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Protocol core-core Version 3 » History » Revision 32

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Greg Burri, 07/09/2009 05:16 PM

Protocols

This page describes the protocols used by Aybabtu for network communication between cores and between core and GUI.

Core <-> Core

See source:protos/network_protocol.proto for message details.

Downloading threads

There is NbDownloadThread threads. Each thread will choose a free chunk and download it.
There is no more than one downloading from B to A. A peer which a download is active is setted as not free.

F : the list of all unfinished download
C : A list of chunk candidates (empty at start)

While not end of F
   - Take the next file in F -> f.
   If the hash chunks of a file are unknown :
      - Ask the hashes to the source (see the message 'GetHashes').
   For each chunk not downloaded or not being downloaded -> c :
      If c has a free peer :
         - add c to C
   If C isn't empty :
      - Take the best chunk in C based on peer.downloadRate.
        If there is more than one best chunk then choose one randomly.
      - Grab the lock for the peer
      - Request the download

Parameters

Most parameters will be stored as constants in their component.

Name Value Unit Explanation/Comments
IMAliveFrequency 0.1 [Hz] The message IMAlive is sent each 10s.
ChunkSize 33554432 [Byte] (32 MB)
LanSpeed 52428800 [Byte/s] (50 MB/s)
TimeRecheckChunkFactor 4 - If the time to download a chunk exceeds TimeRecheckChunkFactor * ChunkSize / LanSpeed the peers are rescanned to choose a better one (better download rate). For example : 4 * 32 / 50 = 2.6 second
SwitchToAnotherPeerFactor 1.5 - During the recheck of the peers to choose a better one the other download rate must be above the current * 1.5.
DownloadRateValidTime 1500 / LanSpeed = 300 s [s] (5 min). The download rate of a peer is only valid during this time after its last update. After that its rate is set to the maximum.
TimeBetweenChunksUpdate 500 / LanSpeed = 10 s [s] Each 10 s a daemon will scan the NumberOfChunkToUpdate first chunks from the first queued downloads to know which peer has which chunk.
NumberOfChunkToUpdate 100 * LanSpeed / ChunkSize = 156 - The first 156 hash chunks (3 kB) will by send periodically to each peer. See message HaveChunks in the proto file.
FindTimeout 15 [s] A search request is abandoned after 15 seconds from the start of the request. See message Find.
GetHashesTimeout 200 [s] Timeout for the message GetHashes.
GetChunkTimeout 10 [s] Timeout for the message GetChunk.
HaveChunksTimeout TimeBetweenChunksUpdate = 10 [s] Timeout for the message HaveChunks.
GetEntriesTimeout 10 [s] Timeout for the message GetEntries.
NbDownloadThread 3 - Number of concurrent downloading thread.
BufferSize 1048576 [Byte] (1MB). This buffer is user when reading or writing a file.
TCPSocketBufferSize 33554432 [Byte] (32Mo). Used when data are received. See QAbstractSocket::setReadBufferSize.

Core <-> GUI

Updated by Greg Burri over 15 years ago · 32 revisions