Re: [re-ECN] Pls respond: Do we have a Congestion Exposure community?

[Bob Briscoe <[e-mail]>]

Piers,

At 13:03 17/09/2009, Piers O'Hanlon wrote:
>Hi Bob,
>
>We just had a chat about our ECN/RTP draft and wondered what
>implications re-ECN (or PCN) would have apart from us avoiding the use
>of the Nonce?

For unicast:
It should involve a change to the sender not the protocol, as long as 
the RTCP feedback tells the sender how much CE it has seen.

For multicast:
re-ECN isn't really required so much, as there's already receiver control.

Anyway, IMHO, ECN is not usefully defined for multicast at the mo 
(effectively each packet duplication appears to duplicate the amount 
of congestion). See
S.5 of this tech report (an I-D I did with Jon Crowcroft, but with 
the pictures as a PDF):
<http://www.bobbriscoe.net/pubs.html#ecnip_tr>

That's why I suggested that ECN in RTP should be done in two bites: 
simple unicast case and all the horrible complicated cases 
(multicast, middleboxes etc).


Bob


>Cheers,
>
>Piers
>
>2009/9/9 Bob Briscoe <[e-mail]>uk>:
> > Piers,
> >
> > At 12:51 08/09/2009, Piers O'Hanlon wrote:
> >>
> >> I know I'm a little late but I'd like to register my interest in this
> >> BoF. I'm involved in some drafts using ECN for RTP which would be
> >> relevant to such work.
> >
> > If we get moving, you might end up adding re-ECN to RTP at the same time as
> > you add ECN :)
> >
> >
> > Bob
> >
> >
> >> Cheers,
> >>
> >> Piers O'Hanlon
> >>
> >>
> >> > Date: Wed, 02 Sep 2009 17:33:36 +0100
> >> > To: [e-mail]
> >> > From: Bob Briscoe <[e-mail]>
> >> > Subject: Pls respond: Do we have a Congestion Exposure community?
> >> >
> >> > Folks,
> >> >
> >> > I'd like to try to arrange a Congestion Exposure (re-ECN) BoF in Nov at
> >> > the Hiroshima IETF. If so, we have to notify the area 
> directors v soon - by
> >> > 24:00 UTC Mon 7 Sep 09. #1 gating function for Area Directors: 
> activity on
> >> > an ietf list.
> >> >
> >> > Therefore, pls respond preferably *on this list* if you're interested in
> >> > being involved, no matter how insignificantly, e.g.
> >> >
> >> > - you want congestion visibility for other stuff you're doing
> >> >  (but don't intend to work on it itself)
> >> > - reviewing docs,
> >> > - alternative way to achieve congestion exposure
> >> > - participate in mailing list discussion,
> >> > - co-authoring docs
> >> > - design ways to do incremental deployment
> >> > - using code for other stuff you're doing
> >> > - thinking up new uses for the protocol
> >> > - breaking it
> >> > - analysing benefits/costs
> >> > - implement protocol
> >> > - implement a demo
> >> > - running or participating in trials
> >> > - standing on the sidelines booing or clapping
> >> > - whatever
> >> >
> >> > Perceived problem:
> >> > Most people want to work on something finite like a new cool
> >> > non-TCP-friendly congestion control. Less people want to go into an
> >> > pseudo-infinite loop fixing IP to allow other cool stuff to 
> happen. If you
> >> > want something like re-ECN to be there, but don't have the 
> bandwidth to work
> >> > on it, that's cool too - please say this - it's still palpable 
> support. And
> >> > you will be likely to have review comments related to how you 
> want to use
> >> > it.
> >> >
> >> > Cheers
> >> >
> >> >
> >> > Bob
> >> >
> >> > ________________________________________________________________
> >> > Bob Briscoe,               Networks Research Centre, BT Research
> >>
> >> ________________________________________________________________
> >> Bob Briscoe,               Networks Research Centre, BT Research
> >> _______________________________________________
> >> re-ECN mailing list
> >> [e-mail]
> >> https://www.ietf.org/mailman/listinfo/re-ecn
> >
> > ________________________________________________________________
> > Bob Briscoe,               Networks Research Centre, BT Research
> > _______________________________________________
> > re-ECN mailing list
> > [e-mail]
> > https://www.ietf.org/mailman/listinfo/re-ecn
> >

________________________________________________________________
Bob Briscoe,               Networks Research Centre, BT Research