Management of Active Services

Abstract. Active networking introduces a new flexible network service paradigm. The passive data carrier is changed to an active, dynamically configurable, data-transport-service machine, through the possibility of performing computation in the network nodes. Utilization of mobile agents allows to deliver service tasks to any place in the network. An agent can execute adaptive filtering on the bypassing data streams, do user intended signalling and handle network management tasks in a distributed manner. Looking at the aspects of network services, benefits arise from the fact that the transmission protocols can be tailored to the application by providing filtering or format conversion within the network. The "one fits all" approach, like TCP/ UDP which can just handle end-to-end loss control are strongly improved. Generally speaking there are two ways in providing active services in the network: the full user based approach, allowing the end user to distribute its own, application dependent stream forwarding agent. It can be used in the open Internet where the mobile agents can provide bridges over legacy systems. Or, the layered approach, giving only the administrator of the network the possibility to deploy new service classes within the network. This is particularly interesting in a Intranet scenario, permitting to deploy new services rapidly and granting the user only the execution of the new service. We are also concerned by service and system security and failure protection aspects of this approach: When an agent becomes mobile and it includes the possibility to reproduce child agents in any number, the problems of agent flooding become apparent. Therefore solutions have to be proposed to guarantee, that the agents which get lost or out of control, will time out and return to their home, or die immediately. A possible solution based on credits is presented and discussed. This paper reviews efforts in the research domain: including the Active IP projects at MIT, theActive Networkingproject at Georgia Institute of Technology and theNetScript approach from Columbia University. Our alternative approach is presented, which allows fast service deployment, examples of service usage and a service and system security concept for the proposed architecture. Active networking introduces a new flexible network service paradigm. The passive data carrier is changed to an active, dynamically configurable, data-transport-service machine, through the possibility of performing computation in the network nodes. Utilization of mobile agents allows to deliver service tasks to any place in the network. An agent can execute adaptive filtering on the bypassing data streams, do user intended signalling and handle network management tasks in a distributed manner. Looking at the aspects of network services, benefits arise from the fact that the transmission protocols can be tailored to the application by providing filtering or format conversion within the network. The "one fits all" approach, like TCP/ UDP which can just handle end-to-end loss control are strongly improved. Generally speaking there are two ways in providing active services in the network: the full user based approach, allowing the end user to distribute its own, application dependent stream forwarding agent. It can be used in the open Internet where the mobile agents can provide bridges over legacy systems. Or, the layered approach, giving only the administrator of the network the possibility to deploy new service classes within the network. This is particularly interesting in a Intranet scenario, permitting to deploy new services rapidly and granting the user only the execution of the new service. We are also concerned by service and system security and failure protection aspects of this approach: When an agent becomes mobile and it includes the possibility to reproduce child agents in any number, the problems of agent flooding become apparent. Therefore solutions have to be proposed to guarantee, that the agents which get lost or out of control, will time out and return to their home, or die immediately. A possible solution based on credits is presented and discussed. This paper reviews efforts in the research domain: including the Active IP projects at MIT, theActive Networkingproject at Georgia Institute of Technology and theNetScript approach from Columbia University. Our alternative approach is presented, which allows fast service deployment, examples of service usage and a service and system security concept for the proposed architecture. HP-OVUA 97 Oliver Huber 2