TCP timekeeping, also known as round-trip time (RTT) estimation, is a mechanism used by the Transmission Control Protocol (TCP) to measure the time it takes for a packet to be sent, acknowledged, and returned to the sender. It is primarily used to determine network congestion and adjust the transmission rate accordingly.
In the case of packet retransmission, TCP uses the RTT to detect lost or delayed packets. When a packet is sent, TCP starts a timer and waits for an acknowledgment from the receiver. If the timer expires before receiving the acknowledgment, TCP assumes the packet was lost and retransmits it. The timer value is based on the estimated RTT for the network and is adjusted dynamically based on the current network conditions.
TCP timekeeping allows for reliable packet transmission in a network by ensuring lost packets are retransmitted in a timely manner. It is a crucial component of TCP’s congestion control algorithm, which aims to prevent network congestion and maintain the quality of service for all network users.
