Abstract: A method and system for routing fibre channel frames using a fibre channel switch element is provided. The switch element includes, a look up table that is indexed by domain, area, a virtual storage area number and/or AL_PA values of frames entering the fibre channel switch element; and logic for generating a column select signal that is used to select a column from the look up table for frame routing information The switch element also includes logic for validating a frame route by performing word depth match. A register is used to load look up table entries and column entries are selected based on the column select signal. The method includes, indexing a look up table with plural fibre channel frame header values; selecting a table value for routing a fibre channel frame based on a column select signal; and routing the frame if a route is valid.

Abstract: A fibre channel switch element for routing fibre channel frame is provided. The switch element includes a fibre channel port that can be configured to support plural data transfer rates. The data transfer rate may be 1 G, 2 G, 4 G, 8 G or 10 G. The switch element includes a clock configuration module for providing a clock signal that is based on the data transfer rate. A receive segment of the fibre channel port sends a signal to a transmit segment to avoid an under flow condition. The receive segment also waits for a certain frame length after a fibre channel frame is written and before the fibre channel frame is read, depending upon a data transfer rate of a source port. Multiple lanes may be configured as a single 10G multi lane port or as multiple individual ports.

Abstract: Method and system for processing frames in a Fibre Channel network is provided. The method includes receiving a frame at a receive port; determining if a translation cache is enabled; determining if there is a match between a received frame header and an entry in the translation cache; generating an encapsulation signal, a de-encapsulation signal, a translation signal or a routing signal; removing data words in the received frame header, if de-encapsulation signal is set; translating the received frame header, if the translation signal is set; encapsulating the frame with an encapsulation header, if the encapsulation signal is set; and routing the frame using translation cache routing if the routing signal is set.

Abstract: A method for credit management in a network system is provided. The method comprises receiving an incoming frame at a receive port of a network device; determining a frame length of the incoming frame; based on the frame length, determining whether to store the frame in a first memory storage space or a second memory storage space, wherein the first memory storage space includes a plurality of slots and each of the plurality of slots can store only one frame regardless of frame size; and the second memory storage space includes a plurality of slots and each of the plurality of slots can store more than one frame; and if the incoming frame is stored in the second memory storage space, transmitting a signal immediately to another port indicating that credit is available.

Abstract: A Fibre Channel switch element in a Fibre Channel network is provided. The Fibre Channel switch element includes a port that replaces a logical unit number (“LUN”) field value in a FCP_CMND frame. The port includes a LUN Mapping cache for replacing the LUN field value in a FCP_CMND frame. The LUN Mapping cache may also generate a value that is added to or subtracted from the LUN field value in the FCP_CMND frame. A control bit is used to activate LUN Mapping cache for mapping LUN values.

Abstract: A method for routing fibre channel frames using a fibre channel switch element is provided. The switch element includes, a receiving segment in a fibre channel port for receiving the frames and a transmit segment that transmits the received frames. The method includes requesting an early frame transfer, wherein the transmit segment of a fibre channel port requests an early frame transfer from a receiving segment of the fibre channel port before a frame has arrived at the transmit segment; activating an early frame transfer; determining if there is a need for aborting the early frame transfer request; and selecting a different source port if there is a need for aborting an early frame transfer request.

Abstract: A method and system for routing frames based on a port's speed using a fiber channel switch element is provided. The method includes, receiving a portion of a frame in a receive buffer of a port; determining a frame length threshold; and setting up a status bit based on the port's speed, the frame length threshold and an amount of frame received. The status bit is sent to a transmit segment of the fiber channel switch element and the frame length threshold value is inversely proportional to the port's speed. Also, if the receive buffer is almost full when a frame arrives at the receive port, then a cut status is based on a frames end of frame (“EOF”) value.

Abstract: A method and system for routing fiber channel frames using a fiber channel switch element is provided. The switch element includes, a look up table that is indexed by domain, area, a virtual storage area number and/or AL_PA values of frames entering the fiber channel switch element; and logic for generating a column select signal that is used to select a column from the look up table for frame routing information. The switch element also includes logic for validating a frame route by performing word depth match. A register is used to load look up table entries and column entries are selected based on the column select signal. The method includes, indexing a look up table with plural fiber channel frame header values; selecting a table value for routing a fiber channel frame based on a column select signal; and routing the frame if a route is valid.

Abstract: A fiber channel switch element for routing fiber channel frame is provided. The switch element includes a fiber channel port that can be configured to support plural data transfer rates. The data transfer rate may be 1 G, 2 G, 4 G, 8 G or 10 G. The switch element includes a clock configuration module for providing a clock signal that is based on the data transfer rate. A receive segment of the fiber channel port sends a signal to a transmit segment to avoid an under flow condition. The receive segment also waits for a certain frame length after a fiber channel frame is written and before the fiber channel frame is read, depending upon a data transfer rate of a source port. Multiple lanes may be configured as a single 10 G multi lane port or as multiple individual ports.

Abstract: A method and system for implementing LUN based hard zoning in a fibre channel network is provided. A LUN field in a Fibre Channel SCSI command frame is compared with a list of LUNS that are allowed for a particular frame source; and the frame is forwarded if the LUN is allowed for the frame source. The comparison is performed by a port receiving the frame by using an address look up table (“ALUT”). Hard zoning is based on various frame fields and/or ALUT control codes. Also provided is a method for processing a reply to a SCSI REPORT LUN command from an initiator. The method includes, intercepting a reply to a REPORT LUN command; editing the reply to remove unauthorized LUNs; and sending the edited reply to the initiator.

