ATM switching fabric
First Claim
1. An asynchronous transfers mode switching fabric, comprising:
- a top input bus;
a bottom input bus;
a left output bus;
a right output bus;
a plurality of pairs of port interface modules wherein each said pair of port interface modules includes a first and second port interface module, said first port interface module coupled to said top input bus, said second port interface module coupled to said bottom input bus, said plurality of pairs of port interface modules for coupling network transmission equipment to said switching fabric;
a plurality of junction modules arranged as a matrix of N rows by N columns wherein each junction module within each row is coupled to said top input bus and said bottom input bus, each row associated with one of said pairs of port interface modules, each junction module within each column coupled to said left output bus and said right output bus, said plurality of junction modules for receiving cells from said top and said bottom input buses, queuing said cells and outputting said cells onto said left and said right output buses;
a plurality of output modules wherein each output module is associated with a single column of said matrix, each said output module coupled to all said junction modules within a column to form a fabric column, said output module for managing the transmission of said cells from each said junction module onto said left and said right output buses;
said first port interface module coupled to said left output bus, said second port interface module coupled to said right output bus, each said pair of port interface modules coupled to one of said output modules, said plurality of pairs of port interface modules for interfacing said switching fabric to said network transmission equipment; and
wherein N is a positive integer.
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Accused Products
Abstract
A distributed, scalable and modular asynchronous transfer mode (ATM) switching fabric is disclosed. The switching fabric includes port interface modules for connecting physical devices to the switch fabric. The switch fabric is arranged as rows of input buses running horizontally and columns of output buses running vertically. A junction module is located at each intersection of input and output buses. A switch can be constructed having any integer number M input and output buses, each input and output bus having an associated port interface module. The switching fabric for the specific case of M=2 is presented. Junction modules buffer and store cells received from the input buses and subsequently output cells onto the output buses. A junction module only accepts cells destined for one of the two output buses connected to itself. One output module is connected to each junction module situated with the same fabric column. Output modules instruct the junction modules when to store and output a cell. They also determine the order upon which cells are output onto the output buses. Communication protocols between output modules and junction modules and between output modules and port interface modules are disclosed. A method of providing N+1 redundancy within the switch fabric is also disclosed. The addition of one spare fabric card provides the means to provide redundancy in the event one of the regularly operating fabric cards fails.
124 Citations
25 Claims
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1. An asynchronous transfers mode switching fabric, comprising:
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a top input bus; a bottom input bus; a left output bus; a right output bus; a plurality of pairs of port interface modules wherein each said pair of port interface modules includes a first and second port interface module, said first port interface module coupled to said top input bus, said second port interface module coupled to said bottom input bus, said plurality of pairs of port interface modules for coupling network transmission equipment to said switching fabric; a plurality of junction modules arranged as a matrix of N rows by N columns wherein each junction module within each row is coupled to said top input bus and said bottom input bus, each row associated with one of said pairs of port interface modules, each junction module within each column coupled to said left output bus and said right output bus, said plurality of junction modules for receiving cells from said top and said bottom input buses, queuing said cells and outputting said cells onto said left and said right output buses; a plurality of output modules wherein each output module is associated with a single column of said matrix, each said output module coupled to all said junction modules within a column to form a fabric column, said output module for managing the transmission of said cells from each said junction module onto said left and said right output buses; said first port interface module coupled to said left output bus, said second port interface module coupled to said right output bus, each said pair of port interface modules coupled to one of said output modules, said plurality of pairs of port interface modules for interfacing said switching fabric to said network transmission equipment; and wherein N is a positive integer. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. An asynchronous transfer mode switching fabric, comprising:
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N port interface circuit cards wherein each port interface card includes a first and second port interface module, said first and said second port interface module for interfacing said switching fabric to and from network transmission equipment; N fabric circuit cards wherein each said fabric circuit card includes N junction modules coupled to an output module, said output module for managing the transfer of cells into and out of said N junction modules; a redundant fabric circuit card coupled to said N port interface circuit cards and said N fabric circuit cards, said redundant fabric circuit card operative upon the failure of one of said N fabric circuit cards; and wherein N is a positive integer. - View Dependent Claims (9, 10, 11, 12, 13, 14, 15)
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16. An asynchronous transfer mode switching fabric, comprising:
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a plurality of pairs of port interface modules wherein each said pair of port interface modules includes a first and second port interface module, said first port interface module coupled to a top input bus, said second port interface module coupled to a bottom input bus, said plurality of pairs of port interface modules for coupling network transmission equipment to said switching fabric; a plurality of junction modules arranged as a matrix of N rows by N columns wherein each junction module within each row is coupled to said top input bus and said bottom input bus, each row associated with one of said pairs of port interface modules, each junction module within each column coupled to a left output bus and a right output bus, said plurality of junction modules for receiving cells from said top and said bottom input buses, queuing said cells and outputting said cells onto said left and said right output buses; a plurality of output modules wherein each output module is associated with a single column, each said output module coupled to all said junction modules within a column to form a fabric column, said output module for managing the transmission of said cells from each said junction module onto said left and said right output buses; said first port interface module coupled to said left output bus, said second port interface module coupled to said right output bus, each said pair of port interface modules coupled to one of said output modules, said plurality of pairs of port interface modules for interfacing said switching fabric to said network transmission equipment; a redundant fabric column coupled to said plurality of pairs of port interface modules and said fabric columns, said redundant fabric column becoming operative upon the failure of one of said fabric columns; and wherein N is a positive integer. - View Dependent Claims (17, 18, 19, 20, 21, 22)
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23. An asynchronous transfer mode switching fabric, comprising:
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a group of M input buses; a group of M output buses; a plurality of groups of port interface modules wherein each said group of port interface modules includes M port interface modules, said group of port interface modules coupled to said group of M input buses, each ith port interface module within said group of port interface modules coupled to an ith input bus within said group of M input buses, said plurality of groups of port interface modules for coupling network transmission equipment to said switch fabric; a plurality of junction modules arranged as a matrix of N rows by N columns wherein each junction module within each row is coupled to one of said groups of M input buses, each row associated with one of said groups of M port interface modules, each junction module within each column coupled to one of said groups of M output buses, said plurality of junction modules for receiving cells from said group of M input buses, queuing said cells and outputting said cells onto said group of M output buses; a plurality of output modules wherein each output module is associated with a single column of said matrix, each said output module coupled to all said junction modules within a column to form a fabric column, said output module for managing the transmission of said cells from each said junction module onto said group of M output buses; said ith port interface module coupled to an ith output bus, each said group of M port interface modules coupled to one of said output modules, said plurality of groups of port interface modules for interfacing said switching fabric to said network transmission equipment; and wherein M and N are positive integers.
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24. An asynchronous transfer mode switching fabric, comprising:
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a group of M input buses; a group of M output buses; N port interface circuit cards wherein each port interface circuit card includes M port interface modules, each ith port interface module coupled to an ith input bus and an ith output bus, said M port interface modules for interfacing said switching fabric to and from network transmission equipment; N fabric circuit cards wherein each said fabric circuit card includes N junction modules coupled to an output module, each said junction module forming an intersection comprising one of said N junction modules coupled to said M input and said M output buses of one of said N port interface circuit cards, said output module for managing the transfer of cells into and out of said N junction modules; a redundant fabric circuit card coupled to said N port interface circuit cards and said N fabric circuit cards, said redundant fabric circuit card operative upon the failure of one of said N fabric circuit cards; and wherein M and N are positive integers. - View Dependent Claims (25)
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Specification