76 results about "Arbitrated loop" patented technology

A multiple use core logic chipset is provided in a computer system that may be configured either as a bridge between an accelerated graphics port ("AGP") bus and host and memory buses, or as an interface bridge between a Fibre Channel Arbitrated Loop ("FC-AL") interface and the host and memory buses. The function of the multiple use chipset is determined at the time of manufacture of the computer system or in the field whether an AGP bus bridge or an FC-AL bridge interface is to be implemented. Selection of the type of bus bridge (AGP or FC-AL bridge interface) in the multiple use core logic chipset may be made by a hardware signal input, or by software during computer system configuration or power on self test ("POST"). Software configuration may also be determined upon detection of either an AGP or a FC-AL bridge interface device connected to the common AGP / FC-AL bus. FC-AL information may be stored in the computer system main memory using the high speed FC-AL bridge interface.

A network storage appliance including one or more integrated switching devices is disclosed. The appliance includes redundant storage controllers that transfer frames of data between storage devices and host computers. The integrated switching devices include a plurality of I / O ports and a data transfer path between each of the I / O ports for providing simultaneous data transfers between multiple pairs thereof. The switches enable the appliance to simultaneously transfer frames between its I / O ports and storage device I / O ports and / or host I / O ports, thereby providing increased data transfer bandwidth over arbitrated loop configurations. Additionally, the switches are intelligent and may be programmed to achieve improved fault isolation. The appliance may also include servers that include I / O ports coupled to the switches for simultaneously transferring data with the storage controllers and / or I / O ports of devices external to the appliance.

A loop isolation circuit (LIC) to enable subdivision of a single daisy-chained communication loop (e.g., FC-AL) into smaller loops and to enable joining of smaller loops into a single larger loop. An LIC comprises essentially two multiplexors configured so as to permit controlled subdivision or joining of two loop portions. In a first selected state, the LIC subdivides a communication loop in which it is inserted into two loops. This configuration sacrifices accessibility among some devices previously on the larger loop for the benefit of enhanced bandwidth and reduced overhead due to node count. Bandwidth is enhanced by enabling simultaneous operation of two (or more) loop portions for establishing and communicating over logical circuit connections. However, when a failure of a redundant loop precludes access to devices, the LIC may be set to a second state to rejoin previously subdivided loops into a larger loop. This configuration restores access among all devices sharing common access to the larger loop. The LIC of the present invention therefore enables communication loop controllers to dynamically reconfigure a daisy-chained loop communication system to enhance performance in normal operation. The LIC of further enables restoration of the larger loop to restore redundant loop configurations. The LIC of the present invention is applicable in many daisy-chained loop communication environments including, but not limited to, Fiber Channel Arbitrated Loop (FC-AL).

A system and method for enabling a network switch to transmit queued packets to a device when opened by the device, and thus to utilize the Fibre Channel Arbitrated Loop (FC-AL) in full-duplex mode when possible. The switch may include a plurality of queues each associated with a device on the FC-AL for queuing incoming packets for the device. The switch may determine a next non-empty queue, open the device associated with the queue, and send packets to the device. The device may send packets to the switch concurrently with receiving packets from the switch, thus utilizing the FC-AL in full-duplex mode. When a device opens the switch to transmit packets to the switch, the switch may determine if there are packets for the device in the queue and, if so, send packets to the device concurrently with receiving packets from the device, thus utilizing the FC-AL in full-duplex mode.

Methods and apparatus for switching Fibre Channel Arbitrated Loop Systems is provided between a plurality of Fibre Channel Loop devices. In one aspect of the invention, the system switches based at least in part on arbitrated loop primitives. An exemplary interconnect system may include a first port and a second port, both including port logic to monitor certain arbitrated loop primitives, a connectivity apparatus, a route determination apparatus including a routing table consisting of ALPA addresses and their associated ports, the route determination apparatus coupled to each port and the connectivity apparatus, where the connectivity apparatus creates paths between the ports based on arbitrated loop primitives. In one embodiment, the connectivity apparatus is a crossbar switch. Examples of the arbitrated loop primitives that cause the switch to create paths between ports includes one or more of the following: ARB, OPN and CLS. In yet other aspects, the system ensures device access fairness through one or more techniques, including a rotating priority system, a counter to count the number of OPNs, especially sequential OPNs, and / or priority based on port type. Device zoning may be implemented. In one implementation, the system includes trunking such that frames may be transferred on multiple ports.

