Congestion Control

• Paramers:

  • std::chrono::microseconds _rcInterval; // UDT Rate control interval

• Timers:

  • QElapsedTimer _lastRCTime; // last rate increase time

• Flags:

  • bool _slowStart{ true }; // if in slow start phase

  • bool _loss{ false }; // if loss happened since last rate increase

• Counters:

  • PacketID _lastAck; // last ACKed seq no

  • PacketID _lastDecSeq; // biggest sequence number when last time the packet sending rate is decreased

  • std::chrono::microseconds _lastDecPeriod{ 0 }; // value of PacketSendPeriod when last decrease happened

  • unsigned _nakCount{ 0 }; // current number of NAKs in the current period

  • unsigned _decRandom{ 1 }; // random threshold on decrease by number of loss events

  • unsigned _avgNAKNum{ 0 }; // average number of NAKs in a congestion period

  • unsigned _decCount{ 0 }; // number of decreases in a congestion epoch