Abstract: A Fiber Channel switch is presented that tracks the congestion status of destination ports in an XOFF mask at each input. A mapping is maintained between virtual channels on an ISL and the destination ports to allow changes in the XOFF mask to trigger a primitive to an upstream port that provides virtual channel flow control. The XOFF mask is also used to avoid sending frames to a congested port. Instead, these frames are stored on a single deferred queue and later processed in a manner designed to maintain frame ordering. A routing system is provided that applies multiple routing rules in parallel to perform line speed routing. The preferred switch fabric is cell based, with techniques used to manage path maintenance for variable length frames and to adapt to varying transmission rates in the system. Finally, the switch allows data and microprocessor communication to share the same crossbar network.

Abstract: A method and apparatus is presented for performing a sequence-level CRC calculation on fiber channel communications within a switching platform domain. A CRC generator searches the data communication for frames that contain the type of data for which a sequence-level CRC is desired, such as for a sequence containing SCSI data. If found, and the type of data allows multiple frames per sequence, the present invention creates a CRC value for the sequence. An intermediate CRC value is stored in a queue to allow the simultaneous calculation of sequence level CRC values for multiple frames. With inbound data, the sequence-level CRC is appended to the end of the sequence data. With outbound data, the calculated value is compared with the appended, expected value, With single-frame fiber channel protocols, the frame-level CRC value is obtained directly from the frames entering the switching platform domain.

Abstract: A storage router and related method are presented for combining multiple Fibre Channel frames together into a single IP datagram for tunneling transmission over an Internet protocol network. The storage router operates by storing incoming Fibre Channel frames in a Fibre Channel frame buffer. When there is sufficient data in the buffer, multiple Fibre Channel frames are taken from the buffer and combined into a single IP datagram. The number of Fibre Channel frames to be combined can be established through a variety of tests, including total bytes of data, number of frames, or through a time-out mechanism. The network layer then fragments the datagram into data link level frames, such as 1500 byte Ethernet frames. When the IP datagram arrives at the final destination, the segmented IP datagram is reconstructed, and the multiple Fibre Channel frames are extracted from the IP datagram and passed on to the recipient Fibre Channel network.

Abstract: A method and apparatus for temporarily deferring transmission of packets/frames to a destination port in a buffered switch is disclosed. When a request for transmission of at least one packet/frame to the destination port is received, it is determined whether the destination port is available to receive the at least one packet/frame. The transmission of the at least one packet/frame is deferred when the destination port is not available to receive the at least one packet/frame. The packet/frame identifier and memory location for each deferred packet/frame is stored in a deferred queue and the process then repeats for the next packet/frame. Periodically, the apparatus attempts to transmit the packets/frames in the deferred queue to their respective destination ports.

Abstract: A self-aligning guide pin has two tapered protrusions. The protrusions seat in recesses in a printed circuit board to properly position and align the guide pin as it is mounted by a screw to the printed circuit board during assembly.

Abstract: A method and apparatus includes a retainment face, which with a rear boundary define a channel. The channel has a first and second opening that enable a tie to be threaded through the channel and around a data cable to secure it in place.

Abstract: A switch segments variable length frames into cells for transmission over a cell-based switch fabric and handles rate differences between the input data rate and the switch fabric data rate. The fabric handles multiple cell packets by maintaining a switch path until a certain number of cells are transmitted as indicated in a length field in the first data cell. The first cell contains a full data payload, and a length field value sufficient to handle a maximum length frame. Subsequent cells can contain less than a full data payload, with the number of valid bytes in the cell being indicated in the length field. The last cell used to segment the frame contains an end of frame indicator. The indicator signals the destination port side of the switch to terminate the packet path in the switch fabric prematurely—before the number of cells indicated in the first data cell.

Abstract: A method and apparatus that recognizes a portion of an address that would be unrecognizable to an intended associated switch or device and manipulates the portion of the address to make it recognizable. The apparatus and method manipulates a discontinuous address to provide the appearance to the associated device, switch or peripheral, that the address is continuous. This provides additional address capacity such that a new address is created within the switch itself for routing data within the switch. All or a portion of the switches in network are preassigned a chassis address, and each chassis also has a specific switch address that is different from the preassigned chassis address. An address adaptor provides translation of addresses and mapping within a switch so that in the event of a port failure, affected frames can be redirected from the failed port by employing the described translation and mapping operations.

Abstract: A Fiber Channel switch is presented that tracks the congestion status of destination ports in an XOFF mask at each input. A mapping is maintained between virtual channels on an ISL and the destination ports to allow changes in the XOFF mask to trigger a primitive to an upstream port that provides virtual channel flow control. The XOFF mask is also used to avoid sending frames to a congested port. Instead, these frames are stored on a single deferred queue and later processed in a manner designed to maintain frame ordering. A routing system is provided that applies multiple routing rules in parallel to perform line speed routing. The preferred switch fabric is cell based, with techniques used to manage path maintenance for variable length frames and to adapt to varying transmission rates in the system. Finally, the switch allows data and microprocessor communication to share the same crossbar network.