Methods and apparatus for switching Fibre Channel Arbitrated Loop Systems is provided between a plurality of Fibre Channel Loop devices. In one aspect of the invention, the system switches based at least in part on arbitrated loop primitives. An exemplary interconnect system may include a first port and a second port, both including port logic to monitor certain arbitrated loop primitives, a connectivity apparatus, a route determination apparatus including a routing table consisting of ALPA addresses and their associated ports, the route determination apparatus coupled to each port and the connectivity apparatus, where the connectivity apparatus creates paths between the ports based on arbitrated loop primitives. In one embodiment, the connectivity apparatus is a crossbar switch. Examples of the arbitrated loop primitives that cause the switch to create paths between ports includes one or more of the following: ARB, OPN and CLS. In yet other aspects, the system ensures device access fairness through one or more techniques, including a rotating priority system, a counter to count the number of OPNs, especially sequential OPNs, and / or priority based on port type. Device zoning may be implemented. In one implementation, the system includes trunking such that frames may be transferred on multiple ports.

A system and method for enabling a network switch to transmit queued packets to a device when opened by the device, and thus to utilize the Fibre Channel Arbitrated Loop (FC-AL) in full-duplex mode when possible. The switch may include a plurality of queues each associated with a device on the FC-AL for queuing incoming packets for the device. The switch may determine a next non-empty queue, open the device associated with the queue, and send packets to the device. The device may send packets to the switch concurrently with receiving packets from the switch, thus utilizing the FC-AL in full-duplex mode. When a device opens the switch to transmit packets to the switch, the switch may determine if there are packets for the device in the queue and, if so, send packets to the device concurrently with receiving packets from the device, thus utilizing the FC-AL in full-duplex mode.

A method and apparatus for preserving loop fairness. Some embodiments include a dynamic half-duplex feature. One aspect includes a communications channel system and method for preserving loop fairness that includes a first channel node having one or more ports, each port supporting and attached to a fibre-channel arbitrated-loop serial communications channel. One of the ports will arbitrate for control of that port's attached channel, wherein control of the channel loop, once arbitration is won, a fairness-preserving apparatus causes control of the communications channel to be released based at least in part on whether a predetermined amount of use has occurred between the first port and the communications channel. In some embodiments, the predetermined amount of use includes a transfer of a first predetermined amount of data. In some embodiments, release of control of the channel is inhibited if less than a second predetermined amount of data remains to be transferred.

Embodiments of the present invention are directed to a device which may be used for communication through an Ethernet network. The device may comprise two modules. A first module may be based on an existing Fibre Channel arbitrated loop HBA technology. The second module may be configured to provide a virtual Fibre Channel arbitrated loop network for the first module utilizing the Ethernet network. In other words the second module may process communications generated by the first module as well as incoming communications from the Ethernet network in order to make it appear to the first module that it is communicating with an actual Fibre Channel Arbitrated Loop network (whereas it is actually communicating through an Ethernet network). Thus, existing Fibre Channel technology can be used for the first module and the overall design cost of the device can be reduced.

One embodiment of the present invention is an integrated circuit implementing a storage-shelf router, used in combination with path controller cards and optionally with other storage-shelf routers, to interconnect SATA disks within a storage shelf or disk array to a high-bandwidth communications medium, such as an FC arbitrated loop. When two, four, six, or eight or more storage-shelf routers are used within a storage shelf, and the interconnections between the storage-shelf routers, disk drives, and external communications media are properly designed and configured, the resulting storage shelf constitutes a discrete, highly-available component that may be included in a disk array or in other types of electronic devices. The storage-shelf router features a disk-drive adaptation layer that allows a storage-shelf router to interface to, and manage, any of many different types of disk drives. The disk-drive adaptation layer includes a disk-profile table and associated firmware logic.

