Digital Equipment Corporation

3com Corporation

Other

Compaq Information Technologies Group, L.p.

Cabletron Systems, Inc.

Enterasys Networks, Inc.

G Paul Koning

William R Hawe

Mark W Sylor

Richard L Rosenbaum

Mark J Seger

Jeffrey R Harrow

Leonard G Fehskens

Colin Strutt

Stanley I Goldfarb

Kenneth W Chapman

Sheryl F Namoglu

Linsey B O'Brien

Robert C Schuchard

Jill F Callander

Matthew J Guertin

Danny L Smith

Timothy M Dixon

Dennis O Rogers

Benjamin M England

David L Aronson

Radia Joy Perlman

Kadangode K Ramakrishnan

Philip John Trasatti

Steven K Wong

Arundahati G Sankar

Ruth E Kohls

Allan B Moore

James L Lemmon, Jr

Christine C Chan-Lizardo

William C Adams, Jr

Peter H Burgess

Robert R Ross

Kathy J Nelson

Henry S Yang

Peter J Roman

Simoni Ben-Michael

Michael Ben-Nun

Floyd J Backes

Moshe De-Leon

Gerard R Plouffe

David J Mitton

Anil V Navkal

Charles W Kaufman

Haim Rochberger

Jerry D Hutchison

Anil G Rijhsinghani

Mark F Kempf

Amar Gupta

Brian Ramelson

Frank A Itkowsky

Ken Benstead

Stanley Chmielecki

Kathy Jo Nelson

Robert R N Ross

Douglas M Washbaugh

Ruth E J Kohls

Jerry Hutchison

A system for managing an assemblage of entities. The entities interface within the assemblage for control of primary information handling functions and further interface with the system to permit the carrying out of management functions. The system includes management modules adapted to carry out management functions by independently interpreting and executing commands and a kernel including a table of dispatch pointers for directing the commands to the respective modules in which they are to be interpreted and executed. In addition, the system includes storage containing domain information defining groups of entities, where the kernel may issue a command to a group by issuing individual commands to appropriate modules.

Entity management system

A switch is provided for use in a communications system for transmitting traffic from a first user to a second user. The first and the second users are interconnected by a primary communications path and a redundant communications path. The switch includes a first port configured to receive hello communications indicative of a proper operation of the primary communications path and a second port for receiving data communications. A switch control monitors the receipt of the hello communications, directs the forwarding of received data communications up to a threshold capacity and, if the received data communications exceed the threshold capacity, drops at least a portion of the received data communications such that forwarded data communications are below the threshold capacity.

Network switch with panic mode

A multistage ATM switch, method and system with switch elements with two input/outputs switchable to two other input/outputs. The switch elements are arranged connected to define a matrix with an input stage an output stage and at least one an intermediate stage. The multi stage switch inputs are presented with address information for data, the address information indicates requests for one of several outputs of said the multi stage switch. The requests are broadcast into the multi stage switch. At each stage the requests are remembered, merged and propagated to connected switching elements of a next stage. At each output of the multi stage switch grants a request if traffic can be accepted and propagates the requested grant to connected switching elements. At each switching element, upon receiving a request grant, the request grant is propagated to an input that requested the granted output port. If both inputs requested the granted port the switch element randomly chooses one of the two inputs and propagates the grant on the randomly chosen input. Upon receiving a request grant at an input of the multi stage switch, data is transmitted on a next time slot.

Non-buffered, non-blocking multistage ATM switch

The routing paths are determined in a step-by-step nature. A Dijkstra algorithm is used and before labeling a link as a routing path, all possible routing paths which are within a predetermined range are compared. One of the paths in the range are chosen at random to be the routing path.

Routing over similar paths

The plurality of nodes in a computer network is divided into a plurality of peer groups. The plurality of peer groups can further be divided into a plurality of upper level peer groups. Routing information for each peer group is summarized according to an algorithm. This summary routing information is then stored in nodes which are not a member of that peer group. The algorithm for summarizing the routing information, represents each peer group as a summary node where nodes of the peer group which connect to other peer groups, are considered ports of the summary node. Metric values for the characteristics of paths connecting these ports are determined. A metric average is computed for all of the port-to-port paths and this average is then halved to give a peer default metric value for a routing path entering into, or exiting from that particular peer group. An exception method can be included, if a particular port has a significantly different metric value for entering into or exiting the peer group from that port. Also a bypass metric can be included in the summarization information if a particular path between ports of the peer group has a metric value which is significantly different from the peer default metric value.

Summarization of routing information in a hierarchical network

A method for connecting a first communication system with a third communications system, by passing through a second communications system, is disclosed. A first frame is received from the first communications system, where the first frame has a multicast address as a destination address. The multicast address requires the frame to be transmitted onto the second multicast address is translated into a functional address. The functional address is written into a second frame, and the second frame is transmitted onto the second communications system. A station receiving the second frame translates the functional address into a multicast address and writes the multicast address into the destination address field of a third frame, and transmits the third frame onto the third communications system.

Many to few group address translation through a network bridge

An apparatus and method for transferring data in a data processing system to and from a host system. A communication adapter or input/output controller device is provided in which queues are utilized to transfer information between the adapter or controller and the host system. In order to minimize the amount of time a system or I/O bus or network is used during transfer of data between the adapter or controller and the host system, and reduce the amount of work that must be performed by the host system, the number of interrupts by the adapter or controller of the host system is limited to the minimum amount necessary by using an interrupt arm mechanism and by keeping track of completion indices stored in the host system.

