Abstract: A method and an apparatus implementing a shaping function in a fixed length cell switching network node adapter supporting output lines in a telecommunication network. The adapter includes a Time Division Multiplexing (TDM) table where each entry is a pointer to a first cell of a queue of cells stored in the adapter for a given traffic. When a new traffic is established, the TDM table is updated. A placement device performs the pre-computation of the best placement of the entries reserved for one traffic in the TDM table. The placement device minimizes the Cell Delay Variation as computed by a Generic Cell Rate Algorithm (GCRA--ITU standard organization) policer. The Cell Delay Variation (CDV) is defined as the deviation of the placement of the cells from their ideal position in an output stream, the ideal placement being when the cells are spaced with an interval corresponding to the period of traffic negotiated at traffic establishment time.

Abstract: The routing paths between origin and destination nodes in a packet switching network are selected more efficiently by reducing the total number of links potentially visited by the routing algorithm. The path selection technique involves two phases, the first phase for principal links identification, and the second phase for selection of the best point-to-point path in the network. Principal paths are minimum hop count paths with a transmission delay less than a specified threshold. The algorithm limits the screening of the network links in the second phase to the principal links and excludes the secondary links. The exploration of a much smaller number of links has the advantage to considerably reduce the computation time required for the path selection. The fact the number of principal links is generally small compared with the total number of links potentially explored, allows to limit the additional processing time necessary in case of unsuccessful attempt.

Abstract: The auto-sequenced state machine according to the present invention has a programmable state duration which is independent from the logic speed, it may be adapted to any Moore state machine and may operate in metastability occurrence of the latches (2) of the state machine. The programming of a granularity of half a clock cycle provides a performance optimization by using a system of two clocks which are in opposite phase. Moreover, the state duration may be programmable on line. The auto-sequenced state machine is composed of a basic Moore state machine to which is connected a device (16) comprising a current state decoder (15) which decodes the current state signals Q(t) from the Moore state machine in order to select one of the biphase state timers (13) and one of the state timing programming circuits (12), and an OR circuit (11) which receives the terminal counts (TC0, . . .

Abstract: A topology manager external to a communications network manages the network and in particular resolves conflicting topology information about the network by dividing the management of the topology data base into two operations--a collection instance and a resolution layer. A collection instance collects all information that its agent node has about the topology of the network. This topology information is processed by the collection instance to determine for each resource in the network whether the resource is new, reachable or has experienced a reachability change. The resolution layer receives the topology resource information from each collection instance. When a resource is indicated as reachable by a collection instance, that resource is placed on a Reach list as an entry from that collection instance.

Abstract: A multipurpose data communication network node for interconnecting both ATM and Variable Length (VL) input/output trunks with all combinations of node input versus output trunk connections. The network node includes ATM/VL Receive Adapters and ATM/VL Transmit Adapters, interconnected via a Switching device (44) operating on ATM like packets (i.e. ATM cells) only. The receive adapter includes means (41, 43) for deriving switchable cells from VL traffic possibly including ATM packets and provided over an input VL trunk and means (45, 46) for deriving switchable cells from ATM packets provided on input ATM trunk. The transmit adapter, includes means (47, 48) for reconstructing VL traffic to be fed onto an output VL trunk, and means (49, 50) for reconstructing ATM traffic to be fed onto an output ATM trunk; both means (47, 48) and (49, 50) being fed with switchable cells irrespective of the traffic origin, being it from VL or ATM trunks.

Abstract: A packet communications network includes a route testing system which launches a plurality of route testing messages from the source node to each of the nodes along the route, including the destination node, and returning to the source node. Time stamps in each of theses testing messages are compared to reception times to determine round trip delays which can be halved and compared to determine link transit times. These link transit times can, in turn, be analyzed to localize congestion or identify failed resources. The source resource is where the data is accumulated for the entire path and then analyzed to determine the location of failed links, if any, the response time from the source to the destination, the response time of each resource in the path, and the location of congested links. Packet switched resources identify the path test command themselves and carry out the testing procedure. Circuit switched resources utilize the control point controlling that resource to carry out the testing procedure.

Abstract: In a packet switched communications system an incoming real-time packet is imbedded after the next block of data of the non-real-time packet being transmitted. This object is accomplished by transmitting each packet along with at least a 1-byte trailer which is used to indicate the packet type, whether the current block of non real time data is preempted or whether the current block of non real time data is resumed.

Abstract: A method and an apparatus for transferring structured data of a constant bit rate traffic in an ATM network. The method uses the recurrence of alignment of the structured data field of length N in a 47 octet SA.sub.-- PDU payload. At the transmitting end the CSI bit of the header of the first SAR.sub.-- PDU is set to 1. It is then set to 0 for the next SAR.sub.-- PDUs until the Nth SAR.sub.-- PDU is reached. It is then again set to 1. This process is repeated until the last SAR.sub.-- PDU has been transmitted.

Abstract: To address Quality of Service (QoS) requirements in a domain of Local Area Networks(LANs) interconnected by at least one FDDI segment, network-wide bandwidth allocation is improved by a high availability Third Party Requestor (3PR) agent. The 3PR receives from the QoS Allocator all information that it needs to ask for bandwidth reservation on the FDDI segment. Following a Station Management standard, the 3PR is able to act on behalf of an FDDI station that will submit synchronous traffic and ask for bandwidth allocation to a Synchronous Bandwidth Allocator (SBA). According to the SBA decision, the 3PR will then answer to the network-centralized QoS Allocator which will grant or deny the allocation over the whole path within the LAN domain. If for some reason, the acting SBA function moves to another station, the 3PR at the new station will become active.

