Performance Analysis of Optical Switched Networks with Two-Way Reservation

Performance of an optical burst switching with two-way reservation is analyzed using queueing theoretical approach in this paper. The switching considered hereafter exploits both the resource sharing nature of packet switching and the highspeed transmission capability of wavelength division multiplexing in optical networks. Under the switching architecture, when a group of packets to be addressed to the same edge node of an optical network and thus to be put in an optical burst gets ready for transmission at an edge node, the node sends a request for service to a centralized control node to get wavelength allocated for the duration of a burst transmission. After an offset interval, a designated wavelength is allocated to the request if available. The delay might cause the degradation of QoS, especially for real time applications. One of possible improvements in the above mechanism is for an edge node to send a request for a slot in advance before it counts an enough number of packets to fill up a slot and to expect that the remaining space in a slot is filled with packets arriving in an offset delay. We first describe a queueing model of a finite buffer where a batch of packets are served in a burst and then derive the probability distribution of the number of packets in the buffer. As for performance measures, we obtain the packet loss probability, the average transmission delay and the utilization factor of bursts