Arq Apr 2026

) before needing an ACK. If a frame is lost, the receiver discards all subsequent frames, and the sender must retransmit all frames starting from the lost one. Better utilization than Stop-and-Wait. Cons: High retransmission overhead in poor channels. 3.3. Selective Repeat ARQ (SR)

Higher bandwidth–delay products require larger window sizes (GBN/SR) to maintain high throughput. 5. Hybrid ARQ (HARQ) ) before needing an ACK

Requires complex buffering and ordering at the receiver. 4. Performance Considerations Cons: High retransmission overhead in poor channels

The receiver sends an ACK to confirm the successful receipt of a packet. the receiver discards all subsequent frames

is a fundamental error-control mechanism used in telecommunications and data link layers to ensure reliable transmission over unreliable communication links. Unlike Forward Error Correction (FEC) , which allows the receiver to correct errors, ARQ relies on the receiver identifying errors and requesting retransmission of data from the sender. This paper covers the primary types of ARQ protocols, their mechanisms, and performance tradeoffs. 2. Fundamental Mechanisms ARQ protocols operate based on two main principles: