Nam is a Tcl/Tk based animation tool that is used to visualize the ns simulations and real world packet trace data. The first step to use nam is to produce a nam trace file. The nam trace file should contain topology information like nodes, links, queues, node connectivity etc as well as packet trace information. In this chapter we shall describe the nam trace format and simple ns commands/APIs that can be used to produce topology configurations and control animation in nam.
The underlying design constraints for nam were that it is able to handle large amounts of trace data and that its animation primitives be adaptable so that it may be used in different types of network visualization. As a result, internally nam reads information from a file and keeps only a minimum amount of animation event information in memory. Its animation event has a fairly simple and consistent structure so that it can many different visualization situations.