Subject: [alto] Protocol issue: non-authoritative information

From: Enrico Marocco <[email-masked]>
Date: Sat, 27 Aug 2011 07:59:42 +0200

In order to fulfill the "server operated by a third-party" requirement,
the ALTO protocol is designed in such a way to allow servers to provide
cost information about networks they are not "authoritative" for.
However, current specification does not provide a means for indicating
some sort of reliability/accuracy level of the provided information.
Such indication could be useful, for instance, in the case of a server
operated by a network operator, when providing (guessed?) cost
information about paths originating and terminating in networks it does
not directly operate.

(Related to this, is also the issue of a clearer specification of the
server behavior when queried about information it does not have nor is
willing to guess. This has been suggested to be addressed with the
definition of a specific error code.)

Possible options (please express and possibly motivate your preference):

  1. do not add anything to the protocol and always assume that the
     server is fully confident in every piece of information it
     provides;

  2. define a binary value field for indicating whether the server is
     authoritative for each network/pid it is providing cost
     information for;

  3. define a discrete or continuous value field for the reliability of
     each piece of cost information provided in responses;

  4. other.

-- 
Ciao,
Enrico

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From: Reinaldo Penno <[email-masked]>
Date: Sat, 27 Aug 2011 15:38:57 -0400

Another option slightly different.

Do not add anything and understand that the ALTO service is a cooperative
service and rely on information from others which can muck with the
information in different ways.

Much like third-party P2P tracker today, you are using a service and nothing
precludes the tracker from giving you good, bad or best information.

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From: "Vijay K. Gurbani" <[email-masked]>
Date: Wed, 31 Aug 2011 13:26:01 -0500

As individual.

> precludes the tracker from giving you good, bad or best information.

A slightly different look: Private bittorrent trackers offer far more
superior download performance than public trackers.  They are
attractive for that reason.

My personal opinion is that (3) is probably overkill, (2) seems
appropriate (where (2) and (3) refer to the options in Enrico's
original email [1]).

[1] http://www.ietf.org/mail-archive/web/alto/current/msg01192.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-masked]
Web:   http://ect.bell-labs.com/who/vkg/

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From: Reinaldo Penno <[email-masked]>
Date: Wed, 31 Aug 2011 14:51:00 -0400

> attractive for that reason.

But this is not related to authoritative of information or not. Private
trackers many times are per invitation (so is the people that matter) and
have Seedboxes.

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From: "Vijay K. Gurbani" <[email-masked]>
Date: Wed, 31 Aug 2011 14:05:33 -0500

On 08/31/2011 01:51 PM, Reinaldo Penno wrote:
> But this is not related to authoritative of information or not.

Ah, fair enough.  The parallel I was trying to get at is
that private tracker networks show higher connectability than
public tracker networks.  A part of that higher connectability
derives from members of the private network being more
conscientious (longer seeding time, more accurate tracking of
a peer leaving the swarm, etc.) and therefore, more worthy
of trust.

The authoritative bit can be seen along that axis: information
is more worthy of trust (not to be confused with completely
trusted).

Thanks,

- vijay

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From: Reinaldo Penno <[email-masked]>
Date: Wed, 31 Aug 2011 15:07:10 -0400

> is more worthy of trust (not to be confused with completely

Also fair enough and certainly maybe more useful angle to it.