Usage of OPNET simulation tool for validation of routing in ATM backbone networks of tactical communication systems

The article presents issues related to dynamic routing in ATM backbone networks, which are part of a new generation of tactical communication systems. A tactical communication system is characterized and is designed in MCI and according to the rules of using ATM and the necessity of using virtual switched connections and dynamic routing. The paper also describes the main features of PNNI (private network-network interface), a routing protocol that meets the imposed requirements. The initial rules are specified for dividing the ATM backbone network into routing domains to limit the amount of non-user traffic sent in the network and decrease the load of the radio relays with this kind of traffic. Based on the exemplary topology of the system, a simulation model has been built in OPNET software and used to verify the accuracy of the proposed division into peer groups. Results captured in particular experiments are presented. Special attention is paid to the amount of information sent in the network in case of a "flat" network and a network divided into routing domains.