US 7,855,966 B2Granted

Network congestion detection and automatic fallback: methods, systems and program products

AssigneeInternational Business Machines Corporation

InventorsYoussef Abdelilah, Gordon T. Davis, Jeffrey H. Derby, Dongming Hwang, Clark D. Jeffries, Malcolm S. Ware, Hua Ye

Life of this patent

Estimating the term…

patentgrep

Loading patent…

Abstract

A codec detects congestion in a packet network and responds via a session control protocol to re-negotiate codec-type and/or parameters with the receiving codec to reduce bit rate for supporting a session. Once the connection and session are established, encoded packets start flowing between the two codecs. A control entity sends and receives network congestion control packets periodically in the session. The congestion control packets provide a “heartbeat” signal to the receiving codec. When the network is not congested, all “heartbeat” packets will be passed through the network. As network congestion increases, routers within the network discard excess packets to prevent network failure. The codecs respond to the missing packets by slowing down the bit rate or proceeding to renegotiate a lower bit rate via the session control protocol. If there are no missing packets, the codecs detect if the session is operating at the highest bit rate, and if not, re-negotiate a higher bit rate.

Claims28

Dependent claims

Network congestion detection apparatus with automatic adjustment of bandwidth in response to congestion, comprising:

first and second codecs respectively coupled to a network, wherein a session is established for transmitting packets between the codecs and packets are initially transmitted at a bit rate selected from a plurality of initial bit rates, one of said initial bit rates comprising a pre-selected slowest bit rate, and another of said initial bit rates comprising a pre-selected fastest bit rate;
a bit rate negotiating component associated with each of said codecs for enabling its associated codec to negotiate transmission bit rates and bit rate changes for said session with the other codec;
a congestion indication component for intermittently transmitting congestion control packets during said session, wherein each congestion control packet contains no data, and said congestion indication component further detects a count of missing packets during said session for use in providing a missing packet count, wherein at least one of said missing packets included in said count comprises one of said congestion control packets;
a threshold device comprising a slowdown threshold component for comparing the missing packet count with a slowdown threshold, and in response to determining that the missing packet count is greater than the slowdown threshold, at a time when the transmission bit rate is greater than said pre-selected slowest bit rate, causing said first codec and said second codec to negotiate a lower transmission bit rate;
and
the threshold device further comprises a speedup threshold component for comparing the missing packet count with a speedup threshold, and in response to determining that the missing packet count is less than the speedup threshold, at a time when the transmission bit rate is less than said pre-selected fastest bit rate, causing said first codec and said second codec to negotiate a higher transmission bit rate.

3 more elements

An apparatus in a packet network for detection of network congestion and automatic adjustment of bandwidth in the network in response to congestion, comprising:

first and second codecs respectively coupled to the network, wherein a session is established for transmitting packets between the codecs and packets are initially transmitted at a bit rate selected from a plurality of initial bit rates, one of said initial bit rates comprising a pre-selected slowest bit rate, and another of said initial bit rates comprising a pre-selected fastest bit rate;
a bit rate negotiating component associated with each of said codecs for enabling its associated codec to negotiate transmission bit rates and bit rate changes for said session with the other codec;
a congestion indication component for intermittently transmitting congestion control packets during said session, wherein each congestion control packet contains no data, and said congestion indication component further detects missing packets during said session for use in providing a missing packet count, wherein at least one of said missing packets included in said count comprises one of said congestion control packets;
and
a threshold device responsive to said missing packet count for determining whether to cause said first codec and said second codec to negotiate, selectively, a slower bit rate to reduce congestion, or a higher bit rate to improve session quality.

2 more elements

A method of congestion detection in a packet network with automatic adjustment of bandwidth, wherein first and second codecs are respectively coupled to the network, said method comprising the steps of:

establishing a session for transmitting packets between the codecs, wherein the packets are initially transmitted at a bit rate selected from a plurality of initial bit rates, one of said initial bit rates comprising a pre-selected slowest bit rate, and another of said initial bit rates comprising a pre-selected fastest bit rate;
operating a bit rate negotiating component that is associated with each of said codecs, to enable its associated codec to negotiate transmission bit rates and bit rate changes for said session with the other codec;
intermittently transmitting congestion control packets during said session, wherein each congestion control packet contains no data;
detecting missing packets during said session for use in providing a missing packet count, wherein at least one of said missing packets included in said count comprises one of said congestion packets;
and
responsive to said missing packet count, determining whether to cause said first codec and said second codec to interact to negotiate a different bit rate.

3 more elements

Dependencies are inferred from the claim text.

Facts

Application: 11/348,417Filed 7 Feb 2006 · continuation in part
Priority: 16 Jul 2001
Published: US 2006/0209898 A121 Sep 2006
Granted: 21 Dec 2010
Term ends: Not estimatedThe source records don’t support an estimate.

Classification15 codes

H04L 47/10
Traffic control in data switching networks: flow control; Congestion control
H04L 12/6418
Hybrid switching systems: hybrid transport
H04L 47/2425
Traffic characterised by specific attributes, e.g. priority or QoS: for supporting services specification, e.g. SLA
H04L 47/263
Using explicit feedback to the source, e.g. choke packets: rate modification at the source after receiving feedback

Family

Application09/906,406Parent of this continuation-in-part · filed 16 Jul 2001
US 2006/0209898 A1Pre-grant publication · published 21 Sep 2006
US 7,068,601 B2Parent of this continuation-in-part
US 2003/0012138 A1Published application
US 7,855,966 B2This patent

From the US filing history. Foreign family members aren’t listed.