Go-Back-N Protocol vs. Selective Repeat Protocol: Know the Difference
By Hifza Nasir & Dua Fatima || Published on May 3, 2025
Go-Back-N Protocol involves retransmitting frames from the error point, while Selective Repeat Protocol only retransmits erroneous frames, optimizing bandwidth.
Key Differences
Go-Back-N Protocol and Selective Repeat Protocol are both ARQ (Automatic Repeat reQuest) protocols used in network communications to ensure data is transmitted correctly and reliably. This can lead to inefficiencies, especially in networks where errors occur frequently. Selective Repeat Protocol, on the other hand, addresses this inefficiency by allowing the receiver to accept and buffer out-of-order frames. This means that only the erroneous frames are retransmitted, not the entire sequence.
Dua Fatima
May 03, 2025
The Go-Back-N Protocol, also known as the sliding window protocol, allows for multiple frames to be in transit at the same time. However, if an error is detected in a frame, all subsequent frames are retransmitted, even if they were received correctly. The selective repeat approach can significantly improve bandwidth utilization and reduce the number of retransmissions, especially in environments with high error rates.
Dua Fatima
May 03, 2025
One key difference between the two protocols is how they manage the window size. In Go-Back-N, the window size is limited by the sequence number space, as the protocol does not allow for frame sorting at the receiver end. This can lead to underutilization of available bandwidth, particularly over high-speed networks.
Dua Fatima
May 03, 2025
Selective Repeat Protocol requires more complex mechanisms for tracking received and acknowledged frames, including maintaining separate acknowledgment for each frame. This increases the complexity of the receiver but allows for more efficient error correction and bandwidth utilization.
Hifza Nasir
May 03, 2025
Error recovery in Go-Back-N Protocol can lead to higher latency, as correctly received frames must wait for the retransmission of lost or erroneous frames before they can be processed. In contrast, Selective Repeat Protocol minimizes this delay by allowing out-of-order frames to be accepted and processed immediately, provided that their sequence numbers fall within the receiving window.
Dua Fatima
May 03, 2025
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Comparison Chart
Error Handling
Retransmits all frames after an error
Only retransmits the erroneous frames
Dua Fatima
May 03, 2025
Efficiency
Lower, due to unnecessary retransmissions
Higher, due to selective retransmissions
Hifza Nasir
May 03, 2025
Receiver Complexity
Simpler, as it discards out-of-order frames
More complex, requires buffering of out-of-order frames
Hifza Nasir
May 03, 2025
Suitability
Better for lower error-rate environments
Better for higher error-rate environments
Hifza Nasir
May 03, 2025
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Go-Back-N Protocol and Selective Repeat Protocol Definitions
Go-Back-N Protocol
Simplifies receiver design by avoiding out-of-order frame acceptance.
Receivers in Go-Back-N discard any frame arriving out of sequence.
Dua Fatima
Feb 26, 2024
Selective Repeat Protocol
Requires acknowledgment for each frame individually.
In Selective Repeat, each frame needs its own acknowledgment.
Hifza Nasir
Feb 26, 2024
Go-Back-N Protocol
Uses a single cumulative acknowledgment for efficiency.
Go-Back-N relies on cumulative acknowledgments to confirm receipt.
Hifza Nasir
Feb 26, 2024
Selective Repeat Protocol
A protocol that retransmits only the erroneous frames.
Selective Repeat enhances efficiency by targeting retransmissions.
Dua Fatima
Feb 26, 2024
Go-Back-N Protocol
Suitable for environments with low error rates.
Go-Back-N is preferred in networks where errors are infrequent.
Dua Fatima
Feb 26, 2024
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Selective Repeat Protocol
Allows receiving out-of-order frames without issue.
Selective Repeat can buffer and reorder frames as they arrive.
Dua Fatima
Feb 26, 2024
Go-Back-N Protocol
A protocol where after an error, all subsequent frames are resent.
In Go-Back-N, a frame loss requires resending all following frames.
Shumaila Saeed
Feb 26, 2024
Selective Repeat Protocol
Incorporates complex receiver logic for frame tracking.
Selective Repeat's complexity lies in its frame tracking mechanism at the receiver.
Hifza Nasir
Feb 26, 2024
Go-Back-N Protocol
Employs a sliding window mechanism to control flow.
The sliding window in Go-Back-N dictates the frame transmission rate.
Hifza Nasir
Feb 26, 2024
Selective Repeat Protocol
More suited for high-speed or error-prone networks.
High-error networks benefit from Selective Repeat's selective retransmissions.
Dua Fatima
Feb 26, 2024
Repeatedly Asked Queries
Which protocol is simpler to implement?
Go-Back-N is simpler due to its straightforward error handling approach.
Hifza Nasir
May 03, 2025
How do these protocols affect bandwidth utilization?
Selective Repeat utilizes bandwidth more efficiently by avoiding unnecessary retransmissions.
Hifza Nasir
May 03, 2025
Is Go-Back-N suitable for high-speed networks?
It can be less efficient on high-speed networks due to its bulk retransmission strategy.
Hifza Nasir
May 03, 2025
What is the main difference between Go-Back-N and Selective Repeat Protocol?
Go-Back-N retransmits all frames after an error, while Selective Repeat only retransmits erroneous frames.
Dua Fatima
May 03, 2025
Can Selective Repeat handle high error rates effectively?
Yes, it's designed to handle high error rates efficiently by retransmitting only incorrect frames.
Shumaila Saeed
May 03, 2025
What makes Selective Repeat more efficient in error-prone environments?
Its ability to selectively retransmit only erroneous frames reduces the number of retransmissions.
Dua Fatima
May 03, 2025
How does window size affect the performance of these protocols?
Larger windows can improve throughput but require more memory and processing power.
Hifza Nasir
May 03, 2025
Can Go-Back-N and Selective Repeat be used together?
They are typically used independently, as they represent different approaches to error handling.
Hifza Nasir
May 03, 2025
Which protocol requires more memory and processing power at the receiver?
Selective Repeat requires more, due to the need to buffer and sort out-of-order frames.
Hifza Nasir
May 03, 2025
How does Go-Back-N handle out-of-order frames?
It discards them, requiring the sender to retransmit.
Shumaila Saeed
May 03, 2025
Do both protocols use sliding windows?
Yes, both use sliding windows, but they manage them differently.
Dua Fatima
May 03, 2025
How do acknowledgments work differently in these protocols?
Go-Back-N uses cumulative acknowledgments, while Selective Repeat requires individual acknowledgments for each frame.
Shumaila Saeed
May 03, 2025
Which protocol is easier for debugging?
Go-Back-N, due to its simpler mechanism.
Dua Fatima
May 03, 2025
How do these protocols impact network congestion?
Selective Repeat can better manage congestion by reducing unnecessary retransmissions.
Dua Fatima
May 03, 2025
Which protocol is better for real-time applications?
Selective Repeat, due to its lower latency in handling errors.
Hifza Nasir
May 03, 2025
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About Author
Written by
Hifza Nasir
Co-written by
Dua Fatima
Shumaila Saeed
Hifza Nasir
Dua Fatima
