International Business Machines Corporation

Willibald A Doeringer

Douglas H Dykeman

Soumitra Sarkar

Diane Phylis Pozefsky

Allan K Edwards

Roger D Turner

Jeffrey Haskell Derby

Ken Van Vu

Kathryn Heninger Britton

Harold D Dykeman

Haldon J Sandick

Johny Mathew

John E Drake, Jr

Liang Li

Tein-Yaw David Chung

Marcia Lambert Peters

James P Gray

Joshua S Auerbach

John H Wilson

Mehdi M Nassehi

Mohan B Sharma

Raymond F Bird

Yue T Yeung

Winston W Chung

Tein-Yaw D Chung

Gunter Karjoth

Winston W-K Chung

Variable length data sequence backtracking a trie structure

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.

General transport layer gateway for heterogeneous networks

A system for interconnecting widely separated local area networks (LANs) by means of a wide area network (WAN) utilizes network level facilities to establish a connection through the wide area network and to create connection table entries at the WAN access point which allow subsequent data frames to be transmitted through the wide area network without such network level operations. More particularly, the various LANs are combined into search groups, represented by address prefixes, to which LAN-initiated connection requests can be broadcast and which can respond so as to establish the data path connections. This system has the connection flexibility of a prior art router and, at the same time, the low overhead of a prior art bridge.

Methods and apparatus for interconnecting local area networks with wide

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.

Protocol selection and address resolution for programs running in

The process for determining the best communication route from a source end station to a destination end station is distributed over both source and destination network nodes. Network nodes, at the interface between a wide area network (WAN) and each subnetwork, contain access agents to control the communication flow between the wide area network and an end station in the subnetwork. The task of selecting the best route between two end stations is distributed between the access agents at the WAN interface in the first subnetwork, and the access agents at the WAN interface in the second subnetwork. Each access agent at one WAN interface obtains the best route from itself to the end station in its subnetwork. Each access agent at the other WAN interface finds the best route from each access agent at the first WAN interface through itself to the end station in its subnetwork. One designated access agent collects all the best route information. This best route information is concatenated, and the route with the least weight is selected as the best route between end stations.

Distributed processing of route selection across networks and subnetworks

Access agents in nodes at the LAN/WAN interface are formed into a group of access agents so that the access agents may be managed by the WAN as a group. The group must maintain group operation integrity in that if communications between agents in the group are broken, the access agents will coalesce into subgroups and continue performing communication jobs as a group activity. Each of the access agents contains a finite state machine to perform the tasks of group formation and maintenance. The formation of interconnected access agents into a group is accomplished by one access agent being identified as a group leader. All other access agents communicating with the group leader within the LAN may then join the group. The maintenance of group activity integrity is accomplished by detecting a break in group communication integrity and thereafter reforming the group into multiple smaller groups. The maintenance of group operation integrity also includes the merger of small groups into a large group when a bridge is added between LAN segments.

Forming and maintaining access groups at the lan/wan interface

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.

Inter-domain multicast routing

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.

Compensation for mismatched transport protocols in a data communications

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Langnau, Switzerland

Willibald A Doeringer