Home page logo

nanog logo nanog mailing list archives

Re: [nanog] Re: Microsoft offering xDSL access
From: Karl Denninger <karl () mcs net>
Date: Fri, 23 Jan 1998 15:40:20 -0600

On Fri, Jan 23, 1998 at 11:55:19AM -0800, Paul A Vixie wrote:
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 

(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?

Uh, it doesn't :-)

(I've done the analysis of this for a cable company a couple of years ago).

Karl Denninger (karl () MCS Net)| MCSNet - Serving Chicagoland and Wisconsin
http://www.mcs.net/          | T1's from $600 monthly to FULL DS-3 Service
                             | NEW! K56Flex support on ALL modems
Fax:   [+1 312 803-4929]     | *SPAMBLOCK* Technology now included at no cost

  By Date           By Thread  

Current thread:
[ Nmap | Sec Tools | Mailing Lists | Site News | About/Contact | Advertising | Privacy ]