[e2e] Skype and congestion collapse.

[Clark Gaylord]

Donald Hoffman wrote:

>But the problem in this case is not with the VoIP traffic, it is with the 
>OTHER traffic.  If I am using VoIP and just web browsing on a reasonable 
>link, there is generally no problem.  The small number of non-VoIP TCP 
>connections generally leave enough fair share for my frugal voice connection.     
>However, my current day job is to design and implement P2P protocols.   
>Generally such protocols can create large numbers of TCP connections per 
>node.   A that point, even with ideal fairness, the proportion of the link 
>left over is less than required for the voice stream.  (Obviously, from a 
>practical standpoint, it is much worse.)  So although the individual TCP 
>flows may be well behaved, the P2P application as a whole is not.   This is 
>  
>
This is why we really do need some notion of QoS other than The Fat 
Pipe.  It doesn't have to be as elaborate as RSVP-disciplined CAC, but 
you need to be able to prioritize traffic that matters and limit the 
amount of traffic that gets prioritized.  It doesn't have to be more 
complex than that, but it has to do at least that.  [Ergo ... left as an 
exercise to the reader.]

Another limiter that would be cool is on the number of flows, but that 
isn't there yet.

--ckg