Telephone switch providing dynamic allocation of time division multiplex resources

• US 5,594,727 A
• Filed: 09/19/1994
• Issued: 01/14/1997
• Est. Priority Date: 09/19/1994
• Status: Expired due to Term

• Current Assignee: Cisco Systems, Inc.
• Original Assignee: Summa Four Incorporated (Cisco Systems, Inc.)
• Inventors: Nelson, Paul, Sandstrom, Peter, Tingley, Alan, St. Hilaire, Kenneth, Kolbenson, Chuck, Tenuta, Gerry
• Primary Examiner(s): Olms, Douglas W.
• Assistant Examiner(s): Jung, Min
• Application Number:
  US08/308,135
• Time in Patent Office: 848 Days
• Field of Search: 370/58.1, 370/58.2, 370/79, 370/95.3, 370/85.7, 370/95.1
• US Class Current: 370/442
• CPC Class Codes: H04J 3/12 Arrangements providing for calling or supervisory signals
• CPC Class Codes: H04J 3/1623 Plesiochronous digital hierarchy [PDH]
• CPC Class Codes: H04Q 11/04 for time-division multiplexing H04Q11/0001 takes precedence
• CPC Class Codes: H04Q 2213/13076 Distributing frame, MDF, cross-connect switch
• CPC Class Codes: H04Q 2213/13103 Memory
• CPC Class Codes: H04Q 2213/13106 Microprocessor, CPU
• CPC Class Codes: H04Q 2213/13292 Time division multiplexing, TDM
• CPC Class Codes: H04Q 2213/13299 Bus
• CPC Class Codes: H04Q 2213/1332 Logic circuits
• CPC Class Codes: H04Q 2213/13332 Broadband, CATV, dynamic bandwidth allocation
• CPC Class Codes: H04Q 2213/1334 Configuration within the switch
• CPC Class Codes: H04Q 2213/13393 Time slot switching, T-stage, time slot interchanging, TSI
• CPC Class Codes: H04Q 2213/13395 Permanent channel, leased line

Abstract

A switch, which connects ports on a customer port module to ports on a network port module via time slots on a dime division multiplexing bus, determines for each connection a number of required time slots, based on the current switch configuration and/or the signal traffic at the associated port. The switch then determines if it has the required number of time slots available generally and if it can make the time slots available to the port. If so, the switch assigns the time slots to the port and completes the connection. The switch determines the number of time slots required by consulting a stored port type indicator table, which lists bandwidth demand based on port type, or by detecting in-band signaling information that indicates the bandwidth demand. If the table indicates that the switch includes non-blocking ports, the switch coordinates the number of time slots allocated to a connection with the number of slots required to be kept free for the non-blocking ports. The switch may thereafter dynamically allocate time slots to the connection, based on signal traffic. The switch may be reconfigured at the request of a customer, by updating routing and port type information stored in the switch. Also, control circuitry in the switch may initiate a reconfiguration, based on signal traffic.

Claims

1. A telephone switching system including:

a time division multiple access bus;

at least one customer port module, the customer port module coupled to receive a number of telephone signals on a plurality of customer ports, and to provide the telephone signals to the time division multiple access bus, and further coupled to receive telephone signals from the time division multiple access bus and to provide the telephone signals at the plurality of the customer ports;

at least one network port module, the network port module coupled to receive a number of telephone signals from a telephone network on a plurality of network ports, and to provide the telephone signals to the time division multiple access bus, and further coupled to receive telephone signals from the time division multiple access bus and to provide the telephone signals to the network on the plurality of network ports; and

means for controlling one or more connections between the plurality ports on the customer port modules and the plurality ports on the network port modules, by which any given telephone signal from a particular customer port module may be connected to a port on a network port module, the connections being made by allocating to the connection time slots on the time division multiple access bus; and

dynamic allocation means for dynamically allocating the number of time slots to each such connection, by allocating, when a customer port is requesting access to a network port, an appropriate number of time slots required to service the connections aid dynamic allocation means including (i) means for detecting protocols that include in-band signaling information that indicates the bandwidth demand of the port; and

(ii) means for determining from the in-band signaling information the number of time slots required to support the bandwidth demand.

