Active network vision and reality

Although active networks have generated much debate in the research community, on the whole there has been little hard evidence to inform this debate. This paper aims to redress the situation by reporting what we have learned by designing, implementing and using the ANTS active network toolkit over the past two years. At this early stage, active networks remain an open research area. However, we believe that we have made substantial progress towards providing a more flexible network layer while at the same time addressing the performance and security concerns raised by the presence of mobile code in the network. In this paper, we argue our progress towards the original vision and the difficulties that we have not yet resolved in three areas that characterize a "pure" active network: the capsule model of programmability; the accessibility of that model to all users; and the applications that can be constructed in practice.