The multitoken interarrival time (MTIT) access protocol for supporting variable size packets over WDM ring network

One of the approaches currently pursued to provide an optical network architecture for supporting the next generation Internet consists of transmitting the Internet protocol (IP) packets directly over the wavelength division multiplexing (WDM) layer. The challenge of this approach is to make the optical bandwidth directly accessible to IP with the statistical multiplexing necessary to support the bursty nature of IP traffic in a cost effective way. This paper proposes a WDM ring architecture with a multitoken interarrival time (MTIT) access protocol designed to achieve a bandwidth efficient multiplexing technique in local and metropolitan network applications. The MTIT protocol achieves efficient multiplexing of all-optically transmitted packets by means of multiple control tokens whose rotation speed along the ring is regulated via the "token interarrival time," as opposed to the "token rotation time" adopted in existing standards. The proposed WDM architecture and protocol provide a unique medium access control that allows one to maintain the channel access delay at a node within a limited range of values, possibly reaching average values that are below the roundtrip propagation time of the ring. In the paper it is shown that the MTIT protocol efficiency grows with the number of wavelengths-in agreement with today's WDM technology trends-and it is not a function of the packet size-a mandatory feature to support IP traffic.