Abstract: A configuration server is incorporated into a distributed router to support multiple route servers in an internetworking system. The multiple route servers in the system provide load sharing and/or standby functionality. In the system route servers provide routing decisions while edge forwarders are the packet forwarding elements. The configuration server is responsible for mapping edge forwarders to route servers.

Abstract: A communication system is provided for transmitting and receiving data cells containing control messaging and customer data, including a real-time development system (RDS) and means for generating a plurality of RDS events and RDS commands at predetermined locations within the communication system. Each of the RDS events having an event identifier and a variable length sequence of data bytes for defining the event. Each of the RDS commands having a command identifier and a variable length identifier for defining the command. The communication system also includes means for transmitting the RDS events and RDS commands as data cells throughout the communication system via identical communication links. The communication system also having means located throughout the communication system for selectively filtering the RDS events and RDS commands from the control messaging data and customer data.

Abstract: A communication system is disclosed having a hub slot adapted to receive any one of a plurality of hub cards for receiving and transmitting data cells; a plurality of universal card slots; a plurality of interface cards insertable into any one of said plurality of universal card slots for receiving incoming ones of said data cells containing data and transmitting outgoing ones of said data cells containing data; an add bus having respective data links connected between individual ones of said universal card slots and said hub slot for receiving said outgoing ones of said data cells from said plurality of interface cards and transmitting said outgoing ones of said data cells to said hub slot; a drop bus having a single data link connected between all of said universal card slots and said hub slot for transmitting said incoming ones of said data cells from said hub slot to said plurality of interface cards; and means within each of said interface cards for filtering said incoming ones of said data cells from sa

Abstract: A network infrastructure comprises a number of connective devices (routers, repeaters, bridges, etc.) to form a communication network for a plurality of end nodes. Message packets originating with an end node are assigned an input virtual network and workgroup identification at the port at which the packet enters the network. This assigned input virtual network and workgroup identification is compared, at each port from which the packet can exit the network infrastructure, with output virtual network and workgroup identification assigned the particular port. If the input virtual network information does not match the output virtual network information, the packet is prohibited from exiting that port. Even if there is a match between the input and output virtual network information, there must also be a match between at least one bit of the input workgroup identification and the output workgroup identification before the packet can exit the port.

Abstract: A method is disclosed for detecting and diagnosing faults in a network. The network has a plurality of nodes through which switched virtual connections can be established. First, all attempts at establishing routes through the network are recorded. Then, the location of a failure is determined by analyzing the attempted routes.

Abstract: There is provided a method and apparatus for the prioritization, multiple queuing and selective processing of PVC management frames by a Frame Relay message processing device. The device had an input port for receiving the messages. It also provides a number of message queues for storing and retrieving the received messages, each of the queues respectively corresponding to one of a number of response priority levels which vary from highest priority to lowest priority. Each of the response priority levels is assigned to a number of message classes associated with predetermined link management processes for communicating the status of message relay links among networking devices. The message processing device has a first processor for determining the message class associated with each of the received messages and for allocating each of the messages to a corresponding one of the queues based upon the response priority level assigned to the determined message class.

Abstract: There is provided a message service device for a switching network. The device provides an input port for receiving messages from a number of network connections. The device includes a storage device for storing a number of predetermined priority levels pertaining to the received messages, one of the priority levels being assigned to each of the network connections. A number of first-in first-out message queues are provided for storing the received messages. The queues respectively correspond to each of the predetermined priority levels. Each queue is associated with at least one of a number of predetermined congestion thresholds whereby a congestion severity status may be determined for each queue. The congestion severity status corresponds proportionally to the number of the congestion thresholds which have been exceeded by the queue. The message service device further provides a processor for determining the network connection associated with each of the received messages.

Abstract: In a communications system, a method is described for controlling the excess usage of a finite resource through which information flows by a plurality of sources having an "excess" state. For each source a determination is made as to whether the source is in the excess state. If the excess information rate is less than a predetermined fair information rate, the information is passed to the resource. If the excess information rate is greater than the fair information rate, the information is discarded.

