Source finding in the network is of uttermost importance. In fact, servers, Kademlia and eMule itself are geared towards a most efficient source acquiring. For best eMule performance some concepts are necessary to understand. The source list of each download is shown by double clicking on it. For the advanced source information and handling the setting Extended Settings -> Show more controls has to be activated.
| • | Finding sources for a download | |
| eMule uses different means to find sources for downloads. Expanding a download by double clicking on it shows how the sources have been found in the Size column. | ||
| - | eD2k Server |
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| - | Kademlia Kademlia offers a very fast way to find sources across a large number of distributed users without the need for central servers. For more Information see the Network Guide. |
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| - | Source Exchange After a source has been added for a particular download, eMule asks this sources if it knows further sources for parts still missing in the own download. If yes, the connected client sends a list containing the sources. |
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| - | Passive Passive sources are other clients who connect. eMule asks them if they could be source for one of its own downloads and if they are not known before they get added as source for the appropriate download. |
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| • | Total number of sources Basically the more sources found for a download the faster the download will be but there is a limit. Too many sources in total will slow down eMule as the connection will be congested by managing the sources, thus slowing down the actual download. The total number of found sources for all downloads is display in the Statistic main windows -> Transfers -> Download -> Found Sources. It should not exceed 3000 by much on most lines. |
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| • | Queue and source status Once another client is added as a source it gets queried for the current source status . Possible source status are: |
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| - | On Queue and QR: xx This is the Queue Rating. It denotes the waiting place in the queue of this client. When the beginning of the queue is reached, i.e. QR:1 this source will start uploading data. Credits modify the progression speed in the queue. |
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| - | Queue Full The maximum queue limit of this source is already reached as too many other clients are already waiting in it. |
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| - | Too many connections Currently eMule is too busy querying other sources so this source gets delayed until a connection is free to query this source. This status usually disappears very quickly. If it does not eMule has to cope with way too many sources. See the point Total number of sources in the paragraph above. |
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| - | No needed part (acronym: NNP) The source does not offer any parts the own download is missing. The available parts of the source are also shown in the colored bar. |
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| - | Asked for another file (acronym: A4AF) One particular source can be used only for one download. If this source would also provide parts for another download, eMule decides which download receives it. The other download will then list this source as Asked for another file. The next paragraph describes eMule's sophisticated handling of these sources. |
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Advanced A4AF Handling
This picture shows some downloads with their found sources (Advanced Controls
turned on). The fourth file for example has 27 sources in total of which 26
are useful and 49 are A4AF.
If downloads belong to a series of files or are split into multiple parts, eMule
will show a source distribution alike the picture above for Filename1_Part_X.
It is most likely that the sources found for one of the files could also provide
parts of the other as they belong together. eMule occupies only one queue place
on the sources hence the high count of AF4A for these files.
There are two controls offered in this context menu to deal with these A4AF
sources on a per file basis. The Priority and the Automatically
Swap All Sources To This File control.
Also the Category context menu offers means of dealing with A4AF sources. Here they are the categories Priority and Download in alphabetical order.
| eMule's advanced A4AF handling decides which file gets a source by following order: | |
| • | Automatically Swap All Sources To This File
(highest importance) Only one file may have this checks and always gets the A4AF sources. |
| • | Category Priority Files in a category with high priority are preferred over files that are uncategorized or in ones of lower priority |
| • | File Priority In a given category the file priority decides which file will receive the sources |
| • | Download in alphabetical order (lowest importance) Assigns the sources according to the file name of the download. In the example above with Filename1_Part_X this would mean the Filename1_Part_1 gets all the A4AF sources, when it is finished all sources are swapped to Part_2 etc. For downloads which fit into this pattern it is recommended to create a category for them. Make sure the files are named in alphabetical order and check this option. To rename a download hit F2 or click the middle mouse button on it or chose Show file details from the context menu. |
Notes: |
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| • | Setting a category to Download in alphabetical order will switch all files to Normal priority. Files later added to this category will retain their set priority. For the files to download alphabetically, make sure to set them to the same priority (not Auto). |
| • | A4AF handling checks if a source may be swapped to a lower priority file just for allowing client to client source exchange. This ensures that even low priority downloads find all possible sources fast. |
| • | Source swapping must obey the minimum reask time in the network. It may take up to 30 minutes before sources are swapped. |
| • | A source with a QR lower 50 will never get swapped from the highest priority download to ensure it starts downloading from it. |
Applies to version: .43a +
Last update on: 2004-07-18 , Monk