One of the most impacting technological developments during the last few years has been the emergence of the Internet. With rapid growth of the Internet, it is becoming increasingly difficult to provide the necessary services to all users within a designated time period. As the gap between the network-line and application-server rates is growing, it is getting easier to launch Distributed Denial of Service (DDoS) attacks against services on the Internet, and remain undetected within the network. Gligor's rate control scheme is a novel mechanism for providing strong access guarantees to clients for accessing public services, by generating and enforcing simple user-level agreements on dedicated special purpose servers.

This thesis studies the results obtained from simulations, when this rate control scheme is applied to two kinds of networks, namely, Content Distribution Networks, and Domain Name Server-based networks. In particular, the server utilization, and client waiting times were studied with the aim of finding bounds on parameters that improve server performance, and of providing clients with reasonable maximum waiting times to service.