System and method for dynamically varying integrated services digital network (isdn) interface bandwidth

1. A method for dynamically varying bandwidth of a primary integrated services digital network (ISDN) interface, the method comprising:

(a) requesting, over a data (D) channel between an end office and a central office switch, allocation of at least one first bearer (B) channel of a first primary rate ISDN interface;

(b) receiving, over the D channel, notification of allocation of the at least one first B channel and, in response, sending data over the at least one first B channel;

(c) monitoring a relationship between a first bandwidth demand parameter and first and second thresholds;

(d) requesting, over the D channel, allocation of at least one second B channel of the first primary rate ISDN interface in response to a predetermined relationship between the first bandwidth demand parameter and the first threshold;

(e) receiving, over the D channel, notification of allocation of the at least one second B channel, and, in response, sending data over the at least one second B channel; and

(f) releasing the at least one second B channel in response to a predetermined relationship between the first bandwidth demand parameter and the second threshold.

2. The method of claim 1 wherein requesting allocation of at least one first B channel includes requesting allocation of one to n B channels, n being an integer equal to the maximum number of B channels provided by a physical interface between the end office and the central office switch.

3. The method of claim 1 wherein the first bandwidth demand parameter includes the amount of data in a send queue and the first threshold includes a first predetermined amount of data in the send queue.

4. The method of claim 3 wherein the second threshold includes a second predetermined amount of data in the send queue.

5. The method of claim 4 wherein the first predetermined amount of data is greater than the second predetermined amount of data.

6. The method of claim 3 wherein the predetermined relationship between the first bandwidth demand parameter and the first threshold includes equality of the first bandwidth demand parameter to the first threshold.

7. The method of claim 3 wherein the predetermined relationship between the first bandwidth demand parameter and the first threshold includes the first bandwidth demand parameter being greater than the first threshold.

8. The method of claim 4 wherein the predetermined relationship between the first bandwidth demand parameter and the second threshold includes equality of the first bandwidth demand parameter to the second threshold.

9. The method of claim 4 wherein the predetermined relationship between the first bandwidth demand parameter and the second threshold includes the first bandwidth demand parameter being less than the second threshold.

10. The method of claim 1 wherein requesting allocation of at least one first B channel includes sending, over the D channel, a bandwidth allocation control protocol message to the central office switch.

11. The method of claim 10 wherein sending a bandwidth allocation control protocol message to the central office switch includes sending, over the D channel, a CALL REQUEST message to the central office switch requesting allocation of a range of B channels from the central office switch.

12. The method of claim 1 wherein requesting allocation of at least one second B channel includes sending, over the D channel, a bandwidth allocation control protocol message to the central office switch.

13. The method of claim 12 wherein sending a bandwidth allocation control protocol message to the central office switch includes sending, over the D channel, a CHANNEL REQUEST message for requesting allocation of a specified number of B channels from the central office switch.

14. The method of claim 1 wherein releasing the at least one second B channel includes sending, over the D channel a bandwidth allocation control protocol message to the central office switch.

15. The method of claim 14 wherein sending a bandwidth allocation control protocol message to the central office switch includes sending, over the D channel, a CHANNEL RELEASE message to the central office switch for requesting release of the at least one second B channel.

16. A method for dynamically varying bandwidth of a primary rate integrated services digital network (ISDN) interface, the method comprising:

(a) requesting, over a data (D) channel between an end office and a central office switch, allocation of at least one first bearer (B) channel of a first primary rate ISDN interface;

(b) receiving, over the D channel, notification of allocation of the at least one first B channel and, in response, transmitting data over the at least one first B channel;

(c) monitoring a relationship between a first bandwidth demand parameter and first threshold;

(d) requesting, over the D channel, at least one second B channel of the first primary rate ISDN interface in response to a predetermined relationship between the first bandwidth demand parameter and the first threshold;

(e) receiving, over the D channel notification of allocation of the at least one second B channel, and, in response, transmitting data over the at least one second B channel and starting a timer; and

(f) releasing the at least one second B channel in response to the timer reaching a predetermined value.

17. The method of claim 16 wherein requesting allocation of at least one first B channel includes requesting allocation of one to n B channels, n being an integer equal to the maximum number of B channels provided by a physical interface between the end office and the central office switch.

