North American Network Operators Group|
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Re: topological closeness....
>one other solution (being implemented, I believe), is a DNS server >that listens to the BGP traffic, so it knows how far away things are, >and when you ask it, it can chose from multiple responses to pick >one "close". > > -mo The only problem that it does not work at all. Which WWW server is closer to me - one with BGP path 1239 3491 690 1333 (cnn.com) or one at 1239 1792 (www.cnc.ac.cn)? The second is in China, for God's sake! There ain't no such thing as global metrics. The only useful kind of metrics is administrative, and therefore they cannot reflect any real characteristics of paths. Even if there are uniform metrics, how do you tell which link is overloaded and which isn't? Cacheing appears to be the only sane way to distribute load. You always know where the closest cacheing server is. Now, there's a problem with coherency, but at least it can be done w/o magic. --vadim - - - - - - - - - - - - - - - - -