Method and apparatus for multimedia conferencing with dynamic bandwidth allocation

• US 6,611,503 B1
• Filed: 05/22/1998
• Issued: 08/26/2003
• Est. Priority Date: 05/22/1998
• Status: Expired due to Term

• Current Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Original Assignee: Tandberg Telecom AS (Cisco Systems, Inc.)
• Inventors: Stewart, Glenn William, Kamitses, James Gerald, Fitzgerald, John Francis
• Primary Examiner(s): Hsu; Alpus H.
• Assistant Examiner(s): NGUYEN, TOAN D
• Application Number:
  US09/083,488
• Time in Patent Office: 1,922 Days
• Field of Search: 370/230,231,232,260,261,263,264,265,270,278,431,468,477 379/202
• US Class Current: 370/260
• CPC Class Codes: H04J 3/1694 Allocation of channels in TDM/TDMA networks, e.g. distributed multiplexers Passive Optical Networks H04Q11/0062
• CPC Class Codes: H04L 65/1101 Session protocols
• CPC Class Codes: H04L 65/4038 with floor control
• CPC Class Codes: H04L 65/752 adapting media to network capabilities
• CPC Class Codes: H04L 65/80 Responding to QoS
• CPC Class Codes: H04L 9/40 Network security protocols
• CPC Class Codes: H04N 7/147 Communication arrangements, e.g. identifying the communication as a video-communication, intermediate storage of the signals selecting H04Q
• CPC Class Codes: H04N 7/148 Interfacing a video terminal to a particular transmission medium, e.g. ISDN

Abstract

The specification discloses a multimedia conferencing service capability for dynamically allocating transmission link bandwidth among video, audio and data channels in response to changes in the utilization of those channels. The capability maximizes video quality when data is not being used and minimizes data transfer time when data is being used in a multimedia conference. A multipoint control unit (MCU) monitors the utilization of T.120 MLP data channels and changes the bandwidth allocation for all of the transmission links in response to changes in the utilization for at least one of the data channels. The utilization is monitored by measuring the data rate of outbound T.120 MLP data channels and comparing the measured data rate to the allocated bandwidth to determine the data channel utilization. The MCU controls and manages a service policy in which video quality is sacrificed in favor of data transfers to a majority of conference sites while conversely, video quality is favored over data transfer time for individual data needs. Since the dynamic bandwidth allocation is provided at the MCU, no changes or upgrades are needed at the endpoint multimedia terminals.

Claims

1. A method for conferencing in a multipoint control unit, the method comprising the steps of:

connecting plural conference sites to the multipoint control unit, each conference site connecting over a respective transmission link having a first information channel and a second information channel and each conference site operable to transmit and receive first information and second information signals to and from other conference sites in the respective first information and second information channels;

allocating for each transmission link a first portion of the transmission link bandwidth to the first information channel and a second portion to the second information channel;

monitoring utilization of each second information channel; and

changing the bandwidth allocation by reallocating the first portion and second portion between the first information and second information channels for all of the transmission links in response to changes in the utilization for at least one second information channel;

wherein each second information channel comprises an inbound data channel and an outbound data channel and the step of monitoring utilization includes measuring the data rate of second information signals in the outbound data channel and comparing the measured data rate to the allocated second information channel bandwidth to determine the data channel utilization.

2. A method for conferencing in a multipoint control unit, the method comprising the steps of:

connecting plural conference sites to the multipoint control unit, each conference site connecting over a respective transmission link having a first information channel and a second information channel and each conference site operable to transmit and receive first information and second information signals to and from other conference sites in the respective first information and second information channels;

allocating for each transmission link a first portion of the transmission link bandwidth to the first information channel and a second portion to the second information channel;

monitoring utilization of each second information channel; and

changing the bandwidth allocation by reallocating the first portion and second portion between the first information and second information channels for all of the transmission links in response to changes in the utilization for at least one second information channel;

wherein the step of changing the bandwidth allocation includes decreasing the first portion allocated to the first information channel and increasing the second portion allocated to the second information channel in equal amounts when the utilization for a number of the second information channels is above a high utilization threshold.

3. The method of claim 2 further comprising increasing the first portion allocated to the first information channel and decreasing the second portion allocated to the second information channel in equal amounts when the utilization for a number of the second information channels is below a low utilization threshold.

4. A method for conferencing in a multipoint control unit, the method comprising the steps of:

connecting plural conference sites to the multipoint control unit, each conference site connecting over a respective transmission link having a video channel and a data channel and each conference site operable to transmit and receive video and data signals to and from other conference sites in the respective video and data channels;

allocating for each transmission link a first portion of the transmission link bandwidth to the video channel and a second portion to the data channel;

measuring the data rate of data signals in each data channel and comparing the measured data rate to the allocated data channel bandwidth to determine the data channel utilization for each data channel; and

changing the bandwidth allocation by reallocating the first portion and second portion between the video and data channels for all of the transmission links in response to changes in the utilization for at least one data channel;

wherein each data channel comprises an inbound data channel and an outbound data channel and the measuring step includes measuring the data rate of data signals in the outbound data channel and comparing the measured data rate to the allocated data channel bandwidth to determine the data channel utilization.

