Hilarie Orman wrote:
Some hint as to the content-type class is often included in the extension
field, isn't it? We've got
hostname components x.y.z...2ld.tld
filename components /a/b/c/.../z.ext
and parameters &this&that&theotherthing
That's a lot of freedom to encode whatever it is that's important. But,
what I'm having trouble understanding is whether or not this is
merely an intra-CDN issue or an inter-CDN issue. I think the crux
of the question is whether or not a vertical ("virtual", "aggregation")
access point can expect to understand the encoding and choose
a surrogate based on that and the information it may have
received from its subsidiary CDN's about available surrogates.
>>> deleuze@ActiVia.net 11/13/00 01:12PM >>>
> From: Fred Douglis <firstname.lastname@example.org>
> >Hilarie raises an interesting question: Does the "Direction System" need
> >to parse the http headers to get more information in order to direct the
> >request to a correct surrogate?
> This should probably be supported, though everything we've done so far
> at just the DNS level has not done that -- instead, one would have
> to embed that sort of info in the DNS name, e.g. images.foo.com versus
I think the direction system clearly needs some information about the type
of data to be delivered:
- a given machine cannot provide all kinds of service. Thus, a CDN may
have to include content specific surrogates (e.g. one for static web, one
for dynamic web, another for streaming...) The direction system would
need content type information to choose the surrogate.
- moreover, a CDN can provide different reach and/or scale to different
traffic types (e.g. streaming probably needs more reach than web).
DNS based redirection works for any present or future application, even if
Although people often make a 'content-aware'/'DNS-based' partition of the
direction systems, DNS based redirection can also be content-aware. It's
simply a matter of including the content type in the domain name. This is
actually already widely in use today (most web servers are named
Such 'typed domain names', can be useful for a CDN direction system but even
more for a direction peering system, where content type information must be
Such a name space would need to be agreed upon by all peerings CDNs.
Dr. Christophe Deleuze Christophe.Deleuze@ActiVia.net
ActiVia Networks http://www.activia.net