Re: [nznog] QoS-IXPs

From a technical perspective, how do you implement it? How do you ensure fairness? What resources do I need to provide to my customers to ensure

I agree that there are always situations where congestion can occur, some more theoretical, and some more real world (Olympics, Elections, Hillary Funeral, etc...). The problem I perceive is an arms race, the sort of thing that the network neutrality people are all scared of. What happens during one of these events if a party A observes that they're getting congestion delivering their content to end users. They're not in a position to magic more bandwidth out of thin air, at least not at short notice, so instead they up the priority of their traffic. Like magic the problem is solved, the exchange fabric prioritises their traffic ahead of everyone elses. Problem occurs when party B, sick of their end users complaining also decides to up their priority. Party A reacts in kind and ups theirs further. Meanwhile the other participants in the exchange, getting annoyed with the deteriorating performance start playing the same games. Before you know it, any potential benefit of QoS has been lost (and a certain amount of credibility). This doesn't even touch on the sensitive topics of "Mr Exchange operator, I'm your biggest customer so I expect you to give me higher priority", or "I'm the exchange operator and I'd like to promote my own product, so let me just tweak that setting". The above is somewhat contrived, but I believe the point is sound. Making QoS work between two parties is easy, they sit down around a table and hammer out an agreement. When you start talking about a neutral exchange with many participants how do you get everyone to agree? Does the exchange operator define a set of rules, maybe an AUP and impose it on all participants? Do you solicit feedback from the users? How do you deal with people breaching those rules? they can take advantage of it? (lets be blunt here, QoS on many platforms is far from trivial). What if some participants want to opt out of using QoS, how do you ensure fairness for them? I don't see any of the above preventing the exchange passing CoS attributes around in BGP, but honouring them is another matter. Dylan On Fri, 2009-03-27 at 12:35 +1300, Richard Wade wrote:

On Fri, Mar 27, 2009 at 10:06 AM, Thomas M. Knoll wrote:

The switch fabric is over engineered and so are the customer ports. Within this constellation, there is no chance and no need for 802.1p. Full stop.

Is there not the consideration of failure or unanticipated traffic event scenarios which mean that prioritisation of certain traffic would be desirable? In the abnormal event of congestion, would not the peers like traffic marked as high priority to be preserved over the L2 matrix? -- r _______________________________________________ NZNOG mailing list NZNOG(a)list.waikato.ac.nz http://list.waikato.ac.nz/mailman/listinfo/nznog