Methods and computer executable instructions for improving communications in a packet switching network

• US 6,212,206 B1
• Filed: 03/05/1998
• Issued: 04/03/2001
• Est. Priority Date: 03/05/1998
• Status: Expired due to Term

• Current Assignee: Hewlett Packard Enterprise Development LP (Hewlett-Packard Enterprise Company)
• Original Assignee: 3Com Corporation (HP Inc.)
• Inventors: Ketcham, Carl
• Primary Examiner(s): Olms, Douglas
• Assistant Examiner(s): Sam, Phirin
• Application Number:
  US09/035,727
• Time in Patent Office: 1,125 Days
• Field of Search: 370/516, 370/232, 370/233, 370/234, 370/235, 370/252, 370/253, 370/260, 370/263, 370/270, 370/519, 370/353, 370/356, 370/396, 370/517, 370/261, 370/508, 370/518
• US Class Current: 370/516
• CPC Class Codes: H04J 3/0632 Synchronisation of packets and cells, e.g. transmission of voice via a packet network, circuit emulation service [CES] queuing arrangements in packet switching elements H04L49/90; synchronising systems for the synchronous transmission of a pulse code modulated video signal with one or more other pulse code modulated signals H04N7/56
• CPC Class Codes: H04L 12/1813 for computer conferences, e.g. chat rooms instant messaging H04L51/04; protocols for multimedia communication H04L65/1101; arrangements for multi-party communication H04L65/403; telephonic conference arrangements H04M3/56; television conference systems H04N7/15
• CPC Class Codes: H04L 2012/5649 Cell delay or jitter
• CPC Class Codes: H04L 49/103 using a shared central buffer; using a shared memory
• CPC Class Codes: H04L 49/206 Real Time traffic
• CPC Class Codes: H04L 65/1069 Session establishment or de-establishment
• CPC Class Codes: H04L 65/1101 Session protocols
• CPC Class Codes: H04L 65/4046 with distributed floor control
• CPC Class Codes: H04L 65/80 Responding to QoS
• CPC Class Codes: H04N 21/43072 of multiple content streams on the same device
• CPC Class Codes: H04N 21/432 Content retrieval operation from a local storage medium, e.g. hard-disk details of retrieval of video data and associated meta data in video databases G06F16/739
• CPC Class Codes: H04N 21/44004 involving video buffer management, e.g. video decoder buffer or video display buffer
• CPC Class Codes: H04N 21/4788 communicating with other users, e.g. chatting arrangements for providing for computer conferences, e.g. chat rooms, to substation in data switching networks H04L12/1813; distributed application using peer-to-peer [P2P] networks H04L67/104
• CPC Class Codes: H04N 21/6125 involving transmission via Internet transmission by internet of broadcast information H04H60/82
• CPC Class Codes: H04N 7/15 Conference systems
• CPC Class Codes: H04Q 11/0478 Provisions for broadband connections

Abstract

Software and methods are provided for improving contemporary communications between two or more terminal locations of a packet switched network. In a packet switched network incoming packets are stored in buffers until, as in a video conference, playback of the packets occurs. As described herein, a concerted method between storing packets in buffers and adjusting the playback of the packets at a destination terminal locations is provided. In a preferred embodiment, a jitter time is set that estimates the arrival times between at least two packets at the destination terminal location. The jitter time corresponds to a set of conditions for the buffers receiving the incoming packets and for the playback of the packets on a display device. Thereafter, an actual arrival time between incoming packets is measured and compared against the jitter time estimate. If the measured time is faster than or slower than the jitter time estimate, packets are not being received into buffers as desired and adjustments to the jitter time and set of conditions are made. If the measured time is slower than the jitter time estimate, a rapid alteration to the buffers and playback is made. In one embodiment, the buffers are enlarged to accommodate the slower arriving packets and the playback is slowed down to make the video conference appear more natural. If the measured time is faster than the jitter estimate, gradual alterations are made. Over time, the buffers are adjusted to accommodate for the rapidly arriving incoming packets to prevent stockpiling in the buffers.

