TCP Error Recovery Flow Control and Data Segmentation

TCP (Transmission Control Protocol) provides reliable, ordered, and error-checked delivery of data between applications running on hosts communicating over an IP network. TCP is responsible for end-to-end data delivery, ensuring that packets are delivered error-free, in order, and with no loss or duplication.

TCP achieves its reliability by implementing error recovery, flow control, and data segmentation. Here’s how each of these functions works:

Error Recovery: TCP uses a mechanism called Positive Acknowledgement with Retransmission (PAR) to detect and recover from packet loss or corruption. When the receiver receives a packet, it sends an acknowledgment (ACK) to the sender. If the sender doesn’t receive an ACK within a certain timeout period, it retransmits the packet. TCP also uses a checksum to detect corrupted packets.

Flow Control: TCP uses a mechanism called sliding window flow control to prevent the sender from overwhelming the receiver with too much data. The sender and receiver agree on a window size, which is the maximum amount of unacknowledged data that can be in transit at any given time. The sender keeps track of the number of unacknowledged packets and adjusts its sending rate to match the receiver’s ability to process the data.

Data Segmentation: TCP breaks up the application data into segments and adds a TCP header to each segment. The header includes sequence and acknowledgment numbers, window size, checksum, and other control information. TCP adjusts the segment size dynamically based on network conditions, to ensure that the segments are not too large or too small.