PROTOCOLS FOR OPTICAL STAR-COUPLER NETWORK USING WDM - PERFORMANCE AND COMPLEXITY STUDY

A network of stations connected via a passive star coupler is considered, in which stations are equipped with fixed transmitters and tunable receivers and use wavelength-division multiplexing. Of concern in such networks is the efficiency of the protocol for coordinating the data transmission between the transmitter and receivers. In this paper, the performance and complexity issues involved in designing such protocols are explored. Two reservation-based protocols with varying degrees of signaling complexity are proposed: 1) the dynamic allocation scheme (DAS), which dynamically assigns slots on a packet-by-packet basis; and 2) the hybrid TDM scheme (HTDM), which combines the TDM and the DAS scheme and allows both preassigned and dynamic slot assignment. Analytical results are derived for the delay performance of the two schemes and compared with that of TDM. It is shown that the performance of DAS under ideal conditions is close to optimal; however, its signaling costs are exorbitantly high. On the other hand, HTDM has lower signaling needs, but has higher delays when compared to DAS. However, when compared to TDM (which incurs minimum signaling costs), HTDM provides lower delays, particularly under nonuniform traffic conditions, and can effectively handle bursty data traffic.