Re: [Roll] [6lo] WGLC for draft-thubert-6man-flow-label-for-rpl-03

Carsten Bormann <cabo@tzi.org> Thu, 14 August 2014 09:05 UTC

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From: Carsten Bormann <cabo@tzi.org>
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To: "Pascal Thubert (pthubert)" <pthubert@cisco.com>
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Cc: Routing Over Low power and Lossy networks <roll@ietf.org>, Ines Robles <mariainesrobles@googlemail.com>, 6man WG <ipv6@ietf.org>, "6lo@ietf.org WG" <6lo@ietf.org>
Subject: Re: [Roll] [6lo] WGLC for draft-thubert-6man-flow-label-for-rpl-03
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On 14 Aug 2014, at 10:54, Pascal Thubert (pthubert) <pthubert@cisco.com> wrote:

> If the 6lo work concludes as an RFC, it should recommend to prefer the 6lo way against the flow label way.

It is a bit more complicated.

If both representations of the RFC 6553 information are in use:
A compressor may need to decide whether a flow label present in an uncompressed packet is an RFC 3697 flow label or one of these.
A decompressor may need to decide whether the information is to be represented in canonical RFC 6553 form or making use of the flow label hack.

In any case, I’m not a big fan of providing two different ways of doing the same thing, at different layers.
In particular not in the constrained environment.

I really would like to hear a technical argument why the flow label hack is needed.
(Or a political one, if that is the reason.)

Grüße, Carsten