Advances in network simulation

The Internets rapid growth has spurred development of new protocols and algorithms to meet changing operational requirements-such as security, multicast transport, mobile networking, policy management, and quality-of-service support. Development and evaluation of these operational tools requires answering many design questions. Despite their value, custom simulators, wide-area test-beds, and small-scale lab evaluations all have drawbacks. Because they use real code, experiments run in testbeds or labs automatically capture important details that might be missed in a simulation. However, building testbeds and labs is expensive, reconfiguring and sharing them is difficult, and they are relatively inflexible. In the current paradigm, directly comparable data would be available only if designers implemented all competing mechanisms within every simulator. The Virtual InterNetwork Testbed (VINT) project, detailed and explained in this article, provides improved simulation tools for network researchers to use in the design and deployment of new wide-area Internet protocols.