International Business Machines Corporation

Douglas H Dykeman

Willibald A Doeringer

Claude Basso

Jeffrey Haskell Derby

Soumitra Sarkar

Ken Van Vu

Diane Phylis Pozefsky

John E Drake, Jr

Allan K Edwards

Roger D Turner

Haldon J Sandick

Fabrice Jean Verplanken

Jean Louis Calvignac

Richard Harold Boivie

Marcia Lambert Peters

Kathryn Heninger Britton

Daniel Orsatti

Paolo Scotton

Patrick Droz

Olen L Stokes

Mehdi M Nassehi

Mohan B Sharma

Robert A Sultan

Tein-Yaw David Chung

Liang Li

Johny Mathew

Marianne Aubry

Gunter Karjoth

Michael Osbourne

Minh-Tri Do Khac

Michael P Kuyper

Address management methods and apparatus are provided for a node serving as peer group leader for a peer group of nodes in one level of the hierarchy of a PNNI hierarchical network, whereby the peer group leader represents the peer group to one or more neighboring nodes in the next level up of the hierarchy. The peer group leader has a memory () for storing peer group topology data (), comprising address data which is supplied to the peer group leader from nodes in the peer group and represents addresses for access by the network, and peer group leader topology data (), comprising address data which is supplied to said neighboring nodes by the peer group leader and represents addresses accessible via the peer group. The address management method comprises: checking whether addresses represented by said address data are accessible via the peer group; notifying said neighboring nodes of changes in the accessibility of addresses so identified; and updating said peer group leader topology data () in accordance with said changes.

Address management in PNNI hierarchical networks

A method is described for sending frames of data from at least two ingresses to one egress in an ATM network. Each frame of data to be sent is partitioned into cells. The egress creates an identification for each of the ingresses and sends the identification to the ingresses. Each of the ingresses includes the received identification in each of the cells and sends the cells to the egress. And then, the egress combines the received cells into frames depending on the included identification.

Method and system for sending frames of data from a plurality of ingresses to one egress in an ATM network

This invention relates to the merging of data cells arriving at an Asynchronous Transfer Mode (ATM) switching node from data frames originating with a number of senders. As is standard in ATM networks, each originating frame is segmented into a series of cells each having Virtual Path Identifier (VPI) and a Virtual Channel Identifier (VCI) in its header portion. On arrival at each switching node, the VCI of the first cell of a frame is overwritten by a new outgoing VCI value that is used for all other cells of the frame. Thus, the actual movement of each cell through the network is controlled only by the cell's VPI, whereas the VCI field is used only to distinguish frames from each other. A feature of the invention is that it can accommodate Early Packet Discard in a simple way by associated any discard indication determined for a frame with the outgoing VCI value which also applies to all cells of the entire frame.

Merging of data cells in an ATM network

Variable length data sequence backtracking a trie structure

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

Growing community of inventors

Rueschlikon, Switzerland

Douglas H Dykeman