Abstract: A multiprotocol transport network (MPTN) gateway provides transparent interconnection of two or more SPTNs running different transport layer protocols to form an integrated heterogeneous MPTN. The MPTN gateway of the present invention has no dependencies on the particular transport protocols running on the SPTNs being interconnected as it utilizes a common transport provider (a Gateway Services Protocol Boundary (GSPB)) between the SPTN transport protocols and the gateway components. The MPTN gateway supports connections between end systems across multiple intermediate networks. The MPTN gateway provides automatic routing based on dynamic participation in the routing protocols of the interconnected SPTNs so that any number of gateways may be interconnected and in any topology desired. As the MPTN gateway has a general architecture and acquires routing information automatically, it supports not only other MPTN nodes and gateways but also non-MPTN nodes and gateways.

Abstract: A packet communications network in which multicast transmissions are made reliable by transmitting acknowledgements to all neighbors of every receiving node, including the source node. This allows the relinquishment of message holding buffers as soon as all near neighbors acknowledge receipt of the message after only tile longest round trip time to the nearest neighbors, rather than the round trip to the furthest destination. Moreover, highly reliable ancillary point-to-point transmission facilities can be used to retransmit multicast messages indicated as being lost by failure of acknowledgment. Finally, network partitions occurring during the multicast procedure do not necessarily lose the multicast message to the remote partitions since any node receiving the message can insure delivery to all other nodes in that partition.

Abstract: The present invention is a general solution to the problem address incompatibility between application programs and transport services. The invention may be embodied in a method for mapping the application program address (program address) to the transport services address (transport Provider address). According to the method, a program address is registered in the network so that it becomes available to other programs that understand the address, even if they are running over a transport protocol that does not understand the address format. When a request is made that a connection be established between a program and a program partner or that a datagram be sent therebetween, the program address is mapped to the transport Provider address (if necessary). The program address is then conveyed to the program partner so that it knows who it is talking to.

Abstract: Disclosed are a method and a system for transmitting a message or data packet from a single sender (21) to a plurality, i.e. a group of receivers, usually called multicasting, within a conventional unicast transmission network, i.e. a network basically not equipped to handle such multicast transmissions, consisting of a plurality of subnetworks (22-24). The nodes or gateways (25-29) connecting the subnetworks maintain tables of multicast receiving stations (or groups of such) and the header of each message includes information defining the groups of the addressed multicast receiving stations.

Abstract: A Transport Layer Protocol Boundary (TLPB) architecture is described which will permit an application program to run over a non-native transport protocol without first generating a protocol compensation package tailored to the transport protocols assumed by the program's application programming interface and by the available transport provider. All transport functions required by the program are converted to standardized or TLPB representations. When a connection between the first application program and a second remote application is requested, the individual required TLPB transport functions are compared to corresponding functions supported by the transport provider. Compensations are invoked only where there is a mismatch. The node on which the remote application program runs is informed of the compensations so that necessary de-compensation operations can be performed before the data is delivered to the remote application program.

Abstract: An automatic span line switch for high speed communication lines is disclosed. The apparatus employs an alarm interface unit which is coupled to a service line terminal in order to detect a line failure mode. Upon detection of such a mode, the system operates to modify the parity bit content of the transmitted digital signal in order to provide a unique code to be transmitted to a remote office connected to a near office and indicative of a span line failure. The apparatus automatically proceeds to switch the failed transmission line to a back-up protection line to enable the near location to communicate with the remote location via the back-up line. All control signals transmitted between the locations are implemented by means of unique codes which are generated by purposely modifying the parity bit content in each successive frame of the transmitted digital signal. The system further describes a priority system for preferentially switching higher priority service lines when multiple failures occur.