Data communication network with transfer port, cascade port and/or frame synchronizing signal

Abstract

A data communication system, such as a local area network, is provided with a capability of transmitting isochronous data. Preferably the system conveys both isochronous data and non-isochronous data by time-multiplexing the data into a recurring frame structure on a four-bit nibble basis. An efficient encoding scheme permits transmission of both isochronous and non-isochronous data over existing media, such as twisted pair, without degrading bandwidth previously achieved for non-isochronous data over the same media, such as using an ethernet system. Bandwidth available for a particular isochronous source/sink is selectable and sustainable with a predefined granularity. The arriving data is de-multiplexed at the hub into separate channels for handling the separate streams by appropriate hardware. Preferably, the present invention can be implemented in a fashion that is transparent to already-installed media access controllers. Preferably, some components of the system can detect the frame-transmission capability of other components and, if such capability is lacking, can fall back to a mode compliant with existing capabilities.

1. In a data communication network for communicating data between a plurality of data stations over a communications medium under control of a processor which outputs a plurality of control signals, apparatus comprising:
 a receive memory means and a transmit memory means;  
 a receive datapath corresponding to each data station coupled between said communications medium and said receive memory means for providing at least some data received over said communications medium to said receive memory means;  
 a transmit datapath corresponding to each data station coupled between said transmit memory means and said communications medium for providing at least some data from said transmit memory means to said communications medium;  
 each said receive datapath including:  
 a deserializer configured to receive serial data from said communications medium and output at least a portion of said received serial data in parallel;  
 means for selectively transmitting, in response to one of said plurality of control signals, said data output by said deserializer to said receive memory means;  
 each said transmit datapath including a serializer configured to receive parallel data and output serial data.  
 
     
     
       2. Apparatus, as claimed in  claim 1 , wherein each of said receiver memory means and said transmit memory means is a buffer. 
     
     
       3. Apparatus, as claimed in  claim 1 , wherein said data received over said communications medium includes status data indicating at least a status of port activities. 
     
     
       4. Apparatus, as claimed in  claim 1 , wherein said data received over said communications medium comprises status data including at least a status of interrupts of at least one of said data stations and wherein each said receive datapath includes a demultiplexer coupled between said communications path and said deserializer for diverting said status data to a first location prior to receipt of serial data in said deserializer. 
     
     
       5. Apparatus, as claimed in  claim 4 , wherein said first location comprises a first register. 
     
     
       6. Apparatus, as claimed in  claim 5 , wherein said apparatus is contained in a first network data station, coupled, via said communications medium, to a plurality of other data stations and wherein said first register stores status data from all said other data stations which are connected to said first network data station. 
     
     
       7. Apparatus, as claimed in  claim 1 , wherein said transmit datapath includes means for generating at least one predetermined data pattern for transmission onto said communications medium. 
     
     
       8. Apparatus, as claimed in  claim 7 , wherein said means for generating includes means for generating a plurality of predetermined data patterns and means for selecting among said plurality of data patterns in response to one of said plurality of control signals. 
     
     
       9. Apparatus, as claimed in  claim 1 , wherein said data stations include at least first and second network data stations, and said apparatus is contained in said first network data station, which is coupled, via said communications medium, to a first plurality of other data stations and also coupled, by said apparatus, via said communications medium, to said second network data station which is coupled to a second plurality of data stations and wherein:
 said transmit datapath includes a first-in-first-out buffer for receiving data from said transmit memory means and holding said data before providing said data to said serializer.  
 
     
     
       10. Apparatus, as claimed in  claim 9 , wherein said first network data station is coupled to said second network data station by physical layer circuitry which multiplexes data for transmission from said first and second network data stations onto said communications medium and demultiplexes said data received over said communications medium. 
     
     
       11. Apparatus, as claimed in  claim 9 , further comprising means for determining whether said serializer receives parallel data from said first-in-first-out buffer or from said transmit memory means, bypassing said first-in-first-out buffer. 
     
     
       12. Apparatus, as claimed in  claim 9 , wherein said first network data station includes a number of receive data paths at least equal to the number of data stations in said first plurality of data stations, and wherein operation of all of the receive datapaths in said first network data station are synchronous. 
     
     
       13. Apparatus, as claimed in  claim 9 , wherein said first-in-first-out buffer is configured to output its contents to said serializer in response to a signal transmitted by said second network data station. 
     
     
       14. In a data communication network for communicating between data stations over a communications medium under control of a processor which outputs a plurality of control signals, apparatus comprising:
 a receive memory device and a transmit memory device;  
 a plurality of receive datapaths for providing at least some data received over said media to said receive memory device;  
 a plurality of transmit datapaths for providing at least some data from said transmit memory device to said communications medium;  
 each of said receive datapaths including 
 a deserializer configured to receive serial data and output at least a portion of said received serial data in parallel;  
 a latch which, in response to one of said plurality of control signals, controllably provides said data output by said deserializer to said receive memory device;  
 
 each of said transmit datapaths including a serializer configured to receive parallel data and output serial data.  
 
     
     
       15. In a data communication network for communicating data between data stations over a communications medium, said network including at least first and second network data stations, said first network data station coupled to a first plurality of said data stations and also coupled to said second network data station, said second network data station being coupled to a second plurality of said data stations, said first network data station comprising:
 a receive memory device and a transmit memory device;  
 a receive datapath coupled between said communications medium and said receive memory means for providing at least some data received over said media to said receive memory device;  
 a transmit datapath coupled between said transmit memory means and said communications medium for providing at least some data from said transmit memory device to said communications medium;  
 a first-in-first-out buffer coupled to said first network data station for receiving data from said transmit memory device and holding said data before providing said data to said second network data station; and  
 wherein said first-in-first-out buffer is configured to output its contents in response to a signal transmitted by said second network data station.  
 
     
     
       16. In a data communication network for communicating isochronous and non- isochronous data between data stations over a communications medium under control of a processor which outputs a plurality of control signals, an apparatus comprising:      a receive memory and a transmit memory;        one or more receive datapaths for providing at least some data received over the communications medium to the receive memory;        one or more transmit datapaths for providing at least some data from the transmit memory to the communications medium;        each of the receive datapaths including      a deserializer configured to receive serial data and output at least a portion of the received serial data in parallel;        a latch which, in response to one of the plurality of control signals, controllably provides the data output by the deserializer to the receive memory;          each of the transmit datapaths including a serializer configured to receive parallel data and output serial data.     
     
     
       17. The apparatus of  claim 16 , wherein the isochronous data comprises data output from a telephone device. 
     
     
       18. The apparatus of  claim 16 , wherein the isochronous data comprises data output from a video device. 
     
     
       19. The apparatus of  claim 16 , wherein the non- isochronous data comprises packetized data.   
     
     
       20. The apparatus of  claim 16 , wherein the non- isochronous data comprises ethernet data.   
     
     
       21. The apparatus of  claim 16 , wherein the communications medium comprises a plurality of physical media. 
     
     
       22. The apparatus of  claim 21 , wherein at least one of the physical media communicates isochronous data and at least one of the physical media communicates non- isochronous data.   
     
     
       23. The apparatus of  claim 16 , wherein apparatus comprises at least a portion of a star- topology network.   
     
     
       24. The apparatus of  claim 16 , wherein the apparatus comprises at least a portion of a ring topology network. 
     
     
       25. The apparatus of  claim 16 , wherein the apparatus comprises at least a portion of a tree topology network. 
     
     
       26. The apparatus of  claim 16 , wherein the non- isochronous data received by the apparatus is coupled to hub circuitry for processing the non - isochronous data.   
     
     
       27. The apparatus of  claim 26 , wherein the non- isochronous data comprises ethernet data.   
     
     
       28. The apparatus of  claim 16 , wherein isochronous data received by the apparatus is coupled to a high bandwidth bus. 
     
     
       29. The apparatus of  claim 28 , wherein the isochronous data is coupled to the high bandwidth bus by an isochronous controller. 
     
     
       30. The apparatus of  claim 29 , wherein the isochronous controller comprises a time slot interchange interface. 
     
     
       31. The apparatus of  claim 29 , wherein the isochronous controller comprises an isochronous switching device. 
     
     
       32. The apparatus of  claim 29 , wherein the isochronous controller includes a local loopback communication path. 
     
     
       33. The apparatus of  claim 16 , wherein the data communicated over the communications medium further comprises maintenance data. 
     
     
       34. The apparatus of  claim 33 , wherein the maintenance data comprises M channel data. 
     
     
       35. The apparatus of  claim 16 , wherein data communicated over the communications medium further comprises signaling data. 
     
     
       36. The apparatus of  claim 35 , wherein the signaling data comprises D channel data. 
     
     
       37. The apparatus of  claim 35 , wherein the signaling data is coupled to at least one signaling processor. 
     
     
       38. The apparatus of  claim 35 , wherein the signaling data is coupled to a remote network data station and controls a communications medium coupled to the remote network data station. 
     
