Abstract: A method and apparatus is disclosed for temporarily deferring transmission of frames to a destination in a data switch. When a request for transmission of a frame to the destination port is received, the congestion status of that destination is determined. If the destination is congested, the frame is stored in a deferred queue. When the status of a destination changes from congested to non-congested, the deferred queue is examined to see if any deferred frames can now be forwarded to their destination. While examining the deferred queue, incoming frames are placed on a backup queue. When the deferred queue is fully analyzed, the backup queue is emptied by either sending those frames to their destination or storing the frames in the deferred queue. While examining the deferred queue, the congested states of the destinations are not allowed to change from congested to non-congested.

Abstract: A method and apparatus is disclosed for temporarily deferring transmission of frames to a destination in a data switch. When a request for transmission of a frame to the destination port is received, the congestion status of that destination is determined. If the destination is congested, the frame is stored in a deferred queue. When the status of a destination changes from congested to non-congested, the deferred queue is examined to see if any deferred frames can now be forwarded to their destination. While examining the deferred queue, incoming frames are placed on a backup queue. When the deferred queue is fully analyzed, the backup queue is emptied by either sending those frames to their destination or storing the frames in the deferred queue. While examining the deferred queue, the congested states of the destinations are not allowed to change from congested to non-congested.

Abstract: A method and apparatus is disclosed for temporarily deferring transmission of frames to a destination in a data switch. When a request for transmission of a frame to the destination port is received, the congestion status of that destination is determined. If the destination is congested, the frame is stored in a deferred queue. When the status of a destination changes from congested to non-congested, the deferred queue is examined to see if any deferred frames can now be forwarded to their destination. While examining the deferred queue, incoming frames are placed on a backup queue. When the deferred queue is fully analyzed, the backup queue is emptied by either sending those frames to their destination or storing the frames in the deferred queue. While examining the deferred queue, the congested states of the destinations are not allowed to change from congested to non-congested.

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 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 for providing an early packet termination such that prior to the complete transmission of the number of cells specified in the first cell of a packet, a crossbar connection is released. The act of releasing the connection is triggered on recognition of an End of Packet bit (EOP) set in any cell of the stream. The feature can be enabled, for example, by a specific act of setting a register bit, connecting a pin to Vcc or ground or some other intentional act. The feature will default to the inactive state upon reset.

Abstract: A method for providing an early packet termination such that prior to the complete transmission of the number of cells specified in the first cell of a packet, a crossbar connection is released. The act of releasing the connection is triggered on recognition of an End of Packet bit (EOP) set in any cell of the stream. The feature can be enabled, for example, by a specific act of setting a register bit, connecting a pin to Vcc or ground or some other intentional act. The feature will default to the inactive state upon reset.

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 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: A device for converting at least four parallel data streams on respective input data lines into one serial data stream on a fiber optic data line. The device includes a first multiplexer for multiplexing at least two of the parallel data streams into a first intermediate output stream and a second multiplexer for multiplexing at least two other of the parallel data streams into a second intermediate output stream. A serializing transmitter is coupled to the first and second multiplexers for serializing the first and second intermediate output streams into the serial data stream. A signal synchronizes the serializing of the first and second intermediate output streams and tags output data in the serial data stream as corresponding to data from each of the respective input data lines. In-band messaging is used to transfer commands and status messages between devices without affecting ongoing data stream communications.

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 for providing an early packet termination such that prior to the complete transmission of the number of cells specified in the first cell of a packet, a crossbar connection is released. The act of releasing the connection is triggered on recognition of an End of Packet bit (EOP) set in any cell of the stream. The feature can be enabled, for example, by a specific act of setting a register bit, connecting a pin to Vcc or ground or some other intentional act. The feature will default to the inactive state upon reset.

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 device for converting at least four parallel data streams on respective input data lines into one serial data stream on a fiber optic data line. The device includes a first multiplexer for multiplexing at least two of the parallel data streams into a first intermediate output stream and a second multiplexer for multiplexing at least two other of the parallel data streams into a second intermediate output stream. A serializing transmitter is coupled to the first and second multiplexers for serializing the first and second intermediate output streams into the serial data stream. A signal synchronizes the serializing of the first and second intermediate output streams and tags output data in the serial data stream as corresponding to data from each of the respective input data lines. In-band messaging is used to transfer commands and status messages between devices without affecting ongoing data stream communications.

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 fibre 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 fibre input/output boards and fibre 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 fibre input/output boards of each of the four chassis.

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