Communications subsystem for computer-based conferencing system using both ISDN B channels for transmission

• US 6,125,398 A
• Filed: 04/24/1997
• Issued: 09/26/2000
• Est. Priority Date: 11/24/1993
• Status: Expired due to Term

• Current Assignee: Intel Corporation
• Original Assignee: Intel Corporation
• Inventors: Bielaszewski, John, Rajamani, Krishnan, Mirashrafi, Mojtaba
• Primary Examiner(s): Follansbee, John A.
• Application Number:
  US08/847,396
• Time in Patent Office: 1,251 Days
• Field of Search: 709/231, 709/235, 709/236, 709/240, 370/229, 370/235, 370/263, 370/264, 370/265, 370/271, 370/366, 370/431, 370/437, 370/441, 370/442, 370/444, 370/468, 370/473, 370/493, 370/536
• US Class Current: 709/236
• CPC Class Codes: H04L 12/1822 Conducting the conference, e.g. admission, detection, selection or grouping of participants, correlating users to one or more conference sessions, prioritising transmission

Abstract

A communications task resides on an audio/communications board of the computer conferencing system. A communications manager and a communications application programming interface reside on a general-purpose host-processor of the computer conferencing system. The communications manager receives local compressed video signals from a video subsystem of the computer conferencing system and passes the local compressed video signals to the communications task. The communications task receives local compressed audio signals from an audio task of the computer conferencing system, the audio task residing on the audio/communications board. The communications task transmits the local compressed video signals and the local compressed audio signals over a communications link to a remote computer conferencing system. The communications task receives remote compressed video signals and remote compressed audio signals over the communications link from the remote computer conferencing system. The communications task passes the remote compressed audio signals directly to the audio task for decompression and playback processing. The communications task passes the remote compressed video signals to the video subsystem for decompression and playback processing.

Claims

1. A communications (comm) subsystem for a computer conferencing system, wherein:

the comm subsystem divides each of a plurality of local data messages of either a first data type or a second data type into an even number of local data packets, regardless of the size of said each local data message, by dividing each local data message into 2J integral local data packets and 2K fractional data packets, so that the data packets of each local data message can be evenly distributed over two physical channels of a dual-channel comm network, wherein;

J is a non-negative integer;

the size of each of the 2J integral local data packets is equal to a maximum local data packet size;

K is 0 only if the size of the local data message is an even multiple of the maximum local data packet size, and when the size of the local data message is not an even multiple of the maximum local data packet size then K is 1 and the size of each of the fractional local data packets is less than the maximum local data packet size; and

the first data type has a higher priority level than the second data type;

the comm subsystem distributes the integral and fractional local data packets of the first and second data types evenly to the two physical channels for transmission to a remote computer conferencing system and based on the priority levels of the first and second data types such that transmission of the local data packets of the first data type interrupts transmission of the local data packets of the second data type without causing loss of synchronization in the transmission of the local data packets of the second data type.

2. The comm subsystem of claim 1, wherein the first data type is audio data and the second data type is video data.

3. The comm subsystem of claim 2, wherein the transmission of the local data packets over the two physical channels is unreliable transmission in which there is no retransmission of data transmitted over the two physical channels.

4. The comm subsystem of claim 1, wherein the transmission of the local data packets over the two physical channels is unreliable transmission in which there is no retransmission of data transmitted over the two physical channels.

5. The comm subsystem of claim 1, wherein the comm subsystem:

receives remote data packets transmitted by the remote computer conferencing system over the two physical channels; and

assembles the remote data packets into remote data messages.

6. The comm subsystem of claim 5, wherein:

the comm subsystem receives remote data packets of the first data type over the two physical channels;

assembles the remote data packets of the first data type into remote data messages of the first data type; and

transmits the remote data messages of the first data type to a first-data-type subsystem for further processing; and

the comm subsystem receives remote data packets of the second data type over the two physical channels;

assembles the remote data packets of the second data type into remote data messages of the second data type; and

transmits the remote data messages of the second data type to a second-data-type subsystem for further processing.

7. The comm subsystem of claim 6, wherein the first data type is audio data and the second data type is video data, and the first-data-type subsystem is an audio subsystem and the second-data-type subsystem is a video subsystem.

8. The comm subsystem of claim 7, wherein:

the comm subsystem receives an even number of remote data packets for each remote data message of the first data type; and

the transmission of remote data packets over the two physical channels is unreliable transmission in which there is no retransmission of data transmitted over the two physical channels.

9. The comm subsystem of claim 8, wherein the dual-channel comm network is an integrated services digital network (ISDN).

10. The comm subsystem of claim 9, wherein the two physical channels are ISDN B channels.

11. The comm subsystem of claim 1, wherein:

the dual-channel comm network is an integrated services digital network (ISDN);

the two physical channels are ISDN B channels;

the first data type is audio data and the second data type is video data;

the transmission of the local data packets over the two B channels is unreliable transmission in which there is no retransmission of data transmitted over the two B channels;

the comm subsystem receives remote audio data packets over the two B channels;

assembles the remote audio data packets into remote audio data messages; and

transmits the remote audio data messages to an audio subsystem for further processing; and

the comm subsystem receives remote video data packets over the two B channels;

assembles the remote video data packets into remote video data messages; and

transmits the remote video data messages to a video subsystem for further processing; and

the comm subsystem receives an even number of remote data packets for each remote data message.

12. In a communications (comm) subsystem for a computer conferencing system, a method for transmitting data over a communications network having N physical channels, where N is an integer greater than 1, the method comprising the steps of:

(a) dividing each of a plurality of local data messages of either a first data type or a second data type into a number of local data packets divisible by N, regardless of the size of said each local data message, by dividing each local data message into N*J integral local data packets and N*K fractional data packets, so that the data packets of each local data message can be evenly distributed over the N physical channels, wherein;

J is a non-negative integer;

the size of each of the N*J integral local data packets is equal to a maximum local data packet size;

K is 0 only if the size of the local data message is exactly equal to N*J integral local data packets, and when the size of the local data message is not an even multiple of the maximum local data packet size then K is 1 and the size of each of the fractional local data packets is less than the maximum local data packet size; and

the first data type has a higher priority level than the second data type;

(b) distributing the integral and fractional local data packets of the first and second data types evenly to the two physical channels for transmission to a remote computer conferencing system and based on the priority levels of the first and second data types such that transmission of the local data packets of the first data type interrupts transmission of the local data packets of the second data type, whereby transmission of the local data packets of the first data type interrupts transmission of the local data packets of the second data type without causing loss of synchronization in the transmission of the local data packets of the second data type.

13. The method of claim 12, wherein:

the first data type is audio data and the second data type is video data; and

the transmission of the local data packets over the N physical channels is unreliable transmission in which there is no retransmission of data transmitted over the N physical channels.

14. The method of claim 12, wherein:

the dual-channel comm network is an integrated services digital network (ISDN), N is 2, and the two physical channels are ISDN B channels;

the first data type is audio data and the second data type is video data; and

the transmission of the local data packets over the two B channels is unreliable transmission in which there is no retransmission of data transmitted over the two B channels.