Modelling, routing and architecture in active networks

This dissertation proposes a new cost model for active networks and employs it to develop novel active routing and agent placement algorithms. In addition, a new architecture for deployment of active network nodes IS proposed which transforms almost any Internet host into an active node using the Java Virtual Machine embedded in the host browser. Cost models implied or expressed in passive networks do not take into account the processing performed at nodes and the alterations of the flows from hop to hop. Furthermore, the roles of network nodes and flows change in the active network paradigm. No longer do the nodes alone compute and enforce the network routes in an indiscriminate fashion. The active packets or flows decide their own routes only with assistance from the network nodes. Through implementations of network mechanisms such as routing, connection admission and reservation, I show the need for and the advantages of the proposed cost model. A practical and flexible active routing algorithm developed based on this model optimally places active processes or agents on the internal nodes of the network to minimize the total end-to-end cost of the flow. Finally, Java applets and Java-enabled web browsers are combined to transform any Internet host to an active node instantly. This approach, which requires no hardware or software installation, forms the basis of successful deployment and test of an interactive service. The power of this ubiquitous approach lies in its potential to expand the coverage of active applications rapidly and seamlessly.