Re: Query re request routing

[Steve Rudkin <srudkin@jungle.bt.co.uk>]

Yes your concept of ACN (and PCN) in the scenarios document is a good fit
for the case I describe.  In your definition of ACN you state that the
request routing is static. Should you not generalise this to allow it to be
dynamic but under the control of the ACN?

I also agree with Reinaldo's subsequent comment that the term "access"
gives the wrong connotations. Perhaps to complement "Publishing Content
Network" you could use "Consuming Content Network".

Cheers,
Steve Rudkin

>-----Original Message-----
>From:	owner-cdn@ops.ietf.org [SMTP:owner-cdn@ops.ietf.org] On Behalf Of
Phil >Rzewski
>Sent:	Monday, March 05, 2001 11:57 PM
>To:	Steve Rudkin
>Cc:	cdn@ops.ietf.org
>Subject:	Re: Query re request routing>
>>In the case of broadband streamed media on-demand, surrogates need to be as
>>close to the edge of the network as possible and content will mostly likely
>>be pushed to the surrogates in advance.
>>In this situation, I would therefore expect that
>>- with respect to any given request, all candidate surrogates will be within
>>the same CDN, (referred to as the destination CDN)
>>- the origin could well be operated by a different CDN though, (referred to
>>as the source CDN)
>>
>>Whilst there is a need to interconnect distribution systems of the source
>>and destination CDNs (and any intermediaries) and to do the same for
>>accounting systems,  is it necessary for the RRS of the destination CDN to
>>interact with other RRSs? If so, why? If not, should the statement that
>>there is a single authoritative RRS for each *content unit* be
>>modified/qualified in some way. Would it be better to say there is a single
>>authoritative RRS for each *request* ?
>
>I agree with this distinction. It's one of the types of things I am trying 
>to capture in Scenarios by enumerating something called an "Access Content 
>Network" (ACN).
>
>As I see it, there are always going to be Access Content Networks that will 
>try to "own" the user's session. This has traditionally been access ISPs 
>(such as those that use transparent interception to redirect people to 
>caching proxies--yes, naughty, but very real) and in the future will 
>probably be the broadband-type ISPs to which you refer. These "first 
>content hop" boxes (called "avatars", to use an OPES term), owned & 
>controlled by that ACN, are there for the enhancement of the user's entire 
>session. A fine example is the avatars that are in the cable head-ends of 
>cable modem providers today. With the CDI model, these avatars become 
>likely candidates to receive content pushes as you say, and they then 
>become "surrogates" in that context (since they're doing the bidding of 
>some origin server by receiving distributions and sending back accounting 
>data). But the request-routing is completely handled within the domain of 
>that ACN. For this model to work, you can assume that the terms of the 
>"negotiated relationship" essentially say that the ACN will be doing all 
>the necessary capacity planning on those avatars in order to maintain an 
>adequate level of service for their user base. By signing the contract, the 
>publishing side basically assumes the ACN will maintain that level of 
>quality. The publisher is free to use measurement systems to verify this, 
>but they're not like they have some actual control method (in the form of 
>authoritative request routing) to ever stop delivery happening from those 
>ACN's avatars.
>
>In summary, the ACN is doing some form of "edge caching" for their user 
>base today, and they're going to keep doing it. Since that "first content 
>hop" is always going to be owned by that ACN, that will always be a 
>potential bottleneck to the user experience (though it won't be if the ACN 
>does their job). So the publisher might as well accept that fact and 
>leverage the fact that it's there (make the most out of it: leverage it for 
>distribution, milk it for accounting data).
>
>There's still plenty of room for the CDI model we've worked with up until 
>today (that the Authoritative Request-Routing system, near the publisher, 
>has ultimate control). That's because there's going to be plenty of 
>Internet "edge" that won't be covered by avatars, but will be covered by 
>CDNs. There might be two CDNs with surrogates in that neighborhood, it's 
>just a case of choosing the "best" at that moment.
>
>--
>Phil Rzewski - Senior Architect - Inktomi Corporation
>650-653-2487 (office) - 650-303-3790 (cell) - 650-653-1848 (fax)
>