Abstract: Method and system for routing fibre channel frames using a fibre channel switch element is provided. The method includes, inserting a time stamp value in a fibre channel frame that is received at a receive segment of the fibre channel switch element; determining if a timeout occurs after a frame arrives at a receive buffer; and processing the frame if the timeout occurred. The method also includes, determining if a delta time value, which provides an accumulated wait time for a frame, is present in frame data; subtracting the delta time stamp value from a global time stamp value and using the resulting time stamp value to determine frame timeout status in the fibre channel switch element. A timeout checker circuit declares a timeout after comparing a time stamp value that is inserted in a fibre channel frame with a programmed time out value and a global counter value.

Abstract: A fibre channel switch element and method for routing fibre channel frames is provided. The switch element includes a receive segment that can add a virtual storage area network (“VSAN”) tagging header to frames that are received by the receive segment; and strip the VSAN tagging header before frames are sent to ports that do not support virtual fabric capability. The receive segment includes a table used for matching fabric extension parameters. An incoming frame's VSAN identity value is compared to a control word entry to generate a value used for routing the incoming frame. The table is used to determine if a frame is part of a virtual fabric. The routing table for each port is used to route frames and the routing table includes entries for supported virtual fabrics.

Abstract: A method and system for transmitting frames using a fibre channel switch element is provided. The switch element includes a port having a receive segment and a transmit segment, wherein the fibre channel switch element determines if a port link has been reset; determines if a flush state has been enabled for the port; and removes frames from a buffer, if the flush state has been enabled for the port. For a flush state operation, frames are removed from a receive buffer of the fibre channel port as if it is a typical fibre channel frame transfer. The removed frames are sent to a processor for analysis. The method also includes, setting a control bit for activating frame removal from the transmit buffer; and diverting frames that are waiting in the transmit buffer and have not been able to move from the transmit buffer.

Abstract: A method and system for routing frames based on a port's speed using a fibre 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 fibre 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 optimizing bandwidth allocation in a fibre channel network having 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 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 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 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.

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: 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 10 G multi lane port or as multiple individual ports.

Abstract: A method and system for routing fibre channel frames using a fibre channel switch element is provided. The switch element includes logic for comparing a credit counter value with a first threshold value to enable a credit limiting feature; and a first counter that receives a signal after a frame has departed from a transmit segment and maintains a maximum value for a certain duration that is based on the first threshold value. The method includes enabling a credit limiting feature, wherein frame transmission from a certain source is delayed when the credit limiting feature is enabled. The first counter is incremented every time a frame departs and holds its maximum value based on the threshold value. When the first counter is at the maximum value, a credit-limiting signal is used to enable the credit limiting feature by setting a control bit in a control register.