18. The method of claim 16 wherein the first bandwidth demand parameter is an amount of data in a send queue.

19. The method of claim 16 wherein the predetermined relationship between the first bandwidth demand parameter and the first threshold includes equality of the first bandwidth demand parameter to the first threshold.

20. The method of claim 16 wherein the predetermined relationship between the first bandwidth demand parameter and the first threshold includes the first bandwidth demand parameter being greater than the first threshold.

21. The method of claim 16 wherein requesting at least one first B channel includes sending, over the D channel, a bandwidth allocation control protocol message to the central office switch.

22. The method of claim 21 wherein sending a bandwidth allocation control protocol message to the central office switch includes sending, over the D channel, a CALL REQUEST message to the central office switch requesting allocation of a range of B channels from the central office switch.

23. The method of claim 16 wherein requesting allocation of at least one second B channel includes sending, over the D channel, a bandwidth allocation control protocol message to the central office switch.

24. The method of claim 23 wherein sending a bandwidth allocation control protocol message to the central office switch includes sending, over the D channel, a CHANNEL REQUEST message for requesting allocation of a specified number of B channels from the central office switch.

25. The method of claim 16 wherein releasing the at least one second B channel includes sending, over the D channel, a bandwidth allocation control protocol message to the central office switch.

26. The method of claim 25 wherein sending a bandwidth allocation control protocol message to the central office switch includes sending, over the D channel, a CHANNEL RELEASE message to the central office switch for requesting release of the at least one second B channel.

27. A system for dynamically varying bandwidth of a primary rate integrated services digital network (ISDN) interface, the system comprising:

(a) a bandwidth watcher associated with a first network element for determining whether a first predetermined relationship exists between a first bandwidth demand parameter and a first threshold; and

(b) a connection maker/breaker for communicating with the bandwidth watcher and for requesting, over a data (D) channel, allocation of at least one bearer (B) channel of a first primary rate ISDN interface from a central office switch in response to receiving notification from the bandwidth watcher that the first predetermined relationship exists between the bandwidth demand parameter and the first threshold;

wherein the bandwidth watcher is adapted to determine whether a second predetermined relationship exists between the first bandwidth demand parameter and a second threshold lower than the first threshold.

28. The system of claim 27 wherein the connection maker/breaker is adapted to request allocation of one to n B channels, n being an integer equal to the maximum number of B channels provided by a physical interface between an end office and a central office switch.

29. The system of claim 27 wherein the first bandwidth demand parameter includes a first amount of data in a send queue associated with the first network element and the first threshold includes a first predetermined level of data in the send queue.

30. The system of claim 27 wherein the connection maker/breaker is adapted to send, over the D channel, a bandwidth allocation control protocol message to the central office switch for requesting allocation of the at least one B channel.

31. The system of claim 27 wherein, in response to determining that the second predetermined relationship exists between the first bandwidth demand parameter and the second threshold, the bandwidth watcher is adapted to instruct the connection maker/breaker to release the at least one B channel provided by the central office switch.

32. The system of claim 27 wherein, in response to receiving notification that the second predetermined relationship exists, the connection maker/breaker is adapted to send, over the D channel, a bandwidth allocation control protocol message to the central office switch for requesting de-allocation of the at least one B channel.

33. A computer program product comprising computer executable instructions embodied in a computer readable medium for performing steps comprising:

(a) determining whether a first predetermined relationship exists between a first bandwidth demand parameter associated with a first network element and a first threshold;

(b) requesting, over a data (D) channel, allocation of at least one bearer (B) channel of a first primary rate integrated services digital network (ISDN) interface from a central office switch in response to determining that the first predetermined relationship exists; and

(c) determining whether a second predetermined relationship exists between the first bandwidth demand parameter and a second threshold lower than the first threshold.

34. The computer program product of claim 33 wherein requesting allocation of at least one B channel includes requesting allocation of one to n B channels, n being an integer equal to a maximum number of B channels provided by a physical interface between the central office switch and an end office.

35. The computer program product of claim 33 comprising, in response to receiving notification of allocation of the at least one first B channel, sending data to the central office switch over the at least one first B channel.

36. The computer program product of claim 33 comprising, in response to determining that the second predetermined relationship exists, releasing the at least one B channel.

37. The computer program product of claim 36 wherein releasing the at least one B channel includes sending, over the D channel, a bandwidth allocation control protocol message to the central office switch for requesting de-allocation of the at least one B channel.