An improved dynamic protocol for variable-sized messages is proposed in WDM-based local network, when nodal transceiver has nonzero tuning time. With the protocol, data channel is assigned dynamically. However, once a node reserves one data channel, it can persistently use the reserved channel till message transmission is finished. The protocol is analyzed with a finite population model and the throughput-delay characteristics are investigated as performance measures.

In this paper, we propose a synchronous reservation protocol that is efficient for supporting variable-sized messages in a wavelength division multiplexing (WDM)-based local network using a passive star topology. A control channel is used to coordinate message transmission on data channels. Time is slotted with fixed-sized slots. The network can accommodate a variable number of nodes and operate independently of the change in the number of nodes. Therefore, any "new" node can join the network anytime without network re-initialization. Moreover, with the protocol, we can avoid data channel and destination conflicts. We analyze the performance according to the variation of the end-to-end propagation delay with respect to one slot time, and validate the results by simulation.

Metro networks are based on SONET/SDH which uses the circuit switching technology. Circuit switching is inappropriate for the Internet traffic which is very bursty nature. Therefore, metro networks can become a bottleneck. In order to resolve this problem, the IEEE 802.17 working group has proposed the Resilient Packet Ring (RPR) technology. In order to provide fairness among stations in the RPR network, two types of RPR fairness mechanisms have been defined. However, the IEEE 802.17 RPR fairness mechanisms have the problem of inefficient use of the available bandwidth after the congestion at a node has been resolved. In this paper, we propose an improved bandwidth allocation in which, after the congestion resolution at a node, the node estimates the number of effective nodes transmitting traffic, measures the remaining bandwidth and fairly allocates the available bandwidth to effective nodes. To show the performance of our proposed mechanism, we have performed simulation and show that the proposed mechanism gives higher bandwidth utilization than the existing RPR fairness mechanisms.