Re: [p2pi] draft-livingood-woundy-p4p-experiences-02 posted

On Wed, Nov 5, 2008 at 2:29 PM, Woundy, Richard <Richard_Woundy at cable.comcast.com> wrote:

Reinaldo,

I can answer the easy questions. We will need some assistance from Pando
(and Yale) for some of the other ones.

>What was the file size in those experiments?

21 megabytes. From section 2: "Pando distributed a special 21 MB
licensed video file as in order to measure the effectiveness of P4P
iTrackers."

>How long would it take to download the file in the three different
scenarios? I know that more consumed bandwidth in access might lead one

to conclude that file was downloaded faster...

To clarify, most of the raw data (download speed and Internet
peering/transit traffic volumes) were collected by Pando Networks from
their P2P clients, not collected by Comcast across its links. So my
assumption is that the Pando client used the content size (21 MB), and
divided by the download time to get the speed.

>Was the file already seeded in Comcast's network? More specifically,
how
was file propagation done?

Any seeding happened outside of Comcast's network, and outside of
Comcast's control. That's really a question for Pando.

>Was PEX, DHT and others enabled in the clients?

Pando would know whether PEX was enabled. It would be safe to assume
that with respect to this trial, DHT was NOT enabled, since Pando
supplied the tracker. (The pTracker in the draft is a tracker operated
by Pando.)

>Was local peer discovery enabled in the clients?

Pando would know.

>BTW, can broadcast/multicast peer discovery work in Cable networks?

Do you mean something like this:
http://bittorrent.org/beps/bep_0026.html?

If so, peer discovery probably would not work over the typical last mile
cable network. Maybe I'm wrong, but I see this protocol as intended for
peer discovery within one's home network / LAN / WiFi network, not over
a cable network.

>So, were clients allowed to become seeders to the outside of Comcast's
network?

Yes, they were.

As a related item, look closely at section 4.2. The amount of aggregate
uploaded data from Comcast clients (per swarm) was about 140,000 MB. The
amount of aggregate downloaded data from Comcast clients (per swarm) was
about 60,000 MB or so. So the typical Comcast client uploaded more than
twice the amount of data that it downloaded.

>How much of the swarm was within Comcast and outside?

Most of the swarm was outside of Comcast. Unfortunately I don't have
access to the size of the global swarm, but I would guess that Comcast
clients represented no more than 15% of the swarm, and maybe as little
as 5%. Those guesses are based on the behavior of the random swarm, e.g.
Comcast clients uploaded to non-Comcast clients 94% of the time in the
random swarm.

-- Rich

-----Original Message-----
From: p2pi-bounces at ietf.org [mailto:p2pi-bounces at ietf.org] On Behalf Of

Reinaldo Penno
Sent: Wednesday, November 05, 2008 11:23 AM
To: Livingood, Jason; p2pi at ietf.org
Subject: Re: [p2pi] draft-livingood-woundy-p4p-experiences-02 posted

Hello Jason/Rich,

This is such an interesting draft. I'm surprised there are no questions
about it. Maybe everybody else is part of P4P one way or another and I'm
not
in the 'in' crowd (;-) so I have questions.

* What was the file size in those experiments? Some post long ago said
the
file size in some P4P experiments was really small, as opposed to the
top
100 torrents where the file size is ~1Gb. I was curious what is the
optimization payback in terms of download time for large files as
opposed
small files.

* How long would it take to download the file in the three different
scenarios? I know that more consumed bandwidth in access might lead one
to
conclude that file was downloaded faster but I'm not sure this is a
straightforward conclusion.

* Was the file already seeded in Comcast's network? More specifically,
how
was file propagation done? All clients started from scratch and had to
start
pulling the file from some other side of the world and then exchanging
pieces? This is mainly due to the discussion in 4.2.

* Was PEX, DHT and others enabled in the clients?

* Was local peer discovery enabled in the clients? BTW, can
broadcast/multicast peer discovery work in Cable networks?

* If more clients finish downloading faster and become seeders you would
think that for popular content Comcast's upstream bandwidth would
increase
due to the number of seeder in its network. So, were clients allowed to
become seeders to the outside of Comcast's network? How much of the
swarm
was within Comcast and outside?

Thanks,

Reinaldo

On 11/3/08 12:49 PM, "Livingood, Jason"
<Jason_Livingood at cable.comcast.com>
wrote:

> For some reason the URL was cut to two lines - trying again:
>
>
http://www.ietf.org/internet-drafts/draft-livingood-woundy-p4p-experienc
> es-02.txt
>
>
>
>> -----Original Message-----
>> From: p2pi-bounces at ietf.org [mailto:p2pi-bounces at ietf.org] On
>> Behalf Of Livingood, Jason
>> Sent: Monday, November 03, 2008 3:35 PM
>> To: p2pi at ietf.org
>> Subject: [p2pi] draft-livingood-woundy-p4p-experiences-02 posted
>>
>> A draft at
>> http://www.ietf.org/internet-drafts/draft-livingood-woundy-p4p
>> -experienc
>> es-02.txt may be of interest to folks that have been
>> interested in P2Pi and ALTO. We have requested time on the
>> ALTO agenda at IETF 73 to present this.
>>
>> Regards
>> Jason
>> _______________________________________________
>> p2pi mailing list
>> p2pi at ietf.org
>> https://www.ietf.org/mailman/listinfo/p2pi
>>
> _______________________________________________
> p2pi mailing list
> p2pi at ietf.org
> https://www.ietf.org/mailman/listinfo/p2pi

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Re: [p2pi] draft-livingood-woundy-p4p-experiences-02 posted

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