Re: [alto] Mandatory and optional in alto protocol

[Richard Alimi <[e-mail]>]

Replying to a couple of specific points here (not necessarily in
relation to the mandatory vs. optional debate)...

On Wed, Aug 3, 2011 at 9:13 AM, manbhard <[e-mail]> wrote:
> Hi,
> I agree with the opinion in the meeting that all services should be
> optional. A client should use an ALTO server that advertises the service it
> needs via the directory service. As mentioned below, downloading full
> network and cost maps (and maintaining them) might be a disincentive for
> certain clients.

The proposal was not to mandate that clients download maps. The
proposal would have been to mandate that servers provide the map
services.  Clients can certainly still request the endpoint services
if they are offered.

> Similarly it might be a disincentive to servers run by SPs
> who do not want to export their prefix list, and if forced to will do quite
> a lot of aggregation which undermines the effectiveness of ALTO.

I'm not convinced (and there has been much previous discussion to this
effect on the list) that using the endpoint services really affords
any additional privacy for an ISP when it comes to aggregations.  If I
were configuring an ISP to provide maps to distrusted clients (which
seems to be the model in mind here), i would assume that ALTO clients
would be sending queries continuously trying to learn as much as
possible about how addresses were grouped together (and the costs if
provided), reconstructing the same maps exposed by the map service
anyways.  Put another way, I wouldn't offer any more-detailed
information via the endpoint services than I would be comfortable
revealing via maps.

> An approach that would satisfy the client and server constraints above would
> be all the services that only provide information (properties, costs) for
> that client only.
>
> -Thanks,
> Manish.
>
>
> On 7/26/11 7:59 AM, "Enrico Marocco" <[e-mail]>
> wrote:
>
>> Hi all,
>>
>> I would like to re-spin the discussion about what features in the
>> protocol should be mandatory and what should be optional, offering a
>> slightly different view from an application developer perspective.
>>
>> Current version of the protocol defines a minimal set of mandatory basic
>> features and a bunch of optional services that, with probably the only
>> exception of the endpoint cost service, basically constitute optimizations.
>>
>> This is certainly the ideal situation from a server implementation and
>> deployment point of view, but I'm worried that from an application
>> developer point of view it may constitute a disincentive for ALTO
>> adoption. The case I have in mind is that of applications intended to
>> run in constrained environment -- in smartphones or browser-embedded
>> VMs, for instance -- where filtering services would enable optimization
>> whilst downloading full network and cost maps, and process them locally,
>> would not be an option.
>>
>> I don't have a strong opinion about whether the right approach would be
>> to put the burden of mandatory implementing the optimization on the
>> server, or the burden of being always prepared for the worst case
>> scenario on the application -- or possibly something in between -- and
>> would appreciate to hear any opinions from the group.
>
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