 12:53, Lars-Erik Jonsson (LU/EAB) wrote:
> Colin, Kristofer, and others,
>
>>> Comment 1:
>>> **********
>>> When reordering is discussed in section 3, it is not made clear how
>>> the HC scheme is supposed to handle reordering. Is the requirement
>>> that the decompressor should be able to correctly decompress all
>>> reordered packets, or is it enough that it can ensure no
>>> incorrectly decompressed packets will be forwarded, i.e. avoid
>>> context damage? I assume that correct decompression is the intention,
>>> but it could be made more clear.
>>
>> I would suggest that the requirement is that packet
>> reordering MUST NOT cause incorrectly decompressed packets
>> to be forwarded on from the decompressor. We would clearly
>> like a solution that lets the decompressor correctly
>> decompress reordered packets, but that's an optimisation
>> rather than a hard requirement.
>
> What does a use of MUST NOT in this context actually mean? Does
> it mean the compressed (or uncompressed) header must be protected
> by a CRC of infinite size? Seriously, I agree with the content of
> your comment, not forwarding incorrect packets is the hard
> requirement. However, this example just makes me more convinced we
> should not use 2119 keywords in this document, but instead write
> what we actually mean our intentions are.

In this context, I really don't care whether the draft says "MUST NOT" 
or "must not"... The intent is clear in either case.

Colin

_______________________________________________
Audio/Video Transport Working Group
avt@ietf.org
https://www1.ietf.org/mailman/listinfo/avt