Re: Advertisement Protocol -- more thoughts

[Alex French <afrench@vianetworks.com>]

I think that in general, this need no be true. I would like to see this 
negotiated as part of the protocol (ie, I have content x, you can get it 
from server y). The primary motivation for this is when you have a 
transitive peering relationship: Content Provider CP contracts to CDN X to 
carry their content. CDN X has in fact bought capacity from CDN Y (a la IP 
transit).

Now, two reasons why the content should be fetched from CDN X and not from 
the CP:

1 - CND X does not want CDN Y talking to the customer's server, since this 
would reveal the transitive relationship. I suppose you could argue that 
this is a good thing for the content provider, but I see it as a 
contractual issue.

2 - The CP does not want each CDN to hit the origin server for the content. 
This is especially true if the content is large, or the number of CDNs is 
large.

Of course, this will not always be the case. IMHO, it should be a 
negotiated parameter.

At 12:28 PM 10/01/2001, Stephen Thomas wrote:
>My further assumption is that if CDN A advertises (and distributes) 
>content to CDN B, CDN B would actually retrieve/access that content from 
>the origin content provider and not from CDN A. Perhaps this is an invalid 
>assumption?
>
>

--
Alex French
Consultant, Technical Services                     E: afrench@vianetworks.com
VIA NET.WORKS, Inc.                                T: +353 (86) 818 8118
12100 Sunset Hills Rd, Reston VA 20190      F: +353 (865) 818 8118