Distributed switching system having at least one module

• US 5,513,177 A
• Filed: 02/13/1991
• Issued: 04/30/1996
• Est. Priority Date: 09/16/1986
• Status: Expired due to Term

• Current Assignee: Hitachi, Ltd.
• Original Assignee: Hitachi, Ltd.
• Inventors: Kato, Takao, Kuwahara, Hiroshi, Gohara, Shinobu, Sakurai, Yoshito, Ohtsuki, Kenichi, Amada, Eiichi
• Primary Examiner(s): Olms, Douglas W.
• Assistant Examiner(s): HOM, SHICK C
• Application Number:
  US07/654,590
• Time in Patent Office: 1,903 Days
• Field of Search: 370/60, 370/60.1, 370/61, 370/63, 370/85.1, 370/94.3, 370/58.1, 370/54, 370/59, 370/58.3, 370/110.1, 370/63, 370/13, 370/95.3, 370/94.1, 379/269
• US Class Current: 370/355
• CPC Class Codes: H04J 2203/0012 Switching modules and their interconnections
• CPC Class Codes: H04L 12/56 Packet switching systems
• CPC Class Codes: H04L 12/5601 Transfer mode dependent, e.g. ATM
• CPC Class Codes: H04L 12/6402 Hybrid switching fabrics
• CPC Class Codes: H04L 2012/5651 Priority, marking, classes
• CPC Class Codes: H04L 2012/5652 Cell construction, e.g. including header, packetisation, depacketisation, assembly, reassembly
• CPC Class Codes: H04L 2012/5681 Buffer or queue management
• CPC Class Codes: H04L 2012/6481 Speech, voice
• CPC Class Codes: H04L 49/101 using crossbar or matrix
• CPC Class Codes: H04L 49/106 using space switching, e.g. crossbar or matrix
• CPC Class Codes: H04L 49/15 Interconnection of switching modules
• CPC Class Codes: H04L 49/1553 Interconnection of ATM switching modules, e.g. ATM switching fabrics
• CPC Class Codes: H04L 49/1584 Full Mesh, e.g. knockout
• CPC Class Codes: H04L 49/205 Quality of Service based
• CPC Class Codes: H04L 49/25 Routing or path finding in a switch fabric
• CPC Class Codes: H04L 49/254 Centralised controller, i.e. arbitration or scheduling
• CPC Class Codes: H04L 49/255 Control mechanisms for ATM switching fabrics
• CPC Class Codes: H04L 49/256 Routing or path finding in ATM switching fabrics
• CPC Class Codes: H04L 49/30 Peripheral units, e.g. input or output ports
• CPC Class Codes: H04L 49/3009 Header conversion, routing tables or routing tags
• CPC Class Codes: H04L 49/3018 : Input queuing
• CPC Class Codes: H04L 49/3081 : ATM peripheral units, e.g. policing, insertion or extraction
• CPC Class Codes: H04L 49/309 : Header conversion, routing tables or routing tags
• CPC Class Codes: H04L 49/35 : Switches specially adapted for specific applications
• CPC Class Codes: H04Q 11/0407 : using a stored programme control
• CPC Class Codes: H04Q 11/0421 : Circuit arrangements therefor
• CPC Class Codes: H04Q 11/06 : Time-space-time switching

Abstract

A switching system for integratedly switching voice, data, image information and the like. The switching system comprises a plurality of front-end modules each adapted to perform a switching processing in association with a subscriber line or a trunk line, and a single or a plurality of central modules for interconnecting the plurality of front-end modules in star-type fashion and switching information prevailing between the front-end modules, in unit of block accommodating the information and a header added thereto to contain connection control information and in accordance with the contents of the header. The front-end modules are connected to the central module via inter-module highways each having frames occurring at a predetermined period and time slots contained in each frame to carry blocks.

Claims

1. A switching system comprising:

a plurality of front-end modules each operating to perform a call processing of information in association with a subscriber line or a trunk line; and

at least one central module for interconnecting said plurality of front-end modules and switching user information between said front-end modules, in units of a block accommodating the information and having a header which contains connection control information for identifying a destination of the information and causing said user information to be switched through said central module; and

said central module being a self-routing switch.

2. A switching system according to claim 1 wherein said front-end modules are connected to said central module via inter-module highways each having frames occurring at a predetermined period and a plurality of time slots contained in each frame to carry blocks.

