Integrated communication link having a dynamically allocatable bandwidth and protocol for transmission of allocation information over the link

• US 5,313,467 A
• Filed: 12/02/1992
• Issued: 05/17/1994
• Est. Priority Date: 11/15/1989
• Status: Expired due to Term

• Current Assignee: Enterasys Networks Incorporated (Extreme Networks, Inc.)
• Original Assignee: Digital Equipment Corporation (HP Inc.)
• Inventors: Smith, Andrew J., Fine, Michael, Varghese, George, Szmauz, Richard L.
• Primary Examiner(s): Olms, Douglas W.
• Assistant Examiner(s): TON, DANG T
• Application Number:
  US07/985,249
• Time in Patent Office: 531 Days
• Field of Search: 370/94.1, 370/60, 370/110.1, 370/84, 370/105.1, 370/79, 370/83, 370/85.3, 370/85.12, 370/85.6, 370/75.3, 340/825.5
• US Class Current: 370/468
• CPC Class Codes: H04J 3/1682 Allocation of channels according to the instantaneous demands of the users, e.g. concentrated multiplexers, statistical multiplexers
• CPC Class Codes: H04Q 11/0435 Details
• CPC Class Codes: H04Q 2213/13332 Broadband, CATV, dynamic bandwidth allocation

Abstract

An integrated communications link in a communications network that is provided with apparatus which allows dynamic allocability of bandwidth among a plurality of channels. At least three different types of information can be carried on these channels, and the bandwidth of these channels are dynamic so that it can be changed according to a determinable scheme. The link also sends error control information with a message that informs the receiver how the bandwidth is to be allocated, this error control information providing an extremely high level of assurance that the receiver of the information will know how the received information is to be allocated.

Claims

1. A system to carry multiple types of information in a multiplexed manner in a framed format, on a multiplexed integrated link, each frame of the framed format being divided into portions, comprising:

at least two integrated link controllers, each integrated link controller operable as a transmitter and a receiver to transmit and receive a plurality of information signals in each frame, each information signal occupying an allocated amount of bandwidth in at least one portion of each frame;

means for dynamically changing the allocation of the bandwidth of each information signal;

means for generating error control information that is transmitted from an integrated link controller operating as a transmitter to an integrated link controller operating as a receiver;

means for allocating the bandwidth of each individual information signal among a plurality of contiguous portions of said frame when the bandwidth of the individual information signal is at least as small as any unoccupied contiguous portions of said frame and among a plurality of non-contiguous portions of said frame when the bandwidth of the individual information signal is larger than all unoccupied contiguous portions of said frame.

2. The system of claim 1, wherein said portions are slots of a preselected bandwidth.

3. The system of claim 1, wherein said multiplexed integrated link is a time multiplexed integrated link.

4. The system of claim 1, wherein each said integrated link controller includes a mask register that holds an allocation mask indicating the allocated amount of bandwidth in a frame for each information signal.

5. The system of claim 4, wherein each mask register includes an input to receive the allocation mask, said mask register input being coupled to said means for dynamically changing the allocation of the bandwidth.

6. The system of claim 5, wherein one of said types of information is data provided to a synchronous line interface and said means for allocating the bandwidth includes means for selectively coupling a data clocking signal to said synchronous line interface only when said data is being provided to said synchronous line interface.

7. The system of claim 6, wherein said integrated link includes a line clock signal and the means for providing data clocking signal includes an AND gate having one input coupled to the integrated link to receive a line clock signal, and another input coupled to the mask register to receive a clock enable signal dependent on the allocation mask in the mask register.

8. The system of claim 5, wherein one portion of said frame is a protocol portion having a dynamically allocatable bandwidth.

9. The system of claim 8, wherein said integrated link controller transmits protocol information in a protocol packet in a vertical manner over a plurality of frames.

10. The system of claim 9, wherein each protocol packet includes an allocation mask.

11. The system of claim 10, wherein the protocol packet further includes switch frame information that indicates to the integrated link controller acting as a receiver at which frame the allocation mask is to be used.

12. The system of claim 11, wherein the means for dynamically changing the allocation of the bandwidth further includes a protocol message buffer in each integrated link controller that is coupled to the integrated link to receive the protocol packet.

