Abstract

The IP/ATM Hybrid Network Simulator (HyNS) reported herein is an extension to LBNL's (Lawrence Berkeley National Labs) Network Simulator version 2--Ns2. Ns2 is written in C++, with an OTcl interpreter as a front-end. Ns2 has good support for IP, but no support for ATM. Since not many researchers are familiar with OTcl, and it is painful to do OTcl and C++ debugging together, the OTcl code is converted into C++ code. In order to support ATM and TCP/IP over ATM, the following components are added: (1) TCP connection to ATM virtual circuit mapping, (2) second layer routing (ATM switching), (3) ATM switch (Virtual Circuit Classifier), and (4) IP/ATM gateway function (segmentation and reassembly). HyNS was developed to provide a means for researchers to analyze the behavior of IP networks or IP over ATM networks without the expense of building a real network.