TCP Network Delay Modeling

• TCP models Internet delay as a gaussian RV with a slowly varying mean and standard deviation

• Retransmission Timeout (RTO) set to mean delay + 4 standard deviations

• This is a tradeoff between:

  • maximizing throughput with packet loss
  • minimizing unnecessary retransmissions

• Round trip time (RTT) measurements made by timer started when certain sequence number sent, stopped when it is acked

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