Computer Science – Methods of error detection | e-Consult

ARQ is a method used in data transmission to ensure reliable delivery of data over a network. It works by requiring the receiver to acknowledge (ACK) the successful receipt of data. If the sender doesn't receive an ACK within a certain timeframe, it assumes the data was lost or corrupted and retransmits it. This process continues until the data is successfully received.

There are different types of ACK methods:

• Stop-and-Wait ARQ: The sender waits for an ACK after transmitting each data packet. If an ACK isn't received, the sender stops transmission and retransmits the packet. This is simple but inefficient as the sender is idle waiting.
• Go-Back-N ARQ: The sender can transmit multiple packets without waiting for ACKs. If a packet is lost or corrupted, the receiver discards all subsequent packets until it receives a correct packet. The sender then retransmits those packets. This is faster than stop-and-wait but can be inefficient if many packets are lost.
• Selective Repeat ARQ: The receiver acknowledges correctly received packets and requests retransmission only for those packets that are lost or corrupted. This is the most efficient method as it avoids unnecessary retransmissions.

The ACK methods contribute to data reliability by providing a mechanism to detect and recover from data loss or corruption. By requiring confirmation of receipt, ARQ ensures that data is delivered accurately and completely.