2. A telephone switching system including:

a time division multiple access bus;

at least one customer port module, the customer port module coupled to receive a number of telephone signals on a plurality of customer ports, and to provide the telephone signals to the time division multiple access bus, and further coupled to receive telephone signals from the time division multiple access bus and to provide the telephone signals at the plurality of the customer ports;

at least one network port module, the network port module coupled to receive a number of telephone signals from a telephone network on a plurality of network ports, and to provide the telephone signals to the time division multiple access bus, and further coupled to receive telephone signals from the time division multiple access bus and to provide the telephone signals to the network on the plurality of network ports; and

means for controlling one or more connections between the plurality ports on the customer port modules and the plurality ports on the network port modules, by which any given telephone signal from a particular customer port module may be connected to a port on a network port module, the connections being made by allocating to the connection time slots on the time division multiple access bus; and

dynamic allocation means for dynamically allocating the number of time slots to each such connection, by allocating, when a customer port is requesting access to a network port, an appropriate number of time slots required to service the connection said dynamic allocating means including (i) means for detecting in-band bonding information concerning the requested type of connection provided within a call originating signal, the bonding information indicating the bandwidth demand of the port; and

(ii) means for determining from the in-band bonding information the number of time slots required to support the bandwidth demand.

3. A telephone switching system including:

a time division multiple access bus;

at least one customer port module, the customer port module coupled to receive a number of telephone signals on a plurality of customer ports, and to provide the telephone signals to the time division multiple access bus and further coupled to receive telephone signals from the time division multiple access bus and to provide the telephone signals at the plurality of the customer ports;

at least one network port module, the network port module coupled to receive a number of telephone signals from a telephone network on a plurality of network ports, and to provide the telephone signals to the time division multiple access bus, and further coupled to receive telephone signals from the time division multiple access bus and to provide the telephone signals to the network on the plurality of network ports; and

means for controlling one or more connections between the plurality ports on the customer port modules and the plurality ports on the network port modules, by which any given telephone signal from a particular customer port module may be connected to a port on a network port module, the connections being made by allocating to the connection time slots on the time division multiple access bus; and

dynamic allocation means for dynamically allocating the number of time slots to each such connection, by allocating, when a customer port is requesting access to a network port, an appropriate number of time slots required to service the connection said dynamic allocation means including means for determining for a customer port (i) a port type and (ii) a required number of time slots associated with the port type wherein the means for determining the customer port type includes a memory for storing port type information that is based on switch configuration.

4. The telephone switching system as in claim 3 wherein the means for determining customer port type includes a means for updating the memory when the switch configuration changes.

5. A telephone switching system as in claim 4 further including means for changing the switch configuration, said means responding to signals relating to switch reconfiguration received over a control channel.

6. A telephone switching system as in claim 3 further including a means for changing the switch configuration, said means responding to customer-initiated requests for switch reconfiguration.

7. A telephone switching system including:

a time division multiple access bus;

at least one customer port module, the customer port module coupled to receive a number of telephone signals on a plurality of customer ports, and to provide the telephone signals to the time division multiple access bus, and further coupled to receive telephone signals from the time division multiple access bus and to provide the telephone signals at the plurality of the customer ports;

at least one network port module, the network port module coupled to receive a number of telephone signals from a telephone network on a plurality of network ports, and to provide the telephone signals to the time division multiple access bus, and further coupled to receive telephone signals from the time division multiple access bus and to provide the telephone signals to the network on the plurality of network ports; and

means for controlling one or more connections between the plurality ports on the customer port modules and the plurality ports on the network port modules, by which any given telephone signal from a particular customer port module may be connect to a port on a network port module, the connections being made by allocating to the connection time slots on the time division multiple access bus; and

means for dynamically allocating the number of time slots to each such connection, by allocating, when a customer port is requesting access to a network port, an appropriate number of time slots required to service the connection; and

means for initiating data flow control service mechanisms to support data services connections, said means initiating the mechanisms when the number of time slots allocated to a connection cannot adequately accommodate the bandwidth demand.