13. The system of claim 12, wherein the means for dynamically changing the allocation of the bandwidth further includes an integrated link processing control coupled between each protocol message buffer and its associated mask register, the integrated link processing control setting the mask register in accordance with the protocol message buffer

14. The system of claim 13, wherein the protocol packet further includes said error control information.

15. The system of claim 14, wherein the error control information includes cyclic redundancy check information.

16. The system of claim 15, wherein the protocol packet is explicitly encoded with s×

log2 (v+d) bits per allocation mask per protocol packet, where s is the number of total slots in a frame, v is a number of voice circuits, and d is a number of data channels.

17. The system of claim 15, wherein the protocol packet is implicitly encoded with (s×

2)+1 bits per allocation mask per protocol packet, where s is the total number of slots in a frame.

18. The system of claim 15, wherein the protocol packet is implicitly encoded with (s×

1)+1 bits per allocation mask per protocol packet, where s is the total number of slots in a frame.

19. The system of claim 15, wherein the protocol packet is implicitly encoded with (s×

1) bits per allocation mask per protocol packet, where s is the total number of slots in a frame.

20. The system of claim 1, wherein the error control information includes cyclic redundancy check information.

21. A system to carry multiple types of information in a multiplexed manner on a multiplexed integrated link, in a framed format, each frame of the framed format being divided into portions, comprising:

at least two integrated link controllers that are couplable to an integrated link, such integrated link controller operable as a transmitter and a receiver to transmit and receive a plurality of information signals in each frame, each information signal occupying an allocated amount of bandwidth in at least one portion of each frame;

means for dynamically changing the allocation of the bandwidth of each information signal;

means for generating error control information that is transmitted from an integrated link controller operating as a transmitter to an integrated link controller operating as a receiver;

means for checking error control information in the integrated link controller operating as a receiver;

means for allocating the bandwidth of each individual information signal among a plurality of contiguous and noncontinguous portions of said frame;

a set of information signal sources coupled to one of said integrated link controllers, and a set of information signal destinations coupled to the other of said integrated link controllers.

22. The communications system of claim 21, wherein the set of information signal sources includes a set of data sources and a set of voice sources, and the set of information signal destinations includes a set of data destinations and a set of voice destinations.

23. The communications system of claim 22, further comprising a first private branch exchange unit coupled between the set of voice sources and one of the integrated link controllers, and a second private branch exchange unit coupled between the set of voice destinations and the other of said integrated link controllers.

24. The communications system of claim 23, further comprising a synchronous line interface in each of said data sources and data destinations, each said synchronous line interface being coupled to one of said integrated link controllers.

25. The system of claim 24, wherein each synchronous line interface and each private branch exchange unit are conventional.

26. The system of claim 25, wherein each mask register includes an input to receive the allocation mask, said mask register input being coupled to said means for dynamically changing the allocation of the bandwidth.

27. The system of claim 26, wherein one of said types of information is data provided to the synchronous line interface and said means for allocating the bandwidth includes means for selectively coupling a data clocking signal to said synchronous line interface only when said data is being provided to said synchronous line interface.

28. The system of claim 27, wherein the means for providing data clocking signals includes an AND gate having one input coupled to the integrated link to receive a line clock signal, and another input coupled to the mask register to receive a clock enable signal dependent on the allocation mask in the mask register.

29. The system of claim 26, wherein one portion of said frame is a protocol portion having a dynamically allocatable bandwidth.

30. The system of claim 29, wherein said integrated link controller transmits protocol information in a protocol packet in a vertical manner over a plurality of frames.

31. The system of claim 30, wherein each protocol packet includes the allocation mask.

32. The system of claim 31, wherein the protocol packet further includes switch frame information that informs the integrated link controller acting as a receiver at which frame the allocation mask is to be used.

33. The system of claim 32, wherein the means for dynamically changing the allocation of the bandwidth further includes a protocol message buffer in each integrated link controller that is coupled to the integrated link to receive the protocol packet.

34. The system of claim 33, wherein the means for dynamically changing the allocation of the bandwidth includes an integrated link processing control coupled between each protocol message buffer and its associated mask register, the integrated link processing control setting the mask register in accordance with the protocol message buffer.

35. The system of claim 34, wherein the protocol packet further includes said error control information.

36. The system of claim 35, wherein the error control information includes cyclic redundancy check information.

37. The system of claim 36, wherein the protocol packet is explicitly encoded with x×

log2 (v+d) bits per allocation mask per protocol packet, where s is the number of total slots in a frame, v is a number of voice circuits, and d is a number of data channels.

