3com Technologies

Broadcom Corporation

Digital Equipment Corporation

Microsemi Frequency and Time Corporation

3com Corporation

Mingoa Limited

Other

Digital Equipment Corp., Patent Law Group

3com Ireland

Anne G O'Connell

Eugene O'Neill

Tadhg Creedon

Con David Cremin

Vincent Gavin

John Hickey

Peter A Saunderson

Mark A Hughes

Una Quinlan

Vincent Groarke

Dipak M Soni

Peter S S Wang

David C Lee

Yves Cognet

William Paul Sherer

Niall Hanrahan

Peter J Wilson

Ciaran Murphy

Eugene G O'Neill

Nuala Sheedy

Maurice Gleeson

Dipak M L Soni

Michael Herbert

Jennifer Hamilton

Donal Casey

Micheal Lardner

Richard Gahan

Sorcha Callaghan

Deidre A Smith

Thomas Sheedy

Niall Finbarr Donovan

John Byrne

A method and associated system for mitigating a Distributed Denial of Service (DDoS) attack on a target device including, receiving a plurality of data packets at a mitigation device, counting a number of occurrences of each destination address signature within each of a plurality of consecutive data packet windows, classifying each data packet window of the plurality of consecutive data packet windows as a potential attack window if the number of occurrences of any one destination address signature within the data packet window exceeds a destination address signature threshold value. The method further includes, determining a total number of potential attack windows within a sliding time window and limiting the transmission of the plurality of data packets from the mitigation device if a total number of potential attack windows within the sliding time window exceeds a potential attack window threshold value.

System and method for mitigating distributed denial of service attacks

The present invention relates to a bale cutting apparatus comprising attachment means for coupling the apparatus to a prime mover and a cutting means to cut through a bale containing fodder. The apparatus has cutting means that is operable to retain the bale against a stop member and cut through the bale such that the fodder is discharged from the bale and any bale covering materials are retained by the apparatus. The present invention eliminates the need to separately remove any covering materials in which the fodder is wrapped.

Bale cutting apparatus and method

Various electronic devices may benefit from appropriate power conservation techniques and tools. For example, low power techniques may benefit small form-factor pluggable applications. An apparatus can include a packet parsing functionality that includes a first order shallow packet parser configured to operate at line rate and a second order deep packet parser configured to operate only on received filtered packets and received packets destined for a management and/or central processing port. The apparatus can also include a microprocessor configured to manage the apparatus and configured to operate at a low duty cycle. The apparatus can further include a packet generator configured to be active only when generating certain packets of interest. The packet parsing function, the microprocessor, and the packet generator can be configured to provide data from a host port of a small form-factor pluggable device toward an optical port of the small form-factor pluggable device.

Low power techniques for small form-factor pluggable applications

A method of providing forward error correction on an Ethernet point-to-point link, constituted of: receiving at one end of the point-to-point link an input data stream, wherein the input data stream is a 10 bit symbol encoded serial data stream at a first data rate; decoding the 10 bit encoded data stream to a 9 bit symbol data stream; increasing the data rate of the 9 bit symbol data stream to a second data rate; for each segment of a predetermined number of 9 bit symbols generating a respective plurality of parity symbols; combining the segments and the generated respective plurality of parity symbols into FEC appended segments; encoding the FEC appended segments into an output 10 bit symbol encoded data stream; and transmitting the output 10 bit encoded stream on the point-to-point link at the second data rate.

Ethernet point to point link incorporating forward error correction

A method of commencement of operation of a communication system such as an Ethernet OAM system enables an endpoint (A) to transmit and receive repetitive connectivity check messages on a link between the endpoint and a remote endpoint (B). A loss of connectivity with the remote endpoint is determined by the absence of received connectivity check messages within a monitoring interval. The commencement of the monitoring interval is delayed until a predetermined number of valid connectivity check messages has been received. The method may be implemented by use of a counter for received connectivity check messages and an additional waiting state in a state machine.

Detection of link connectivity in communication systems

A method of determining frame loss between two management points (C, D) in an Ethernet network, in which the management points each transmit frames to each other and each of the two management points transmits to the other, in regular intervals, measurement messages which contain current counts of frames transmitted and received by the respective transmitting management point. At least one of the two management points responds to a received management message to compute from counts of actual packets transmitted and/or received by a given one of the management points the frame loss at the given management point. At least one of the management points computes the frame loss only once in a measurement interval which consists of a multiplicity of the regular intervals and employs in the computation the counts indicated by the measurement message most recently received by the one of the management points.

Enhancing accuracy of service level agreements in ethernet networks

According to an example embodiment, a technique may be provided for managing a label data base of which each entry comprises a data field for insertion into a respective packet in a multicast transmission and a validity field. The technique may include, for example, (a) establishing a fixed size for a cluster of labels, (b) associating with each cluster a pointer to another cluster, (c) establishing a sentinel cluster of which all entries are indicated to be invalid and of which the cluster pointer points to this sentinel cluster, (d) establishing a root table which defines the number of replications of the packet in a multicast group and identifies a first label cluster associated with the multicast group and (e) establishing a chain of clusters of which each cluster which is full of valid entries points to the next cluster in the chain and the last cluster which contains valid entries points to the sentinel cluster.