8. A telephone switching system including:

a time division multiple access bus;

at least one customer port module, the customer port module coupled to receive a number of telephone signals on a plurality of customer ports, and to provide the telephone signals to the time division multiple access bus, and further coupled to receive telephone signals from the time division multiple access bus and to provide the telephone signals at the plurality of the customer ports;

at least one network port module, the network port module coupled to receive a number of telephone signals from a telephone network on a plurality of network ports, and to provide the telephone signals to the time division multiple access bus, and further coupled to receive telephone signals from the time division multiple access bus and to provide the telephone signals to the network on the plurality of network ports; and

means for controlling one or more connections between the plurality ports on the customer port modules and the plurality ports on the network port modules, by which any given telephone signal from a particular customer port module may be connected to a port on a network port module, the connections being made by allocating to the connection time slots on the time division multiple access bus;

means for dynamically allocating the number of time slots to each such connection, by allocating, when a customer port is requesting access to a network port, an appropriate number of time slots required to service the connection; and

a buffer memory, disposed between one or more customer ports and the time division multiple access bus, for buffering data that cannot be immediately transferred to time slots.

9. A telephone switching system as in claim 8 further includes means for initiating data flow control service mechanisms to support data services connections, the means initiating the mechanisms when the buffer memory contents exceed a predetermined critical capacity.

10. A telephone switching system as in claim 8 wherein the means for allocating a number of time slots to each connection includes:

detecting means for detecting, during the progress of a call, a need for additional or lesser bandwidth; and

means for dynamically allocating, during the progress of a call, a number of time slots to support that additional or lesser bandwidth.

11. The telephone switching system of claim 10 wherein the detecting means detects a need for additional or lesser bandwidth by monitoring the contents of the buffer memory.

12. A telephone switching system including:

a time division multiple access bus;

at least one customer port module, the customer port module coupled to receive a number of telephone signals on a plurality of customer ports, and to provide the telephone signals to the time division multiple access bus, and further coupled to receive telephone signals from the time division multiple access bus and to provide the telephone signals at the plurality of the customer ports;

at least one network port module, the network port module coupled to receive a number of telephone signal from a telephone network on a plurality of network ports, and to provide the telephone signals to the time division multiple access bus and further coupled to receive telephone signals from the time division multiple access bus and to provide the telephone signals to the network on the plurality of network ports; and

means for controlling one or more connections between the plurality ports on the customer port modules and the plurality ports on the network port modules, by which any given telephone signal from a particular customer port module may be connected to a port on a network port module, the connections being made by allocating to the connection time slots on the time division multiple access bus; and

dynamic allocation means for dynamically allocating the number of time slots to each such connection, by allocating, when a customer port is requesting access to a network port, an appropriate number of time slots required to service the connection said dynamic allocation means including

(i) detecting means for detecting, during the progress of a call, a need for additional or lesser bandwidth; and

(ii) means for dynamically allocating, during the progress of a call, a number of time slots to support that additional or lesser bandwidth.

13. A telephone switching system including:

a time division multiple access bus;

at least one customer port module, the customer port module coupled to receive a number of telephone signals on a plurality of customer ports, and to provide the telephone signals to the time division multiple access bus, and further coupled to receive telephone signals from the time division multiple access bus and to provide the telephone signals at the plurality of the customer ports;

at least one network port module, the network port module coupled to receive a number of telephone signals from a telephone network on a plurality of network ports, and to provide the telephone signals to the time division multiple access bus, and further coupled to receive telephone signals from the time division multiple access bus and to provide the telephone signals to the network on the plurality of network ports; and

means for controlling one or more connections between the plurality ports on the customer port modules and the plurality ports on the network port modules, by which any given telephone signal from a particular customer port module may be connected to a port on a network port module the connections being made by allocating to the connection time slots on the time division multiple access bus; and

dynamic allocation means for dynamically allocating the number of time slots to each such connection, by allocating when a customer port is requesting access to a network port, an appropriate number of time slots required to service the connection said dynamic allocation means including

(i) means for determining which of the customer ports are non-blocking; and

(ii) means for refraining from allocating to other than a non-blocking port a number of time slots required to service each of the non-blocking ports.

