Automatic Repeat Request (ARQ) is a protocol used in data transmission to ensure data is received correctly at the destination. Here's how it works:

1. **Data Transmission**: The sender transmits a data packet to the receiver. This packet also includes error detection information, typically in the form of a checksum.

2. **Error Detection**: Upon receiving the data packet, the receiver uses the error detection information to check for errors. If no errors are detected, the receiver sends an acknowledgment (ACK) back to the sender.

3. **Acknowledgment**: The sender waits for an acknowledgment from the receiver. If the sender receives an ACK, it understands that the packet was received correctly and moves on to send the next packet.

4. **Timeout and Retransmission**: If the sender does not receive an ACK within a certain time frame (known as the timeout period), it assumes that the packet was lost or corrupted during transmission. The sender then retransmits the same packet.

5. **Negative Acknowledgment**: In some ARQ protocols, the receiver sends a negative acknowledgment (NAK) if it detects an error in the received packet. Upon receiving a NAK, the sender knows to retransmit the packet.

6. **Sequence Numbers**: To keep track of packets, each one is assigned a sequence number. This helps the receiver identify if packets arrive out of order or if any are missing. It also helps the sender know which packet to retransmit if a NAK is received.

7. **Retransmission Strategies**: Depending on the ARQ protocol, different strategies may be used for retransmission. For example, in Stop-and-Wait ARQ, the sender waits for an ACK after each packet before sending the next. In Go-Back-N ARQ, the sender continues to send a number of packets without waiting for ACKs, but if a packet error occurs, it goes back and retransmits that packet and all following ones.

This process continues until all data is transmitted and received correctly. The ARQ protocol is a fundamental part of reliable data transmission, ensuring that data integrity is maintained even in the presence of transmission errors.

Question

Automatic Repeat Request (ARQ) is a protocol used in data transmission to ensure data is received correctly at the destination. Here's how it works:

1. **Data Transmission**: The sender transmits a data packet to the receiver. This packet also includes error detection information, typically in the form of a checksum.

2. **Error Detection**: Upon receiving the data packet, the receiver uses the error detection information to check for errors. If no errors are detected, the receiver sends an acknowledgment (ACK) back to the sender.

3. **Acknowledgment**: The sender waits for an acknowledgment from the receiver. If the sender receives an ACK, it understands that the packet was received correctly and moves on to send the next packet.

4. **Timeout and Retransmission**: If the sender does not receive an ACK within a certain time frame (known as the timeout period), it assumes that the packet was lost or corrupted during transmission. The sender then retransmits the same packet.

5. **Negative Acknowledgment**: In some ARQ protocols, the receiver sends a negative acknowledgment (NAK) if it detects an error in the received packet. Upon receiving a NAK, the sender knows to retransmit the packet.

6. **Sequence Numbers**: To keep track of packets, each one is assigned a sequence number. This helps the receiver identify if packets arrive out of order or if any are missing. It also helps the sender know which packet to retransmit if a NAK is received.

7. **Retransmission Strategies**: Depending on the ARQ protocol, different strategies may be used for retransmission. For example, in Stop-and-Wait ARQ, the sender waits for an ACK after each packet before sending the next. In Go-Back-N ARQ, the sender continues to send a number of packets without waiting for ACKs, but if a packet error occurs, it goes back and retransmits that packet and all following ones.

This process continues until all data is transmitted and received correctly. The ARQ protocol is a fundamental part of reliable data transmission, ensuring that data integrity is maintained even in the presence of transmission errors.

Knowee AI · Accepted Answer