Abstract: Method and system for checking frame-length in a Fiber Channel frames is provided. The method includes extracting a R_CTL value from a Fiber Channel frame; comparing the extracted R_CTL value of the Fiber Channel frame with R_CTL values stored in a Content Addressable Memory Table; determining a maximum frame-length and a minimum frame-length of the Fiber Channel frame for the extracted R_CTL value from the Content Addressable Memory Table; and marking the Fiber Channel frame so that it can be discarded if the frame-length is less than the minimum frame-length of the Fiber Channel frame or greater than the maximum frame-length of the Fiber Channel frame. The system includes a processor that accesses a CAM stored in memory; and a receive port that extracts and compares a R_CTL value of the Fiber Channel frame.

Abstract: A method and system for controlling power consumption in a fibre channel switch element having a plurality of ports and plural links to communicate over a network is provided. The switch element includes, a power control module that is used to provide power to only active ports after firmware of fibre channel switch element determines the active ports. The method includes, determining active ports of the fibre channel switch element, after all the ports are shut down in a known state; and providing power to only the active ports. All ports are powered up during fibre channel switch element reset and then powered down (except a common port) so that the ports are shut down in a known state.

Abstract: Method and system for routing Fibre Channel Class F frames using a Fibre Channel switch element port is provided. The method includes parsing a Fibre Channel frame at a receive port of a Fibre Channel switch; and automatically routing a Class F frame that is destined to a Domain Controller. The switch element includes a receive port for parsing a Fibre Channel frame, storing a Domain Steering Table and automatically routing a Class F frame that is destined for a Domain Controller.

Abstract: A method for assigning virtual lanes (VL) in a fibre channel switch is provided. The fibre channel switch element includes a virtual lane cache that can compare incoming frame parameters based on which virtual lanes may be assigned; and a register to store parameters used for virtual lane assignment. The method includes, determining if VL assignment is to be based on an incoming frame parameter or a programmed value; determining if an incoming frame is a preferred frame; and assigning a preferred routing priority if the incoming frame is designated as a preferred frame. The method also includes, determining if a fabric topology is known; and assigning virtual lanes based on a known fabric topology.

Abstract: A method and system for detecting congestion and over-subscription in a fiber channel switch element is provided. A counter is updated if a frame cannot be transmitted due to lack of credit; then the counter value is compared to a threshold value; and an event is triggered if the counter value varies from the threshold value. Also, provided is a first register that maintains information regarding a rate at which a source port can transfer data; a counter that counts entries corresponding to a number of frames to be transmitted at a given time; and a second register that determines an over-subscription rate.

Abstract: A method and system for routing fiber channel frames using a fiber channel switch element is provided. The switch element includes, a port with a buffer having more than one memory slot for receiving fiber channel frames, wherein the port tracks a relative age of a first memory slot with respect to at least another memory slot; and frames are transmitted from a memory slot based on the relative age. The method includes, determining a relative age of a first memory slot with respect to at least another memory slot; and transmitting a frame from a memory slot based on the relative age. The method also includes, sending frames that have resided in a memory slot for a greater period compared to frames residing in at least another memory slot; and setting age bits in plural memory slots when frames are written and the relative age is determined based on the age bits. An aging table may be used to store the age bits of the plural memory slots.

Abstract: A fibre channel switch element and method for processing frames in a fibre channel network is provided. The switch element includes an address mapping cache that receives an incoming fibre channel frame in a receive and/or transmit segment, wherein the address mapping cache compares a D_ID of an incoming frame in the receive segment and/or a S_ID in the transmit segment; and if a FR_Header is received then a D_ID or S_ID is compared from a fibre channel header that follows the FR_Header; and if a compare fabric identifier flag is set, then the fabric identifier is compared. The address mapping cache may also be used for routing frames from one virtual fabric to another by comparing a VF_ID field to a Virtual fabric identifier in a VFT_Header.

Abstract: Method and system for managing frame traffic in a Fibre Channel network with plural switch elements with receive and transmit ports is provided. The method includes limiting a number of R_RDYs sent between frames, when frames are waiting to be transmitted at a given time, for minimizing a number of ordered sets transmitted between frames. The switch element includes a R_RDY control module that stores a number of R_RDYs that a port has to send, stores an actual number of R_RDYs that are sent since a last frame is transmitted; stores a number of R_RDYs that are sent between frames and this number of R_RDYs can be programmed to be less than two; and stores a threshold value that is less than or equal to a maximum R_RDY count value.

Abstract: A method and system for optimizing bandwidth allocation in a fiber channel network having a fiber channel switch element, is provided. The switch element includes, a port control module having a receive and transmit segment, wherein the transmit segment is programmed to block frame transmission from a particular frame source port for a certain duration based on a programmable threshold value. The method includes, enabling a bandwidth limitation counter; and programming the threshold value for blocking frame transmission from a frame source port for a certain duration and during this duration, other source ports may be chosen for frame transmission. After a frame is transmitted from a source port, a tag valid blocking from the same source port is used to block frame transmission. A quality of service register is used to store the threshold value and the threshold value is programmable.

Abstract: A method and system for keeping an arbitrated loop open during a frame gap using a fibre channel switch element is provided. The switch element includes a port control module having a receive and transmit segment, wherein the transmit segment activates a timer whose value determines a duration during which the arbitrated loop remains open; determines if a last frame from a sequence of frames from a source port has been transmitted; modifies the timer value if a higher priority frame for transmission is unavailable; and keeps the arbitrated loop open until the timer reaches a certain value. If a higher priority frame is available for transmission before the timer value is modified then the higher priority frame is transmitted and the timer value is re-initialized.