Dynamic bandwidth allocation within a communications channel

• US 6,775,303 B1
• Filed: 12/23/1999
• Issued: 08/10/2004
• Est. Priority Date: 11/19/1997
• Status: Expired due to Term

• Current Assignee: Hanger Solutions, LLC (IP Investments Group LLC)
• Original Assignee: Digi International Inc.
• Inventors: Wahl, Steve, Rustad, Mark, Rogers, Glenn A., Stripsky, Terry A.
• Primary Examiner(s): VANDERPUYE, KENNETH N
• Application Number:
  US09/471,709
• Time in Patent Office: 1,692 Days
• Field of Search: 370/352, 370/353, 370/354, 370/523, 370/468, 370/465, 370/493, 370/522, 370/524, 370/442, 370/495
• US Class Current: 370/523
• CPC Class Codes: H04J 3/125 One of the channel pulses or the synchronisation pulse is also used for transmitting monitoring or supervisory signals
• CPC Class Codes: H04J 3/1623 Plesiochronous digital hierarchy [PDH]
• 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 11/0421 Circuit arrangements therefor

Abstract

A communications device is presented that allows dynamic bandwidth allocation of an unswitched data path based upon the current utilization of one or more switched data channels. The device operates over the local loop of a digital communications carrier, such as a T1 line, that has a variety of time division multiplexed channels. Each data channel can be configured to operate as a channel dedicated to carrying unswitched data on the unswitched data path, or as a switched channel. Switched channels maintain status information about their current status, allowing switched data communication when the channel'"'"'s status is active, and permitting the unswitched data path to utilize the channel when the channel'"'"'s status is idle. In one embodiment, channel status information is passed to a remote unit by altering a redundant robbed-bit signaling bit in a multiframe. In a second embodiment, channel status is determined by monitoring switching information that is already transmitted about the channel. In the second embodiment, a preset time delay is required to properly synchronize bandwidth switching. Unswitched data is transmitted over the switched data channels utilizing all bit locations other than the locations taken by the four robbed-bit signaling bits. A method for dynamically reallocating the bandwidth of an unswitched data path utilizing these same techniques is also presented.

Claims

1. A method for dynamically allocating bandwidth, the method comprising:

allocating a bandwidth in a plurality of data channels, wherein the plurality of data channels includes at least one switched data channel and a dedicated data channel, wherein the at least one switched data channel includes a first portion of the bandwidth, and wherein the dedicated data channel includes a second portion of the bandwidth;

detecting at least one signaling bit that is indicative of whether the at least one switched data channel is idle, wherein the at least one signaling bit is carried on at least one of the at least one switched data channel and a dedicated signaling channel; and

reallocating the bandwidth, wherein when the at least one switched data channel is idle, the first portion of the bandwidth of the at least one switched data channel is reallocated to the dedicated data channel such that the dedicated data channel includes the first and second portions of the bandwidth, and wherein when the at least one switched data channel is busy, the first portion of the bandwidth is reallocated to the at least one switched data channel from the dedicated data channel.

2. The method of claim 1, wherein detecting includes detecting the at least one signaling bit that is embedded in the at least one switched data channel, wherein the at least one signaling bit includes a robbed-bit signaling bit.

3. The method of claim 1, wherein allocating includes encoding an indication of an allocation of the first portion of the bandwidth for the at least one switched data channel into a data stream of the at least one switched data channel.

4. The method of claim 3, wherein encoding includes encoding such that the plurality of channels defines a digital transmission carrier, wherein the digital transmission carrier includes T1, wherein T1 includes a multiframe, wherein the at least one signaling bit includes a robbed-bit signaling bit, and wherein encoding uses the multiframe and the robbed-bit signaling bit.

5. The method of claim 1, wherein detecting includes resetting the at least one signaling bit with a value of another signaling bit upon receipt of an extended superframe.

6. The method of claim 1, wherein reallocating includes reallocating in a local loop environment.

7. The method of claim 6, wherein reallocating includes reallocating in the local loop environment that excludes Integrated Services Digital Network.

8. A method for dynamically allocating bandwidth, the method comprising:

allocating a bandwidth in a plurality of data channels, wherein the plurality of data channels includes at least one switched data channel and a dedicated data channel, wherein the at least one switched data channel includes a first portion of the bandwidth, and wherein the dedicated data channel includes a second portion of the bandwidth;

monitoring at least one signaling bit that is indicative of whether the at least one switched data channel is idle, wherein the at least one signaling bit is carried on at least one of the at least one switched data channel and a dedicated signaling channel; and

reallocating the bandwidth after a predetermined time after the act of monitoring is executed, wherein when the at least one switched data channel is idle, the first portion of the bandwidth of the at least one switched data channel is reallocated to the dedicated data channel such that the dedicated data channel includes the first and second portions of the bandwidth, and wherein when the at least one switched data channel is busy, the first portion of the bandwidth is reallocated to the at least one switched data channel from the dedicated data channel.

9. The method of claim 8, wherein monitoring includes monitoring by a transmitting device and a receiving device.

10. The method of claim 8, wherein monitoring includes monitoring the at least one signaling bit, wherein the at least one signaling bit is embedded in the at least one switched data channel.

11. The method of claim 8, wherein monitoring includes monitoring the at least one signaling bit, wherein the at least one signaling bit is transmitted through the dedicated data channel, wherein the dedicated data channel is an Integrated Services Digital Network D channel.

12. The method of claim 8, wherein reallocating include reallocating after the predetermined time, wherein the predetermined time is measured in at least one of a frame and a multiframe interval.

13. The method of claim 9, wherein the transmitting device and the receiving device simultaneously execute the act of reallocating.

14. A method for increasing bandwidth of data transfer on a switched data channel, wherein the switched data channel transmits data as frames, wherein a reserved bit in each frame is reserved for a robbed-bit signaling bit, the method comprising:

a) defining one or more blocks of un-switched data;

b) using an unused reserved bit of a first frame to establish a communication protocol for a block of un-switched data;

c) using unused reserved bits of frames subsequent to the first frame to transmit portions of the block of un-switched data; and

d) repeating b through c for subsequent blocks of un-switched data.