Methods and apparatus for Fibre Channel interconnection is provided between a plurality of private loop devices through a Fibre Channel private loop device interconnect system. In the preferred embodiments, the Fibre Channel private loop device interconnect system is a fabric or an intelligent bridging hub. In one aspect of this invention, a Fibre Channel private loop device is connected to two or more Arbitrated Loops containing, or adapted to contain, one or more private loop devices. Preferably, the interconnect system includes a routing filter to filter incoming Arbitrated Loop physical addresses (ALPAs) to determine which Fibre Channel frames must attempt to be routed through the fabric. Numerous topologies of interconnect systems may be achieved. In another aspect of this invention, a method is provided for implementing a logical loop of private loop devices by segmenting the logical loop into a plurality of sets, assigning each set to a physical Arbitrated Loop and connecting the Arbitrated Loops to a Fibre Channel private loop device interconnect system. Additional methods are provided for restricting attached devices to Arbitrated Loop physical addresses within certain ranges. Additionally, methods are provided for resetting hosts, the method generally comprising the steps of detecting the addition of a storage device to a first Arbitrated Loop, and thereafter, resetting the Arbitrated Loop or loops on which a host or hosts reside on second Arbitrated Loop. Methods for operation with use of SCSI initiators generate a link service reject when no address match is found, or when an address match is found, but where no device with the destination ALPA exists on the Arbitrated Loop corresponding to the destination.

Methods and apparatus for switching Fiber Channel Arbitrated Loop Systems is provided between a plurality of Fiber Channel Loop devices. In one aspect of the invention, the system switches based at least in part on arbitrated loop primitives. An exemplary interconnect system may include a first port and a second port, both including port logic to monitor certain arbitrated loop primitives, a connectivity apparatus, a route determination apparatus including a routing table consisting of ALPA addresses and their associated ports, the route determination apparatus coupled to each port and the connectivity apparatus, where the connectivity apparatus creates paths between the ports based on arbitrated loop primitives. In one embodiment, the connectivity apparatus is a crossbar switch. Examples of the arbitrated loop primitives that cause the switch to create paths between ports includes one or more of the following: ARB, OPN and CLS. In yet other aspects, the system ensures device access fairness through one or more techniques, including a rotating priority system, a counter to count the number of OPNs, especially sequential OPNs, and / or priority based on port type. Device zoning may be implemented. In one implementation, the system includes trunking such that frames may be transferred on multiple ports.

The present invention enables the coupling and decoupling of multiple processing devices to a network without disrupting the network. In an embodiment, the invention provides a switch having a network port and several initiator ports each configured for coupling to a processing device. The switch is configured to route data from the network port to the initiator ports and from the initiator ports to the network port. A management agent facilitates operation of the switch by processing port initializations, replying to device registration requests, and processing predetermined unsolicited discovery commands. During operation, the management agent enables configuration changes caused, for example, by the coupling and / or decoupling of processing device to initiator ports.

Embodiments of the invention support improvements in network performance in networks such as storage area networks. This is particularly important in networks such as those implementing virtualization. These improvements, therefore, support improved mechanisms for performing processing in network devices such as switches, routers, or hosts. These improvements include various different mechanisms which may be used separately or in combination with one another. These mechanisms include methods and apparatus for processing traffic in an arbitrated loop, performing striping to support fairness and / or loop tenancy, performing configuration of network devices such as switches to enable virtualization to be performed closest to the storage device (e.g., disk), ascertaining a CPU efficiency that quantifies the impact of virtualization on a processor, and configuring or accessing a striped volume to account for metadata stored in each storage partition.

A system for selectively routing data within a fiber channel arbitrated loop, including an intra-loop router configured to be coupled between a first segment and a second segment of the fiber channel arbitrated loop. The intra-loop router includes a router controller configured to be coupled with the first and second segments, and a processing system coupled with the router controller. The processing system is configured to receive fiber channel frames and cause those frames to be re-transmitted onto a selected one of the first and second segments of the fiber channel arbitrated loop.

An enclosure services processor card is arranged to selectively split a fiber-channel arbitrated-loop (FC-AL) into two split loops. The card is adapted to plug into a backplane for a rack enclosure and includes a first switch operatively connected to a hub for the FC-AL. The hub comprises a plurality of port bypass circuits, each port bypass circuit being connected to a pair of tracks which in use connect to a respective one of each of the devices comprising the fiber channel arbitrated loop. The hub further comprises a pair of switches operatively controlled by the first switch, the pair of switches being disposed between respective port bypass circuits at which the loop is to be split. In a first state the pair of switches connect the devices in a single loop and in a second state the pair of switches divide the devices into two split loops.

