Aids to the development of network simulators

Abstract

In this paper we describe the features of a program designed to simulate computer networks. The networks are assumed to consist of hosts attached to one or more network nodes (communication units) which in turn communicate with one another via one or more communication channels. The program accounts for user-host, host-node, node-node, node-host, and host-user protocols, as well as network topology and hardware characteristics. As reported in a later section, the program has been primarily used to conduct simulations to ascertain the performance (in terms of message or packet throughput and delay) for a variety of node-node channel access protocols, for nodes connected to a single common communication medium (e.g. a multi-drop cable or radio channel). It is, however, possible to accommodate networks in which nodes may be connected to several separate communication channels. Further, it is possible to simulate the behavior of store-end-forward networks as they can be viewed as a network in which the nodes are connected to multiple communication links. For either class of network the program can be used to verify protocol correctness or to assess network performance.