Subject: RE: Usage of IPv6 flow label

From: "Thomas Eklund" <[email-masked]>
Date: Sun, 19 Nov 2000 16:33:49 +0100

Hi Alex,

> The argument boils down to **forcing "read-only" onto flow labels does
> not pay**. On the contrary.
> I think that the MPLS work is a significant progress on the
> concept, and
> mechanisms of labeling flows, and as you know [(-:],  I think IPv6
> should borrow from it, rather than going against, or going on a path
> that was started before the MPLS effort, but so far didn't go
> far enough
> to be sufficiently significant.
>

I agree with you Alex.

And I also think that IPv6 should "borrow the mechanisms". An I would like
to see a combine model for use of the flow-label where the "intserv"/per
flow model would exist in the access and that a aggregated/"differv"/"mpls"
like model with possibility to re-write the flow label would exist...

 -- thomas

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From: Jim Bound <[email-masked]>
Date: Tue, 21 Nov 2000 00:30:48 -0500

Thomas,

>like model with possibility to re-write the flow label would exist...

The only way I for one would support what your saying is if we also
defined the first bit of the flowlabel to denote it can be rewritable.
That first bit set or not is decided by the client or the clients
network (meaning a zone within which the client exists authoritatively).

If this bit is set then any e-2-e predications are lost and users would
need to understand that.

The other option is to use the traffic class bits.

But I also think the flowlabel can be used when defined by the client
and set by the client to assist greatly the evolution of the ECN model
and help with increasing bandwidth efficiency with TCP to notify a
client with a fast path for the search to find the clients entry in the
table.  So I will argue what the router folks have done with MPLS will
need to be done by those wanting faster searches for congestion and lost
packets with TCP.

Steve's position is par excellence and I would like to see your response
to Steve as Alex has?

/jim

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From: Alex Conta <[email-masked]>
Date: Tue, 21 Nov 2000 18:53:27 -0500

Jim,

So, you would not support Thomas's solution, if the second bit would
denote that the
label is rewritable? 
  [Just kidding (-:....]

Seriously now... if labels are entities known and stored by routers, as
part of a flow state, whether
that is part of a forwarding table, or classification rules table, then,
carrying a "read-only/write" bit of information in each and every
packet's header is not necessary.

I have difficulties parsing your second part of the message....

Alex