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 routing module applies a plurality of routing rules simultaneously to determine routing for a Fibre Channel frame. Each rule independently determines whether the rule applies to the frame as well as a routing result for the frame. The routing result includes a port address, a zoning indicator, and a priority designation that can be used to route the frame over a virtual channel in an interswitch link. A selector chooses between the results returned by the rules. A component receives routing results specifying an ISL group and selects a physical ISL for the frame. An in-band priority determined by the content of the frame header can also be used in place of the priority designation in the routing result.

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 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 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 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 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.