Claims

1. In a distributed computing environment having an originating terminal location sending a plurality of packets to a destination terminal location, a method for improving communications between said terminal locations, at said destination terminal location the steps comprising:

estimating a jitter time between said packets arriving at said destination terminal location;

defining a set of conditions corresponding to said jitter time for at least one buffer, said one buffer for temporarily storing said packets;

measuring an actual arrival time between said packets arriving at said destination terminal location;

comparing said jitter time to said actual arrival time to determine whether said set of conditions should be altered, said set of conditions including a size of said one buffer; and

when said actual arrival time is slower than said jitter time, increasing said size of said one buffer.

2. A method for improving communications according to claim 1, wherein said step of comparing said jitter time to said actual arrival time comprises the step of subtracting between said jitter time and said actual arrival time.

3. A method for improving communications according to claim 1, further comprising the step of playing back said packets at a playback speed while slowing down said playback speed for a portion of said packets.

4. A method for improving communications according to claim 1, wherein said actual arrival time is substantially equal to said jitter time further comprising the step of maintaining said set of conditions for said one buffer.

5. A method for improving communications according to claim 1, wherein said actual arrival time is faster than said jitter time further comprising the step of adding additional buffers to accommodate stockpiling said packets.

6. A computer readable medium having computer executable instructions for performing the steps as recited in claim 1.

7. A computer readable medium according to claim 1, wherein said actual arrival time is substantially equal to said jitter time further comprising computer executable instructions for performing the step of maintaining said buffer size of said buffer.

8. A method of communicating between a plurality of terminal locations in a packet network, comprising the steps of

establishing a communications link between said terminal locations;

at one of said terminal locations, sending a plurality of information packets; and

at another of said terminal locations,

i) estimating an arrival time between at least two of said information packets;

ii) receiving at least two of said information packets;

iii) measuring an actual arrival time between said at least two of said received information packets;

iv) storing said at least two of said received information packets in a buffer;

v) comparing said arrival time to said actual arrival time to determine whether a size of said buffer should be altered; and

vi) when said actual arrival time is slower than said arrival time, increasing said size of said buffer.

9. A method of communicating according to claim 8, further comprising the step of playing back said information packets at a playback speed while slowing down said playback speed for a portion of said information packets.

10. A method of communicating according to claim 8, at said another of said terminal locations wherein said actual arrival time is substantially equal to said arrival time further comprising the step of maintaining said size of said buffer.

11. A method of communicating according to claim 8, at said another of said terminal locations wherein said step of comparing said arrival time to said actual arrival time to determine whether a size of said buffer should be altered further comprises the step of subtracting between said arrival time and said actual arrival time.

12. A method of communicating according to claim 8, at said another of said terminal locations further comprising the step of speeding up a playback of a portion of said information packets.

13. A computer readable medium having computer executable instructions for performing the steps at said another of said terminal locations as recited in claim 8.

14. In a video conference between at least two terminal locations in a packet network, a method for improving the playback of information packets containing audio or video information sent from one of said terminal locations and received by the other of said terminal locations, at said other of said terminal locations the steps comprising:

estimating a jitter time between said information packets sent from said one of said terminal locations;

defining a size for a buffer, said buffer for storing said information packets upon receipt from said one of said terminal locations until said information packets are played at said playback speed

defining a playback speed for said information packets corresponding to said jitter time;

measuring an actual time between said information packets sent from said one of said terminal locations;

comparing said jitter time to said actual time to determine whether said playback speed should be altered; and

altering said size of said buffer if said jitter time and said actual time are not substantially equal.

15. A method of improving the playback of information packets according to claim 14, wherein said actual time is slower than said jitter time further comprising the step of increasing said size of said one buffer.

16. A method of improving the playback of information packets according to claim 14, wherein said actual time is slower than said jitter time further comprising the step of slowing down said playback speed for a portion of said information packets.

17. A method of improving the playback of information packets according to claim 14, wherein said actual time is substantially equal to said jitter time further comprising the step of maintaining said playback speed.

18. A computer readable medium having computer executable instructions for performing the steps at said other of said terminal locations as recited in claim 14.

19. A computer readable medium having computer executable instructions for performing the steps of:

storing a jitter time that estimates the time between reception of a plurality of packets;

establishing a buffer size in a computer for a buffer corresponding to said jitter time;

comparing said jitter time to an actual arrival time between said packets to determine whether said buffer size should be altered; and

when said actual arrival time is greater than said jitter time, increasing said buffer size of said buffer.

20. A computer readable medium according to claim 19, further comprising computer executable instructions for performing the step of slowing down a playback of a portion of said packets.