In the near future, networks based upon the IEEE 802.6 metropolitan area network standard will become widespread. Eventually, networks of this type will be possible using both conventional point-to-point fiber and new photonic implementations. In both cases, it is possible to decouple the physical and logical topologies of the network yielding a rearrangeable bus. This capability magnifies the benefits of a media access protocol with destination slot release. In this paper, a media access protocol is introduced which provides destination slot release at each station. The REQPASS Protocol is a way of achieving fair bandwidth allocation in the presence of network overload conditions. REQPASS combines the request protocol with a slot release mechanism which permits request erasures on the reverse bus. A novel analytic model is introduced which accurately computes the mean queueing delay for individual stations. The success of the model is attributed to the fact that in a network with slot reuse, traffic independence approximations are more reasonable.>

Traffic processing algorithms are introduced for SIGnet (slotted interconnected-grid network), which is intended for local and metropolitan area backbone communication networks using multichannel optical transmission media. The design is motivated by the development of inexpensive multichannel capabilities based on dense wavelength division multiplexing (WDM) and future coherent optical systems. In SIGnet, the virtual topology is piecewise regular and permits bandwidth allocation and network evolution which is much more easily accomplished than in previous designs. SIGnet employs deflection routing to accommodate nonisochronous traffic. However, a multilink grid topology provides a closer match to the actual physical topology in many networks. This work includes an introduction to the network design and presents results obtained concerning the traffic processing algorithms which have been investigated.>

The photonic bus network (PBNet) approach to the design of small backbone networks is considered. The basic building block of PBNets consist of a linear multihop network interconnected in a bidirectional bus virtual topology using point-to-point optical channels. The system is designed to exploit transmissive optical star technology employing multichannel coherent lightwave modulation, but a wavelength-division implementation is also possible. The NCounter Protocol is introduced as a way of achieving fair bandwidth allocation in the presence of network overload conditions. Due to the optical implementation, there is considerable flexibility in PBNet topological design and bandwidth deployment. New design algorithms are introduced for this purpose. Performance results show that substantial improvements in system operation are possible using the proposed design techniques. In addition, the concept of receiver allocation is introduced which permits simple performance evolution of fixed-channel PBNets.>

Traffic processing algorithms are discussed for the slotted interconnected-grid network (SIGnet). SIGnet is intended for use as a high-performance backbone in metropolitan and extended-metropolitan areas. The system is designed to exploit the use of existing wavelength division multiplexing and coherent lightwave technologies. When accommodating nonisochronous traffic classes, the virtual topology in SIGnet is piecewise regular. As a result, bandwidth allocation and network evolution are easily accomplished. The philosophy of the design is to drastically minimize the buffering and protocol requirements at the transmit nodes, thus giving a highly cost-effective implementation. The SIGnet architecture is introduced, and results are given for certain traffic processing algorithms which have been investigated. A two-stage analytic model is presented which allows for the calculation of both detailed link traffic flow rates and the mean queueing delay at individual nodes. The results indicate that in typical subnetworks, reasonable accuracy may be obtained over a wide range of parameter values using link independence assumptions.>