[bittorrent] Choking based on network closeness?

Justin Cormack justin at street-vision.com
Mon Jul 11 17:15:02 EDT 2005


On 11 Jul 2005, at 21:28, Brian Dessent wrote:

> Justin Cormack wrote:
>
>
>> It came up on the list before, and there were some uses for it. The
>> main problem is that no one seems to have enough information to
>> measure closeness, unless you actually work for a large ISP or run  
>> BGP.
>>
>> If some metric that could be made available to more developers could
>> be found then some progress might be made...
>>
>
> And even then it's worthless.  Suppose peer A is right down the street
> from me on the same ISP but has his upload throttled very low, and  
> peer
> B is thousands of miles away (lets say, Sweden, for the sake of
> argument) with a fat pipe and generous limits.  In terms of what's  
> best
> for the host, it should choke peer A and reciprocate as much as  
> possible
> with B.  And the protocol already does this.  Any attempt to add some
> kind of "hops away" or "geographical distance" metric is just going to
> make things worse.  Just say no...

That wasnt the situation where it was required. It was where the host  
B in Sweden is paying for bandwidth to wherever you are and it wants  
to limit traffic to you (if it sends blocks only once to expensive  
countries say, and lets them be distributed once there by local  
hosts). Its only an issue for certain people.

Justin




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