Object-oriented communication structures for multimedia data transport

The evolving multimedia applications generate requirements for complex transport capabilities, i.e., functional features, in the end-to-end communication system such as handling of heterogeneity among communicating terminals, supporting finer levels of user-specifiable quality of data transport service, and synchronization of various data streams for delivery at users in real time. Accordingly, the communication system may be viewed as extending the basic capabilities provided by the backbone network (e.g., bandwidth allocation) into a set of transport capabilities suitable for complex applications. This paper presents: (1) an object-oriented view of the user interface to the communication system with an elegant separation of data transport functionalities, and (2) an approach to the design of underlying transport protocols. The object-orientation decomposes an application-level data transport into a set of network channel objects, with each channel object handling a separate data stream. The object interactions are modeled using a "data-flow programming" style, which allows a richer set of protocols to implement the communication system and offers flexibility to accommodate complex and heterogeneous subscriber services/terminals. The "data-flow programming" method also allows a high degree of communication level parallelism among data transport through channels. The view of a multimedia communication system as a "parameterizable black-box", as underscored in the object-oriented structuring, allows easier interworking of the communication system with existing networks and easier integration of multimedia transport into programming environments.