NIST ATM/HFC Network Simulator

The simulator is used as a network planning tool by simulating various network configurations and traffic loads, and obtaining statistics such as utilization of network links and throughput rates of virtual circuits. It can be used to answer questions such as: where will the bottlenecks be in the circuits?; what is the effect of changing the speed of a link?; or will adding a new application cause congestion?

The simulator can also be used as a protocol analysis tool to study the total system effect of a particular ATM network protocol. For example, one can investigate the effectiveness of various flow control mechanisms for ATM networks and address such issues as mechanisms for fair bandwidth allocation, protocol overhead, and bandwidth utilization. The simulator is designed in such a way that modules simulating components of an ATM network can be easily changed, added, or deleted.

The NIST ATM Network Simulator gives the user an interactive modeling environment with a graphical user interface. NIST has developed the tool using both C language and the X Windows System running on a UNIX^TM-based platform. The tool is based on a network simulator developed at MIT that provides support for discrete event simulation techniques.

The network to be simulated consists of several components sending messages to one another. Broadband Terminal Equipment (B-TE) simulates ATM host nodes and applications. Switches and B-TE components are interconnected with Physical Links, which are also considered components. ATM Applications are logical entities that run on the B-TE hosts, and can be considered as traffic generators capable of emulating variable or constant bit rate traffic sources.

To execute a simulation, the user creates a network consisting of any number of ATM switches and hosts interconnected by links of variable speeds. Virtual connections between any two hosts are manually established, and applications on hosts are selected and initiated. While a simulation is running, various instantaneous performance measures can be displayed in graphical/text form on the screen or saved to file for subsequent analysis.

To facilitate the exchange of information among the users of the simulator, we have established a users' email list.

For information regarding subscribing to the NIST ATM Simulator Users' Email List, click here.

• The NIST ATM Network Simulator Software, Version 4.1, Request Form

• MANUAL: The NIST ATM/HFC Network Simulator, Operation and Programming Guide, Version 4.0, December 1998