     
       39. The apparatus of  claim 35 , wherein the signaling data is generated or processed by a signaling processor. 
     
     
       40. The apparatus of  claim 16 , wherein data communicated over the communications medium comprises signaling and/or maintenance data, wherein the signaling and/or maintenance data comprises data selected from the group consisting of error condition data, requested connection data, maintenance data, and control data. 
     
     
       41. The apparatus of  claim 16 , wherein the isochronous and non- isochronous data are multiplexed and coupled to a time division multiplexed bus.   
     
     
       42. The apparatus of  claim 16 , wherein the isochronous and non- isochronous data are coupled to/from the communications medium through a multiplexer/demultiplexer.   
     
     
       43. The apparatus of  claim 16 , wherein the apparatus further comprises a cascade port, wherein the cascade port is coupled between first and second isochronous hubs without using a backbone network. 
     
     
       44. The apparatus of  claim 16 , wherein the communications medium comprises a portion of a local area network. 
     
     
       45. The apparatus of  claim 16 , wherein the communications medium comprises a portion of a wide area network. 
     
     
       46. The apparatus of  claim 16 , wherein the plurality of control signals control the apparatus. 
     
     
       47. The apparatus of  claim 46 , wherein the data is coupled to/from the communications medium through a plurality of physical layer devices. 
     
     
       48. The apparatus of  claim 47 , wherein the processor communicates with one or more of the physical layer devices. 
     
     
       49. The apparatus of  claim 47 , wherein the processor communicates with each of the physical layer devices. 
     
     
       50. The apparatus of  claim 48 , wherein the processor requests status information from a physical layer device. 
     
     
       51. The apparatus of  claim 48 , wherein the processor requests status information from a physical layer device by providing a physical layer device address. 
     
     
       52. The apparatus of  claim 47 , further comprising a register for receiving status information for one or more of the physical layer devices. 
     
     
       53. The apparatus of  claim 47 , wherein the processor receives an interrupt in the event of an activity change of a physical layer device. 
     
     
       54. The apparatus of  claim 47 , wherein the processor receives signaling data. 
     
     
       55. The apparatus of  claim 48 , wherein the processor receives an interrupt that indicates that a signaling channel receiver or transmitter of a physical layer device needs to be processed by the processor. 
     
     
       56. The apparatus of  claim 16 , wherein data communicated to/from the communications medium is coupled to an HDLC controller. 
     
     
       57. The apparatus of  claim 56 , wherein the data coupled to the HDLC controller comprises signaling data. 
     
     
       58. In a data communication network for communicating isochronous and non- isochronous data between data stations over a communications medium including at least first and second network data stations, the first network data station being coupled to one or more first data stations and also coupled to the second network data station, the second network data station being coupled to one or more second data stations, the first network data station comprising:      a receive memory and a transmit memory;        a receive datapath coupled between the communications medium and the receive memory, wherein the receive datapath provides at least some data received over the communications medium to the receive memory;        a transmit datapath coupled between the transmit memory and the communications medium wherein the transmit datapath provides at least some data from the transmit memory to the communications medium;        a first - in - first - out buffer receiving the at least some data from the transmit memory and holding the data before communicating the data to the second network data station; and        wherein the first - in - first - out buffer is configured to output its contents in response to a signal transmitted by the second network data station.     
     
     
       59. The apparatus of  claim 58 , wherein the isochronous data comprises data output from a telephone device. 
     
     
       60. The apparatus of  claim 58 , wherein the isochronous data comprises data output from a video device. 
     
     
       61. The apparatus of  claim 58 , wherein the non- isochronous data comprises packetized data.   
     
     
       62. The apparatus of  claim 58 , wherein the non- isochronous data comprises ethernet data.   
     
     
       63. The apparatus of  claim 58 , wherein the communications medium comprises a plurality of physical media. 
     
     
       64. The apparatus of  claim 63 , wherein at least one of the physical media communicates isochronous data and at least one of the physical media communicates non- isochronous data.   
     
     
       65. The apparatus of  claim 58 , wherein the first and second network data stations form at least a portion of a star- topology network.   
     
     
       66. The apparatus of  claim 58 , wherein the first and second network data stations form at least a portion of a ring topology network. 
     
     
       67. The apparatus of  claim 58 , wherein the first and second network data stations form at least a portion of a tree topology network. 
     
     
       68. The apparatus of  claim 58 , wherein non- isochronous data received by the first network data station is coupled to hub circuitry for processing the non - isochronous data.   
     
     
       69. The apparatus of  claim 68 , wherein the non- isochronous data comprises ethernet data.   
     
     
       70. The apparatus of  claim 58 , wherein the isochronous data received by the first network data station is coupled to a high bandwidth bus. 
     