3. A switching system according to claim 1 wherein said central module comprises:

a plurality of time switches connected to said plurality of front-end modules,

a space switch connected to said plurality of time switches, and

means for generating a read address or a write address for each time switch from header information for each block incoming from each front-end module, in such a manner that a plurality of blocks having the same destination do not coexist at a time; and

wherein said address generating means comprises

a first status managing memory for monitoring every frame an idle/busy status of a link in association with an incoming highway of said space switch,

a second status managing memory for monitoring every frame an idle/busy status of a link in association with an outgoing highway of said space switch, and

a circuit for generating the read address or the write address for each of said plurality of time switches by looking up said first and second status managing memories.

4. A switching system comprising:

a plurality of front-end modules each adapted to perform switching processing in association with a subscriber line or a trunk line; and

at least one central module for interconnecting said plurality of front-end modules, and including means for switching user information through said central module between said front-end modules in a unit of a block, each block accommodating information as a part of the user information and a header appended thereto, said header including connection control information for controlling said switching through said central module;

said central module being a self-routing switch;

wherein said front-end modules are connected to said central module via inter-module highways, each front-end module having means for transmitting on said inter-module highways information in frames occurring at a predetermined period, each frame having a plurality of blocks;

wherein each of said front-end modules comprises;

means for determining a destination path for communicating information coming from the subscriber line or the trunk line;

means for transmitting a block which accommodates the information and a header containing a destination front-end module number to a highway connected with said central module by loading said block on the time slots on said highway; and

status managing means for storing idle/busy status of the subscriber line or the trunk line.

5. A switching system comprising:

a plurality of front-end modules each adapted to perform switching processing in association with a subscriber line or a trunk line; and

at least one central module for interconnecting said plurality of front-end modules, and including means for switching user information through said central module between said front-end modules in a unit of a block, each block accommodating information as a part of the user information and a header appended thereto, said header including connection control information for controlling said switching through said central module;

said central module being a self-routing switch;

wherein each of said front-end modules comprises;

status managing means for storing idle/busy status of the subscriber line or the trunk line.

6. A switching system comprising:

a plurality of front-end modules each adapted to perform switching processing in association with a subscriber line or a trunk line;

each of said front-end modules having means for transmitting on inter-module highways user information to be delivered between said front-end modules in a unit of a block having a fixed length, each block accommodating information as a part of the user information and a header appended thereto, said header including connection control information for controlling switching; and

comprising status managing means for storing idle/busy status of the subscriber line or the trunk line; and

at least one central module for interconnecting said plurality of front-end modules via said inter-module highways, and including means for switching user information through said central module between said front-end modules in a unit of said block, said switching through said central module is controlled by said connection control information of said header in said block;

said central module being a self-routing switch having no call processor for call processing.

7. A switching system comprising:

a plurality of front-end modules each adapted to perform a switching processing in association with a subscriber line or a trunk line; and

at least one central module for interconnecting said plurality of front-end modules, and including means for switching user information through said central module between said front-end modules in a unit of a block, each block accommodating information as a part of the user information and a header appended thereto, said header including connection control information for controlling said switching through said central module;

said central module being a self-routing switch;

wherein said front-end modules are connected to said central module via inter-module highways, each front-end module having means for transmitting on said inter-module highways said block;

wherein each of said front-end modules comprises;

means for determining a destination path for communicating information coming from the subscriber line or the trunk line,

means for transmitting a block which accommodates the information and a header containing a destination front-end module number to a highway connected with said central module by loading said block on said highway, and

status managing means for storing idle/busy status of the subscriber line or the trunk line.

8. A switching system comprising:

a plurality of front-end modules each adapted to perform a switching processing in association with a subscriber line or a trunk line; and

at least one central module for interconnecting said plurality of front-end modules, and including means for switching user information through said central module between said front-end modules in a unit of a block, each block accommodating information as a part of the user information and a header appended thereto, said header including call identifier for controlling said switching;

said central module being a self-routing switch;

wherein said front-end modules are connected to said central module via inter-module highways, each front-end module having means for transmitting on said inter-module highways said block;

wherein each of said front-end modules comprises;

means for determining a destination path for communicating information coming from the subscriber line or the trunk line,

means for transmitting a block which accommodates the information and a header containing a destination front-end module number to a highway connected with said central module by loading said block on said highway, and

status managing means for storing idle/busy status of the subscriber line or the trunk line.

