USS (Upload Speed Sense) Group:
USS (work of ZZ ) dynamically finds current, best upload rate from the range of "Min upload in kB/s" and "Max upload in kB/s". "Max upload in kB/s" can be found automatically by selecting "Auto" box. USS lower the upload when other applications are using your connection or when mule is downloading very fast (important for ADSL user when download can be limited by upload). The key of USS to work is pinging a host. USS can find the proper host to ping for you (just select "Auto" box, on the right of "URL/IP to ping:" input box). If searching fails (very rearly) it uses host given in "URL/IP to ping". If you know which host to ping
unselect "Auto" box and input own address. By pinging, USS gets replies from host and on this basis it knows what to do (increase or decrease current upload). USS has to have a value to comapre with received respons from host, this value is "Max ping allowed". It would be the best if you could know what is proper ping for your connection (if you know, then select "Max ping allowed" box and input it). If you don't know, do not select "Max ping allowed" box, instead use intuitive slider above (it will find the proper ping for on the base of lowest ping calculated during preparation of USS). When you move slider on the left upload will be lower but you can surf the net easily, on the right - opposite behaviour.
Minimize number of opened slots - when this option is selected eMule will open less slots than original if it is possible (if less users can take more bandwidth). It means that the chunks will arrive faster to users.
Cumulate bandwidth for upload slots (idea of ZZ: Slot Focus - but a bit diffrent) - when this option is not selected eMule tries to upload to all users on upload queue with the same speed. Selecting this option is causing that eMule always upload to one user (Priority client - no matter wheter he has slow or fast connection) and then rest bandwidth gives for the fastest users (faster spread of chunks). Priority client is always client which was first on upload queue (stayed the longest), thanks to this for every client ("fast", "slow") will be a turn to get data.
Session up:down limit (1:4) (idea of ZZ, changed by MorphNext) - instead of 1:3 and 1:4 ratio for download (or unlimited when upload higher than 10) there is limit 1:4 for session. As long as you have downloaded less than 4 times the amount you uploaded (or you are uploading higher than 10kB/s) the limit of download is the same as value entered in "Connection tab" (so it can be unlimited). When you have downloaded more - the download is limited to preserve 1:4 session ratio.
Include overhead - eMule upload not only file data. It comunicates with other users (queue ranks, names of files, hashes, etc), server. If you want this upload can within limits defined in "Connection" tab or USS.
Manage of active connection - when this option is selected and you have too high values of "Max connections" and "Max connections per 5 sec for your connection, they will be adjusted automatically when needed.
Include connection overhead - not only eMule communicates between users, system and network layer also (on diffrent level). This system communication can take a lot of bandwidth especially when sorces are loaded (SLS system, or a file with a lot sources from server). It's almost impossible to calculate this overhead exactly, but an approximate is acceptable. You can include this overhead within upload limits (USS or "Connection tab"). Keep in mind that to have the unlimited download or 1:4 ratio with this option selected the limits for upload were chaned:
- unlimited download needs minimum 11kB/s upload instead of 10
- 1:4 ratio needs minimum 3.5 kB/s upload instead of 3
Include TCP Ack Packets - every data received needs to be acknowledged (it is TCP ACK packet), so it's generating upstream. The amount of overhead is hardly to calculate exactly, it depends on many settings (e.g RWIN). But as with "Include connection overhead" some approximation can be done (64kB/s downstream needs circa 1.5kB/s upstream). You can include this overhead within upload limits but then Session up:down limit (1:4) is enforced.
Here you can see what's happening with USS, what are the limits of download (limited by settings described above - so you don't have to calculate them) and what host is pinged. USS/DSS can be Disabled / Preparing / Succesfull / Failed.