14. A telephone switch for connecting signals from customer premise equipment through one or more ports on a customer port module to one or more ports on a network port module, the switch including:

a time division multiple access bus;

means for controlling one or more connections between the ports on the customer port module and the ports on the network port module, by which any given telephone signal from a particular customer port module may be connected to a port in a network port module, the connections being made by assigning to the connection time slots on the time division multiple access bus; and

dynamic allocation means for dynamically allocating the number of time slots assigned to each such connection, by allocating, when a customer port is requesting access to a network port through the switch, an appropriate number of time slots required to service the connection said dynamic allocation means including (i) means for detecting protocols that include in-band signaling information the indicates the bandwidth demand of the port; and

(ii) means for determining from the in-band signaling information the number of time slots required to support the bandwidth demand.

15. A telephone switch for connecting signals from customer premise equipment through one or more ports on a customer port module to one or more ports on a network port module, the switch including:

a time division multiple access bus;

means for controlling one or more connections between the ports on the customer port module and the ports on the network port module, by which any given telephone signal from a particular customer port module may be connected to a port in a network port module, the connections being made by assigning to the connection time slots on the time division multiple access bus; and

dynamic allocation means for dynamically allocating the number of time slots assigned to each such connection, by allocating, when a customer port is requesting access to a network port through the switch, an appropriate number of time slots required to service the connection said dynamic allocation means including (i) means for detecting in-band bonding information concerning the requested type of connection provided with a call originating signal, the in-band bonding information indicating the bandwidth demand of the port; and

(ii) means for determining from the in-band bonding information the number of time slots required to support the bandwidth demand.

16. A telephone switch for connecting signals from customer premise equipment through one or more ports on a customer port module to one or more ports on a network port module, the switch including:

a time division multiple access bus;

means for controlling one or more connections between the ports on the customer port module and the ports on the network port module, by which any given telephone signal from a particular customer port module may be connected to a port in a network port module, the connections being made by assigning to the connection time slots on the time division multiple access bus; and

dynamic allocation means for dynamically allocating the number of time slots assigned to each such connection, by allocating, when a customer port is requesting access to a network port through the switch, an appropriate number of time slots required to service the connection said dynamic allocation means including means for determining for a customer port (i) a port type and (ii) a required number of time slots associated with the port type wherein the means for determining customer port type includes a memory for storing port type information that is based on switch configuration.

17. The telephone switch as in claim 16 wherein the means for determining customer port type includes a means for updating the memory whenever the switch configuration changes.

18. A telephone switch as in claim 17 wherein the switch includes means for changing the switch configuration, said means responding to signals relating to switch reconfiguration received over a control channel.

19. A telephone switch as in claim 16 wherein the switch includes means for changing the switch configuration, said means responding to customer-initiated requests for switch reconfiguration.

20. A telephone switch for connecting signals from customer premise equipment through one or more ports on a customer port module to one or more ports on a network port module, the switch including:

a time division multiple access bus;

means for controlling one or more connections between the ports on the customer port module and the ports on the network port module, by which any given telephone signal from a particular customer port module may be connected to a port in a network port module, the connections being made by assigning to the connection time slots on the time division multiple access bus; and

dynamic allocation means for dynamically allocating the number of time slots assigned to each such connection, by allocating, when a customer port is requesting access to a network port through the switch, an appropriate number of time slots required to service the connection said dynamic allocation means including (i) means for detecting, during the progress of a call, a need for additional or lesser bandwidth; and

(ii) means for dynamically allocating, during the progress of a call, a number of time slots to support that additional or lesser bandwidth.

