simple alternative to fastrak
 

I have been reading with interest several articles about fasttrack/swarming etc.

i came up with an idea quite some time ago (posted in the sourceforge forum i beleive) wherby if someone is downloading a file then this file is automaticaly shared and given high priority. Even in its partialy downloaded state, this can still be of benefit to some clients requesting a segment of the file.

thus files that are in high demand will be more widely available and big servers that have these files will become less overloaded benefiting all.

this idea does not need a change in the standard just implementation in the client.

the file is simply reported the same as the original file and requests for bytes outside the available bytes are delayed untill they are available or are rejected.

with this a user with no files to share would no longer detract as much bandwidth from the network, if at all, even with an asymetric bandwidth as one rarely downloads dificult to find files at max download rate so the file might well be uploaded to some else at a similar rate - thus detracting nothing from the network.

this seems to be just as good if not beter than fasttrack/swarming, as the availability is automaticaly increased in direct proportion to the demand.

with the ability to control upload bandwidth independantly from download bandwidth people like me with asymetric bandwidths will not suffer from reduced download speed.

Colin

Sharing of partial files is something that will be eventually supported and implemented by gnucleus. Step by step downloading over gnutella is becoming more advanced.

I've seen a bad side of this using eDonkey (which does this) - sometimes you'll wind up with a bunch of people missing the same parts of the file and no one having the full thing. This usually happens when the original source vanishes before anyone else gets a complete copy.

It can be very frustrating since you never know if you'll ever find the other parts or not. I've spent days trying to download large files only to find it was all a waste. I'd rather know beforehand that the full file exists intact. A popular file will still become well distributed over time.

yes i can see how this may be a problem, there seems to be drawbacks to however u try to improve the loading situation.

however i have tried many times to dl a file with only 1 host only to get 3/4 of the way thru it and the server is then busy for ever and eventualy becomes unavailable. anything that improves distribution would i think give u more chance of geting the whole file, as at least someone will be more likely to have got the whole file.

maybe there can be some administration of this problem - the simplest being to expire the incomplete partial downloads after a few days or so of failing to get any more of the file, at least this would drasticaly reduce the number of hosts reported as having the file available, maybe eliminate it - or simply only share the partial download while activly downloading.

more complicated would be for the client to report what portions of the file it has - maybe this could just be in the filename itself ? then a client cld use this information to tell if all portions are available.

neither would not need any change to the protocol.