[nanog] Re: Microsoft offering xDSL access

Paul A Vixie paul at vix.com
Fri Jan 23 19:55:19 UTC 1998

> HTTP is not nearly as cacheable as you would think, and caching it has some
> bad side effects in many cases - which your customers will likely bitch 
> about.

(temptation to advertise a product here resisted with some difficulty.)

> Let's say that you can cache 50% of the HTTP traffic, which frankly, from
> what I've seen is HIGHLY aggressive, but I'll be nice and give you that for
> the sake of argument.

50% is easy with two level caching.  you just need fat pipes between the two
levels, and high availability at the root of the hierarchy, and a LOT of users
to help get as much variety as possible in the requests.  i've seen 65% when
the wind was behind it.

> Ok, so its only 500:1 assuming 50% effectiveness on the HTTP side.
> It still won't work.
> Now, if you intend to rate-shape (as opposed to tossing packets on the floor
> when you get overcommitted) then you ARE committing fraud if you don't tell
> the truth about it.  And, frankly, the customer really gets hosed with this
> kind of model - because you have to be pretty predictive for this to give
> you any kind of net gain in effective utilization, which means you apply the
> chokes BEFORE the peak levels get hit.

and this differs from the cable modem internet market in precisely which way?

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