King

King is a novel technique that allows accurate estimation of latencies
between hosts by using nearby DNS servers. The insight is that
service providers often place DNS servers close to the computers they
service. By performing a cleverly constructed sequence of DNS queries
between two nameservers close to the two test points, an accurate
latency measurement can be obtained. What is interesting about this
technique is that it allows accurate latency measurement between any
two arbitrary points. Furthermore, this technique allows measurements
between endpoints which might otherwise be hidden behind firewalls.

There is no doubt that not only is this a great way to use virtual
landmarks for finding latency between nodes. However, as a 2002
paper, I suspect that the appearance of wireless links will make the
long latency effect of the final link to be more common. Now it is
2005 and many people rely solely on WiFi within their own homes or
offices. How to account for this possible slow last-hop (especially
since many WiFi base-stations also provide some kind of fire-walled
NAT) would be an interesting topic for future research.

This is really the only weakness that I can think of. I downloaded
the King tool and gave it a try. It is a really cool little tool.
Received on Thu Nov 03 2005 - 10:23:39 EST