Hybrid Techniques: Combining Circuit and Packet Switching

http://link.springer.com/content/pdf/10.1007/978-94-011-6070-4_21.pdf

Recent papers have introduced a multiplexing structure for mixing voice and data traffic in an integrated telecommunications system. This structure utilizes a master frame format of a time division statistical multiplex facility. A certain portion of the frame is allocated to voice calls, and data traffic is assigned to the remaining frame capacity. To achieve a high transmission utilization, data are allowed to use any residual voice capacity momentarily available due to statistical variations in the voice traffic. The voice traffic is treated as a loss system and data packets are buffered. In this paper we derive exact analytical expressions for the key system perfomance measures, the probability of loss for voice calls, and the expected waiting time for data packets. Actually, two cases are considered, the one discussed above, called the movable boundary case, and one where the boundary is fixed; i.e., data are not allowed to utilize the residual voice capacity. The computational aspects of calculating actual numbers are discussed in some detail, and results are presented for typical cases.

A Model for Evaluating the Performance of an Integrated Circuit- and Packet-Switched Multiplex Structure

Results are developed for data traffic performance in an integrated multiplex structure which includes circuit-switching for voice and packet-switching for data. The results are obtained both through simulation and analysis, and show that excessive data queues and delays will build up under heavy loading conditions. These large data delays occur during periods of time when the voice traffic load through the multiplexer exceeds its statistical average. A variety of flow control mechanisms to reduce data packet delays are investigated. These mechanisms include control of voice bit rate, limitation of the data buffer, and combinations of voice rate and data buffer control. Simulations indicate that these flow control mechanisms provide substantial improvements in system performance.

Data Traffic Performance of Integrated Circuit- and Packet-Switched Multiplex Structure

This paper examines some of the fundamental problems associated with the design and performance of integrated systems and networks that switch both voice and data. Specifically, the need for an integrated approach to the switching and transmission of voice and data is explored and alternative design considerations are discussed. One approach, described in detail, utilizes a distributed architecture to implement variable width channel allocations for the dynamic union of voice and data. Key performance criteria which aid the systems designer in evaluating the merits of a proposed unified design are identified. Examples are illustrated and supportive material is provided by a comprehensive bibliography.

Hybrid Techniques: Combining Circuit and Packet Switching

References

A Model for Evaluating the Performance of an Integrated Circuit- and Packet-Switched Multiplex Structure

Data Traffic Performance of Integrated Circuit- and Packet-Switched Multiplex Structure

Design approaches and performance criteria for integrated voice/data switching

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