layer 4 switch for efficient/scaleable cache use?

I've been unable to find a layer 4 http switch that really understands
what is needed to be an efficient frontend for a cache farm (multiple
cache boxes at the same place). Of course you want the same URLs to
go to the same cache box (minimizing disk usage, icp traffic, etc).
But you also want even load distribution, even in the case where there
are so many hits to one site that a single cache box can't handle it.
Ie, if www.acme.com is getting lots of hits, an efficient thing to do
would be to send all of http://www.acme.com/[a-n].* to cache1 and
http://www.acme.com/[m-z].* to cache2*. You cannot simple create some
hash value based on the ip address or domain name www.acme.com. And
of course, if cache1 goes down, its load needs to be distributed among the
remaining boxes.

Anyone know of layer 4 switches that do this? We need flexible and
dynamic load distribution that always (or at least under steady state
conditions) directs the same request to the same single cache.

* - bad example and a hash value is better that splitting the alphabit,
but you get the idea.
Received on Wed Mar 03 1999 - 12:22:00 MST