3Com Corporation

3Com Technologies

Richard A Gahan

Eugene O'Neill

John F Hickey

Edele O'Malley

Kam Choi

William Paul Sherer

Bryan J Donoghue

Con David Cremin

Sorcha O'Callaghan

Raymond Beechinor

Ciaran Murphy

David Nolan

John Healy

A system of switch modules contains input demultiplexers connected to ports on each of the modules and output multiplexers connected to each of the modules. Each module has output and input interfaces for mesh links and at least one output interface is looped back to an input interface on the same module. The arrangement reduces module-to-module traffic and corresponding increases the transmit bandwidth of a module.

High-speed switch architecture

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

A storage assembly includes a plurality of multi-unit storage device is provided with a failover procedure that does not require hot-swap capability. Individual units are aggregated into a storage array by an aggregation procedure such as RAID. When a failure occurs data from the failed unit is transferred to a hot spare unit. Also, data from other units is transferred by simulating failure of those units and then the complete device can be removed. In small storage networks all the units may be aggregated as a single array and a spare auxiliary device is summoned and integrated into the array prior to the simulated failure. In larger systems there may be two layers of aggregation and failover is run by the second level of aggregation.

Storage disk failover and replacement system

A method of transmitting data ( ) generated in an upper layer protocol such as iSCSI in a transport protocol such as TCP or SCTP, without requiring separate reads for check code generation and transmission. The upper layer protocol data is read into a transmission engine ( ) that calculates the error check codes and inserts them into the transport protocol transmission. To prevent having to recalculate error codes in the event of loss of transmitted data and a retransmission request, the engine preferably also writes the error check codes into the memory so that the can be retrieved if retransmission is necessary.

Calculation and transmission of error check codes

A direct data placement implementation for a data reassembly process. Data within a protocol data unit is placed directly in preassigned application buffers. The network interface card has buffer space into which message headers, segment headers and indicators of escaped data and size of escaped data are placed. A single buffer can contain this information for a complete PDU (or message) and is handed over to enable the next process to run on a per message basis.

Direct data placement and message reassembly

A method for distributing addressed data packets from an input channel to a multiplicity of packet queues includes receiving said addressed data packets and, responsive to first hashed addresses, distributing the addressed data packets to said queues in accordance with said first hashed addresses. A first hash function is applied to selected address data of each of said addressed data packets to produce said first hashed addresses. At the same time a succession of different hash functions is applied to said selected address data in each of the packets to produce second hashed addresses and occurrences of each of the second hashed addresses are counted so as to obtain for each of said different hash functions a respective one of a plurality of set of counts, each such set representing the distribution of said packets that would occur in said queues if the respective one of the different hash functions had been applied to said addressed data packets. The sets of counts are analyzed to determined which one of them represents a best distribution of said packets and the hash function associated with the best distribution is applied to incoming packets in place of the said first hash function.

System and method for dynamically mapping a high speed link to a multiplicity of low speed trunked links

An Ethernet network or other CSMA/CD network includes a hub that is modified to generate a jamming signal on a communication line when a packet received over that line is directed to an unavailable destination. The destination may be unavailable due to full transmit buffers, full receive buffers, or congestion in other parts of the hub architecture. Jamming is detected by the source node as a collision and causes retransmission of the packet from the source node. The decision to jam may include a determination of the packet's priority which may be determined based on the packet's destination or source address.

Growing community of inventors

Gory, Ireland

Richard A Gahan