[bittorrent] New P2P protocols

Nick Johnson arachnid at notdot.net
Sun Mar 27 16:49:43 EST 2005


On 27/03/2005, at 10:37 PM, Justin Cormack wrote:

> On Sun, 2005-03-27 at 13:54 +1200, Nick Johnson wrote:
>> Any of these components (save perhaps homomorphic hashing) can be
>> implemented as an extension to BT in the form of a new protocol.
>> Multicast is an extension to unicast transmission to provide better
>> efficiency on small networks. Locality based tracking likewise. Merkle
>> trees are established as an extension, and DHT based tracking can 
>> serve
>> as a simple replacement, as you suggest.
>> The real issue is to decide what to start with!
>
> Some of them have prerequirements. As multicast is UDP based, that
> requires changing BT to use UDP first. This in itself requires either
> doing the whole erasure code stuff first (which is a really big change)

Not at all: Leave the standard unicast connections as-is, but develop a 
seperate protocol for multicast, using Online Codes. I'm thinking 
something along these lines: 'active' peers on the multicast channel 
still connect via TCP, but they use their connections for control 
(choke/unchoke/have) messages only. Actual data is sent Online encoded 
via multicast. What blocks are sent is as described previously: 
Whatever block is most wanted by all the 'active' peers on the 
multicast channel.

-Nick Johnson




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