Re: [rohc] Byte-alignment

["Lars-Erik Jonsson" <lars-erik.jonsson@ericsson.com>]

Some days ago, I sent this question to the list. Since there have been no
arguments against the opinions I raised in this issue, I would like to make a
request to put this into the requirements document. Even if it is obvious to me
that the scheme should be byte-aligned, I know that it is not clear to all of
those involved in this. Therefore the requirements document must state that only
byte-aligned solutions should be considered.

Micke, will you include that in some way??

BR
/Lars-Erik





>Hi all ROHC-ers!
>
>Discussion of technical issues on this list is of fundamental importance to get
>results in the WG. I will therefore start with a discussion about the
>byte-alignment issue and I hope we can clear this out easily.
>
>The question is whether there is any reason to design a robust header
>compression framework that can support non-byte-aligned versions of the scheme.
>I do not think so. All link-layers I have seen are byte-aligned and that is
also
>preferrable from an implementation point of view.
>
>This question is important because the answer gives different approaches to the
>problem.
>1) When designing a non-byte-aligned scheme, the objective is to make all
fields
>as small as possible on a bit-level.
>2) For byte-aligned schemes the objective is instead to squeeze as much
>information as possible into 1, 2 or several bytes. Then the smallest possible
>header size must always be used.
>
>We MUST always have versions of the scheme that are designed byte-aligned. A
>non-byte-aligned scheme may be instantiated to byte-alignment but will not make
>use of all bits in an optimal way.
>
>I think it is important to clarify that (and if) we are only considering
>byte-aligned solutions. Some mechanisms for non-byte-aligned solutions will not
>be usable at all in a byte-aligned scheme and we could then ignore such
>mechanisms when discussing solutions.
>
>Regards!
>/Lars-Erik
>
>
>--------------------------------------------------------------
>Lars-Erik Jonsson, M.Sc. - Ericsson Research
>AWARE - Advanced Wireless Algorithm Research at Erisoft
>Box 920, S-971 28 Luleå, Sweden
>E-mail: lars-erik.jonsson@ericsson.com
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