     
       71. The apparatus of  claim 70 , wherein the isochronous data is coupled to the high bandwidth bus by an isochronous controller. 
     
     
       72. The apparatus of  claim 71 , wherein the isochronous controller comprises a time slot interchange interface. 
     
     
       73. The apparatus of  claim 71 , wherein the isochronous controller comprises an isochronous switching device. 
     
     
       74. The apparatus of  claim 71 , wherein the isochronous controller includes a local loopback communication path. 
     
     
       75. The apparatus of  claim 58 , wherein data communicated over the communications medium further comprises maintenance data. 
     
     
       76. The apparatus of  claim 75 , wherein the maintenance data comprises M channel data. 
     
     
       77. The apparatus of  claim 58 , wherein data communicated over the communications medium further comprises signaling data. 
     
     
       78. The apparatus of  claim 77 , wherein the signaling data comprises D channel data. 
     
     
       79. The apparatus of  claim 77 , wherein the signaling data is coupled to at least one signaling processor. 
     
     
       80. The apparatus of  claim 77 , wherein the signaling data is coupled to the second network data station and controls a communications medium coupled to the second network data station. 
     
     
       81. The apparatus of  claim 77 , wherein the signaling data is generated or processed by a signaling processor. 
     
     
       82. The apparatus of  claim 58 , wherein data communicated over the communications medium comprises signaling and/or maintenance data, wherein the signaling and/or maintenance data comprises data selected from the group consisting of error condition data, requested connection data, maintenance data, and control data. 
     
     
       83. The apparatus of  claim 58 , wherein the isochronous and non- isochronous data are multiplexed and coupled to a time division multiplexed bus.   
     
     
       84. The apparatus of  claim 58 , wherein the isochronous and non- isochronous data are coupled to/from the communications medium through a multiplexer/demultiplexer.   
     
     
       85. The apparatus of  claim 58 , wherein the first- in - first - out buffer is coupled to a cascade port, wherein the cascade port is coupled between first and second isochronous hubs without using a backbone network.   
     
     
       86. The apparatus of  claim 58 , wherein the communications medium comprises a portion of a local area network. 
     
     
       87. The apparatus of  claim 58 , wherein the communications medium comprises a portion of a wide area network. 
     
     
       88. The apparatus of  claim 58 , wherein the first network data station further comprises a processor, wherein the processor outputs a plurality of control signals for controlling the first network data station. 
     
     
       89. The apparatus of  claim 88 , wherein the data is coupled to/from the communications medium through a plurality of physical layer devices. 
     
     
       90. The apparatus of  claim 89 , wherein the processor communicates with one or more of the physical layer devices. 
     
     
       91. The apparatus of  claim 89 , wherein the processor communicates with each of the physical layer devices. 
     
     
       92. The apparatus of  claim 90 , wherein the processor requests status information from a physical layer device. 
     
     
       93. The apparatus of  claim 90 , wherein the processor requests status information from a physical layer device by providing a physical layer device address. 
     
     
       94. The apparatus of  claim 89 , further comprising a register for receiving status information for one or more of the physical layer devices. 
     
     
       95. The apparatus of  claim 89 , wherein the processor receives an interrupt in the event of an activity change of a physical layer device. 
     
     
       96. The apparatus of  claim 89 , wherein the processor receives signaling data. 
     
     
       97. The apparatus of  claim 90 , wherein the processor receives an interrupt that indicates that a signaling channel receiver or transmitter of a physical layer device needs to be processed by the processor. 
     
     
       98. The apparatus of  claim 58 , wherein data communicated to/from the communications medium is coupled to an HDLC controller. 
     
     
       99. The apparatus of  claim 97 , wherein the data coupled to the HDLC controller comprises signaling data. 
     
     
       100. In a data communication network for communicating isochronous and non- isochronous data between data stations over a communications medium including at least first and second network data stations, the first network data station being coupled to one or more first data stations and also coupled to the second network data station, the second network data station being coupled to one or more second data stations, a method comprising the steps of:      storing data received from the communications medium in a receive memory of the first network data station;        providing data stored in a transmit memory of the first network data station to the communications medium, wherein data received from the transmit memory is buffered with a first - in - first - out buffer, wherein the data is held by the first - in - first - out buffer before the data is communicated to the second network data station; and        wherein the first - in - first - out buffer is configured to output its contents in response to a signal transmitted by the second network data station.     
     
     
       101. The method of  claim 100 , wherein the isochronous data comprises data output from a telephone device. 
     
     
       102. The method of  claim 100 , wherein the isochronous data comprises data output from a video device. 
     
     
       103. The method of  claim 100 , wherein the non- isochronous data comprises packetized data.   
     
     
       104. The method of  claim 100 , wherein the non- isochronous data comprises ethernet data.   
     
     
       105. The method of  claim 100 , wherein the communications medium comprises a plurality of physical media. 
     
     
       106. The method of  claim 105 , wherein at least one of the physical media communicates isochronous data and at least one of the physical media communicates non- isochronous data.   
     
     
       107. The method of  claim 100 , wherein the first and second network data stations form at least a portion of a star- topology network.   
     
     
       108. The method of  claim 100 , wherein the first and second network data stations form at least a portion of a ring topology network. 
     
     
       109. The method of  claim 100 , wherein the first and second network data stations form at least a portion of a tree topology network. 
     
     
       110. The method of  claim 100 , wherein non- isochronous data received by the first network data station is coupled to hub circuitry for processing the non - isochronous data.   
     
     
       111. The method of  claim 110 , wherein the non- isochronous data comprises ethernet data.   
     
     
       112. The method of  claim 100 , wherein the isochronous data received by the first network data station is coupled to a high bandwidth bus. 
     
     
       113. The method of  claim 112 , wherein the isochronous data is coupled to the high bandwidth bus by an isochronous controller. 
     
     
       114. The method of  claim 113 , wherein the isochronous controller comprises a time slot interchange interface. 
     
     
       115. The method of  claim 113 , wherein the isochronous controller comprises an isochronous switching device. 
     
     
       116. The method of  claim 113 , wherein the isochronous controller includes a local loopback communication path. 
     
     
       117. The method of  claim 100 , wherein data communicated over the communications medium further comprises maintenance data. 
     
     
       118. The method of  claim 117 , wherein the maintenance data comprises M channel data. 
     
     
       119. The method of  claim 100 , wherein data communicated over the communications medium further comprises signaling data. 
     
     
       120. The method of  claim 119 , wherein the signaling data comprises D channel data. 
     
     
       121. The method of  claim 119 , wherein the signaling data is coupled to at least one signaling processor. 
     
     
       122. The method of  claim 119 , wherein the signaling data is coupled to the second network data station and controls a communications medium coupled to the second network data station. 
     
     
       123. The method of  claim 119 , wherein the signaling data is generated or processed by a signaling processor. 
     
     
       124. The method of  claim 100 , wherein data communicated over the communications medium comprises signaling and/or maintenance data, wherein the signaling and/or maintenance data comprises data selected from the group consisting of error condition data, requested connection data, maintenance data, and control data. 
     
     
       125. The method of  claim 100 , wherein the isochronous and non- isochronous data are multiplexed and coupled to a time division multiplexed bus.   
     
     
       126. The method of  claim 100 , wherein the isochronous and non- isochronous data are coupled to/from the communications medium through a multiplexer/demultiplexer.   
     
     
       127. The method of  claim 100 , wherein the first- in - first - out buffer is coupled to a cascade port, wherein the cascade port is coupled between first and second isochronous hubs without using a backbone network.   
     
     
       128. The method of  claim 100 , wherein the communications medium comprises a portion of a local area network. 
     
     
       129. The method of  claim 100 , wherein the communications medium comprises a portion of a wide area network. 
     
     
       130. The method of  claim 100 , wherein the first network data station further comprises a processor, wherein the processor outputs a plurality of control signals for controlling the first network data station. 
     
     
       131. The method of  claim 130 , wherein the data is coupled to/from the communications medium through a plurality of physical layer devices. 
     
     
       132. The method of  claim 131 , wherein the processor communicates with one or more of the physical layer devices. 
     
     
       133. The method of  claim 131 , wherein the processor communicates with each of the physical layer devices. 
     
     
       134. The method of  claim 132 , wherein the processor requests status information from a physical layer device. 
     
     
       135. The method of  claim 132 , wherein the processor requests status information from a physical layer device by providing a physical layer device address. 
     
     
       136. The method of  claim 131 , further comprising a register for receiving status information for one or more of the physical layer devices. 
     
     
       137. The method of  claim 131 , wherein the processor receives an interrupt in the event of an activity change of a physical layer device. 
     
     
       138. The method of  claim 131 , wherein the processor receives signaling data. 
     
     
       139. The method of  claim 131 , wherein the processor receives an interrupt that indicates that a signaling channel receiver or transmitter of a physical layer device needs to be processed by the processor. 
     
     
       140. The method of  claim 100 , wherein data communicated to/from the communications medium is coupled to an HDLC controller. 
     
     
       141. The method of  claim 140 , wherein the data coupled to the HDLC controller comprises signaling data.