Abstract: A method of providing a service application on a data processing apparatus comprising an interconnect and a plurality of data processing nodes, the method comprising the steps of, registering a service class at the interconnect, the service class having an associated service descriptor, generating a service object at a data processing node, the service object comprising an instance of the service class, and storing subscription information at the interconnect to permit messages to be routed to the service object in accordance with the service descriptor.