A polling model is a system of multiple queues accessed by a single server in cyclic order. Polling models provide performance evaluation criteria for a variety of demand-based, multiple-access schemes in computer and communication systems. This paper presents an overview of the state of the art of polling model analysis, as well as an extensive list of references. In particular, single-buffer systems and infinite-buffer systems with exhaustive, gated, and limited service disciplines are treated. There is also some discussion of systems with a noncyclic order of service and systems with priority. Applications to computer networks are illustrated, and future research topics are suggested.

Queuing analysis of polling models

An optical communication structure is proposed for multiprocessor arrays which exploits the high communication bandwidth of optical waveguides. The structure takes advantage of two properties of optical signal transmissions on waveguides, namely, unidirectional propagation and predictable propagation delays per unit length. Because of these two properties, time-division multiplexing (TDM) of messages has the same effect as message pipelining on optical waveguides. Two TDM approaches are proposed, and the combination of the two is used in the design of the optical communication structure. Analysis and simulation results are given to demonstrate the communication effectiveness of the system. A clock distribution method is proposed to address potential synchronization problems. Feasibility issues with current and future technologies are discussed. >

Time-division optical communications in multiprocessor arrays

A hypercube-based structure in which optical multiple access channels span the dimensional axes is introduced. This severely reduces the required degree, since only one I/O port is required per dimension. However, good performance is maintained through the high-capacity characteristics of optical communication. The reduction in degree is shown to have significant system complexity implications. Four star-coupled configurations are studied as the basis for the optical multiple access channels, three of which exhibit the optical self-routing characteristic. A performance analysis shows that through the integration of agile sources or receivers, and wavelength division multiple access, systems can be developed with significant increases in performance yet at a reduction in communication subsystem complexity. >

Wavelength division multiple access channel hypercube processor interconnection

Media access control protocols for an optically interconnected star-coupled system with preallocated wavelength-division multiple-access channels are discussed. The photonic network is based on a passive star-coupled configuration in which high topological connectivity is achieved with low complexity and excellent fault tolerance. The channels are preallocated to the nodes with the proposed approach, and each node has a home channel it uses either for data packet transmission or data packet reception. The performance of a generalized random access protocol is compared to an approach based on interleaved time multiplexing. Semi-Markov analytic models are developed to investigate the performance of the two protocols. The analytic models are validated through extensive simulation. The performance is evaluated in terms of network throughput and packet delay with variations in the number of nodes, data channels, and packet generation rate. >

Low-complexity multiple access protocols for wavelength-division multiplexed photonic networks

A protocol for multiaccess communication over unidirectional bus networks is proposed, and its performance capabilities are determined. Under this protocol, time is slotted with a slot equaling a packet's transmission time. A station with a packet to send persists in transmitting its packet in an empty slot with probability p/sub i/ until it is successful. Three criteria for fairness in selection of the p/sub i/ are modeled using Markov chains, which are solved to obtain the proper p/sub i/ that satisfy each fairness criterion. Unlike previous studies of unidirectional bus networks, stations are allowed to buffer more than one packet. The average packet delay for this protocol is bounded, and the maximum achievable throughput approaches unity with increasing buffer size. Further, the protocol provides better delay versus throughput behavior for fixed packet lengths than previous round-robin schemes, its performance is insensitive to bus characteristics, and it appears to be particularly well suited for fiber-optic network applications requiring long distances and high bandwidths. Simulation results that confirm the predicted performance are included. >

The p/sub i/-persistent protocol for unidirectional broadcast bus networks

Local area communications networks based on packet broadcasting techniques provide simple architectures and efficient and flexible operation. Various ring systems and CSMA contention bus systems have been in operation for several years. More recently, a number of distributed demand assignment multiple access (DAMA) schemes suitable for broadcast bus networks have emerged which provide conflict-free broadcast communications by means of various scheduling techniques. Among these schemes, the Token-Passing Bus Access method uses explicit tokens, i.e., control messages, to provide the required scheduling. Others use implicit tokens, whereby stations in the network rely on information deduced from the activity on the bus to schedule their transmissions. In this paper we present many implicit-token DAMA schemes in a unified manner grouped according to their basic access mechanisms, and compare them in terms of performance and other important attributes.

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Papers

Demand Assignment Multiple Access Schemes in Broadcast Bus Local Area Networks