Can P2P applications learn to play fair on networks?

Tue Oct 23 15:12:35 UTC 2007

Iljitsch van Beijnum wrote:
> On 23-okt-2007, at 15:43, Sam Stickland wrote:
>
>>> What I would like is a system where there are two diffserv traffic 
>>> classes: normal and scavenger-like. When a user trips some 
>>> predefined traffic limit within a certain period, all their traffic 
>>> is put in the scavenger bucket which takes a back seat to normal 
>>> traffic. P2P users can then voluntarily choose to classify their 
>>> traffic in the lower service class where it doesn't get in the way 
>>> of interactive applications (both theirs and their neighbor's).
>
>> Surely you would only want to set traffic that falls outside the 
>> limit as scavenger, rather than all of it?
>
> If the ISP gives you (say) 1 GB a month upload capacity and on the 3rd 
> you've used that up, then you'd be in the "worse effort" traffic class 
> for ALL your traffic the rest of the month. But if you voluntarily 
> give your P2P stuff the worse effort traffic class, this means you get 
> to upload all the time (although probably not as fast) without having 
> to worry about hurting your other traffic. This is both good in the 
> short term, because your VoIP stuff still works when an upload is 
> happening, and in the long term, because you get to do video 
> conferencing throughout the month, which didn't work before after you 
> went over 1 GB.
Oh, you mean to do this based on traffic volume, and not current traffic 
rate? I suspose an external monitoring/billing tool would need track 
this and reprogram the neccessary router/switch, but it's the sort of 
infrastructure most ISPs would need to have anyway.

I was thinking more along the lines of: everything above 512 kbps (that 
isn't already marked worse-effort) gets marked worse effort, all of the 
time.

Sam