Principle: Real time

• Plays an important role in distributed systems

  • Timeouts to decide when to retry a transmission
  • Stability of load control systems using feedback
  • “Bounded waiting” locking

(1) Timeouts -- to decide when to retransmit

• On a failure, e.g., a lost Internet IP packet, as part of an end-to-end protocol
• If the timeout is wrong, performance will suffer but the system will usually still work
• When timeouts are used to control congestion, making them too short can cause the bandwidth to drop to 0

Sender

Receiver

Message send

Message resend

timeout

Message ack

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