Re: [p2pi] [p2prg] Mythbustering P2P traffic localization

Song Haibin <melodysong@huawei.com> Sat, 28 February 2009 07:47 UTC

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Date: Sat, 28 Feb 2009 15:47:41 +0800
From: Song Haibin <melodysong@huawei.com>
In-reply-to: <49A7C407.5080106@inria.fr>
To: 'Arnaud Legout' <arnaud.legout@inria.fr>, 'Enrico Marocco' <enrico.marocco@telecomitalia.it>
Message-id: <00c401c99978$d5dd38a0$100ca40a@china.huawei.com>
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Cc: p2p-hackers@lists.zooko.com, p2pi@ietf.org, p2prg@irtf.org, alto@ietf.org
Subject: Re: [p2pi] [p2prg] Mythbustering P2P traffic localization
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Hi Arnaud,

>section 8.2
>it is not clear what you mean in "as shown in [Le Blond], the right
>balance of randomness and
>  locality depends on the P2P algorithm". We did not explore several P2P
>protocols, but only BitTorrent.
>We show that BT is extremely robust to high locality (as long as there
>is enough randomness within each ISP).
>We cannot conclude for any other P2P protocol.

I guess if locality will weaken a swarm depends on in which proportion the
pieces of the resource the local peers have; and the balance of the cotent
pieces distribution among these local peers.

>"On the other hand, P2P systems not adopting the tit-for-tat approach
>  (e.g. the eDonkey network) should not be damaged by locality-based"
>It is not clear to me. Peer selection (tit-for-tat like choking algo in
>BT) is not the only one factor of efficiency, there is also piece
>diversity.
>Edonkey/emule also use rarest first (but a less efficient peer selection
>algorithm). Therefore, as locality adversely impact
>piece diversity, my bet is that Edonkey/emule will suffer from locality.

What do you mean with "less efficient" by saying "Edonkey/emule also use
rarest first (but a less efficient peer selection algorithm)"?

Regards,
Song Haibin