9. A switching system comprising:

a plurality of front-end modules each adapted to perform a switching processing in association with a subscriber line or a trunk line; and

at least one central module for interconnecting said plurality of front-end modules, and including means for switching user information through said central module between said front-end modules in a unit of a block, each block accommodating information as a part of the user information and a header appended thereto, said header including connection control information for controlling said switching through said central module;

said central module being a self-routing switch;

wherein said front-end modules are connected to said central module via inter-module highways, each front-end module having means for transmitting on said inter-module highways said block;

wherein each of said front-end modules comprises;

means for determining a destination path for communicating information coming from the subscriber line or the trunk line,

means for transmitting a destination front-end module number in accordance with each block to said central module, and

status managing means for storing idle/busy status of the subscriber line or the trunk line.

10. A switching system comprising

a plurality of front-end modules each adapted to perform a switching processing in association with a subscriber line or a trunk line;

and

at least one central module for interconnecting said plurality of front-end modules, and including means for switching user information through said central module between said front-end modules in a unit of a block, each block accommodating information as a part of the user information and a header appended thereto, said header including connection control information for controlling said switching through said central module;

said central module being a self-routing switch;

wherein said front-end modules are connected to said central module via inter-module highways, each front-end module having means for transmitting on said inter-module highways said block;

wherein each of said front-end modules comprises;

means for transmitting a destination front-end module number in accordance with each block to said central module, and

status managing means for storing idle/busy status of the subscriber line or the trunk line.

11. A switching system comprising:

a plurality of front-end modules each adapted to perform a switching processing in association with a subscriber line or a trunk line; and

at least one central module for interconnecting said plurality of front-end modules, and including means for switching user information through said central module between said front-end modules in a unit of a block, each block accommodating information as a part of the user information and a header appended thereto, said header including connection control information for controlling said switching through said central module;

said central module being a self-routing switch;

wherein said front-end modules are connected to said central module via inter-module highways, each front-end module having means for transmitting on said inter-module highways said block;

wherein each of said front-end modules comprises;

means for determining a destination path for communicating information coming from the subscriber line or the trunk line, and

status managing means for storing idle/busy status of the subscriber line or the trunk line.

12. A switching system comprising:

a plurality of front-end modules each adapted to perform a switching processing in association with a subscriber line or a trunk line; and

at least one central module for interconnecting said plurality of front-end modules, and including means for switching user information through said central module between said front-end modules in a unit of a block, each block accommodating information as a part of the user information and a header appended thereto, said header including connection control information for controlling said switching through said central module;

said central module being a self-routing switch;

wherein said front-end modules are connected to said central module via inter-module highways, each front-end module having means for transmitting on said inter-module highways said block;

wherein each of said front-end modules comprises;

means for transmitting a block which accommodates the information and a header containing a destination front-end module number to a highway connected with said central module by loading said block on said highway, and

status managing means for storing idle/busy status of the subscriber line or the trunk line.

13. A switching system comprising:

a plurality of front-end modules each adapted to perform a switching processing in association with a subscriber line or a trunk line; and

at least one central module for interconnecting said plurality of front-end modules, and including means for switching user information through said central module between said front-end modules in a unit of a block, each block accommodating information as a part of the user information and a header appended thereto, said header including call identifier for controlling said switching through said central module;

said central module being a self-routing switch;

wherein said front-end modules are connected to said central module via inter-module highways, each front-end module having means for transmitting on said inter-module highways said block;

wherein each of said front-end modules comprises;

means for determining a destination path for communicating information coming from the subscriber line or the trunk line, and

status managing means for storing idle/busy status of the subscriber line or the trunk line.

14. A distributed switching system, comprising:

a plurality of front-end modules operating independently of each other;

each front-end module having a call processing processor for performing call processing in association with a subscriber line or a trunk line, and means for transmitting on inter-module highways user information between said front-end modules in a unit of a block having a fixed length, each block accommodating information representing at least a part of the user information and a header appended thereto, said header including connection control information for controlling switching; and

at least one central module for interconnecting said plurality of front-end modules via said inter-module highways, said central module including means for switching user information through said central module between said front-end modules in a unit of said block, said switching being controlled by said connection control information of said header in said block;

said central module being a self-routing switch.

