Re: Comments on draft-fz-6man-ipv6-alt-mark-09

[Tom Herbert <[e-mail]>]

On Mon, May 18, 2020 at 7:39 PM Brian E Carpenter
<[e-mail]> wrote:
>
> Tom,
>
> > It's unclear to me how the FlowMonID is set, how it's used, and why
> > the Flow Label isn't sufficient for this purpose.
>
> That was proposed by the authors and discarded a long time ago, because
> the usage was incompatible with RFC6437. I can't remember the details
> without looking up long-expired drafts and old email. But generally:
> you can't encode semantics in conformant flow labels, because they are
> pseudo-random.
>
Brian,

AFAICT the FlowMonID is just another type of flow identifier in the
packet. For the purposes of correlating flows in the network I believe
it is redundant to the flow label and would otherwise add a lot of
complexity to implement. I think what you might be referring to are
earlier proposals to put the loss signal bits in the flow label and
not use an EH-- that idea is indeed infeasible at this point. IMO, we
should be able to eliminate FlowMonID from the option, but still need
the two signaling bits in the option hence the alt marking option
would contain one byte of data.

Tom

> Regards
>    Brian