[squid-users] Why Squid is great (was: fourth cache off??)

I think this is a good time to suggest a new doctrine on caching and
cache placement. The way to get the most out of a cache is not to buy
a really big one and centralize it, but get a bunch of small ones and
put them topologically close to users.

The main point of a cache is not to serve lots of requests, but rather
to improve the network experience for a certain user population.
Specifically, it reduces latency. Yes, it also saves on bandwidth,
but the reason people care about that bandwidth savings is that users
would have to wait longer if it were used by many requests for popular
content.

Now, the way a cache works best is if it is "near" its user
population. A server delivers content more and more slowly not only
when it is on the other side of a long WAN link, but also as the
number of router and even bridge hops go up. The worst hops are, in
general, at MAEs and other ISP boundaries, but even local router and
bridge hops add their own slownesses, with store/forward latency, and,
queueing latency, and lost packets which cause the worst slowdowns of
all. That loss rate increases quasi-inverse-exponentially with hops,
so keeping down hops is important even on LANs.

What does this have to do with Squid? Well, the best way to keep
servers near clients, maximizing their effectiveness, is not to buy a
really big machine room cache from which to serve the entire company,
but rather to buy several, and place each near a different group.

The best way to do that is buy cheap caches with good latency. And
that means Squid. The swelltech entry that we were all watching had
latency almost as good as any of the Big Guys.

So what can a Squid vendor do to sell to a T3-connected ISP? If
the ISP has just or two offices and POPs, then you're toast. If they
have several POPs, well, maybe now we're in business. Sell them one
for each.

Certainly, a big company, looking to improve effectiveness of even big,
fat network connections, will be a possibility. Try to sell 'em one
cache per group/remote office.

Of course, those of you in the Squid business have to get this out to
your customers. Put at least a bit about it on your front page.
Explain it in a white paper (I intend to do this for pushcache when
timing is appropriate). Say something about it in the next cacheoff
round. Mention it when big customers call.

-- 
Jon Kay        pushcache.com                      jkay@pushcache.com
http://www.pushcache.com/                             (512) 420-9025
Squid consulting				  'push done right.'