[e2e] opening multiple TCP connections getting popular

[Keith Moore]

>> PPT slides are here: http://www3.ietf.org/proceedings/07mar/slides/ 
>> tsvarea-3/tsvarea-3.ppt
>>     
>
> Thanks, that's very interesting! (and thanks to David Ros too,
> who also pointed me to these slides in a private email)
>
> So ... the reasons they give are bugs, bugs, bugs.
>   

not just bugs, but bugs in devices that violate the e2e and layering
model because they are components of the network that mess with protocol
elements that are supposed to be opaque to the network. 

related problems include: that their (dys)functions are not easily
observable by the parties affected by them (i.e. they can't easily
determine what device is screwing up their applications), and similarly,
there's no good way for the parties who are responsible for installing
such devices to learn that the devices are screwing with applications.

it is arguable that there need to be some guidelines for implementors of
such devices.  but IETF has always had a difficult time making
recommendations for how to violate their protocols in such a way as to
minimize harm.  (e.g. "if you must do this evil thing, do it this way
rather than this other way"). 

from an IRTF perspective, maybe it would be useful for someone to
collect information about failures caused by devices of this sort,
analyze the reasons for these failures, and determine whether there are
ways for such devices to do what they intend to do without causing
unintended failures.  also it would be useful to see whether there are
ways for failures caused by such devices to become more
visible/accountable to endpoints, or for those failures to become more
visible to the maintainers for such devices.

I don't think that this means that work on congestion control etc. is
hopeless - I think it means that vendors need to learn  how to implement
intermediaries that rarely cause failures that aren't intended as a
matter of policy, and also how to arrange things that when such failures
do occur that the endpoints can recover from them.