Management of storage and retrieval of data labels in random access memory

Multicast packets that are received on a port of a network device and forwarded to multiple output ports are stored in memory and respective primary control entries which define them are converted to secondary control entries defining multiple unicast packets before a scheduling algorithm is applied. The packets are reconstituted after the application of the scheduling algorithm has been applied to the control entries. For VPLS packets that are received on a single port and replicated multiple times on one or more output ports, a replication database may be used in conjunction with a replication engine to convert the control entry for a received packet into multiple control entries defining unicast packets for each of the destination ports before the scheduling algorithm is applied. This method is applicable to the replication of packets onto a Virtual Private LAN.

Maintenance of bandwidth allocation for traffic including multicasts

A network switch () for a packet-based data communication network, comprises a plurality of ports for the reception and transmission of data and means for establishing a database for controlling the passage of data between the ports. The database comprises a data table () for holding data entries each comprising a media access control address and an identification of a port, and a pointer table () of which the entries each comprise a network address and an associated pointer to an entry in the said data table. The pointers are accessed by hashing network addresses in received packets.

Organization of databases in network switches for packet-based data communications networks

The present invention relates to transparent access to network attached storage devices, configured to any of several protocols, such as SCSI over IP, NAS or NASD. In particular, the present invention provides for using a switch to transparently aggregate storage devices. The switch appears as a virtual storage device. It responds to requests to initiate file sessions and selects one of a plurality of storage devices to participate in the file session. A file session can be handed off to a different storage device. Both the setup and handoff are transparent to the client and its TCP/IP client. The present invention may be practiced either as a method or device. It may provide a virtual storage device or it may aggregate storage devices already attached to a network.

Virtually addressing storage devices through a switch

A method of operating a network device in a communication system for the transmission of data packets which include network addresses identifying sources and destinations of data, the network device being capable of both bridging and routing decisions and including a forwarding database by means of which a packet including network address data can be forwarded to at least one port and thereby to at least one network path identified by a network address, and packets can be forwarded to at least one port in response to a media access control address. The method comprises establishing a data table which contains entries comprising a network address of an end station to which a packet is destined, a respective media access control address and an identification of at least one port to which the packet will be directed within the device. The table is accessed in response to network addresses and media access control addresses, whereby the same table can be used for both routing and bridging decisions.

Integrated data table in a network

The present invention relates to transparent access to network attached devices, such as network attached storage devices, Web servers or database servers. In particular, the present invention provides hand-off protocols that are transparent to a network client, with the advantage that physical devices can be added to, replaced on or removed from a network without reconfiguring network clients or applications running applications at levels above the network clients. One aspect the present invention is a method for handing off TCP sessions in a system including a client in communication with a switch and to or more devices. This method includes determining in the first device that a handoff should take place, identifying a second device to take over the session, sending handoff messages to and receiving an acknowledgment from the second device, and reporting the handoff to and receiving an acknowledgment from the switch. The devices applying this method may be disk drives, Web servers, database servers or any other device that benefits from being clustered. A device according to the present invention may comprise: a switch including logic for routing messages among a client and a plurality of devices and logic responsive to an instruction to reprogram its routing messages and to confirm the road reprogramming is complete; a first device including logic to determine when a TCP session should be handed off to another device, logic to instruct a second device to accept a handoff, and logic to instruct a switch to reprogram its routing of messages; wherein the second device is in communication with the switch and includes logic responsive to an instruction to accept a handoff and to confirm acceptance of the handoff. The first and second devices may be disk drives, Web servers, database servers or any other device that benefits from being clustered. Logic may be included to determine when to handoff a TCP session and to identify a second device to receive the handoff, consistent with the method of present invention.

Transparent access to network attached devices

A last-in first-out data stack is able to store a plurality (n) of elements wherein the plurality is greater than two. For each of n storage locations in the stack a selector is adapted to receive n elements read out from the stack and a new element. The selector is arranged to make a controllable selection of its received elements. Combinational logic capable of performing logic manipulations on the selection of elements provides a resultant for pushing onto the stack.

Last-in first-out data stacks and processing data using such data stacks

A network switch comprises a first device which includes a store for data packets, a second device which includes a plurality of ports from which the packets may be transmitted, a plurality of temporary stores each associated with one of the ports, a data bus connecting the first device to the second device, a unit for maintaining a count of units of storage space in respect of each of the ports, a unit for incrementing the respective count on transmission of data from one of the stores, and a unit for decrementing the count in response to dispatch of data from the temporary store in the first device to the second device.

Growing community of inventors

Dublin, Ireland

Anne G O'Connell