Programmable and active networks allow specified classes of users to deploy dynamic network services adapted to data streams requirements. Based on our experience in high performance active networking, this paper compares two alternative approaches for adding dynamic solutions in the network: heavy and lightweight dynamic network services. We propose and describe solutions to efficiently manage and deploy heavy services (requiring resources and closely linked with middleware or applications) and lightweight network services (generic and pragmatic solutions with limited impact on network infrastructure). Experiments on local and wide area platforms are presented.