d/l-u/l in P2P

[nil_3]

Whenever anybody uploads a file in a P2P network(say, Limewire), does this have any impact on his download speed?

[siriusb]

It does. The exact amount of impact depends on the efficiency of the protocol. But rest assured that it is never more than a few hundred bytes per second per peer (or per connection). This data is the tcp level ACK, application-level ack (the p2p program), connection maintenance bytes (keep-alives) and, maybe, validating data (hash, etc). There maybe other things that maybe defined in the protocol.