38. The system of claim 36, wherein the protocol packet is implicitly encoded with (s×

2) +1 bits per allocation mask per protocol packet, where s is the total number of slots in a frame.

39. The system of claim 36, wherein the protocol packet is implicitly encoded with (s×

1)+1 bits per allocation mask per protocol packet, where s is the total number of slots in a frame.

40. The system of claim 36, wherein the protocol packet is implicitly encoded with (s×

1) bits per allocation mask per protocol packet, where s is the total number of slots in a frame.

41. The system of claim 21, wherein the error control information includes a cyclic redundancy check.

42. A method of switching the allocation of bandwidth of information signals in a transmitting integrated link controller and a receiving integrated link controller coupled by a time division multiplexed link that carries multiple information signals in a framed format, each frame in said framed format being divided into slots of a preselected bandwidth, an allocation mask stored in a mask register indicating the number of slots each information signal is allocated, comprising:

sending protocol information from said transmitting integrated link controller in protocol packets and transmitted over a plurality of frames, each protocol packet containing an allocation mask, and error control information, each protocol packet being transmitted over a plurality of frames;

receiving said protocol packets in said receiving integrated link controller; and

using the received allocation mask to dynamically switch the allocation of the bandwidth.

43. The method of claim 42, wherein the protocol packet contains switch frame information that indicates at which frame the receiving integrated link controller is to begin using the allocation mask contained in the received protocol packet.

44. The method of claim 43, wherein the switch frame information is a number of frames after a specified frame at which the receiving integrated link controller is to use the received allocation mask.

45. The method of claim 44, wherein each protocol packet contains cyclic redundancy check information for that protocol packet, and further comprising performing a cyclic redundancy check using said cyclic redundancy check information.

46. The method of claim 45, further comprising redundantly sending particular protocol information in a set of successive protocol packets.

47. The method of claim 46, wherein the step of using the received allocation mask includes loading a mask register with the allocation mask if the cyclic redundancy check information for any one of the set of successive protocol packets is correct.

48. The method of claim 47, further comprising reinitializing the transmitting integrated link controller and the receiving integrated link controller when a pre-determined number of successive protocol packets contain incorrect cyclic redundancy check information.

49. The method of claim 48, wherein the multiple information signals include a number of voice signals and a set of data signals.

50. The method of claim 49, further comprising establishing priority of voice signals over data signals, such that the bandwidth allocated to the set of data signals is reduced when the number of voice signals to be carried over said multiplexed link is increased.

51. The method of claim 50, further comprising increasing the bandwidth allocated to the set of data signals when the number of voice signals carried over the multiplexed link is decreased.

52. The method of claim 51, further comprising:

detecting silence in a particular voice signal, increasing the bandwidth allocated to the set of data signals and reducing the bandwidth allocated to the particular voice signal;

detecting a resumption of the particular voice signal; and

decreasing the bandwidth allocated to the set of data signals and increasing the bandwidth allocated to the particular voice signal.

53. The method of claim 52, wherein the protocol information is sent in a protocol channel with dynamically changeable bandwidth in said frames.

54. The method of claim 42, wherein each protocol packet contains reliability information indicating the reliability of the allocation mask, and further comprising performing a reliability check using said reliability information.

55. The method of claim 54, wherein the reliability information is cyclic redundancy check information.

56. The method of claim 55, further comprising monitoring the quality of the time division multiplexed link using the cyclic redundancy check information.

57. The method of claim 42, further comprising repeatedly sending the same allocation mask after said allocation mask is used to dynamically switch the allocation of the bandwidth such that the allocating of bandwidth is self-stabilizing.

58. The method of claim 57, further comprising sending protocol information that includes information which causes said protocol information to no longer be sent in subsequent frames.

59. The method of claim 42, wherein the reliability of the switching of the allocation of the bandwidth is adjustable and related to bandwidth of the protocol information and a speed of switching the allocation of the bandwidth.

60. A controller for a system of the type capable of carrying multiple types of information in a multiplexed manner in a framed format, each frame of the framed format being divided into portions, the system capable of having a link joining at least two of the controllers, the controller comprising:

transmission means for transmitting and receiving a plurality of information signals in each frame, each information signal occupying an allocated amount of bandwidth in at least one portion of each frame;

means for dynamically changing the allocation of the bandwidth of each information signal;

means for generating error control information, said error control information capable of being transmitted from a controller operating as a transmitter to a controller operating as a receiver; and

,

means, responsive to said means for dynamically changing the allocation of the bandwidth and responsive to said means for generating error control information, for allocating the bandwidth of each individual information signal among a plurality of contiguous and non-contiguous portions of said frame.

