A call for p2p expertise

[guyhaw]

I'm interested in how the p2p eMule system works - scheduling at client and (?) server ends, data-integrity checks, file-availability knowledge etc.
Would also like to know details like how to find out my in-practice up/down bandwidths.
Any pointers to info about p2p generally and eMule in particular v welcome: web sources, aacademic papers, whatever.
... and since p2p can't email us, asking us to re-share files, maybe we need a separate thread here for 'lost sources'.
Thanks - g

[Kirill Kryukov]

Hi Guy, there actually too many materials in the internet about eDonkey 2000 network and different clients. Google search can really get lot of info. First of all please check the links that I posted on the EGTB Online project page:
http://www.afterdawn.com/guides/archive ... torial.cfm
http://www.emule-help.com/
http://www.emule-project.net/home/perl/help.cgi?l=1

eMule forum is excellent place to ask questions too.

I'm interested in how the p2p eMule system works - scheduling at client and (?) server ends

Scheduling at client side works as simple queue. The queue may work differently in different clients. In eMule it works by computing score. The higher is your score the sooner you will start downloading. Score depends on waiting time, upload/download ratio with particular client, upload priority of the requested file, on client you use, and on something else probably.

There is no scheduling on server side. Servers simply provide information about who has what files. After your client gets this information, you talk directly to another client, peer-to-peer. (also can be indirectly when another client is behind firewall).

data-integrity checks

Custom algorithm based on MD4, as I heard. All chunks of 9 MB are checked individually, and then the complete file is checked again. Hash of the file is used to represent the file on the network.

file-availability knowledge

in eD2K network it is provided by servers. eMule also supports serverless network called KAD which allows to locate files very fast.

Would also like to know details like how to find out my in-practice up/down bandwidths

You set upload/download bandwidth in eMule options. It then tries to follow your setting. Then you can see the actual bandwidth in statistics view of eMule.

and since p2p can't email us, asking us to re-share files, maybe we need a separate thread here for 'lost sources'.

Such threads appear here time to time. BTW eMule has messaging capability, you can send quick messages and chat with other users, without email.

Best,
Kirill