North American Network Operators Group

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Re: Transparent Caching Solutions - Information Wanted

  • From: Paul A Vixie
  • Date: Wed Feb 04 12:17:32 1998

several folks have sent replies to me personally which may be of general

> Hit rates are user population dependent. We have seen hit rates
> as high as 30% from a single T1 connected customer (with a population
> of less then 500 people).

so have we.  but that was a computer club with its own POP and they were
mostly sharing interesting (i.e., pornographic) URL's over an IRC back

we've got ~80 transparent caching units out in the field, and most of them
are in "normal" modem pools where the users don't know each other and the
communitities of interest have broader splay.

> ... in some special cases you really can predict what would best be in the
> cache beforehand.  You then win from a speed standpoint (pre fetched data
> is served up faster).

yes, that's true -- in some special cases you can exercise prescience and
if you can then the hit rate goes up by a lot as does the downstream data

however, to make this work you have to continuously feed the primary caches
new prescient data (or prescient metadata by which prescient data can be
fetched).  interest factor is in other words dynamic and shortlived.