[re-ECN] Problem Statement (was Re: Pls bash: Congestion Exposure (re-ECN) BoF inHiroshima?)

[ken carlberg <[e-mail]>]

Toby,

here are some comments/questions as food for thought...

> One of the strengths of the Internet is its ability to share  
> capacity and avoid congestion collapse by using distributed  
> algorithms executed on its end-hosts.  While the resulting  
> allocation of capacity is fair in a certain mathematical sense, it  
> is not necessarily fair in other economic or philosophical senses.

is "fairness" also determined by temporal qualities?...instantaneous  
condition versus some period of time, or accumulated accounting.

> Further, end-hosts have means to "game the system" to increase their  
> access to capacity, and to progress communications even in the  
> presence of persistent congestion. As a consequence ISPs feel they  
> have to police "heavy users" to free up resources for the bulk of  
> their customers. This involves making assumptions about the wishes  
> of their customers which in turn is eroding trust between ISPs,  
> customers, content providers and application writers.
>
> ISPs have a variety of measures available to them to reduce  
> congestion, or to skew access to capacity amongst their users,  
> ranging from the complex (per-user fair queuing, volume-based  
> billing) to the crude (per-application prioritization or rate  
> capping).  A problem with such mechanisms is that they control the  
> wrong quantity: it is not the total volume or absolute rate of  
> traffic of a particular user or application that impedes service to  
> other users; rather, it is the excess traffic that causes others to  
> experience congestion that is the real problem.

at the risk of being picky, what is considered "excess traffic"?  Is  
it traffic beyond that negotiated or configured per aggregate or  
application, or some standard deviation above previous traffic levels  
of a flow?  As a reviewer, I could easily find myself asking "excess  
in relation to what?"

> Current work at the IETF [LEDBAT, ALTO] and IRTF [ICCRG] is looking  
> at new approaches for controlling bulk data transfer rates.  But  
> ISPs have no means for enforcing their use and indeed may even be  
> hindering their deployment through their crude attempts at traffic  
> control. This means the ISPs still have an incentive to deploy the  
> flawed tools at their disposal to manage capacity and reduce  
> congestion.  What ISPs lack is a way to measure or even see the  
> congestion caused by a user’s excess traffic on an end-to-end  
> basis.  Such a measure could be used to build trust between  
> operators and end-users and between different tiers of operators. In  
> short the Internet lacks a system for accountability

if you are making an argument for "trust" between operators and end- 
users, don't you have to advocate complimentary efforts like  
integrity?  Or is Security (other than recognizing its importance)  
outside the scope of the BoF?

Finally, I'd also shy away from bringing up PCN at this point.  There  
is no dependency on it, and I think its best not to increase the  
probability of confusing reviewers that have just a few cycles to read  
and decide what is being proposed.  But I like what has been written  
so far.

-ken