Subject: RE: Usage of IPv6 flow label

From: "Thomas Eklund" <[email-masked]>
Date: Tue, 21 Nov 2000 17:59:55 +0100

Hi Jim,

> 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).

Yes, I agree here in fact I'm writing a draft on this topic and the way I
have intended to see it (then we can debate if people agree) is that we
should have a dual-semantics of the flowlabel and inside the flow-label have
one bit telling if the flowlabel is globally unique and possibly one bit
telling if its ESP encrypted (see earlier discussion about changing the
length field to ip header length field)

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

Agree.

>
> The other option is to use the traffic class bits.

If the bit is not set, you mean? If so of course - I agree.

>
> 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.

Why do you think we need to take extra bits from the flow-label? The way I
thougth most people saw it was to use to two unassigned bits in IPv4
ToS/IPv6 Traffic Class field for ecn??

> 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.

But why not use the extra two bits for ECN and use the flowlabel with dual
semantics:
1) intserv/per flow identification set by the client in the access
2) mpls like semantics in the core with a possibility to do mpls-like TE (I
say mpls like since it should be the same management software operating on a
different traffic plane - v6 header instead of mpls header)

-- thomas

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From: "JIM FLEMING" <[email-masked]>
Date: Tue, 21 Nov 2000 12:16:24 -0600

----- Original Message -----
From: Thomas Eklund <[email-masked]>
> ToS/IPv6 Traffic Class field for ecn??

What "unassigned bits" in IPv4 TOS ?

Next, are we going to see that 0100 is the version number "4" and clearly
those 0's are not being used for much, so they are "unassigned" ? If so,
let's
make them 0101 (i.e. 5) and hope that the unassigned bit makes it to the
other "end", (as in end-to-end)...let's see how far the IPv4 header gets
with
a 0101 in the first few bits....?...what fun...

Jim Fleming
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From: Jim Bound <[email-masked]>
Date: Tue, 21 Nov 2000 19:34:26 -0500

Hi Thomas,

>length field to ip header length field)

OK I will read it.  But I don't support changing the header length field
at all.

>If the bit is not set, you mean? If so of course - I agree.

Yes.

>ToS/IPv6 Traffic Class field for ecn??

Because the diff serv bits are too precious rather take one from 20 than
the few left in tos/class.  But I am not convinced this is the correct
technical answer but might be the only answer.  I got at least 4
different inputs in the customer base for four different uses of the
flowlabel.  But the good news is the needs all aggregate to I hope two
solutions we are discussing now.

>different traffic plane - v6 header instead of mpls header)

Think I answered above on why not the tos/class field.

I suppose if we can bit-twiddle the ECN bits to do what they need to do
and get a differentiation for flowlabel that would be cool.

regards,
/jim

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From: "JIM FLEMING" <[email-masked]>
Date: Wed, 22 Nov 2000 00:47:18 -0600

http://www.ftc.gov/opa/2000/11/wireless.htm
http://www.ftc.gov/os/2000/11/wirelesswrkshp.htm

"SUMMARY: The Federal Trade Commission ("Commission") has set
December 11-12, 2000 as the dates for a public workshop examining
emerging wireless Internet and data technologies and the privacy, security,
and consumer protection issues they raise."

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Jim Fleming