Abstract: A communication system comprising a hub slot adapted to receive any one of a plurality of hub cards for receiving and transmitting data cells; a plurality of universal card slots; a plurality of interface cards insertable in any one of the plurality of universal card slots for receiving incoming ones of the data cells containing data and transmitting outgoing ones of the data cells containing data; an add bus having respective data links connected between individual ones of the universal card slots and the hub slot for receiving the outgoing ones of the data cells from the plurality of interface cards and transmitting the outgoing ones of the data cells to the hub slot; a drop bus having a single data link connected between all of the universal card slots and the hub slot for transmitting the incoming ones of the data cells from the hub slot to the plurality of interface cards; and an arrangement within each of the interface cards for filtering the incoming ones of the data cells from the drop bus and thereby

Abstract: In a method implementing redundancy in LAN/WAN bridging/switching elements, LAN/WAN traffic is sent to active and inactive elements using multicast techniques. The active element bridges the data traffic and the inactive drops it.

Abstract: A multi-network environment comprises a plurality of different digital networks, a network manager associated with each network, a system manager at each customer premises for requesting a desired service, a customer agent for implementing instructions received from the customer agent, and a call processing unit associated with each network for implementing instructions received from a customer agent to route a call through the networks.

Abstract: An integrated network management system for multiple networks of different topology domains employs hierarchical pass-through routing and multi-network service management through the network.

Abstract: A method of detecting loopbacks on trunks in digital networks, comprises the steps of detecting an out-of-service trunk, continually placing a predetermined bit pattern on an outgoing channel of a trunk card, continually monitoring a receive channel of the trunk card to detect said bit pattern, and identifying the presence of a loopback when said bit pattern is persistently detected on the receive channel. This method avoids the need to dedicate a trunk channel for signaling purposes. By detecting the presence of loopbacks, intelligent networks can be prevented from unjustifiably clearing an alarm condition and returning traffic to a fault path.

Abstract: An arrangement is disclosed for parsing packets in a packet-based data transmission network. The packets include packet headers divided into fields having values representing information pertaining to the packet. The arrangement includes an input receiving fields from the packet headers of incoming packets, a memory for storing information related to possible values of said fields, and a device for retrieving the stored information appropriate to a received field value. The retrieving device comprises a look-up engine including at least one memory organized in a hierarchical tree structure, and a controller for controlling the operation of the memory. The arrangement is capable of performing fast look-up operations at a low cost of implementation.

Abstract: A packet switching network supporting X-series protocol access employs PVC (Permanent virtual connection) trunks as the backbone trunks for the network.

Abstract: A clock recovery unit provides a clock recovery function in the receiving entity of a system to implement adaptation of constant bit-rate (CBR) services over an asynchronous transfer mode (ATM) or ATM-like network. Incoming cells are periodically sampled for buffer fill level L.sub.i. The maximum fill level of undelayed cells Lx.sub.j is extracted from successive series of a predetermined whole number M of buffer-fill samples L.sub.i. A frequency adjustment logic unit provides at its output a bit stream at a given clock frequency f.sub.j. The frequency adjustment logic unit makes incremental adjustments to the clock frequency f.sub.j tending to cause the steady state mean of the fill level Lx.sub.j, or its derivative, to move toward zero.

Abstract: A computer communications network comprises a plurality of interconnected ATM switches forming a WAN or LAN area network over which ATM cells are transmitted, and a plurality of user devices including LAN interface adapters for connection to one or more to local area networks (LANs). An interface device connects at least some of the respective ATM switches to the LAN interface adapters. The interface adapts the ATM cells for transport over the LANS. The user devices can thus communicate through the LAN interface adapters transparently with the wide area network.

Abstract: Data traffic such as cell streams in an ATM communication network frequently contain data destined for multiple output ports having different transmission data rates. In order to accurately schedule such traffic a clocking signal unique to each output data rate is required. This invention provides systems and methods for generating the necessary clock signals utilizing a single timing reference.

Abstract: A router for sending and receiving data over a virtual connection in a packet-switched network, such as a frame relay network, includes a device for detecting congestion in received data packets, and a device for adjusting the transmission rate of packets into the network when congestion is detected.

Abstract: A method is described for detecting a loopback condition in a trunk. A predetermined bit pattern is inserted in an outgoing channel, and a corresponding incoming channel is continually monitored to detect the presence of the predetermined bit pattern. In this way, premature restoration of faulty circuits can be prevented.