On Mon, Oct 31, 2011 at 7:51 AM, Vijay K. Gurbani <[email protected]> wrote:
> On 10/31/2011 08:49 AM, Bill Roome wrote:
>>
>> I don't have complaints, but I do have an observation: A client
>> cannot distinguish between "pids are invalid" and "pids are valid but
>> this server doesn't have reliable cost data for that pair."
>>
>> Does that bother anyone?
>
> The problem, at least as I understand it, is not predicated on a PID
> being valid or invalid.
>
> The validity (or lack thereof) of the PIDs is a function on whether
> they appear in the network map and cost map. Presumably, if they
> appear there, the PIDs are valid.
I agree with Vijay and Ben that looking at the Network Map should be
sufficient (presumably the ALTO Client already has it in order to
interpret the Cost Map).
> However, the greater question is this: does the ALTO provider know
> authoritatively the cost between all PIDs? That is the issue
> under discussion.
>
> Clearly, the ALTO provider cannot know the costs between all PIDs.
> Again, consider our sample topology we used for the bakeoff [1]. In
> that topology, the ALTO provider had authoritative costs for
>
> mypid{1,2,3} -> mypid{1,2,3} +
> peeringpid{1,2} +
> transitpid{1,2} +
> defaultpid
>
> However, asking the ALTO server to provide a cost between defaultpid
> (Internet) and transitpid1 is useless, since at best, the server will
> be indulging in a guess (and at worst, it'd be lying).
I agree - so, just to be sure I'm understanding correctly, do you
think that letting the Cost Map be a sparse matrix solves this issue?
Or do you think there is something else that should be done?
Thanks,
Rich
>
> [1] http://www.ietf.org/mail-archive/web/alto/current/msg01147.html
>
> 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
>
_______________________________________________
alto mailing list
[email protected]
https://www.ietf.org/mailman/listinfo/alto