Apparatus and method for controlling interrupts to a host during data

A system for controlling the transmission of cells from a network node over multiple virtual circuit is disclosed. The disclosed system performs traffic shaping for all virtual circuits connected with the network node. The system includes a virtual circuit table with one or more entries. Each virtual circuit table entry corresponds to a virtual circuit established with the network node. Each virtual circuit table further includes one or more Cell Rate Accumulator fields and a Time Stamp field. The system includes a schedule table having one or more entries. Each schedule table entry further includes one or more Cell Rate Accumulator fields and corresponding predetermined value fields. A schedule table loading process determines a virtual circuit on which a packet is to be transmitted, and then calculates a time elapsed since a last previous write of a virtual circuit table entry corresponding with that virtual circuit. The schedule table loading process then adds the time elapsed to the value of the Cell Rate Accumulator fields in that virtual circuit table entry, and stores the result of the addition into the corresponding Cell Rate Accumulator fields of the schedule table entry. The system further includes a process for periodically incrementing the Cell Rate Accumulator fields in the schedule table entry. A scanning process periodically increments the Cell Rate Accumulator fields. A transmitting process transmits a cell on the virtual circuit when the value of the Cell Rate Accumulator fields is greater than or equal to the corresponding predetermined values.

Traffic shaping system with virtual circuit table time stamps for

A system for managing an assemblage of entities. The entities interface within the assemblage for control of primary information handling functions and further interface with the system to permit the carrying out of management functions. The system includes management modules adapted to carry out management functions by independently interpreting and executing commands, a kernel including a table of dispatch pointers for directing the commands to the respective modules in which they are to be interpreted and executed, and an enroller for enrolling new modules into the system by adding further pointers to the table. In addition, the system includes: a module adapted to independently interpret and execute selected management-related commands; stored records relating to accessed management information, each record indicating an associated time; an information manager, responsive to commands having a time schedule, for retrieving information from the records or accessing information from the entities, including a scheduler for issuing subsidiary accesses or retrievals at possibly multiple times according to the schedule; storage containing domain information defining groups of entities, where the kernel may issue a commands to a group by issuing individual commands to appropriate modules; a common command syntax including fields for identifying the entity and the operation to be performed; a module that stores rules identifying alarm conditions, including a generator for generating rules and an alarm detector for detecting an alarm condition in response to the rules; a module adapted to carry out self-management functions by interpreting and executing commands.

Extensible entity management system including a dispatching kernel and

A system for controlling the transmission of cells from a network node over multiple Virtual Circuits (VCs) is disclosed. The system performs traffic shaping, as required by connection based systems such as Asynchronous Transfer Mode (ATM), for each VC connected with a network node, so that the Quality of Service (Qos) parameters established when the connection was established are not exceeded. The system includes a process for scheduling the transmission of cells from the network node. The scheduling process periodically scans a table having entries corresponding to virtual circuits connected with the network node. During each scan of the table, the scheduler increments a sustainable rate accumulator field, a peak rate accumulator field, and a latency accumulator field of each table entry that corresponds with a virtual circuit that is open, and for which there is a cell ready to be transmitted. The scheduler further determines if the sustainable rate accumulator value is greater than or equal to a predetermined value and whether the peak rate accumulator value is greater than or equal to a predetermined value. If both conditions are true, then a cell may be transmitted on the virtual circuit corresponding with that table entry. The system further provides that transmissions are scheduled on virtual circuits having the greatest latency since previous transmissions.

Traffic shaping system with transmit latency feedback for asynchronous

Extensible entity management system including rule-based alarms

A connection apparatus for connecting a first communication system with a second communication system and a third communication system. A first frame is received from the first communication system, where the first frame has a multicast address as a destination address, and where the destination address requires the first frame to be transmitted onto the second communication system. The multicast address is translated into a functional address, and the functional address is written into a second frame transmitted onto the second communication system. The second frame is received and is transmitted onto a third communication system, and the functional address is translated into a multicast address for the third communication system, and the multicast address is written into a destination field of the frame as it is transmitted onto the third communication system. The second communication system may be a token ring system based upon an IEEE 802.5 standard, and the functional address may be written into a DSAP field and into a PROTOCOL TYPE field of an 802.5 Standard frame.

A plurality of physical addresses are derived from address information stored in an address memory of a bridge or other multi-port communication device, wherein the stored address information does not directly specify all the addresses. In a first embodiment, the stored addressing information specifies a single address value from a first block of preferably consecutive address values. A processor uses the first address value to derive a second address value from a second, different block of preferably consecutive address values, and then assigns both as, e.g., port addresses. In a second embodiment of the invention, the address memory stores address information which specifies a range of preferably consecutive address values, for instance, the first and last address values of the range. A processor fetches these address values from the address memory, identifies all address values within the range, and assigns them as, e.g., port addresses.

Method and apparatus for deriving addresses from stored address

A device and related method for coupling segments of an extended local area network (LAN) in such a way that message traffic employing inter-network protocols such as TCP/IP will be handled without the difficulties usually associated with bridges, and without the complexity and expense of full IP router capability. The device operates like a bridge for non-TCP/IP traffic. For TCP/IP traffic it operates in a bridge-like manner but maintains a database associating extended LAN segment addresses with port numbers in the device, so that packets can be automatically forwarded over a spanning tree connecting the network segments. A host computer in any network segment can address others in different network segments of the extended LAN as though all were in a single LAN. The device of the invention functions to block the flow of ARP messages and to generate ARP replies that render the device of the invention transparent to hosts within the extended LAN. The device is also transparent to true IP routers, which may still be used to effect communication with points outside the extended LAN.

Bridge-like internet protocol router

Growing community of inventors

Brookline, NH, United States of America

G Paul Koning