Routing as a flow control strategy within an integrated circuit/packet-switched communications network

Abstract

The introduction of economical voice digitization techniques and dramatic increases in the speed of electronic switching systems have now made possible the integration of voice and data traffic over the same communications network. Known as an "integrated" network, such a combined facility possesses characteristic advantages which make this technology the wisest choice for future communications systems. Recognizing this, researchers are pursuing design questions relevant to the integrated environment. Analysis of alternative architectures has not only convinced many of these researchers that integration of voice and data is a viable technique, but has also caused them to conclude that the Slotted Envelope Network (SENET) system described by Coviello and Vena is one of the most promising alternatives offered thus far. This research accepts the premise that the SENET-type integrated environment will eventually become commonplace. Leaping forward into that timeframe, however, one finds that many of the questions central to effective management of scarce communications resources remain unanswered. One of these is how to reduce congestion in this type of environment. Focusing on that question, this effort extends current research by investigating the viability of routing strategy as a mechanism for reducing congestion in the integrated communications environment. In doing so, it exploits the notion that congestion occurs when an excessive volume of traffic is channelled down a given communications link. A FORTRAN-based simulation of the integrated SENET environment is developed and then used to examine the characteristics of seven alternative routing strategies. The performance of these strategies is compared both amongst themselves and with "optimality". Performance is measured in terms of user-visible metrics. Based on the experimental results obtained, this research concludes that fixed routing, the technique assumed by most models examined in the literature, is not as effective a tool for reducing congestions as would be a strategy based on link utilization...