A key feature of active networks is the capability to dynamically deploy services. In this paper, we present a scheme to classify service deployment mechanisms of existing or future active network architectures. Distributed algorithms (services), as being implemented in active networks, can be described based on active packets or as distributed programs running on active nodes. Although both programming models are basically equivalent, some services are more naturally implemented in either way. This paper proposes an active node architecture that supports the implementation and deployment of services according to both programming models. We point out that a combination of in-band and out-of-band service deployment is needed to dynamically deploy services implemented in either model. Furthermore, we argue that composing services from service logic implemented in either programming model is beneficial for the design of efficient and flexible services. We reason that a service abstraction in the form of a service description language is necessary to cope with real world scenarios.