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Re: delay as a metric, aggregation



On 28-sep-2005, at 14:48, Cedric de Launois wrote:

I elaborated a solution some months ago to estimate delays associated
with a couple of src-dst prefixes. I proposed to associate synthetic
coordinates to a prefix. The euclidean distance between two coordinates
aims to predict the delay between the prefixes. The synthetic
coordinates are computed in a very scalable way by using an algorithm
taken from the p2p litterature.

Yes, I remember your paper and our discussion in Brussels.

I don't remember off the top of my head whether your system had significant downsides or what those are, but do you feel it's so good that it negates the need for actual measurements?

A hybrid system where there are measurements for big hubs and computed estimates for smaller sites could also make sense.

The coordinates of a prefix can be stored in the DNS, using a new
resource record :

Getting the info to the client is probably the most challenging part. The downside of a new RR is that the number of DNS queries is slowly exploding here... It used to be just A, now both A and AAAA, in the future probably also SRV, and so on.

Iljitsch