Efficient dissemination of personalized information using content-based multicast

In this paper we evaluate the situations in which CBM is advantageous. The benefits of CBM depend critically upon how well filters are placed at interior nodes of the IP multicast tree, and the costs depend upon those introduced by filters themselves. Further, we consider the benefits of allowing the filters to be mobile so as to respond to user mobility or changes in user interests, and the corresponding costs of filter mobility. We consider two criteria: minimizing total network bandwidth utilization and minimizing mean information delivery delay. For each criterion we develop an optimal filter placement algorithm, as well as a heuristic that executes faster than the optimal algorithm. Finally, we evaluate all the algorithms by means of simulation experiments. Our results indicate that filters can be effective in substantially reducing bandwidth and delay. We also find filter mobility is worthwhile if there is sufficient locality in the interests of users, or there is marked large-scale user mobility. We conclude with suggestions for further work.