Re: [v6ops] Net Neutrality question

[Ivan Pepelnjak <[e-mail]>]

When we wrote Diffserv, at the request of certain network operators, we duplicated the Cascade implementation of Frame Relay in four Diffserv PHBs - the Assured Forwarding Service, RFC 2597. The premise is that a service provider can measure the rate at which traffic arrives from a customer or peer, mark the first <mumble> BPS packets AFn1, the next <mumble> BPS packets AFn2, the third <mumble> BPS packets AFn3, and discard anything above that out of hand. Couple that with an AQM implementation that applies different parameters to the different DSCPs (when a queue builds up, the probability of loss of AFn1 is close to zero, probability of loss of AFn2 is a little higher, and the probability of loss of AFn3 is a lot higher), and senders that exceed their contracts are likely to experience loss first. 

It occurs to me that this service could be used in such a network to accomplish a goal similar to RFC 6057, but in a different way. We're not targeting an application, nor are we targeting a specific subscriber or peer. We're targeting any subscriber or peer that exceeds his contract, and only doing so if and when the result is network congestion. We do use loss, but we use it in a way that at least tries to interact with TCP in a gentle way. 

It’s easy to measure user-generated traffic at ingress interface, but really hard to identify and measure per-user traffic sent from the Internet toward the user, as no router I’ve seen so far enables you to measure and mark traffic per-destination-IP (or prefix) and that’s how some people might be using the DPI boxes.

In other words, I have yet to see something that would give every user (identified by IP address or prefix) a fair share of bandwidth.

Note: please don’t start the NAT-breaks-this-idea discussion. I’m well aware of that ;)

Hope this helps,
Ivan