This is an old revision of the document!
Long-Time Seeding
Long-Time Seeding, a unique feature of BitComet, helps users to get data from peers who have 100% of the torrent contents. For some out-dated torrents, it's a common occurence that there are no seeds and in that case, if the number of aggregate copies inside the swarm for the pieces for that torrent is lower than 1, then the task cannot be finished.
It's Long-Time Seeding that may save you from waiting forever for some seeds to join the swarm, by asking former peers which have 100% of the torrent file(s) to upload through Long-Time Seeding even if the task is stopped in their client.
Since LT-Seeds upload even when the task is stopped in the Task List, in this way, LT-Seeding may also help revive a dead torrent (i.e. if the peers who managed to finish their download through LT-Seeding will keep seeding the task long enough to create other BT seeds into the swarm or at least to create multiple aggregate copies).
LT-Seeding upload is done through the LT-Seeding protocol which is proprietary to BitComet. LT-Seeding upload is independent of the upload done through the BitTorrent protocol and can be done in parallel with that or alone, depending on the state of the task (seeding or stopped).
LT-Seeds are peers which hold 100% of the files for the task irrespective whether the task is in an active state (seeding) or stopped. That is to say, if LT-Seeding is enabled in BitComet Options and also enabled for a particular task, then once that task has finished downloading the client will become and remain an LT-Seed for that task until the task is deleted from the Task List (or until LT-Seeding is manually disabled, either individually for that task or globally in BitComet Options). This doesn't mean that the task will constantly upload through LT-Seeding, but just like a BitTorrent seed it will be available when requested.
LT-Seeding clients use a server (the equivalent of a tracker, in the BitTorrent protocol) for querying and finding peers (LT-Seeds) for the tasks which have LT-Seeding enabled. This is done by using a unique LT-hash which is being computed for every file of the task.
If that option is enabled (see below), then at the creation of any .torrent file, for each file of the task, BitComet will calculate and embed in the .torrent file a 20 byte file-hash (the LT-Seeding hash).
For .torrent files which don't contain the LT-hash(es) (i.e. created with other torrent makers), the first BitComet client in the swarm which finishes the download, will calculate the LT-hash(es) and upload them to the server, making them available to the other BitComet peers, so that they may search for LT-Seeds for that task at any time later.【Only suitable for BitComet Client】
- Enable/Disable Long-Time Seeding
- Auto Upload Rate Control: In all the later versions of BitComet you can choose to let the client manage the bandwidth allocated to LT-Seeding upload, automatically. The client will use any unused upload bandwidth (up to the maximum upload rate set in Options–>Connection) and dynamically release it for normal BT upload, as soon as a task requests it.
- Upload rate limit for Long-Time Seeding: If you wish to manually control and assign bandwidth for LT-Seeding upload, you can limit the upload rate using this option. 【Overall upload rate limit has higher priority than the Long-Time Seeding upload rate limit】
Requirement for Long-Time Seeding: A BitComet client must have an open port! LAN users must make sure they have an open port (i.e. the status light is green). If you don't have an open port yet and don't know how to open it check this topic.
Choosing the Long-Time Seeding protocol: In Options → Advanced you can choose the transport protocol for LT-Seeding, by using this option: bittorrent.connection.ltseed_protocol_selection.
0 means using only TCP protocol, 1 means using only UDP protocol and 2 means using both protocols.
BitComet by default enables search for Long-Time seeds in a BitTorrent task that is using a .torrent file made with BitComet, by calculating LT-hashes for each file of the torrent and including them in the .torrent file, at creation time.
Read this for Comet Passport related Long-Time seeds information.
You can watch real-time info about the speed at which your client is uploading by LT-Seeding, in the Statistics panel of the Detailed Info Pane.
Bear in mind that when your client is uploading by LT-Seeding, that upload speed, gets added to the BitTorrent upload speed which is displayed in the Task View window. That total will be displayed in the titlebar of BitComet, as well as in the floating window or on the Statistics tab.
However when your client is downloading through LT-Seeding, that speed is added to your download speed in the Task View pane, as well. You can watch the connected LT-Seeds and the speed at which you're downloading from them, in the Peers tab.
