Crossroads Systems, Inc.

Kip Cr P1 LP

Keith M Arroyo

Stephen K Wilson

Robert A Reynolds

A system and method are disclosed for processing commands to network target devices through a SCSI router in a Fiber Channel network having a plurality of Fiber Channel hosts. The system may be configured to receive a command, and determine that the command requires a transfer of data larger than a threshold size. The system may also be configured to receive a plurality of data blocks associated with the command, store the plurality of data blocks in at least one buffer, and determine if there is an initial amount of data in the at least one buffer. The system may be further configured to forward at least one of the plurality data blocks, and request an additional data block associated with the command.

Streaming methods and systems for network devices

Streaming method and system for fibre channel network devices

A system and method are disclosed for processing commands to network target devices through a SCSI router in a Fiber Channel network having a plurality of Fiber Channel hosts. The system and method are implemented in the SCSI router and include receiving a command from one of the plurality of Fiber Channel hosts and, if the command is for a transfer of data larger than a threshold size, streaming the data to the target device. If a preset size memory block is free, a data block is requested from the Fiber Channel host that issued the command. Otherwise, the method of this invention waits to request the data block until the preset size memory block is free. The SCSI router receives the data block and stores the data block in a FIFO queue. The method of this invention repeats until an initial number of data blocks are stored in the FIFO queue. The command and the first data block received are forwarded to the network target device. The target device requests additional data blocks as needed and the SCSI router forwards the data blocks in the FIFO queue until a trigger number of data blocks remain in the FIFO queue. Additional data blocks are requested and received from the Fiber Channel host simultaneously with the forwarding of data blocks to the target device. The target device requests data blocks from the SCSI router until all of the data associated with the command has been transferred.

A method and system are disclosed for processing multiple commands to a streaming target device through a SCSI router in a Fibre Channel network provisioned with one or more Fiber Channel hosts. The system and method are implemented in the SCSI router and include creating a FIFO queue, receiving a first command from one of the Fibre Channel hosts in the Fibre Channel network, and forwarding the first command to the streaming target device. When a subsequent command is issued to the streaming target device, the SCSI router can receive the subsequent command and determine whether the streaming target device has completed execution of the previous command. If the streaming target device has completed execution of the previous command, the subsequent command can be forwarded to the streaming target device. If the streaming target device has not completed executing the previous command, the subsequent command can instead be placed in the FIFO queue. Upon execution of the previous command by the streaming target device, the method of this invention can forward the subsequent command from the FIFO queue to the streaming target device. The method of this invention can repeat for any additional subsequent commands.

Method and system for multi-initiator support to streaming devices in a fibre channel network

A method and system are disclosed for processing a unit attention signal from a target device in a Fiber Channel-to-SCSI network having a plurality of Fiber Channel hosts. One embodiment of the method includes the steps of, in a router: (a) receiving a first command for said target device from a first one of said Fiber Channel hosts; (b) forwarding said first command to said target device; (c) determining, at said target device, if said target device has undergone a status changing event since last receiving any command; (d) if said target device has undergone such a status changing event, then; (1) at said target device, issuing said UA signal in response to said first command; (2) forwarding said UA signal to said router and caching said UA signal at said router; (3) updating a register for said target device to indicate said UA signal is outstanding; (4) forwarding said UA signal to said first host and updating a UA table to indicate said UA signal has been forwarded to said first host; and (e) repeating steps (a)-(d) for a subsequent command from any of said Fiber Channel hosts, wherein said first command is said subsequent command and wherein said first host is the issuing host.

Method and system for persistent unit attention in a fibre channel storage router

A method and system for maintaining node states across network address changes in a Fibre Channel network includes steps and instructions for maintaining in each of a plurality of nodes, including target and initiator nodes, a triplet table including a triplet of data having the network address, node, name, and port name for each of other ones of said plurality of nodes with which the particular node communicates. The instructions permit sending from each of the plurality of nodes to the other ones of the nodes with which each of the plurality of nodes communicates the triplet of data following the resumption of communication occurring after a break in communication. The triplet of data identifies the event that the nodes are communicating with the same nodes both before and after said break in communication, the invention further includes instructions for continuing communications among said nodes without performing further recovery steps.

Method and system for managing I/O transmissions in a fibre channel network after a break in communication

Streaming method and system for fiber channel network devices

A method and system are disclosed for processing tagged commands from a Fibre Channel host in a Fibre Channel network to one or more SCSI streaming target devices through a SCSI router. The method includes the step of determining whether the command is a tagged command. If the command is a tagged command, then the command processing method of the current invention determines whether the intended target device is a streaming target device. If the intended target device is a streaming target device, the method and system of the present invention can convert the command's format from a tagged command format to an un-tagged format and forward the command to the intended target device. Flags in an internal SCSI router register can be set to track which, if any, devices attached to the SCSI router can support tagged commands. Upon completion of the command, the method of the present invention can forward the command complete message to the issuing Fibre Channel host.

Method and system for un-tagged command queuing

A method and system for maintaining a unique reserve command relationship between an initiator and a target device in a Fibre Channel network across network address changes after a break in communication. The present invention maintains triplet tables containing data triplets, comprised of the network address, the port name, and the node name, for each initiator and each target device. Following a break in network communication that results in the network address of an initiator and/or a target device changing, the method of the present invention updates the recorded network addresses for the initiators and the target devices, maintains any previously-existing unique reserve command relationships and continues with I/O transmission. Although the network address of an initiator may change, the node name and port name of the initiator will remain the same. By comparing the initiator port name and node name contained in a reserve table maintained in the target device to the node name and port name corresponding to the now updated network address for an initiator with which it was in a unique reserve command relationship prior to the break in communication, a target device can then simply update the network address for the initiator and no disruption in I/O traffic will result.

Growing community of inventors

Austin, TX, United States of America

Keith M Arroyo