Performance evaluation of dynamic routing based on the use of satellites and intelligent networks

Abstract

A dynamic routing scheme for public switched telephone networks is introduced which employs satellite broadcast to distribute network load data. The proposed network architecture closely resembles the IN (Intelligent Network) architecture, whereby the IN SCPs (Service Control Points) serve as so‐called Routing Control Points (RCPs). The key functions of an RCP are (i) to execute the routing algorithm and issue routing instructions in response to routing queries it receives from its associated switches for calls which overflow from the default network links, and (ii) to monitor and evaluate the pattern of received routing queries to obtain an estimate for the traffic loads present in each RCP's domain of associated switches. Satellite broadcast is used to distribute the load information among all RCPs in the network in a periodic fashion. This paper also reports on the results of extensive call‐by‐call simulations. The objective of the simulations was to validate this new routing scheme and compare its performance with well‐known existing schemes. Real traffic and network data as measured in the Austrian PSTN were used in the simulations. The main results are that, under all realistic network and traffic conditions including link and node failures, the proposed scheme yields lower blocking rates and significantly less routing and crankback attempts than the existing dynamic routing schemes. Note that this is achieved in the absence of any load measurements within the switches. As regards the periodic satellite based RCP‐RCP broadcast for the PSTN studied, it was shown that an update period of 10 seconds yields an excellent routing performance which is close to the limit of a vanishing update period.