16. A distributed switching system, according to claim 14, further comprising:

status managing means, included in each of said front-end modules, for storing idle/busy status of the subscriber line or the trunk line.

17. A distributed switching system, according to claim 14, further comprising:

status managing means, included in each of said front-end modules, for storing idle/busy status of the subscriber line or the trunk line.

15. A distributed switching system comprising:

a plurality of front-end modules operating independently of each other;

each front-end module having a call processing processor for determining a destination path for communication information coming from a subscriber line or a trunk line, and

means for transmitting on inter-module highways user information between said front-end modules in a unit of a block having a fixed length, each block accommodating information representing at least a part of the user information and a header appended thereto, said header including connection control information for controlling switching; and

at least one central module for interconnecting said plurality of front-end modules via said inter-module highways, said central module including means for switching user information through said central module between said front-end modules in a unit of said block, said switching being controlled by said connection control information of said header in said block;

said central module being a self-routing switch.

18. A distributed switching system, according to claim 15, wherein said connection control information included in said header contains a destination front-end module number for controlling switching.

19. A distributed switching system comprising:

a plurality of front-end modules operating independently of each other, each of said front-end modules having a call processing processor for performing switching processing in association with a subscriber line or a trunk line and for effecting priority control of user information, and means for transmitting on inter-module highways user information between said front-end modules in a unit of a block having a fixed length, each block accommodating information representing at least a part of the user information and a header appended thereto, said header including connection control information containing a destination front-end module number for use in controlling switching; and

at least one central module for interconnecting said plurality of front-end modules via said inter-module highways, said control module including means for switching user information through said central module between said front-end modules in a unit of said block, said switching being controlled by said connection control information of said header in said block;

said control module being a self-routing switch.

20. A distributed switching system, according to claim 19, wherein said priority control is based on whether said user information is voice or data information.

21. A distributed switching system comprising:

at least one front-end module accommodating a first incoming/outgoing circuit; and

at least one central module connected to said front-end module through a second incoming/outgoing circuit;

said front-end module including call setting means, accommodating said first incoming/outgoing circuit, for setting a call from said first incoming/outgoing circuit, and header setting means for adding information to a header of a fixed-length block to be transmitted from said first incoming/outgoing circuit to said second incoming/outgoing circuit, said information indicating a front-end module to be connected;

said central module including self-routing means, said self-routing means having a self-routing function for switching said fixed-length block through said central module in accordance with said information contained in said header of said fixed-length block thereby transmitting said fixed-length block to said front-end module to be connected via said second incoming/outgoing circuit;

said second incoming/outgoing circuit being operative to transmit said fixed-length block having said header and an information field, said header containing said information indicating said front-end module to be connected and said information field containing information to be transmitted from said first incoming/outgoing circuit to said front-end module to be connected.

22. A distributed switching system, according to claim 21 wherein said front-end module further comprises:

a call processing processor for performing call processing in association with said first incoming/outgoing circuit.

23. A distributed type switching system comprising:

a plurality of front-end modules, each front-end module operatively associated with a first incoming/outgoing circuit;

a second incoming/outgoing circuit for interconnecting said plurality of front-end modules;

each front-end module including call setting means for establishing a call from said first incoming/outgoing circuit to said second incoming/outgoing circuit, and header setting means for adding information to a header of a fixed-length block to be transmitted from said first incoming/outgoing circuit to said second incoming/outgoing circuit, said information indicating a destination to which said call is to be established via said second incoming/outgoing circuit and causing said fixed-length block to be self-routed through a self-routing switch;

said second incoming/outgoing circuit being operative to transmit said fixed-length block having said header and an information field, said header containing said information indicating a destination to which said call is to be established via said second incoming/outgoing circuit and said information field containing information to be transmitted from said first incoming/outgoing circuit to said destination.

24. A distributed switching system comprising:

a plurality of front-end modules each having control means for performing call processing control, means for determining a destination path for communication information coming from a subscriber line or a trunk line, means for transmitting to a highway a block which accommodates the communication information and a header containing a destination front-end module information, means for managing the status of the subscriber line or trunk line by constantly storing an idle/busy status indication thereof, means for deciding the idle/busy status of the subscriber line or trunk line, and means for transmitting and receiving a result of the decision between the plurality of front-end modules; and

at least one central module for interconnecting said plurality of front-end modules via said highway, said control module includes a self-routing channel, for switching communication information through said central module between said front-end modules in a unit of said block, said switching being controlled by said destination front-end module information of said header in said block.