21. A telephone switch for connecting signals from customer premise equipment through one or more ports on a customer port module to one or more ports on a network port module, the switch including:

a time division multiple access bus;

means for controlling one or more connections between the ports on the customer port module and the ports on the network port module, by which any given telephone signal from a particular customer port module may be connected to a port in a network port module, the connections being made by assigning to the connection time slots on the time division multiple access bus; and

dynamic allocation means for dynamically allocating the number of time slots assigned to each such connection, by allocating, when a customer port is requesting access to a network port through the switch, an appropriate number of time slots required to service the connection said dynamic allocation means including (i) means for determining which of the customer ports are non-blocking; and

(ii) means for reserving a number of time slots required to service each of the non-blocking ports for which the control means has not made a connection.

22. A method of connecting signals from a customer port on a customer port module to a network port on a network port module, the method including the steps of:

A. receiving at a customer port module signals that indicate a connection request to a network port module;

B. determining a bandwidth demand for the port requesting the connection;

C. dynamically allocating to the requesting port a number of time slots required to meet the bandwith demand including

a. determining a port type for the requesting port;

b. determining a required number of time slots to service the port;

c. determining if the requesting port is a non-blocking port;

d. if the port is a non-blocking port, allocating to the port the required number of time slots;

e. if the port is not a non-blocking port, determining if the required number of time slots are available and do not reduce the number of available time slots below the number required to service the non-blocking ports, and if such time slots are available allocating the time slots to the port;

f. if such time slots are not available informing the port that the network is busy; and

D. establishing a connection between the requesting port and a network port.

23. The method of connecting signals from a customer port on a customer port module to a network port on a network port module of claim 22, wherein the step of determining if time slots are available further includes the steps of:

v. comparing a number of time slots required to be kept free for the non-blocking ports with a number of available time slots;

vi. determining if the number of time slots available exceeds the number of time slots required to be kept free by a number of time slots that is equal to or exceeds the number of time slots required by the requesting customer port;

vii. if so, assigning the required number of time slots to the requesting port and

viii. if not, refraining from assigning the time slots to the requesting port.

24. A method of connecting signals from a customer port on a customer port module to a network port on a network port module, the method including the steps of:

A. receiving at a customer port module signals that indicate a connection request to a network port module;

B. determining a bandwidth demand for the port requesting the connection by

a. detecting protocols that include in-band signaling information that indicates the bandwidth demand of the requesting port; and

b. determining from the in-band signaling information the number of time slots required to support the bandwidth demand;

C. dynamically allocating to the requesting port a number of time slots required to meet the bandwidth demand; and

D. establishing a connection between the requesting port and a network port.

25. A method of connecting signals from a customer port on a customer port module to a network port on a network port module, the method including the steps of:

A. receiving at a customer port module signals that indicate a connection request to a network port module;

B. determining a bandwidth demand for the port requesting the connection by

a detecting in-band bonding information concerning the requested type of connection provided within a call originating signal; and

b. determining from the in-band bonding information the number of time slots required to support the bandwidth demand;

C. dynamically allocating to the requesting non a number of time slots required to meet the bandwidth demand; and

D. establishing a connection between the requesting port and a network port.

26. A method of connecting signals from a customer port on a customer port module to a network port on a network port module, the method including the steps of:

A. receiving at a customer port module signals that indicate a connection request to a network port module;

B. determining a bandwidth demand for the port requesting the connection

C. buffering data from a port until an appropriate number of time slots can be allocated to the connection;

D. dynamically allocating to the requesting port a number of time slots required to meet the bandwidth demand; and

E. establishing a connection between the requesting port and a network port.

27. The method of connecting signals from a customer port on a customer port module to a network port on a network port module of claim 26 further including the steps of:

detecting, during the progress of a call, a need for additional or lesser bandwidth; and

dynamically allocating, during the progress of a call, a number of time slots to support the additional or lesser bandwidth.

28. The method of connecting signals from a customer port on a customer port module to a network port on a network port module of claim 27, wherein the step of detecting a need for additional or lesser bandwidth includes detecting when the contents of the buffer exceed a predetermined maximum capacity level or fall below a predetermined minimum capacity level, respectively.