To Minimize SACK Option Space by Using Segment-Based Algorithm

TCP Selective ACK (SACK) Scheme is used by receiver to notify sequence space information of receiving buffer to sender. In standard SACK scheme, however, each SACK block has to be described by eight bytes, which may introduce significant overhead and restrict other schemes to use TCP option space. Moreover, in some worse cases, some unnecessary retransmission may be triggered, especially when errors burst in forward path and reverse path is severely congested. This paper introduces a segment-based SACK algorithm. Theoretical analysis result shows that the proposed algorithm can significantly reduce the SACK overhead so as to save the more TCP option space for those schemes that need it as well.