tcp-sack-rfc2018

TCP Selective Acknowledgment (SACK) is an RFC 2018 mechanism that solves performance degradation caused by multiple packet losses within a single window. You need SACK to optimize reliable data transmission over lossy or high-delay network paths where traditional cumulative acknowledgments fail.

The sender scoreboard manages retransmission strategies by tracking selectively acknowledged data blocks, allowing precise identification of missing segments. This approach preserves congestion control while avoiding unnecessary retransmissions of already received packets during multiple packet loss scenarios.

Receiver behavior rules dictate how to construct SACK-Permitted and SACK options, specifying the exact format for reporting received data blocks to the sender. These rules ensure accurate block-reporting for non-contiguous data segments during transmission.

Yes, you can use SACK implementation guidelines to debug network throughput issues in high-latency environments. Understanding SACK option formats and sender retransmission strategies helps identify inefficient retransmissions causing bottlenecks over lossy links.

Performance degrades because traditional cumulative acknowledgments only confirm the last in-order packet, forcing the sender to retransmit all subsequent data. TCP Selective Acknowledgment solves this by allowing the receiver to confirm non-contiguous blocks, preventing unnecessary retransmissions.