n using the packet to validate a new implementation of the protocol. 61.4.5.4 Test suites 61.4.5 Monitors as active stations The process of using the network monitor to send sequences of packets to particular network devices in order to test their behaviour Although most of the network monitor's functionality is concerned can be automated. The patterns of packets, together with details of with passively watching all of the traffic on the network, and the expected responses, form a suite of tests. Key parameters, such processing the data in ways already described. There are some as the destination address, will have to be changed each time the test features of a monitor that require it to participate actively in the suite is applied, but this still forms quite a powerful testing facility. communication on the network. A few network monitors now provide support for the use of test suites. The real benefit for the user comes from the level of analysis that the monitor performs on the results of applying a test suite. It is 61.4.5.1 Testing connections clear that the maximum benefit would arise from the use of artificial intelligence in the analysis of the results. At least one network The role of a cable tester and the more sophisticated physical analysis tool now attempts to provide a limited form of this. network analyser have already been discussed. Most network moni- tors also provide a limited cable test feature, but with poor accuracy. 61.4.6 Effective use Some monitors also perform echo tests on stations specified by the user. Network monitors are frequently used only in a trouble shooting The echo test involves the monitor transmitting a special type of capacity. So, for example, when users complain of sporadic inter- packet to a network station and then waiting for a reply. If a valid ruptions in their service from a network server, the network monitor reply is received within the timeout period, this shows that the is wheeled out to solve the problem. At that time, the monitor is used station is present on