A Low Cost and Flexible Network Testbed

New network technologies and services encourage the search for new networking ideas and new protocols; the main problem that we encounter developing this ideas is to test the result of our work in a realistic test environment. In this paper we describe how it is possible to build a low cost network testbed, easy to modify and based on the integration of open source software. Beside we show, as an example, a practical implementation of such a testbed and some tests performed about improving packet transmission reliability using different redundant transmission techniques. We identified two different techniques of redundant transmission on an IP network and we performed some transmission tests emulating situations of network malfunctioning that proof how the use of redundant transmission permits to strongly reduce the effects of network problems