In this paper we present an application-driven study of active networks, identifying unique and practical applications that make full use of the active infrastructure. We explore a class of applications in network monitoring that indicate a clear need for programmability as offered by active networking technology.

We have built several monitoring applications on an active substrate that is synthesized from off-the-shelf components. We demonstrate the flexibility provided while showing that for certain application workloads such a system can efficiently operate at modern backbone network speeds. Our performance study also leads to design considerations for scaling up the infrastructure to future network speeds.