Hewlett-packard Development Company, L.p.

Hewlett-packard Company

Randolph B Haagens

Mallikarjun Chadalapaka

Jeffrey Clifford Mogul

Richard Fitzhugh Wrenn

Thomas A Keaveny

Richard J Wagner

A system and method for detecting path failure in a network are described. The system and method include a network interface which receives packets over particular connections, and an agent able to monitor the network interface and start a no-traffic timer for each particular connection when a packet is received on the connection. The agent is further able, when the no-traffic timer expires, to check for outgoing data on the particular connection, and compare a count of previously sent test packets against a limit. If the count is below the limit the agent sends a new test packet on the particular connection, the test packet provides an indication of the state of a network path associated with the particular connection. If the count is above the limit the agent initiates failover procedures for the associated path.

Fast detection of path failure for TCP

An efficient technique for performing remote asynchronous mirroring includes receiving a stream of command requests, performing the requested commands, relaying the requested commands to a target while embedding an explicitly-defined or implied task precedence graph in the relayed commands to enable increased concurrency in tasks performed by the target.

Command management using task attributes

There is disclosed a data communications link adapter providing flow of data control and status information between an input/output (I/O) Backplane and a fiber optic Frontplane. The adapter represents a melding of I/O channel extender technology and data communications technology: a dedicated processor handles link layer protocol, leaving to software only higher protocol layers; a flow-through architecture is provided by the adapter; a combination of windowing and handshaking are used; and a relatively short frame of sixteen bytes is employed. The adapter includes a backplane adapter portion which serves to interconnect host equipment, a processor portion dedicated to layer 3 (circuit operations), a protocol controller dedicated to layer 2 (physical layer) operations, a fiber optic interface portion dedicated to layer 1 (physical link) operations, and an arbiter portion which couples the processor to a data path connecting the backplane adapter and the protocol controller. The arbiter controls data accesses that use a portion of the data path connecting the backplane adapter to the protocol controller and a data path between the protocol controller and the processor. A variety of data integrity measures are implemented on all data paths. The adapter facilitates data flow-through by buffering internal to the protocol controller, and has extensive data flow control features.

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Roseville, CA, United States of America

Randolph B Haagens