25. A distributed switching system having a front end-module operatively associated with a first incoming/outgoing circuit and a second incoming/outgoing circuit, said front-end module comprising:

call setting means for establishing a call from said first incoming/outgoing circuit to said second incoming/outgoing circuit; and

header setting means for adding information to a header of a fixed-length block to be transmitted from said first incoming/outgoing circuit to said second incoming/outgoing circuit, said information indicating a destination to which said call is to be established via said second incoming/outgoing circuit and causing said fixed-length block to be self-routed through a self-routing switch;

said second incoming/outgoing circuit being operative to transmit said fixed-length block having said header and an information field, said header containing said information indicating a destination to which said call is to be established via said second incoming/outgoing circuit and said information field containing information to be transmitted from said first incoming/outgoing circuit to said destination.

26. A distributed switching system method comprising the steps of:

establishing a call from a first incoming/outgoing circuit to a second incoming/outgoing circuit and adding information to a header of a fixed-length block to be transmitted from said first incoming/outgoing circuit to said second incoming/outgoing circuit, said information indicating a destination to which said call is to be established via said second incoming/outgoing circuit and causing said fixed-length block to be self-routed through a self-routing switch; and

transmitting said fixed-length block having said header and an information field to said destination to which said call is to be established, said information field containing information to be transmitted from said first incoming/outgoing circuit to said destination.

27. A distributed switching method having comprising the steps of:

establishing a call from a first incoming/outgoing circuit to a second incoming/outgoing circuit;

adding information to a header of a fixed-length block to be transmitted from said first incoming/outgoing circuit to said second incoming/outgoing circuit, said information indicating a destination to which said call is to be established via said second incoming/outgoing circuit and causing said fixed-length block to be self-routed through a self-routing switch; and

transmitting said fixed-length block having said header and an information field to said destination to which said call is to be established, said information field containing information to be transmitted from said first incoming/outgoing circuit to said destination.

28. A distributed switching said method comprising the steps of

performing switching processing in association with a subscriber line or a trunk line;

transmitting on highways user information in a unit of a block having a fixed-length, each block accommodating information representing at least a part of the user information and a header appended thereto, said header including connection control information for controlling switching; and

switching user information on said highways through a self-routing switch in a unit of said block in accordance with said connection control information of said header in said block.

30. A distributed switching method, according to claim 28, further comprising the step of:

storing idle/busy status of the subscriber line or the trunk line.

29. A distributed switching system method comprising the steps of:

determining a destination path of communication information coming from a subscriber line or a trunk line;

transmitting on highways user information in a unit of a block having a fixed-length, each block accommodating information representing at least a part of the said user information and a header appended thereto, said header including connection control information for controlling switching; and

switching user information on said highways through a self-routing switch in a unit of said block in accordance with said connection control information of said header in said block.

31. A distributed switching system method comprising the steps of:

performing switching processing in association with a subscriber line or a trunk line and effecting priority control of user information;

transmitting on highways user information in a unit of a block having a fixed-length, each block accommodating information representing at least a part of the user information and a header appended thereto, said header including connection control information containing destination for use in controlling switching; and

switching user information on said highways through a self-routing switch in a unit of said block in accordance with said connection control information of said header in said block, said self-routing switch not including a call processor for call processing.

32. A distributed switching system, comprising:

a plurality of front-end modules operating independently of each other;

each front-end module having a call processing processor for processing a call incoming from a subscriber line or a trunk line and a transmission line for transmitting to inter-module highways information in a unit of a packet (cell) of a fixed length, accommodating a header and user information, said header containing connection control information; and

at least one central switching module for connecting said plurality of front-end modules via said inter-module highways, said central module including a switch for autonomously switching said user information through said central module to a destination front-end module in a unit of said fixed-length packet by using said connection control information contained in the header of the fixed-length packet;

said central module being a self-routing switch.