Abstract: A method and system for bootstrapping a processor from a volatile memory device connected to the processor is disclosed. The first processor is bootstrapped from flash device. The reset lines of the second processor are asserted. The boot code for the second processor is loaded from the flash device into the volatile memory device. The reset lines of the second processor are de-asserted, wherein the processor then boots from the boot code stored in the volatile memory device. The same boot-strapping method can be extended to multi-drop systems where number of secondary processor can be more than one. A switchable means for the second processor to boot from volatile memory as described or from flash memory. A method also describes a mechanism to boot from synchronous volatile memory devices.

Abstract: A storage router and related method are presented for combining multiple host frames, such as Fibre Channel frames, together into a single datagram for tunneling transmission over an IP or similar network. The storage router operates by storing incoming host frames in a host frame buffer. When there is sufficient data in the buffer, multiple host frames are batched together, compressed, and converted into an IP datagram. The number of host frames to be batched together can be established through a variety of tests, including total bytes of data, number of frames, or through a time-out mechanism. The network layer then fragments the datagram into data link level frames, such as 1500 byte Ethernet frames. When the datagram arrives at the final destination, the segmented datagram is reconstructed, decompressed, and the multiple host frames are then extracted and passed on to the recipient host frame network.

Abstract: A fiber channel backplane configuration is capable of modular expansion, e.g., from 64 ports to 128 ports or 256 ports by a simple operation. The backplane includes connectors that provide permanent and jumper/vertical connections to support 64 user port switch in a single chassis. For a 128 port switch, two 64 port chassis are used. In the 128 port configuration, the connectors are configured to provide permanent and jumper/vertical connections to make intra-chassis and inter-chassis connections between the fabric switch and fabric input/output boards. Using jumper plugs, the jumper connectors provide vertical connections between the fiber input/output boards and fiber switch boards of two chassis. For a 256 port switch configuration, four 64 port chassis assemblies are used. The connectors are configured to provide each switch with permanent, vertical, horizontal, and diagonal connections to the fiber input/output boards of each of the four chassis.

Abstract: An enclosure for computer-based telephone switching equipment that suppresses the radiation of electromagnetic interference through the use of multiple overlapping seals and apertures.

Abstract: A method and apparatus for imparting fault tolerance in a switch or the like, particularly in a fibre channel director switch employed in connection with storage area network.

Abstract: A method of adapting a native ESCON director to provide fibre channel switching capability includes providing a fibre channel port adapter comprising one or more boards that can be installed into slots in a multi-protocol channel switch having a central switch; connecting said port adapter to a Fibre Channel device; wherein said method permits interconnection through said central switch, thereby allowing connection between and exchange of information between any two desired ports

Abstract: A method and apparatus is presented for performing a sequence-level CRC calculation on fiber channel communications within a switching platform domain. Specifically, the disclosed invention utilizes a CRC generator to monitor data communication between an external interface and a fiber channel controller. The CRC generator searches the data communication for frames that contain the type of data for which a sequence-level CRC is desired, such as for a sequence containing SCSI data. When found, the CRC generator performs an 8B/10B decode, strips off any fill bytes, and performs a CRC calculation on the data payload. If the found frame is the first frame in the sequence, the CRC is done starting with a reset value. If the frame is not the first, an intermediate value containing the previous CRC calculation results for this sequence is retrieved and used to perform the CRC calculations. Upon completion of the calculation for the frame, a determination is made whether the sequence is complete.

Abstract: A method and apparatus is presented providing high-performance lossless data compression implemented in hardware for improving network communications. A compression module useful in a switching platform is also presented capable of compressing data stored in buffer memory. Instructions for a compression task are assigned to the compression module by a microprocessor writing a control block to a queue in stored local memory. The control block informs the compression module of the size and location of the unprocessed data, as well as a location in the buffer memory for storing the processed data and the maximum allowed size for the compressed data. Using this technique, the microprocessor can limit the compression of data to those data streams allowing compression, to those segments that are susceptible to compression, and to those segments that are large enough to show a transmission speed improvement via compression.

Abstract: A system for extending a communications link between a host computer and peripheral device provides true emulation of the peripheral data storage device. The system includes a host extender for communicating directly with the host computer and a peripheral extender for communicating directly with the peripheral device. The host attached and peripheral extenders communicate across the extended communications link. The host extender initially transmits a channel program to the peripheral extender. The system uses the channel program to obtain format information of a particular track of the peripheral device. The host extender stores this format information and uses it to emulate the peripheral device to the host computer.

Abstract: High frequency transmitter and receiver circuits are AC coupled for party line transmission over coaxial cable where the circuits are connectable to the cable by use of stinger taps and thereby eliminate the need to interrupt service when connecting the circuits to the cable. The transmitter circuit includes oppositely polled current sources which are alternately switched to the coaxial cable via the stinger tap or to a dummy load by current switches connected to data inputs via buffer circuits. A transmit enable circuit controls the current sources to be active or inactive and to prevent unbalances from saturating either current sources. The receiver includes a high input impedance biasing network and buffer amplifier that maintain the high input impedance even when power is off. Capacitance at the tap is reduced by a capacitor drive circuit which feeds input signal back to transmitter blocking diodes and to the trunk tap.