Method for managing variation in a data flow rate

• US 7,697,553 B2
• Filed: 05/19/2004
• Issued: 04/13/2010
• Est. Priority Date: 05/23/2003
• Status: Expired due to Fees

• Current Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Original Assignee: Tandberg Telecom AS (Cisco Systems, Inc.)
• Inventors: Kalgraf, Olav Luraas, Karlsen, Per Arne
• Primary Examiner(s): Ngo; Ricky
• Assistant Examiner(s): Oveissi; David
• Application Number:
  US10/850,362
• Publication Number:
  US 20050013312A1
• Time in Patent Office: 2,155 Days
• Field of Search: 370/229, 370/231, 370/230, 370/235, 370/232, 370/233, 370/234, 370/252
• US Class Current: 370/412
• CPC Class Codes: H04L 47/10 Flow control; Congestion control
• CPC Class Codes: H04L 47/2416 Real-time traffic
• CPC Class Codes: H04L 47/263 Rate modification at the source after receiving feedback
• CPC Class Codes: H04L 47/30 in combination with information about buffer occupancy at either end or at transit nodes
• CPC Class Codes: H04L 65/1101 Session protocols
• CPC Class Codes: H04L 65/1104 Session initiation protocol [SIP]
• CPC Class Codes: H04L 65/1106 Call signalling protocols; H.323 and related
• CPC Class Codes: H04L 65/4038 with floor control
• CPC Class Codes: H04L 65/80 Responding to QoS
• 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 21/6373 for rate control , e.g. request to the server to modify its transmission rate flow control in packet networks H04L47/10
• CPC Class Codes: H04N 21/64707 for transferring content from a first network to a second network, e.g. between IP and wireless
• CPC Class Codes: H04N 7/15 Conference systems
• CPC Class Codes: Y02D 30/50 in wire-line communication networks, e.g. low power modes or reduced link rate

Abstract

The present invention discloses a method of detecting overproduction of data when an H.323 endpoint is transmitting more video or other data than initially negotiated, and makes it produce less by utilizing standard flow control procedures. Flow control messages are sent periodically, incrementally instructing the H.323 endpoint to transmit lower amounts of bit rates, until the video rate received from the endpoint is equal to or lower than the initially negotiated rate, or some other fixed rate.

Claims

1. A method of adjusting a flow rate of data transmitted from a first packet switched H.323 or SIP configured video conference terminal and received in a H.323/H.320 video conference gateway, the method comprising:

storing the received data temporarily in one or more buffers in the H.323/H.320 video conference gateway before being captured for further processing;

after each data capturing from said one or more buffers,

comparing, at the H.323/H.320 video conference gateway, a fill level of the one or more buffers with a predefined level, wherein said predefined level is equal to a maximum amount of data in a H.320 frame, into which data captured from the one or more buffers is inserted, if said fill level is lower than said predefined level, then resetting a counter,

if said fill level is greater than said predefined level, then

incrementing, at the H.323/H.320 video conference gateway, said counter, and

comparing, at the H.323/H.320 video conference gateway, said counter with a predefined counter limit,

if said counter is greater than said predefined counter limit, then

resetting, at the H.323/H.320 video conference gateway, said counter, and

decreasing the flow rate of the transmitted data by transmitting, at the H.323/H.320 video conference gateway, a flow control message to the first packet switched terminal instructing the first packet switched terminal to decrease the flow rate according to a flow rate value included in said flow control message.

2. A method according to claim 1, wherein the flow rate is decreased by a predefined constant value.

3. A method according to claim 2, further including the following steps prior to the step of decreasing the flow rate:

comparing a difference between the flow rate and said predefined constant value with a predefined flow rate limit, and

carrying out the step of decreasing the flow rate only if said difference is greater that said predefined flow rate limit.

4. A method according to claim 1, wherein said data is video, audio, or other multimedia data transmitted from the first packet switched video conference terminal to a circuit switched terminal via the H.323/H.320 video conference gateway in a video conference.

9. The method of claim 1, wherein the counter keeps track of a number of data capturing events from the one or more buffers since a last time the fill level of the one or more buffers was below the predefined threshold.

5. A method of communication comprising:

temporarily storing, at the H.323/H.320 video conference gateway, data received from a first packet switched H.323 or SIP configured video conference terminal in one or more buffers before being captured for further processing,

detecting, at a H.323/H.320 video conference gateway, overproduction of data transmitted from the first packet switched H.323 or SIP configured video conference terminal,

after data capturing from said one or more buffers,

comparing, at the H.323/H.320 video conference gateway, a fill level of the one or more buffers with a predefined level, wherein said predefined level is equal to a maximum amount of data in a H.320 frame, into which data captured from the one or more buffers is inserted,

if said fill level is greater than said predefined level,

then incrementing, at the H.323/H.320 video conference gateway, a counter, and

comparing said counter with a predefined counter limit, and

if said counter is greater than said predefined counter limit,

then resetting said counter, and

adjusting, at the H.323/H.320 video conference gateway, a flow rate of the transmitted data by transmitting a flow control message from the second to the first packet switched terminal to instruct the first packet switched terminal to decrease the flow rate according to a non-zero flow rate value included in said flow control message.

6. A method according to claim 5, wherein said data is video, audio, or other multimedia data transmitted from the first packet switched video conference terminal to a circuit switched terminal via the H.323/H.320 video conference gateway in a video conference.

7. A method according to claim 5, wherein the flow rate is decreased by a predefined constant value.

8. A method according to claim 7, further including prior to adjusting the flow rate:

comparing a difference between the flow rate and said predefined constant value with a predefined flow rate limit, and

carrying out the step of adjusting the flow rate only if said difference is greater that said predefined flow rate limit.