An integrated circuit implementing a storage-shelf router, used in combination with path controller cards and optionally with other storage-shelf routers, to interconnect SATA disks within a storage shelf or disk array to a high-bandwidth communications medium, such as an FC arbitrated loop. Various embodiments of the present invention provide a tunneling mechanism through the storage-shelf interface provided by one or more storage-shelf routers within a storage shelf to enable external processing entities to directly access various components within the storage shelf. In one embodiment of the present invention, a WRITE-BUFFER command and a READ-BUFFER command are added to the command interface supported by storage-shelf router. These commands are exchanged via the FCP protocol over the fiber channel in the same manner that SCSI commands are packaged within the FCP protocol. In certain cases, the information packaged within the WRITE-BUFFER and READ-BUFFER commands is directly exchanged with internal disk drives. In other cases, the information is extracted and written to various data structures maintained within internal components of the storage shelf. The WRITE-BUFFER and READ-BUFFER commands essential provide a breach or tunnel in the high-availability storage-shelf virtual interface provided by one or more storage-shelf routers within a storage shelf, allowing an external processing entity to exchange information through the tunnel without intervention by, but facilitated and supported by, the one or more storage-shelf routers within the high-availability storage shelf.

A self-test method and system for facilitating reliable and fault-tolerant operation of a multi-peripheral-device enclosure for use in high-availability computer systems. The reliable and fault-tolerant multi-peripheral-device enclosure uses a three-tiered port bypass control strategy for diagnosing and isolating malfunctioning peripheral devices within the multi-peripheral-device enclosure, and uses a similar a three-tiered port bypass control strategy for isolation of the entire multi-peripheral-device enclosure from a communications medium that interconnects the multi-peripheral-device enclosure with one or more host computers. This three-tiered port bypass control strategy is employed by a self-test routine to isolate the multi-peripheral-device enclosure from external processing elements in order to test peripheral devices and other components within the multi-peripheral-device enclosure, and to isolate any detected defective or malfunctioning components.

A system and method enables a file server, to support multi path input / output operations for Fibre Channel devices. Upon each Fibre Channel Arbitrated Loop initialization event generated, the system and method updates a path and device instance to track multiple paths to a given device. While the file server is attempting input / output operations, the failure of a given path can be corrected by the use of another path associated with a given device. The data structures generated by the low levels of the storage operating system are exposed for use by upper level services for routing a storage device identification purposes.

An architecture is provided for implementing bypass, repeater and retimer functions in high-speed multi-port SERDES bypass ports and devices. Specifically, this architecture uses clock recovery to implement a repeater function which retransmits data synchronously at a recovered-clock rate, providing very low-latency as no elastic-buffers are required to perform clock-rate compensation. It also supports a full retiming function where incoming data is retransmitted synchronously to the local-clock domain, in which case elastic-buffers are needed to compensate for differences between incoming clock and local-clock domains. The architecture disclosed herein is advantageously used for Fibre-Channel Arbitrated Loop (FCAL) applications. It can also be leveraged in other applications like Infiniband, XAUI, PCI-Express to create a single device that be used as “eye-opener” to extend reach with low-latency when operated in “repeater mode” and as retiming device when operated as “retimer-mode”. It can also perform as an amplifier with very low-latency when operated in bypass-mode.

A system and method of detecting / eliminating a faulty port in a fiber channel-arbitrated loop, which implements early location / elimination of a port which causes a faulty on a loop in an FC-AL. If no faulty is found in loop 7 at step 914, it can be determined that its own port normally works. Then, an enable instruction is issued to a node destined to a port on the loop 7 from loop 8 at step 915. If a fault is detected in the loop 7 at step 916, it can be determined that the port which has issued the enable instruction at step 915 has been issued faulty. The port which has issued the enable instruction at step 915 is registered as a faulty port at step 918. A bypass instruction is issued from the loop 8 at step 919.

A method and system including apparatus for detecting and blocking an invalid request to a target wherein fiber channels interconnect the data processing configuration. A request made from a hub such as a fabric switch to an internal fiber channel arbitrated loop is blocked by substituting IDLE characters for the frames of data included with the request. The substitution of IDLE signals can also occur within an internal fiber channel arbitrated loop system where access is blocked to a confidential data storage system. If the request is legitimate, the data frames are passed to the target and the requested data is transmitted back to the requester. If the request is refused as being an unauthorized request, the data frames are replaced with IDLE characters and no transfer of confidential data occurs.

