[e2e] TCP Loss Differentiation

David P. Reed dpreed at reed.com
Mon Feb 23 09:01:03 PST 2009

Broken middleboxes need to be shamed and blamed.  Can't get there if you 
don't decide to move firmly in a good direction.

Is the Internet ecology so broken that good things that are pretty 
simple just cannot be deployed at all?  What does that imply for any 
hope at all for a "clean slate" other than omphalocentric research by 
hypercautious academics who will never have an impact (other than 
sucking money from NSF and DARPA)?  :-)

Lars Eggert wrote:
> Hi,
> On 2009-2-21, at 3:46, David P. Reed wrote:
>> I think we have no serious debate on any of these things.  I know
>> Cisco's products support ECN, it's really an endpoint stack problem, and
>> the word "lead" was meant to suggest use of Cisco's bully pulpit (white
>> papers, etc.).
> FYI - and this may be clear to you but maybe not to everyone - it's 
> not so much an endpoint problem in the sense that ECN wasn't 
> implemented, it's an endpoint problem in the sense that turning it on 
> makes broken middleboxes misbehave, to a degree where Microsoft for 
> example has decided to leave it off in Vista. See Dave Thaler's slides 
> from a recent IETF meeting:
> http://www.ietf.org/proceedings/07mar/slides/tsvarea-3/sld6.htm (and 
> the one following)
> So we're realistically looking at a deployment delay of max(OS upgrade 
> cycle, NAT upgrade cycle).
> That same slide deck has interesting information on the deployment 
> feasibility of several other TCP features (window scaling, DSACK, F-RTO).
> Lars

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