Re: [v6ops] draft-cc-v6ops-wlcg-flow-label-marking-00.txt

["Dale W. Carder" <[e-mail]>]

Thus spake Brian E Carpenter ([e-mail]) on Fri, Jun 30, 2023 at 10:50:24AM +1200:
> 
> I'd never thought about using a Hamming code to generate flow labels.
> But since a given flow must use the same flow label throughout, you can
> only use the regular 5-tuple as input to the Hamming code. I don't
> believe that a Hamming code will give you a discrete uniform distribution,
> but I'm not an expert in that area. An expert known as ChatGPT says:
> "No, a Hamming code does not produce a discrete uniform distribution...
> The non-uniformity of the distribution arises from the fact that Hamming
> codes prioritize error detection and correction capabilities over
> uniformity of codeword distribution."
> 
> So I think that simply using a stateless hash is the best way. These
> days I like FNV (draft-eastlake-fnv) which is easy and cheap to implement.

I think our idea was that it may be possible to explore other encodings to
do something more best-effort towards a uniform distribution.  As our 
usecase of the flow label is for telemetry, the encoding must be reversible,
which likely rules out a lot of approaches.  It might be good to find someone 
with more knowledge in this area.

Dale