This research proposes a new way of thinking about our current networks using a notion called active networking. Rather than just passive transport vehicle, active networks perform active computation on the messages that are in transit and hence facilitate far more functional capabilities than what is possible with today’s Internet. The authors present an active network architecture to customize the Internet according to a user’s need in which quality-of-service guarantees can be met for each individual application or end-user. We also discuss important issues related to implementation, security and management of such active networks.