Subject: Re: draft-declercq-ppp-ds-sla-negotiation-00.txt

From: Vernon Schryver <[email-masked]>
Date: Tue, 7 Mar 2000 14:04:18 -0700 (MST)

> From: James Carlson <[email-masked]>
> To: [email-masked], [email-masked],
>         [email-masked], [email-masked]

> ...
> > I half disagree.  I think a new NCP to negotiate what is clearly an
> > aspect of IP would be wrong.
>
> Except that it's not so clearly an aspect of *just* IP.  The
> differential queuing services negotiated here could just as easily
> apply to diff-serv for MPLS over PPP, couldn't they?

Yes, if you fiddle with queuing for IP, then you'll probably affect queuing
for other things, which is an arguement for doing it outside of IPCP if
you do it in PPP.  On the other hand, IP is a major protocol so anything
you do to IP will affect other traffic and so on those grounds be pushed
into a new NCP, which wouldn't make sense.  Don't the DiffServ bits only
appear only in IP headers?  If so, wouldn't one expect negotiation of
them, if in PPP, to be in IPCP?

> ...
> Yep; that's exactly what I was saying.  Pop it up to a more closely
> related signaling function -- diffserv extensions to {insert your
> favorite hop-by-hop signaling protocol here}.

yes.

That extending IPCP would be easy is irrelevant to finding the right
place to put it.

It should be repeated that changing the DiffServ parameters with IPCP
would bounce the link and lose packets, while using your favorite
IP or higher hop-by-hop signalling protocol would not.

Vernon Schryver    [email-masked]

---

From: James Carlson <[email-masked]>
Date: Tue, 7 Mar 2000 16:09:55 -0500 (EST)

> them, if in PPP, to be in IPCP?

There's a very strong relationship between MPLS and IP.  In some
traffic engineering deployments, it's assumed that MPLS LSPs are used
to explicitly route to IP-referred objects (BGP next-hops, ABRs, and
such) based on TE constraints.  One would expect that the diffserv
PHBs are created in that context.

(Again, I'm *NOT* advocating a new NCP.  Only that it makes a little
more sense than doing this in IPCP.)

-- 
James Carlson, System Architect                     <[email-masked]>
IronBridge Networks / 55 Hayden Avenue   71.246W   Vox:  +1 781 372 8132
Lexington MA  02421-7996 / USA           42.423N   Fax:  +1 781 372 8090
"PPP Design and Debugging" --- http://people.ne.mediaone.net/carlson/ppp