3com Corporation

Avocent Huntsville Corporation

3com Technologies

Cloudium Systems Limited

John F Hickey

Edele O'Malley

Kevin Jennings

Kam Choi

Kevin Loughran

Jerome Nolan

Ken Power

Martin McDonell

William Paul Sherer

Richard A Gahan

Paul Hough

Peter Shelley

John Joseph Browne

Daniel M O'Keeffe

Mark A Hughes

Lai-Chin Lo

Michael Joseph Gleeson

Raymond Beechinor

Paul O'Keeffe

Aidan Quinn

Mark Leyden

Ray Beechinor

Vincent Carr

Paul Linehan

Tom Gibbs

Iain Campbell

In a virtualized desktop system an interfacing module is coupled to peripheral ports of a target device. The interfacing module is connected to a network. A digital user station is connected to the network. The digital user station is configured to be coupled to peripherals. The interfacing module and digital user station use respective hardware engines to communicate via said network.

USB based virtualized media system

A server computer that is connected over a network to one or more remote client computers includes specialized hardware for handling computationally-intensive signal processing operations involving video, audio, and/or other signals. As a result, users of the client computers experience little or no delay when accessing over the network applications that are hosted on the server.

Offloading the processing of signals

A video compression routine encodes pixels using frame location relationships by using packets with variable length opcode.

Video compression algorithm

Systems and methods of controlling and optimizing system latency in order to minimize system latency between remotely operating computing devices over a communications network are disclosed. A method of controlling and optimizing latency over a computer network from a first computing device to a second computing device includes identifying a condition associated with the transmission of a video signal, receiving the video signal at a computing device, determining whether the condition is met after receiving the video signal, and displaying the video signal on a display device when the condition is met.

Controlling and optimizing system latency

In a virtualized desktop system, a digital user station communicates with an interfacing module coupled to a target device via a network. The digital user station controls the power of the target device and the interfacing module by determining the power status of the interfacing module and sending a power control packet to the target device the interfacing module is coupled to.

Dynamic power cycling

An interfacing module connected to a network. A target network device connected to the network. An interfacing module is associated with a target network device. An interfacing module is coupled to a peripheral port of a target network device. Interfacing module identification data is stored in a memory portion of the target network device. The network address of the target network device is determined. The network address of the interfacing module is determined. At a remote location the network address of the target network device is used to read the interfacing module identification data from the memory portion of the target device via the network.

Device and method for configuring a target device

Access of a malfunctioning server to a data storage facility is blocked. Characteristics such as IAmAlive signals from a server are monitored and when out of profile a malfunction is indicated and data access of that server is inhibited. Characteristics continue to be monitored for a return from the malfunction. The system can be used in a resilient cluster of servers to shut out a malfunctioning server and enable its recovery to be indicated so as to enable readmittance to the cluster.

Server monitoring and failover mechanism

Trunking or other relationship is defined between ports on different devices in a cascade-connected stack of network devices. When network communications are passed via the cascade connection an indication is included of whether it originated from a port that is part of a trunk and thereby port-mismatch errors can be avoided.

Trunking in stacked communication devices

A trie searching technique employs entries each including a pointer to the next block in the search and a status indication and also including start and end indexes which define a selected section of the trie key identifying an entry within the block identified by the pointer. Thereby the program for selection of the search key is defined by the trie entries themselves, enabling a general variety of search selections and jumps to avoid any unnecessary parts of the trie search key.

Method and apparatus for searching databases employing a trie search structure

A sub-system for forming part of a packet-data communication system for the transmission of data packets which contain media access control addresses and protocol addresses. The sub-system comprises a multiple-port network switch for forwarding data packets in response to an examination of the packets on the basis of the packets protocol addresses, and for performing said examination when a destination address in the packet corresponds to the media access control address of the switch, the switch being arranged for forwarding a packet on the basis of a media access control address therein when the destination address of the packet does not correspond to the media access control address of the switch, said switch including a forwarding database which comprises entries which relate a protocol address with a media access control address and an identification of a particular port of the switch. This switch may perform routing within a local-area network. The switch is configured so that protocol addresses may not be learned in the database in respect of the particular port. A network router, which may perform routing functions in respect of a wide-area network, is connected to the switch only by way of the particular port. The sub-system enables the switch to off-load from the router routing functions for the local-area network.

Network switch with self-learning routing facility

The present invention is based on a ring architecture wherein each chip in the multiplicity of chips is connected in a chain so that it can receive packets from the next previous chip in the chain and forward packets to the next following chip in the chain, whereby to form a ring. Before a packet is placed on the ring by a device it is provided with a 'masking' field which identifies each of the other devices and the ports within any such device to which the packet must be sent in order to achieve a multicast. When a device in its turn receives such a packet it will examine the masking field to determine whether the field identifies that device. If so, the packet, which may be held in temporary storage, may be processed for forwarding from a port of that device. The device will strip from the masking field the identification of the respective device and transmit the packet with a thus modified masking field to the next device in turn. If a packet does not contain any indication of another device in the ring, the packet will not be transmitted and therefore will naturally terminate.

Packet multicasting in a ring architecture

A network switch including a port for the reception and transmission of data packets, and a receive buffer store connected to the port, detecting a predetermined state of fullness of the buffer store, initiating in response to the state of fullness the production of control frames for signaling to a source of packets to pause the sending of packets to the switch, counting said frames to obtain a measure of congestion of the switch, and responsive to a rate of change of measure to enable the discarding of packets received by the buffer when rate is higher than a first predetermined value and to disable the discarding of packets when the rate of change of the measure is below a second predetermined value.

System and method for congestion control in packet-based communication networks

A forwarding database in a network switch is established and maintained by performing a look-up for a source address read from an incoming frame to find a match between the source address in the frame and the source address in an entry which includes that source address, a port number and an age field. New entries are made if matches are not found, so that the forwarding database facilitates the dispatch of frames to destination addresses corresponding to source addresses in the table. The switch maintains a system age, such as a two-bit field, which is changed from time to time and the current system age is entered in the table as the age field when a source address entry is made. When said source address is found by a look-up process, it is updated with the current system age only if the age field of the entry and the current system age do not correspond. There is a saving of bandwidth arising from the avoidance of write cycles when an age field of an entry corresponds to the current system age.

Restriction of source address up-dating in network switches

Trunking or other relationship is defined between ports on different devices in a cascade connected stack of network devices. When network communications are passed via the cascade connection an indication is included of whether it originated from a port which is part of a trunk and thereby port-mismatch errors can be avoided.

Apparatus for trunking in stacked communication devices

A forwarding database in a network switch is established and maintained by performing a look-up for a source address read from an incoming frame to find a match between the source address in the frame and the source address in an entry which includes that source address, a port number and an age field. New entries are made if matches are not found, so that the forwarding database facilitates the dispatch of frames to destination addresses corresponding to source addresses in the table. The performance of a source address look-up is inhibited in the absence of a token, a reservoir of tokens being decremented each time a source address look-up is performed and incremented from time to time, at a selectable rate. The process facilitates the performance of a destination address look-up for every received frame by restricting the bandwidth made available for source address look-ups.

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Tipperary, Ireland

John F Hickey