5. A method for conferencing in a multipoint control unit, the method comprising the steps of:

connecting plural conference sites to the multipoint control unit, each conference site connecting over a respective transmission link having a video channel and a data channel and each conference site operable to transmit and receive video and data signals to and from other conference sites in the respective video and data channels;

allocating for each transmission link a first portion of the transmission link bandwidth to the video channel and a second portion to the data channel;

measuring the data rate of data signals in each data channel and comparing the measured data rate to the allocated data channel bandwidth to determine the data channel utilization for each data channel; and

changing the bandwidth allocation by reallocating the first portion and second portion between the video and data channels for all of the transmission links in response to changes in the utilization for at least one data channel;

wherein the step of changing the bandwidth allocation includes decreasing the first portion allocated to the video channel and increasing the second portion allocated to the data channel in equal amounts when the data channel utilization for a number of the data channels is above a high utilization threshold.

6. The method of claim 5, further comprising increasing the first portion allocated to the video channel and decreasing the second portion allocated to the data channel in equal amounts when the data channel utilization for a number of the data channels is below a low utilization threshold.

7. The method of claim 5 further comprising inhibiting transmission of video signals from the sites when the data channel utilization for a number of the data channels is above the high utilization threshold.

8. The method of claim 7 further comprising increasing the first portion allocated to the video channel and decreasing the second portion allocated to the data channel in equal amounts and uninhibiting transmission of video signals from the sites when the data channel utilization for a number of the data channels is below a low utilization threshold.

9. The method of claim 7 further comprising increasing the first portion allocated to the video channel and decreasing the second portion allocated to the data channel in equal amounts and uninhibiting transmission of video signals from the sites after a time interval starting with the inhibiting step.

10. In a multipoint control unit having plural conference sites connected thereto over respective transmission links having a first information channel and a second information channel and each conference site operable to transmit and receive first information and second information signals to and from the other conference sites in the respective first information and second information channels, an apparatus comprising:

means for allocating for each transmission link a first portion of the transmission link bandwidth to the first information channel and a second portion to the second information channel;

means for monitoring utilization of each second information channel; and

means for changing the bandwidth allocation by reallocating the first portion and second portion between the first information and second information channels for all of the transmission links in response to changes in the utilization for at least one second information channel;

wherein each second information channel comprises an inbound data channel and an outbound data channel and the means for monitoring utilization includes means for measuring the data rate of second information signals in the outbound data channel and means for comparing the measured data rate to the allocated second information channel bandwidth to determine the data channel utilization.

11. In a multipoint control unit having plural conference sites connected thereto over respective transmission links having a first information channel and a second information channel and each conference site operable to transmit and receive first information and second information signals to and from the other conference sites in the respective first information and second information channels, an apparatus comprising:

means for allocating for each transmission link a first portion of the transmission link bandwidth to the first information channel and a second portion to the second information channel;

means for monitoring utilization of each second information channel; and

means for changing the bandwidth allocation by reallocating the first portion and second portion between the first information and second information channels for all of the transmission links in response to changes in the utilization for at least one second information channel;

wherein the means for changing the bandwidth allocation includes means for decreasing the first portion allocated to the first information channel and means for increasing the second portion allocated to the second information channel in equal amounts when the utilization for a number of the second information channels is above a high utilization threshold.

12. The apparatus of claim 11 further comprising means for increasing the first portion allocated to the first information channel and means for decreasing the second portion allocated to the second information channel in equal amounts when the utilization for a number of the second information channels is below a low utilization threshold.

13. In a multipoint control unit having plural conference sites connected thereto over respective transmission links having a video channel and a data channel and each conference site operable to transmit and receive video and data signals to and from other conference sites in the respective video and data channels, an apparatus comprising:

a control processor for allocating for each transmission link a first portion of the transmission link bandwidth to the video channel and a second portion to the data channel;

a data processing unit coupled to the data channels for measuring the data rate of data signals in each data channel and comparing the measured data rate to the allocated data channel bandwidth to determine the data channel utilization for each data channel; and

wherein the control processor receives the data channel utilization for each data channel from the data processing unit and changes the bandwidth allocation by reallocating the first portion and second portion between the video and data channels for all of the transmission links in response to changes in the utilization for at least one data channel.

14. The apparatus of claim 13 wherein the control processor changes the bandwidth allocation by decreasing the first portion allocated to the video channel and increasing the second portion allocated to the data channel in equal amounts when the data channel utilization for a number of the data channels is above a high utilization threshold.

15. The apparatus of claim 14 wherein the control processor further changes the bandwidth allocation by increasing the first portion allocated to the video channel and decreasing the second portion allocated to the data channel in equal amounts when the data channel utilization for a number of the data channels is below a low utilization threshold.

16. A conferencing system comprising:

plural conference sites each coupled to a first end of a respective transmission link having a video channel and a data channel and each conference site operable to transmit and receive video and data signals to and from other conference sites in the respective video and data channels;

a multipoint control unit coupled to a second end of the respective transmission links, comprising;

a control processor for allocating for each transmission link a first portion of the transmission link bandwidth to the video channel and a second portion to the data channel;

a data processing unit coupled to the data channels for measuring the data rate of data signals in each data channel and comparing the measured data rate to the allocated data channel bandwidth to determine the data channel utilization for each data channel; and

wherein the control processor receives the data channel utilization for each data channel from the data processing unit and changes the bandwidth allocation by reallocating the first portion and second portion between the video and data channels for all of the transnission links in response to changes in the utilization for at least one data channel.

17. The system of claim 16 wherein the control processor changes the bandwidth allocation by decreasing the first portion allocated to the video channel and increasing the second portion allocated to the data channel in equal amounts when the data channel utilization for a number of the data channels is above a high utilization threshold.

18. The system of claim 17 wherein the control processor further changes the bandwidth allocation by increasing the first portion allocated to the video channel and decreasing the second portion allocated to the data channel in equal amounts when the data channel utilization for a number of the data channels is below a low utilization threshold.