Vijay,
On 31 Jan 2012, at 15:08, Vijay K. Gurbani wrote:
> On 01/31/2012 05:14 AM, stefano previdi wrote:
> ben> This might be a case where we'd need a PID property to distinguish
> ben> "transit" PIDs from "End Host" PIDs.
> ben>
> stefano> sounds pretty reasonable to me.
>
> Ben: I suspect that your question had a foundation of some sort
> and was not simply a fishing expedition ;-)
The question does have a foundation :-) Partly I'm trying to understand
precisely what I can & can not infer from an ALTO map and Bill & Rich's
follow-up confirm a lot of that for me. We probably want to add some text to
the protocol spec to clarify that because I suspect if I'm asking the question
then someone else looking to use ALTO for a purpose that wasn't originally in
scope and who hasn't been involved with ALTO from day 1 might have similar
questions.
At the same time I'm trying to think through the applicability of ALTO to a
number of CDN-related scenarios.
One scenario is whether I can get enough "resolution" out of an ALTO map to
represent the network topology (as it pertains to a CDN) sufficiently. If I
need to augment what I can get from ALTO with raw IGP/BGP routing to get a
sufficient (for the CDN) topology then it negates a good chunk of the value
provided by ALTO IMO. It's worth clarifying here that by "sufficient topology
for a CDN" I don't mean being able to translate a network map back into the raw
network topology, I only need enough topology to overlay a CDN topology on top
of. After thinking a bit more about this I think ALTO as-is probably provides
sufficient information for the purpose although not in the most efficient form
(but that's not showstopper).
The other scenarios relate to using ALTO maps for more than just CDN cache
selection and in those scenarios I'm thinking that ALTO is still probably OK
and I can achieve a lot of what I need without needing ALTO to expose me a
graph, provided there are some common constraints applied by the ALTO server
(like not renaming PIDs) but I need to give those scenarios some more thought.
I might have a couple of ideas for extensions once I'm done (like enabling
entries in the IRD to be given a name/ID) but that's a separate topic.
> Let me ask you this: is the PID property that you would like to put
> in useful for CDN-usage in ALTO? If so, and since others
> (Stefano) appear to agree, then it is worth a larger discussion on
> the need of such a property to support emerging usages of ALTO.
I'm starting to conclude I don't need the PID property to achieve what I want
but I haven't 100% convinced myself of that yet. I think the idea of PID
properties is interesting though so if there's a discussion on them I'll get
involved. I might have some other use cases but I haven;t really given them any
thought yet.
Ben
>
> Thanks,
>
> - vijay
> --
> Vijay K. Gurbani, Bell Laboratories, Alcatel-Lucent
> 1960 Lucent Lane, Rm. 9C-533, Naperville, Illinois 60566 (USA)
> Email: vkg@{bell-labs.com,acm.org} / [email protected]
> Web: http://ect.bell-labs.com/who/vkg/
_______________________________________________
alto mailing list
[email protected]
https://www.ietf.org/mailman/listinfo/alto