Abstract: Method for automatically adapting and configuring the speed of a terminal adapter (30) to the rate 56 Kbps or 64 Kbps which is used by a calling adapter (20). After sending the CONNECT message via the ISDN NETWORK to the calling terminal adapter (20) in accordance with CCITT Q.931 Recommendations, the called TA (30) is initialized to a rate of 64 Kbps and then continuously transmits (204) an alignment pattern ALL.sub.-- ONES while starting a first timing process (T1). This first timing process will cause the called TA to switch to a 56 Kbps speed if the 64 Kbps validation process does not succeed. The method then involves the step of checking (206) the reception of a ALL.sub.-- ZEROS pattern coming from said calling adapter (20) before the end of said first predetermined period (T1). If this case, a 64 Kbps validation process will be performed which comprises the checking whether a ALL.sub.-- ONES pattern is received within a second period (T2), in which case the 64 Kbps rate configuration will be validated.

Abstract: A computer network in which resources are dynamically located through the use of LOCATE requests includes multiple cache server nodes, network nodes which have an additional obligation to build and maintain large caches of directory entries. Cache server nodes play a key role in the LOCATE process and can prevent redundant network-wide broadcasts of LOCATE requests. Where an origin cache server node receives a request from a served node, the cache server node searches its local directories first, then forwards the request to alternate cache server nodes if necessary. If the necessary information isn't found locally or in alternate cache server nodes, the LOCATE request is then broadcast to all network nodes in the network. If the broadcast results are negative, the request is forwarded to selected gateway nodes to permit the search to continue in adjacent networks.

Abstract: The object of the invention is to perform an automatic decomposition of a packet switching network in backbone nodes and subareas nodes to speed up the routing path search without degrading the optimization criterion of the routing algorithm and without generating additional control messages on the network.Currently, routing algorithms compute all the available paths in the network, from the source node to the destination node before to select an optimal route. However, networks are rarely fully meshed. They are usually built around a hierarchical structure: a set of nodes, interconnected by high throughput lines, are used to build a backbone with a high degree of meshing and then, local nodes are grouped in geographical subareas themselves attached to the backbone. Routing algorithms can take advantage of this particular network topology to drastically reduce the complexity of paths computation.

Abstract: Managed Object Instances (MOIs) in a network of OSI computing systems are created, or deleted, without disrupting their interaction with other managed object instances. This is accomplished by a multi-phase commit process operation where in the first phase, a create or delete request is verified, and the CMIP platform places the created or deleted MOI on a pending list in the CMIP platform, along with information identifying the location of the MOI in a hierarchy of MOIs. In the second phase, the object being created or deleted is asked to accept, or reject, the request. The object responds saying that it accepts or rejects the request. If the request is acceptable, the CMIP platform finishes the object's connection to the tree hierarchy, or disconnects the object from the tree. Then the CMIP platform sends back a message to the object to acknowledge the creation of the object, or to tell the object to delete itself. Finally, the CMIP platform sends a request completion message to the manager.

Abstract: Currently, routing algorithms compute all the available paths in the network, from a source node to a destination node before selecting the optimal route. The route computation is often time and resource consuming. Some paths are not acceptable due to the particular geographical configuration of the network. In the real world, large transport networks are not fully meshed. The present invention is based on the observation that networks are usually built around a hierarchical structure. A set of nodes, interconnected by high throughput lines, are used to build a `Backbone` (401) with a high degree of meshing to allow the redundancy and reliability required by the user. The other nodes or `local` nodes (404) are attached to one or several backbone nodes. It is the network designer responsibility, at the configuration time to define for each node what is its attribution: backbone (402) or local node (404).

Abstract: A packet switching communication system is improved by using a packet header structure which does not require a fixed format. The packet header comprises a chain of 2 byte command/data segments. Each command/data segment contains generic bits and a routing field. One of the generic bits (bit 1) allows the header to be extended with another command/data segment.

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: A plurality of processes share a single set of non-resettable counters which are sampled periodically. Each process maintains a list of counter relationships unique to its own process and compares at each sample time the current sampled counter values with a selected function of previously received counter values for each relationship in its list and establishes a counter reset value which is a selected function of the current sampled value when the previously selected function is satisfied.

Abstract: 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.

Abstract: A new event forwarding discriminator (EFD) EFD named the persistent/impervious event forwarding discriminator (PI EFD) is described herein. The PI EFD is monitored by the agent infrastructure in such a way that if the agent goes down, and thus the PI EFD goes down, the agent rebuilds or restores the PI EFD with all its attributes. The PI EFD immediately creates an event notification indicating a create PI EFD event has occurred. This event notification is of the type passed by the PI EFD to the manager. The manager then knows the poll its other EFDs at the agent and recreate them as necessary.To foil rogue managers, the PI EFD can not be deleted by other managers. Also, the PI EFD has limited attributes that can be changed. A rogue manager can only add himself to the destination list; it can not otherwise change the attributes of the PI EFD.

Abstract: 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.