RE: hard questions: request routing

[Eric Dean <eric@crystalballinc.com>]

> One concern with this approach would be transient routing loops.  Simply
> providing a path vector in the RR protocol does not prevent transient routing
> loops. The severity of the problem depends on the dynamic of the topology
> changes. Providing similar information on a per request basis would prevent
> that problem, however, it is a rather ugly solution.

By topology changes, you mean with respect to the client

> Another concern here is that the goal for CDI is slightly different from L3
> peering (best effort connectivity). CDNs were invented to decrease latency,
> increase throughput and reduce cost. Therefore, forcing everybody to use a

Another important differentiator is that IP networks are
destination-based, while CDN's are client source based.  Request routing
looks at the source of the requestor making content requests.  I don't
understand why simple path-vectors do not address loop prevention.  

> At this point I think the most sensible solution might be to restrict
> the number of redirections to at most: 
> 
> content owner->authoritative CDN->second level CDN 

I'm not sure how such restrictions can be imposed.