Subject: [alto] Is an endpoint-services-only server legal?

From: Wendy Roome <[email-masked]>
Date: Wed, 24 Jul 2013 13:04:38 -0400

Here's a new question for you: should an ALTO server that only offers the
endpoint cost and properties services be considered a legitimate ALTO
server?

I think the protocol currently requires an ALTO server to provide a full
network map and full cost map service, so an endpoint-only server is
illegal.

However, I think we should allow them. Why? Because that's what clients
want. Clients really care about costs between endpoints. Clients do not
care about PIDs.

So why have PIDs and full cost maps at all? PIDs are necessary to make the
endpoint space manageable. But PIDs are not an end to themselves, just a
means to an end. Full cost maps exist for high performance clients, like
busy p2p trackers, who might need to do 100's of queries per second.

But for low-volume clients, an endpoint cost service is perfectly
adequate, and much easier to use.

Incidentally, a provider could work around the network map requirement by
defining a trivial network map with one default PID (for 0.0.0.0/0) and a
dummy cost map that returns no costs. But should we force a server to
resort to that subterfuge?

In terms of the protocol document, I think that just means dropping the
"MUST provide" sentences from {10.1.1} and {10.1.2}.

	- Wendy Roome

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From: "Y. Richard Yang" <[email-masked]>
Date: Wed, 24 Jul 2013 13:41:31 -0400

Hi Wendy,

> "MUST provide" sentences from {10.1.1} and {10.1.2}.
I agree with this point. As my understanding of the potential deployment of
ALTO evolves, I see more diverse deployment scenarios. The case of only an
endpoint property service (e.g., to help with DC localization with a simple
mechanism), or only an endpoint cost service (proxidor), as you nicely
argued for, appear to be legitimate deployment scenarios for me, and adding
"dummy" maps to satisfy the spec to be conforming appears to be less
elegant/pure. How about we listen others' feedback, and then make a
decision in the next few days?

Thanks!

Richard

>         - Wendy Roome
>
>
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From: "Vijay K. Gurbani" <[email-masked]>
Date: Wed, 24 Jul 2013 20:24:28 -0500

On 07/24/2013 12:41 PM, Y. Richard Yang wrote:
> I agree with this point. As my understanding of the potential deployment
> of ALTO evolves, I see more diverse deployment scenarios. The case of
> only an endpoint property service (e.g., to help with DC localization
> with a simple mechanism), or only an endpoint cost service (proxidor),
> as you nicely argued for, appear to be legitimate deployment scenarios
> for me, and adding "dummy" maps to satisfy the spec to be conforming
> appears to be less elegant/pure. How about we listen others' feedback,
> and then make a decision in the next few days?

Richard, all: A while ago, we went through the exercise to determine
which services should be considered mandatory.  We did not get too far
in establishing consensus on the issue.

I think it is best not to open up that discussion again, especially if
our thinking has not evolved much beyond what it was when we last
tackled this issue.

Specifying dummy maps may not be elegant, but it allows us to proceed
with a documented plan of action.

Thanks,

- vijay
-- 
Vijay K. Gurbani, Bell Laboratories, Alcatel-Lucent
1960 Lucent Lane, Rm. 9C-533, Naperville, Illinois 60563 (USA)
Email: vkg@{bell-labs.com,acm.org} / [email-masked]
Web: http://ect.bell-labs.com/who/vkg/  | Calendar: http://goo.gl/x3Ogq

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From: Sebastian Kiesel <[email-masked]>
Date: Thu, 25 Jul 2013 09:55:16 +0200

> in establishing consensus on the issue.

AR-23 in RFC 6708  is based on consensus - or at least dud not cause
significant opposition.

> our thinking has not evolved much beyond what it was when we last

+1

Sebastian