Method and apparatus for controlling concurrent data transmission from multiple sources in a channel communication system
First Claim
1. A data communications system comprisinga channel switch,a plurality of client information sources connected over data communications channels to said channel switch for transmitting frames of data,at least one peripheral device connected by a data channel to said channel switch,said channel switch combining information from said information sources according to a frame protocol, said protocol defining a predetermined method for selecting which pending information source data to deliver to said peripheral device, and for limiting the connection line capacity of each source to a non-zero selected number of frames of data based upon connection criteria parameters that can vary from information source to information source.
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Abstract
A method and apparatus for communicating multiple threads, concurrently on a single channel, features a process for prioritizing and limiting the transmission time allocated to any particular host. The invention features providing a channel switch capable of communicating with a plurality of client sources, the sources being connected for transmitting frames of data to the channel, and to at least one storage device connected to the channel. The information transmission is formatted and controlled at the switch in accordance with a frame protocol and the protocol provides a predetermined method for selecting which information host to connect to which channel and for how long. The switch allocates connection line capacity to the sources according to a selected priority and the credit or buffer available to the source. Accordingly, an average priority waiting is associated with each information source.
172 Citations
10 Claims
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1. A data communications system comprising
a channel switch, a plurality of client information sources connected over data communications channels to said channel switch for transmitting frames of data, at least one peripheral device connected by a data channel to said channel switch, said channel switch combining information from said information sources according to a frame protocol, said protocol defining a predetermined method for selecting which pending information source data to deliver to said peripheral device, and for limiting the connection line capacity of each source to a non-zero selected number of frames of data based upon connection criteria parameters that can vary from information source to information source.
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2. A fibre channel communications system comprising
a fibre channel switch, a plurality of client information sources connected to said fibre channel switch for transmitting frames of data, at least one mass storage device connected by a data channel to said fibre switch, said fibre channel switch combining information from said information sources according to a frame protocol, said protocol defining a predetermined method for selecting which information source data to deliver to said storage device, and for limiting the connection line capacity of each source to a non-zero selected number of frames of data, at least some sequences of frames on the data channel containing a number of data frames less than the number of frames forming a natural sequence boundary at the client information source.
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6. A method of communicating frames of data through a channel switch between a plurality of client information sources having pending data and a peripheral device comprising the steps of
determining the credit available to each of the information sources, determining a priority value, expressed as a non-zero number of frames, dedicated to each of the information sources, and communicating with said connected client information sources in a round robin protocol taking into account the credit and priority value associated with each information source.
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7. A method of communicating frames of data through a fibre channel switch between a plurality of client information sources and a storage system having at least one mass storage device comprising the steps of
determining the credit available to each of the information sources, determining a priority value, expressed as a non-zero number of frames, dedicated to each of the information sources, and communicating with said connected client information sources in a round robin protocol taking into account the credit and priority value associated with each information source, at least some sequences of frames on the data channel containing a number of data frames less than the number of data frames forming a natural sequence boundary at the client information source.
Specification