----- Original Message ----- From: "Cameron Byrne" <cb.list6@xxxxxxxxx> To: "Dearlove, Christopher (UK)" <Chris.Dearlove@xxxxxxxxxxxxxx> Cc: <braden@xxxxxxx>; <ietf@xxxxxxxx> Sent: Tuesday, March 05, 2013 8:01 PM On Tue, Mar 5, 2013 at 3:55 AM, Dearlove, Christopher (UK) <Chris.Dearlove@xxxxxxxxxxxxxx> wrote: > I've no idea about the example quoted, but I can see some of their motivation. <snip> In the 3GPP case of GSM/UMTS/LTE, the wireless network will never drop the packet, by design. It will just delay the packet as it gets resent through various checkpoints and goes through various rounds of FEC. The result is delay, TCP penalties that assume delay is loss, ... the end result is that every 3GPP network in the world (guessing) has proxies in place to manipulate TCP so that when you go to speedtest.net your $serviceprovider looks good. Is this good cross-layer optimization, no... but this is how it is. So, fundamentals of CC and TCP have resulted in commercial need for middleboxes in the core of the fastest growing part of the internet. This is sometimes known as "tcp optmization" or "WAN acceleration", both murky terms. <tp> Interesting, there is more life in Congestion Control than I might have thought. But it begs the question, is this something that the IETF should be involved with or is it better handled by those who are developping LTE etc? (It is true that the IETF did TCP without any skin in X.25, 802.3 and so on but this sounds different). Alternatively, when the ICCRG was looking for things to do, I did raise the question of how true it was that (presumed) packet loss was due to congestion (a fundamental assumption of the IETF) and got the impression that that was regarded as an answered question and not a topic for research. From what you say, it sounds more as if the ICCRG should have been looking at it. Tom Petch The issues in CC result is the re-invention of congestion control at higher layers like http://en.wikipedia.org/wiki/QUIC And, fun things like draft-ietf-rtcweb-data-channel CB > -- > Christopher Dearlove > Senior Principal Engineer, Communications Group > Communications, Networks and Image Analysis Capability > BAE Systems Advanced Technology Centre > West Hanningfield Road, Great Baddow, Chelmsford, CM2 8HN, UK > Tel: +44 1245 242194 | Fax: +44 1245 242124 > chris.dearlove@xxxxxxxxxxxxxx | http://www.baesystems.com > > BAE Systems (Operations) Limited > Registered Office: Warwick House, PO Box 87, Farnborough Aerospace Centre, Farnborough, Hants, GU14 6YU, UK > Registered in England & Wales No: 1996687 > > -----Original Message----- > From: ietf-bounces@xxxxxxxx [mailto:ietf-bounces@xxxxxxxx] On Behalf Of Martin Rex > Sent: 05 March 2013 00:42 > To: braden@xxxxxxx > Cc: ietf@xxxxxxxx > Subject: Re: congestion control? - (was Re: Appointment of a Transport Area Director) > > Bob Braden wrote: >> On 3/4/2013 10:20 AM, Roger Jørgensen wrote: >> > I'll ask a rather basic question and hope someone will answer in an >> > educational way - Why is congestion control so important? And where >> > does it apply? ... :-) >> >> Ouch. Because without it (as we learned the hard way in the late 1980s) \ >> the Internet may collapse and provide essentially no service. > > It is PR like this one: > > http://www.fujitsu.com/global/news/pr/archives/month/2013/20130129-02.ht ml > > That gets me worried about folks might try to "fix" the internet > mostly due to the fact that they really haven't understood what > is already there any why. > > -Martin > > > ******************************************************************** > This email and any attachments are confidential to the intended > recipient and may also be privileged. If you are not the intended > recipient please delete it from your system and notify the sender. > You should not copy it or use it for any purpose nor disclose or > distribute its contents to any other person. > ******************************************************************** >