33. A distributed switching system, comprising:

first switching means having means for performing a call processing in accordance with information from a subscriber line or trunk line; and

second switching means, coupled to said first switching means, for switching information transmitted/received by the subscriber line or trunk line,

said switching by said second switching means being performed in units of a fixed-length packet which has a header added thereto that contains destination information indicating a destination of said transmitted/received information, said switching by said second switching means being performed autonomously in accordance with contents of said header;

said second switching means being a self-routing switch for switching fixed-length packets each having a header by using information indicating a destination contained in said header.

34. A distributed switching system, comprising:

first switching means having means for performing a call processing in accordance with information from a subscriber line or trunk line; and

second switching means, coupled to said first switching means, for switching information transmitted/received by the subscriber line or trunk line,

said switching by said second switching means being performed in units of a fixed-length packet which has a header added thereto that contains destination information indicating a destination of said transmitted/received information, said switching by said second switching means being performed autonomously in accordance with contents of said header;

wherein said first switching means includes a call-processing processor to perform said call processing and said second switching means being a self-routing switch which is independent of said call processing and includes a hardware circuitry, to switch fixed-length packets.

35. A distributed switching system, comprising:

first switching means having means for performing a call processing in accordance with information from a subscriber line or trunk line; and

second switching means, coupled to said first switching means, for switching information transmitted/received by the subscriber line or trunk line,

said switching by said second switching means being performed in units of a fixed-length packet which has a header added thereto that contains destination information indicating a destination of said transmitted/received information, said switching by said second switching means being performed autonomously in accordance with contents of said header;

said second switching means being a self-routing switch which includes means for extracting destination information contained in the header of a fixed-length packet and a further switch for switching said fixed-length packet autonomously by using said destination information, said further switch including time switches connected to said plurality of first switching means and a space switch for interconnecting said time switches, said further switch further including a first status managing means for monitoring an idle/busy status of an incoming link of said space switch, a second status managing means for monitoring an idle/busy status of an outgoing link of said space switch and controlling means for controlling said plurality of time switches by referring to said destination information and first and second status managing means;

wherein said first status managing means includes a first memory for storing, as data thereof, the idle/busy status of incoming links of said space switch at addresses defined by that information contained in headers which indicates call-sending first switching means,

said second status managing means includes a second memory for storing, as data thereof, the idle/busy status of outgoing links of said space switch at addresses defined by that information contained headers which indicates call-receiving first switching means,

said controlling means includes means for preventing collision of a plurality of fixed-length packets, wherein said collision preventing means executes a calculation by using outputs of said first and second memories to find an idle link of the space switch and converts the result of the calculation to a read or write address of a time switch so that a fixed-length packet output from the time switch is input to said idle link.

36. A distributed switching system, comprising:

first switching means having means for performing a call processing in accordance with information from a subscriber line or trunk line; and

second switching means, being a self-routing switch coupled to said first switching means, for switching information transmitted/received by the subscriber line or trunk line,

said switching by said second switching means being performed in units of a fixed-length packet which has a header added thereto that contains destination information indicating a destination of said transmitted/received information, said switching by said second switching means being performed autonomously in accordance with contents of said header;

wherein said first switching means includes a plurality of first switching means each coupled to said second switching means via transmitting means for carrying a plurality of fixed-length packets and wherein each of said plurality of first switching means includes;

means for determining a destination of information input from a subscriber line or trunk line;

means for sending out onto an associated transmitting means a fixed-length packet containing said input information and information indicating one of said plurality of first switching means which is a destination of said input information;

status managing means for storing idle/busy status of a subscriber line or trunk line;

means for deciding whether a subscriber line or trunk line is idle or busy; and

means for transmitting/receiving an output of said deciding means to/from that first switching means, via an associated transmitting means, to/from which said input information is transmitted/received;

wherein said call processing is such that, after sending first switching means determines an information destination, a call is sent by use of fixed-length packets each comprising;

call controlling information containing call identification information; and

a header added to said call controlling information, said header including destination information specifying destination first switching means, and that, upon reception of said call controlling information by the destination first switching means, said destination first switching means determines whether the subscriber line or trunk line by which said call is to be received is idle or busy and, then idle, captures said subscriber line or trunk line and then responds to said reception of said call controlling information by using a fixed-length packet formed by adding a header containing destination information indicating the call sending first switching means to call controlling information containing call identification information,

said call processing is completed upon reception of the response by said sending first switching means.