Method for down-speeding in an IP communication network

• US 20070025251A1
• Filed: 06/13/2006
• Published: 02/01/2007
• Est. Priority Date: 06/15/2005
• Status: Active Grant

• Current Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Original Assignee: Tandberg Telecom AS (Cisco Systems, Inc.)
• Inventors: Overgaard, Tarjei
• Granted Patent: US 7,525,914 B2
• Time in Patent Office: Days
• US Class Current: 370/232
• CPC Class Codes: H04L 47/10 Flow control; Congestion control
• CPC Class Codes: H04L 47/26 using explicit feedback to the source, e.g. choke packets
• CPC Class Codes: H04L 47/29 using a combination of thresholds
• CPC Class Codes: H04L 65/1101 Session protocols
• CPC Class Codes: H04L 65/1106 Call signalling protocols; H.323 and related
• CPC Class Codes: H04L 65/403 Arrangements for multi-party communication, e.g. for conferences data switching systems for conference H04L12/18; arrangements for connecting several subscribers to a common circuit, i.e. affording conference facilities H04M3/56; television conferencing systems H04N7/15
• CPC Class Codes: H04L 65/80 Responding to QoS

Abstract

The present invention discloses a method for providing a packet loss detection and down speeding mechanism for maintaining acceptable quality during a video call. Different scenarios of packet loss requiring different down speeding degrees are accommodated by a two-parted method combined by a low-part and a high-part decision and down speeding mechanisms. The method has a consecutively measured packet loss as input, and uses weighted packet loss parameter of recently measured packet loss to decide whether to down speed, and if so, whether the low-part or high-part down speeding mechanism should be used.

Claims

1. A method of adjusting a flow rate of data transmitted from a first conference device and received at a second conference device wherein a current packet loss consecutively is being measured in the data received at a second conference terminal, the method comprising:

calculating a new value for a first parameter by adding a weighted first fraction of a last value of the first parameter and a weighted second fraction of the current packet loss, wherein the first fraction is higher than said second fraction,

if the current packet loss is lower than a predefined first threshold, then

calculating a new value for a second parameter by adding a weighted fraction of a last value of said second parameter and a weighted fraction of the current packet loss, wherein the last value is weighted higher than the current packet loss, if the first parameter is higher than a predefined second threshold, then

reducing the flow rate of data transmitted from the first conference device with a third fraction of the amount of the current packet loss, if the second parameter is higher than a predefined third threshold, then

reducing the flow rate of data transmitted from the first conference device with a fourth fraction of the current packet loss.

2. A method according to claim 1, wherein the first and the second conference devices are video conference endpoints.

3. A method according to claim 1, wherein the first fraction is 0.9 and the second fraction is 0.1.

4. A method according to claim 1, wherein the first threshold is 6%.

5. A method according to claim 1, wherein the second threshold is 5%.

6. A method according to claim 1, wherein the third threshold is 1%.

7. A method according to claim 1, wherein the third fraction is 0.67.

8. A method according to claim 1, wherein the fourth fraction is 0.1.