A Complete Framework to Support Controlled Burst Retransmission in Optical Burst Switching Networks

It is widely accepted that retransmitting bursts in Optical Burst Switching networks improves the throughput at higher layers. Since the data is transported in large bursts and there are burst losses due to contention, indiscriminate retransmission can defeat the purpose of burst-level retransmissions. For many applications, retransmission after a certain time would be of no use and it may not be necessary to retransmit all the lost packets. We propose a framework for retransmission with parameters to control the retransmission rate and thus the increase in the network load. We propose a network model for controlled retransmission and a modified functional architecture of the ingress node. The existing work lacks an accurate analysis to estimate the impact of retransmissions on the network load while studying the improvement in the end-to-end packet recovery. We provide theoretical analysis to evaluate the load at each node due to both fresh and retransmitted bursts. We propose some metrics to quantify the benefit of retransmission and the impact of the retransmission parameters proposed on the network performance. We show that with controlled retransmission, the buffer requirement at the ingress node is proportional to the steady-state rate of retransmitted bursts. We validate the analytical model arid also study the impact of retransmission on the network performance with extensive simulations.