Automatic Repeat Query (ARQ)

Automatic Repeat Query (ARQ)

Automatic Repeat reQuests(ARQ)

What is an automatic repeat request(ARQ)?

• An automatic repeat request is a protocol that notifies the sender that an error has occurred and that the data received is incorrect

• It works as follows:

  • If an error is detected the receiver sends a negative acknowledgement transmission to indicate the data is corrupted

  • If no error is detected the receiver sends a positive acknowledgement transmission meaning the data is correct

  • If the receiver does not send any acknowledgement transmission then the sender waits for a certain time period known as a time-out before automatically resending the data

  • This process is repeated until all data has been received and acknowledged