61. The system of claim 60, wherein said portions are slots of a preselected bandwidth.

62. The system of claim 60, wherein one portion of said frame is a protocol portion having a dynamically allocatable bandwidth.

63. The system of claim 60, wherein said integrated link controller transmits protocol information in a protocol packet in a vertical manner over a plurality of frames.

64. The system of claim 63, wherein the protocol packet further includes said error control information.

65. A system to carry at least three types of information in a multiplexed manner in a framed format, on a multiplexed integrated link, each frame of the framed format being divided into portions, comprising:

at least two integrated link controllers, each integrated link controller operable as a transmitter and a receiver to transmit and receive a plurality of information signals in each frame, each information signal occupying an allocated amount of bandwidth in at least one portion of each frame;

means for dynamically changing the allocation of the bandwidth of each information signal;

means for generating error control information that is transmitted from an integrated link controller operating as a transmitter to an integrated link controller operating as a receiver;

means for checking error control information in the integrated link controller operating as a receiver; and

means for allocating the bandwidth of each individual information signal among a plurality of contiguous and non-contiguous portions of said frame.

66. A system to carry multiple types of information in a multiplexed manner on a multiplexed integrated link, in a framed format, each frame of the framed format being divided into portions, comprising:

at least two integrated link controllers that are couplable to an integrated link, such integrated link controller operable as a transmitter and a receiver to transmit and receive a plurality of information signals in each frame, each information signal occupying an allocated amount of bandwidth in at least one portion of each frame;

means for dynamically changing the allocation of the bandwidth of each information signal;

means for generating error control information that is transmitted from an integrated link controller operating as a transmitter to an integrated link controller operating as a receiver;

means for checking error control information in the integrated link controller operating as a receiver;

means for allocating the bandwidth of each individual information signal among a plurality of contiguous portions of said frame when the bandwidth of the individual information signal is at least as small as any unoccupied contiguous portions of said frame and among a plurality of non-contiguous portions of said frame when the bandwidth of the individual information signal is larger than all unoccupied contiguous portions of said frame;

a set of information signal sources coupled to one of said integrated link controllers, and a set of information signal destinations coupled to the other of said integrated link controllers.

67. A controller for a system of the type capable of carrying multiple types of information in a multiplexed manner in a framed format, each frame of the framed format being divided into portions, the system capable of having a link joining at least two of the controllers, the controller comprising:

transmission means for transmitting and receiving a plurality of information signals in each frame, each information signal occupying an allocated amount of bandwidth in at least one portion of each frame;

means for dynamically changing the allocation of the bandwidth of each information signal;

means for generating error control information, said error control information capable of being transmitted from a controller operating as a transmitter to a controller operating as a receiver; and

,

means, responsive to said means for dynamically changing the allocation of the bandwidth and responsive to said means for generating error control information, for allocating the bandwidth of each individual information signal among a plurality of contiguous portions of said frame when the bandwidth of the individual information signal is at least as small as any unoccupied contiguous portions of said frame and among a plurality of non-contiguous portions of said frame when the bandwidth of the individual information signal is larger than all unoccupied contiguous portions of said frame.

68. A system to carry at least three types of information in a multiplexed manner in a framed format, on a multiplexed integrated link, each frame of the farmed format being divided into portions, comprising:

at least two integrated link controllers, each integrated link controller operable as a transmitter and a receiver to transmit and receive a plurality of information signals in each frame, each information signal occupying an allocated amount of bandwidth in at least one portion of each frame;

means for dynamically changing the allocation of the bandwidth of each information signal;

means for generating error control information that is transmitted from an integrated link controller operating as a transmitter to an integrated link controller operating as a receiver;

means for checking error control information in the integrated link controller operating as a receiver; and

means for allocating the bandwidth of each individual information signal among a plurality of contiguous portions of said frame when the bandwidth of the individual information signal is at least as small as any unoccupied contiguous portions of said frame and among a plurality of non-contiguous portions of said frame when the bandwidth of the individual information signal is larger than all unoccupied contiguous portions of said frame.