ONE (the Ohio Network Emulator) is a tool that enables researchers to emulate a network between a pair of interfaces on a single Solaris-based workstation. The user can control various features of the network, such as propagation delay, queueing characteristics and bandwidth. In addition, the tool interfaces with Satellite ToolKit (STK) to emulate variable propagation delays based on the orbits of satellites. ONE was initially developed by Ohio University's Internetworking Research Group. The program is now maintained in conjunction with the NASA Glenn Research Center's Satellite Networks and Architectures Branch.
The most recent version of ONE is one-3.0, which can be downloaded here. This tarball contains the ONE source code and information on compiling and using ONE.
The HTML version of the ONE manual, which is distributed with the source, can also be found online here.
There are a couple of mailing lists of interest to ONE users. Users can subscribe to the ONE users mailing list by sending a message to firstname.lastname@example.org, with the text 'subscribe one-users' in the body. The mailing list is also archived on the web at one.grc.nasa.gov. There is also a ONE maintainers mailing list, which can be reached at the address email@example.com.