Date Added: Jul 2011
Protocol design and development is not a straightforward process. Each approach must be validated for interactions and side-effects in the existing network environments. But the Internet itself is not a good test environment, since its components are not controllable and certain problem situations (like congestion or error conditions) are difficult to reproduce. Various testbeds have been built up to fill this gap. Most of these testbeds also support link emulation, i.e., using software to mimic the characteristic behaviour of certain kinds of network links (like bandwidth bottlenecks or error-prone radio transmissions).