Have you ever noticed that your network connection sometimes feels fast and then suddenly slow, even when nothing obvious has changed? A request that takes 20 ms at one moment can take 80 ms the next, and sometimes it does not return at all. Terms li...

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Round Trip Time (RTT) measures how long packets take to travel to a server and back, but it constantly changes due to network conditions. Baseline RTT represents the minimum observed RTT without temporary delays, while jitter is the extra delay added on top of baseline RTT. TCP learns network timing by tracking SRTT (smoothed RTT) and RTTVAR (RTT variance) from acknowledgment samples. When delays exceed the Retransmission Timeout (RTO), calculated as SRTT plus a multiple of RTTVAR, TCP interprets the delay as packet loss and retransmits, even though the original packet may still arrive later.

How TCP Turns Round Trip Time and Jitter into Packet Loss