Apparatus and method for speech transport with adaptive packet size

• US 6,370,163 B1
• Filed: 03/11/1998
• Issued: 04/09/2002
• Est. Priority Date: 03/11/1998
• Status: Expired due to Term

• Current Assignee: Unify Inc. (Atos SE)
• Original Assignee: Siemens Communications Incorporated (Siemens AG)
• Inventors: Shaffer, Shmuel, Beyda, William Joseph
• Primary Examiner(s): Ton, Dang
• Assistant Examiner(s): NGUYEN, TOAN D
• Application Number:
  US09/041,468
• Time in Patent Office: 1,490 Days
• Field of Search: 370/252, 370/254, 370/231, 370/238, 370/229, 370/235, 370/236, 370/245, 370/445, 370/473, 370/493, 370/508, 370/519
• US Class Current: 370/519
• CPC Class Codes: H04L 43/50 Testing arrangements
• CPC Class Codes: H04L 47/115 using a dedicated packet
• CPC Class Codes: H04L 47/36 by determining packet size, e.g. maximum transfer unit [MTU]
• CPC Class Codes: H04M 7/006 Networks other than PSTN/ISDN providing telephone service, e.g. Voice over Internet Protocol (VoIP) , including next generation networks with a packet-switched transport layer H04L65/00 takes precedence; aspects not specific to the type of network H04M3/00; special services in those networks H04M3/42

Abstract

A system and method for adaptive packet-length IP telephony includes a first IP telephony communication device located on a data network and enabled to establish an IP telephony connection to a second IP telephony communication device. Optionally, the first communication device is enabled to access network topology information from a server regarding a network segment connecting the first and second communication devices. If the network topology reflects the presence of a low efficiency router on the network segment, the first communication device enters a fixed packet-length operational mode. If the network topology indicates an absence of a low efficiency network router on the segment, the first communication device enters an adaptive packet-length operational mode. In the adaptive packet-length operational mode, prior to establishing the IP telephony connection, the first communication device determines an end-to-end transmission delay by transmitting a test packet to the second communication device with instructions to return a first acknowledgment message. Based on the first end-to-end transmission delay, a control program associated with the first communication device calculates a permissible packet length for IP telephony packets transmitted from the first communication device to the second communication device via the IP telephony connection. After establishment of the IP telephony connection, the first communication device transmits a second test packet which generates a second end-to-end transmission delay data set. Based on the second data set, the control program calculates a second permissible packet length.

Claims

1. A method for adaptive packet-length speech transport over a data network comprising the steps of:

determining an end-to-end transmission delay between said first and second communication devices, including obtaining data from a server regarding a network topology of a network segment between said first and second communication devices;

calculating a permissible packet length for transmission of voice information over a voice-over-data-network connection between said first and second communication devices at least partially based upon said end-to-end transmission delay, said step of calculating including calculating said permissible packet length based on an inverse correlation between packet length and said determined end-to-end transmission delay such that calculations of short permissible packet lengths are associated with determinations of long end-to-end transmission delays, said inverse correlation being determined prior to said transmission of said voice information; and

transmitting voice information over said voice-over-data-network connection from said first communication device to said second communication device in a first set of packets having a length conforming to said permissible packet length.

2. The method of claim 1 wherein said step of determining said end-to-end transmission delay occurs during said step of establishing said voice-over-data-network connection.

3. A The method of claim 1 wherein said step of determining said end-to-end delay includes comparing an address of said first communication device to an address of said second communication device to determine if said first and second communication devices are located on a same network segment of said network.

4. The method of claim 1 wherein said step of determining said end-to-end transmission delay includes transmitting a first test packet from said first communication device to said second communication device and receiving a first responsive acknowledgment from said second communication device.

5. The method of claim 4 wherein said step of determining said end-to-end delay includes calculating a time interval between said transmission of said test packet and said receiving said responsive acknowledgment, dividing said time interval in half, and adjusting for a processing time of said responsive acknowledgment.

6. The method of claim 4 wherein said step of determining said end-to-end delay includes receiving a first end-to-end delay data set with said responsive acknowledgment from said second communication device, said end-to-end transmission delay data set reflecting a time interval between a departure of said test packet from said first communication device and an arrival of said test packet at said second communication device.

7. The method of claim 4 wherein said step of calculating said permissible packet length includes:

establishing a predetermined end-to-end transmission delay tolerance for propagation of said first set of packets;

determining a maximum possible packet length based on said predetermined end-to-end delay tolerance;

adjusting said maximum possible packet length for said end-to-end transmission delay determined from said transmission of said first test packet, said adjusting being based on said inverse correlation between said selected permissible packet length and said determined end-to-end transmission delay; and

further adjusting said maximum possible packet length for a safety factor, said safety factor requiring a reduction in packet size in anticipation of fluctuating data network traffic.

