Using the ns-2 simulation environment to implement and evaluate Bandwidth Broker models

In this paper we present and compare four different models of implementing a Bandwidth Broker in a DiffServ network. We describe the relevant implementation aspects in the well-known ns-2 simulator and present a number of experiments that were conducted in order to verify our implementation, analyze the performance characteristics of the various alternatives and evaluate the usefulness of the ns-2 simulation environment for similar purposes. We present our experiments that aim at investigating a number of issues related to the operation of Bandwidth Broker modules, and in particular how the acceptance rate, the network overhead and the response time for each Bandwidth Broker model are affected by the network topology, the available buffers for incoming requests and the advance time from the moment a request is submitted to the moment the reservation should take place.