Abstract: A telecommunications service node includes a multi-level architecture comprising an operating system layer interfaced using a compile time linked interface to a service framework layer, and a service application layer interfaced using an object oriented, run time linked interface to the service framework layer. Run time linking of the service applications supports the introduction or modification of service applications during run time execution of the service node. Each service application inherits from the same base class, and is defined by certain criteria which need to be met in order to execute the service. A trader maintains a reference to each available service application. When a certain service needs to be performed, a set of criteria for that certain service are evaluated by the trader, and a particular one of the service applications within the service layer defined to meet the criteria set is selected. The selected service application is then invoked to support the certain service.