8. The method of claim 1 further comprising the steps of:

determining a current end-to-end transmission delay between said first and second communication devices after said step of establishing said voice-over-data-network connection by transmitting a second test packet from said first communication device to said second communication device and receiving a second responsive acknowledgment from said second communication device;

calculating a current permissible packet length for transmission of voice information over said voice-over-data-network connection between said first and second communication devices based at least partially on said current end-to-end transmission delay; and

transmitting voice information over said voice-over-data-network connection between said first and second communication devices in a second set of packets having a length conforming to said current permissible packet length.

9. A system for adaptive packet-length speech transport over a data network comprising:

a first communication device having an adaptive packet-length operational mode, said first communication device being located on said data network and being enabled to establish a voice-over-data-network connection with a second communication device, said first communication device being configured to access end-to-end transmission delay data pertaining to a first network segment between said first and second communication devices, said first communication device further being configured to transmit a first voice data packet of a first length based upon said end-to-end transmission delay data while in said adaptive packet-length operational mode, said end-to-end transmission delay being based on adjusting for transmission time intervals both from said first to said second communication device and from said second to said first communication device, including utilizing data from a server that identifies a type of device on said first network segment; and

a call control program in communicative contact with said first communication device, said call control program being configured to calculate a first permissible packet length for said first voice data packet transmitted from said first communication device via said voice-over-data-network connection, said first permissible packet length being based at least partially upon said end-to-end transmission delay data accessed by said first communication device.

10. The system of claim 9 wherein said first communication device is configured to transmit a first test packet to said second communication device during said establishment of said voice-over-data-network connection, said first test packet including instructions to return a first responsive acknowledgment message, said first communication device being further configured to calculate a first end-to-end transmission delay based on a time interval between said transmission of said first packet and receipt of said first responsive acknowledge message and an adjustment for a processing time for transmission of said first responsive acknowledge message from said second communication device.

11. The system of claim 10 wherein said first communication device is configured to transmit a second test packet to said second communication device after said establishment of said voice-over-data-network connection, said second test data packet including instructions to return a second acknowledge message, said first communication device being further configured to transmit a second voice data packet of a second length calculated by said call control program based at least in part on a second end-to-end transmission delay.

12. The system of claim 9 wherein said server is in communicative contact with said first communication device, said server being configured to discover a network topology of said first network segment between said first and second communication devices and a second network segment between said first communication device and a third communication device, said server being further configured to transmit first and second network topology data sets to said first communication device, said first network topology data set including said network topology of said first network segment reflecting an absence of a low efficiency router on said first network segment, said second network topology data set including a network topology of said second network segment reflecting a presence of said low efficiency router on said second network segment, said first communication device being configured to enter said adaptive packet-length operational mode in response to said first network topology data set and to enter a fixed packet-length operational mode in response to said second data set.

13. The system of claim 12 wherein said server is configured to differentiate between a high efficiency router and said low efficiency router, said high efficiency router causing a smaller end-to-end data transmission delay than said low efficiency router.

14. The system of claim 9 wherein said first communication device is enabled for video-teleconferencing over said voice-over-data-network connection with said second communication device.

15. A method for adaptive packet-length speech transport over a data network comprising the steps of:

establishing a voice-over-data-network connection between a first communication device and a second communication device via said data network;

determining whether a low efficiency router is located on a network segment between said first and second communication devices;

if it is determined that no low efficiency router is located on said network segment between said first and second communication devices, transmitting a first test packet from said first communication device to said second communication device via said network segment to determine a first end-to-end transmission delay over said network segment between said first and second communication devices;

calculating a first permissible packet length for transmission of voice data packets over said voice-over-data-network connection, said packet-length calculation occurring prior to said voice-over-data-network connection being established; and

transmitting a first set of voice data packets from said first communication device to said second communication device via said voice-over-data-network connection, said voice data packets having a first length determined based at least partially upon said first end-to-end transmission delay.

16. The method of claim 15 further comprising the steps of:

transmitting a second test packet from said first communication device to said second communication device after said voice-over-data-network connection being established to determine a current end-to-end transmission delay on said network segment comprising said voice-over-data-network connection;

calculating a second permissible packet length based upon said current end-to-end transmission delay; and

transmitting a second set of voice data packets from said first communication device to said second communication device based on said second permissible packet length.

17. The method of claim 15 further comprising the step of calculating an estimated intrinsic transmission delay based upon a network topology between said first and second communication devices.

18. The method of claim 15 wherein said step of establishing said voice-over-data-network connection between said first and second communication devices includes providing video-teleconferencing.