Re: [p2pi] Refining the ALTO problem statement [Was: Re: discussing P2PI-related standardization in Dublin]

Enrico Marocco <enrico.marocco@telecomitalia.it> wrote:
> 
> To follow up on Jon's thoughts and to reflect discussions that happened
> during the MIT workshop and on the mailing list, Vijay and I are going
> to update the problem statement draft the ALTO BoF proposal is based on
> (draft-marocco-alto-problem-statement-00).
>... 
> + Type(s) of information that is provided to the oracle for rendering an
>   equitable decision:
>   * List of peer candidate IP addresses;
>   * Parameter to optimize (cost, delay, ...);

   I think we could reasonably expand this, so as to provide more for the
oracle to work from.

   There are two well-known cases:

1. We want a well-known range of bandwidth for a possibly well-known
   length of time.

2. We want to transfer a well-known number of bytes within a fairly
   well-known period of time.

   In the first case, "No path will work" is a useful answer, and we
should have a way of saying so.

   In the second case, an estimate of how long the transfer _would_
take is very useful information, and we should have a way of passing
that back. (Users will typically abort transfers that aren't making
enough progress; and giving them information to abort sooner would be
a good thing.)

   (I really like calling this an "oracle" service, because it must
necessarily make predictions about the future. However poor those
predictions may prove, the oracle _can_ have a better (statistical)
basis for them than either end-point.)

   Latency is also possibly an issue in the first case: it's probably
a good idea to report expected latency for each path. (Optimizing for
it may or may not be useful.)

--
John Leslie <john@jlc.net>
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