Proactive loss recovery using forward segment redundancy in optical burst-switched (OBS) networks

Data burst contentions occur in optical burst-switched (OBS) networks due to one-way signaling and bufferless nature of the core network. A single burst loss containing multiple TCP segments can trigger drastic reactions from the corresponding TCP sources. TCP sender interprets segment loss as network congestion, resulting in throttling send rate. In this paper, we propose a new forward segment redundancy (FSR) mechanism that minimizes segment loss during burst contentions in the core and also recovers from segment loss in the forward direction using redundant segments placed in each data burst. In FSR mechanism, redundant TCP segments are added to each burst assembled at the ingress node before transmission to the destination. The segment losses due to contentions are minimized using a modified burst segmentation mechanism, and most lost segments are recovered in the forward direction using redundant segments. Using FSR, we observe significant improvement in TCP performance over OBS networks.