Abstract: A communications system may be used for transmitting and/or receiving data over a network. The communications system includes means responsive to requests for a desired quality of service specifying at least two quality of service parameters, such as bandwidth, latency, error rate, and so on, for determining whether or not the requested quality of service is available. The quality of service requests specify the desired quality of service in terms of logical expressions involving two or more of said at least two quality of service parameters. This allows, for example, a desired quality of service to accept a higher error rate if the available bandwidth is higher. In the preferred embodiment, each quality of service parameter is specified in terms of a range between minimum and a maximum acceptable values.

Abstract: A communications system may be used for transmitting and/or receiving data over a network. The system needs to exchange capability information with other systems in the network, in order to determine which forms of communication can be mutually supported. The exchange of information includes logical expressions involving two or more parameters. This allows, for example, a system to indicate that a higher error rate will occur if the throughput is increased. In the preferred embodiment, each capability parameter is specified in terms of a range between a minimum and a maximum acceptable value.

Abstract: A system and method for establishing a communication channel between a source node and a destination node via a heterogeneous communication network comprising at least one intermediate node is disclosed. A request for a communication channel having specified characteristics is issued by the source node to the most immediately adjacent of a possible plurality of intermediate nodes. Each intermediate node determines whether or not it has the available communication resources to support the request. If so, sufficient communication resources are reserved in order to support the request and the request is forwarded to the next intermediate node. The determination by each intermediate node is continued until the destination is reached. After determination by the intermediate node as to whether or not the communication channel can be supported, an indication reflecting the determination is returned to the source node via the intermediate nodes.

Abstract: A programmable workstation for collaborative working in a network comprises a conventional operating system and network control layer for controlling physical routing of data between nodes. A collaborative application subsystem which interfaces with conventional telephones is responsive to a predetermined call from a collaboration call manager to establish the call manager at the node to handle incoming events which are not specific to any application program instances at the node.

Abstract: A programmable workstation for collaborative working in a network comprises a conventional operating system and a network control program layer. Additionally, the workstation includes a collaborative application support subsystem for interfacing with application programs. The subsystem is responsive to predetermined application program calls to create a logical network model of a collaborative environment. The model comprises sharing sets of application programs, which share data and resources across nodes and logical dedicated data channels connecting members of the sharing set. The subsystem cooperates with the network layer to establish the physical links necessary to implement the model in a physical network, transparently to the application program.