Methods and apparatus for switching Fiber Channel Arbitrated Loop Systems is provided between a plurality of Fiber Channel Loop devices. In one aspect of the invention, the system switches based at least in part on arbitrated loop primitives. An exemplary interconnect system may include a first port and a second port, both including port logic to monitor certain arbitrated loop primitives, a connectivity apparatus, a route determination apparatus including a routing table consisting of ALPA addresses and their associated ports, the route determination apparatus coupled to each port and the connectivity apparatus, where the connectivity apparatus creates paths between the ports based on arbitrated loop primitives. In one embodiment, the connectivity apparatus is a crossbar switch. Examples of the arbitrated loop primitives that cause the switch to create paths between ports includes one or more of the following: ARB, OPN and CLS. In yet other aspects, the system ensures device access fairness through one or more techniques, including a rotating priority system, a counter to count the number of OPNs, especially sequential OPNs, and / or priority based on port type. Device zoning may be implemented. In one implementation, the system includes trunking such that frames may be transferred on multiple ports.

An integrated circuit implementing a storage-shelf router used alone, or in combination with other storage-shelf routers, and in combination with path controller cards, to interconnect the disks within a storage shelf or disk array to a high-bandwidth communications medium, such as an FC arbitrated loop, through which data is exchanged between the individual disk drives of the storage shelf and a disk-array controller. A set of interconnected storage-shelf routers within a storage shelf can be accessed through a single port of an FC arbitrated loop or other high-bandwidth communications medium. Because, in one implementation, eight storage-shelf routers can be interconnected within a storage shelf to provide highly available interconnection of sixty-four disk drives within the storage shelf to an FC arbitrated loop via a single FC-arbitrated-loop port, a single FC arbitrated loop including a disk-array controller, may interconnect 8,000 individual disk drives to the disk-array controller within a disk array. The storage-shelf router can serve to translate FC-based communications protocols into one or more communication protocols appropriate to the internal links, providing for use of less expensive, non-FC-compatible disk drives within the storage shelf.

Methods and apparatus for Fibre Channel interconnection is provided between a plurality of private loop devices through a Fibre Channel private loop device interconnect system. In the preferred embodiments, the Fibre Channel private loop device interconnect system is a fabric or an intelligent bridging hub. In one aspect of this invention, a Fibre Channel private loop device is connected to two or more Arbitrated Loops containing, or adapted to contain, one or more private loop devices. Preferably, the interconnect system includes a routing filter to filter incoming Arbitrated Loop physical addresses (ALPAs) to determine which Fibre Channel frames must attempt to be routed through the fabric. Numerous topologies of interconnect systems may be achieved. In another aspect of this invention, a method is provided for implementing a logical loop of private loop devices by segmenting the logical loop into a plurality of sets, assigning each set to a physical Arbitrated Loop and connecting the Arbitrated Loops to a Fibre Channel private loop device interconnect system. Additional methods are provided for restricting attached devices to Arbitrated Loop physical addresses within certain ranges. Additionally, methods are provided for resetting hosts, the method generally comprising the steps of detecting the addition of a storage device to a first Arbitrated Loop, and thereafter, resetting the Arbitrated Loop or loops on which a host or hosts reside on second Arbitrated Loop. Methods for operation with use of SCSI initiators generate a link service reject when no address match is found, or when an address match is found, but where no device with the destination ALPA exists on the Arbitrated Loop corresponding to the destination.

The detection, removal and reinsertion of possibly malfunctioning devices from an arbitrated loop is disclosed. When a new device is first connected to a storage switch and a loop is formed and begins initialization, a LOOP_DOWN event is sent to a processor and a loop down timer is started for each port in the loop. If initialization is successful, a LOOP_UP event is sent to the processor and the loop down timer is reset for each port in the loop. However, if one of the loop down timers times out, a problem occurred during the initialization. The port associated with the timed out timer is bypassed so that the devices in the remainder of the loop can continue trying to complete the initialization. The processor initiates a PTBI event on the bypassed device. If the bypassed device is operating properly, it is re-inserted back into the loop.

A method and system including apparatus for detecting and blocking an invalid request to a target wherein fibre channels interconnect the data processing configuration. A request made from a hub such as a fabric switch to an internal fibre channel arbitrated loop is blocked by substituting IDLE characters for the frames of data included with the request. The substitution of IDLE signals can also occur within an internal fibre channel arbitrated loop system where access is blocked to a confidential data storage system. If the request is legitimate, the data frames are passed to the target and the requested data is transmitted back to the requester. If the request is refused as being an unauthorized request, the data frames are replaced with IDLE characters and no transfer of confidential data occurs.