Choosing a deployment method depends on the cost of the bandwidth.
It comes down to a minimization problem. That's the original motivation
for caching/replication and will always be a critical part of Internet
scalability.
It's interesting to compare this to the evolution of distribution of other
forms of content, historically. New technology rolls through the same
set of economic forces as the old.
An important question that Andrew Odlyzko of ATT Research has been
noting for some time, is that historically there is a greater economic
incentive for person-person communication that for content distribution,
and therefore, it may be more important to engineer infrastructure for
the former rather than the latter.
Hilarie
Patrick McManus <mcmanus(_at_)appliedtheory(_dot_)com> 09/21/00 05:39PM >>>
[Mark Nottingham: Mon, Sep 18, 2000 at 08:14:08PM -0700]
It's interesting that Web caching seems to be losing ground to CDNs
so rapidly; to me, this illustrates the point perfectly. Web caching
was always performed in the interest of the access provider, not the
content provider (or arguably even the user). As a result, content
providers don't trust Web caches.
I think your conclusion doesn't go far enough. I completely agree that
caching is moving from a information consumer to information provider
driven model, but I think this is because of both a lack of trust on
the part of the information provider (as you assert) and a desire to
see more thorough deployments. Information consumers, in many
situations, didn't have sufficient motivation to deploy the
infrastructure that the providers do and this limited the breadth of
installations.
CDN as an extension of hosting has really come, and I suspect will be
with us for a while.. it makes interesting economic models available
as choices.. (can I go with a bargain basement origin hosting
facility if I have a decent CDN? Probably depends on your content..)
-P