Wing S Chau

US Patent:

7233600, Jun 19, 2007

Filed:

Dec 17, 1998

Appl. No.:

09/216004

Inventors:

Wing C. Chau - Los Altos Hills CA, US
Madhu Grandhi - Fremont CA, US

Assignee:

Cisco Technology, Inc. - San Jose CA

International Classification:

H04L 12/28

US Classification:

370431, 370464

Abstract:

The present invention relates to a system and method of managing DSP resources within a network interface system (NIS). A Digital Signal Processing (DSP) resource manager dynamically allocates DSP resources to ensure that a DSP resource is always available to process an incoming call. The DSP resource manager reserves a sufficient number of DSP resources in a PCM group in order to ensure processing of any active communication channels. Each time a call is received and assigned to a T1 channel, the DSP resource manager recalculates the number of idle voice channels and the number of PCM resource channels which must be reserved to ensure processing of all idle voice channels. The DSP resource manager also recalculates DSP resource availability in the PCM group each time a call is deactivated. By tracking the number of idle voice channels in the system as well as the number of idle DSP resource channels in the PCM group, the DSP resource manager can reallocate the resources as necessary to optimize the ability of the system to fulfill enhanced compression mode requests, while also ensuring that there are sufficient resources available to process any call in PCM mode.

US Patent:

7916653, Mar 29, 2011

Filed:

Sep 6, 2006

Appl. No.:

11/516933

Inventors:

Scott Firestone - Mountain View CA, US
Randall B. Baird - Austin TX, US
Wing Cheong Chau - Los Altos Hills CA, US
Shantanu Sarkar - San Jose CA, US

Assignee:

Cisco Technology, Inc. - San Jose CA

International Classification:

G01R 31/08
H04L 12/66

US Classification:

370252, 370352

Abstract:

In one embodiment, a first audio waveform is produced at a first side of a network connection and then encoded and sent by a first endpoint device to a second endpoint device at a second side of the network connection. A second audio waveform is then detected after being played out by the first endpoint device, the second audio waveform having been produced at the second side of the network connection in response to the second endpoint device playing out the first audio waveform. A round-trip delay is then calculating based on a time period measured from output of the first audio waveform to detection of the second audio waveform. It is emphasized that this abstract is provided to comply with the rules requiring an abstract that will allow a searcher or other reader to quickly ascertain the subject matter of the technical disclosure.

US Patent:

58058273, Sep 8, 1998

Filed:

Mar 4, 1996

Appl. No.:

8/610706

Inventors:

Wing Cheong Chau - Los Altos CA
Dar-Ren Leu - San Jose CA

Assignee:

3Com Corporation - Santa Clara CA

International Classification:

H04L 1246

US Classification:

39520077

Abstract:

A communication server includes one or more ISDN ports or other wide area network ports, one or more local area network ports, a plurality of processors and data channel resources which execute a process for distributing data channel signal processing among the plurality of processors. The process includes maintaining resource information for a set of processors on the communication server, the resource information concerning levels of utilization of processors in said set of processors; detecting, in processors corresponding to particular input/output ports of the server, activity in data channels through input/output ports managed by the processors; sending requests in response to the detected activity from the corresponding processors to a managing processor on the communication server, said requests identifying compression or decompression services needed for the detected activity; selecting in the managing processor in response to the resource information and the request, service processors from the set of processors in the server to provide compression or decompression services identified in the request for the detected activity on the data channel; and routing the detected activity on the data channels to the selected service processors.

US Patent:

62787055, Aug 21, 2001

Filed:

Apr 8, 1997

Appl. No.:

8/835532

Inventors:

Wing Cheong Chau - Los Altos Hills CA
Darren Leu - San Jose CA
Chandy Nilakantan - Cupertino CA
Jeffrey Kaiping Pao - San Jose CA
Wayming Daniel Tai - Cupertino CA
Xiaohu Wang - Milpitas CA

Assignee:

3Com Corporation - Santa Clara CA

International Classification:

H04L 1266

US Classification:

370352

Abstract:

The present invention provides a modular architecture for connecting a plurality of telephone lines to a computer network. The invention binds a plurality of network access servers together so that they form a single system image to clients dialing into the plurality of network access servers. The invention operates by providing a tunneling mechanism for communication between the network access servers. The tunneling mechanism facilitates packet re-forwarding so that a call dialed into a physical port in a network access server can be re-forwarded through a logical port in another network access server. This allows a call to be routed through a physical port in a network access server even if no logical port is available in the network access server. Packet re-forwarding also allows multilink connections through physical ports in multiple network access servers to be routed through a single logical port in a network access server. Packet re-forwarding also provides support for spoofing; if the telephone line is torn down during spoofing, the logical port is maintained so that the connection may be reestablished through a physical port in another network access server.

US Patent:

60119101, Jan 4, 2000

Filed:

Apr 8, 1997

Appl. No.:

8/833663

Inventors:

Wing Cheong Chau - Los Altos Hills CA
Darren Leu - San Jose CA
Chandy Nilakantan - Cupertino CA
Jeffrey Kaiping Pao - San Jose CA
Wayming Daniel Tai - Cupertino CA
Xiaohu Wang - Milpitas CA

Assignee:

3Com Corporation - Santa Clara CA

International Classification:

G06F 1300

US Classification:

39520059

Abstract:

The present invention provides a modular architecture for connecting a plurality of telephone lines to a computer network. The invention binds a plurality of network access servers together so that they form a single system image to clients dialing into the plurality of network access servers. The invention operates by providing a tunneling mechanism for communication between the network access servers. The tunneling mechanism facilitates packet re-forwarding so that a call dialed into a physical port in a network access server can be re-forwarded through a logical port in another network access server. This allows a call to be routed through a physical port in a network access server even if no logical port is available in the network access server. Packet re-forwarding also allows multilink connections through physical ports in multiple network access servers to be routed through a single logical port in a network access server. Packet re-forwarding also provides support for spoofing; if the telephone line is torn down during spoofing, the logical port is maintained so that the connection may be reestablished through a physical port in another network access server.

US Patent:

60260858, Feb 15, 2000

Filed:

Apr 8, 1997

Appl. No.:

8/835536

Inventors:

Wing Cheong Chau - Los Altos Hills CA
Darren Leu - San Jose CA
Chandy Nilakantan - Cupertino CA
Jeffrey Kaiping Pao - San Jose CA
Wayming Daniel Tai - Cupertino CA
Xiaohu Wang - Milpitas CA

Assignee:

3Com Corporation - Santa Clara CA

International Classification:

H04L 1202

US Classification:

370352

Abstract:

The present invention provides a modular architecture for connecting a plurality of telephone lines to a computer network. The invention binds a plurality of network access servers together so that they form a single system image to clients dialing into the plurality of network access servers. The invention operates by providing a tunneling mechanism for communication between the network access servers. The tunneling mechanism facilitates packet re-forwarding so that a call dialed into a physical port in a network access server can be re-forwarded through a logical port in another network access server. This allows a call to be routed through a physical port in a network access server even if no logical port is available in the network access server. Packet re-forwarding also allows multilink connections through physical ports in multiple network access servers to be routed through a single logical port in a network access server. Packet re-forwarding also provides support for spoofing; if the telephone line is torn down during spoofing, the logical port is maintained so that the connection may be reestablished through a physical port in another network access server.

US Patent:

62332325, May 15, 2001

Filed:

Apr 8, 1997

Appl. No.:

8/835534

Inventors:

Wing Cheong Chau - Los Altos Hills CA
Darren Leu - San Jose CA
Chandy Nilakantan - Cupertino CA
Jeffrey Kaiping Pao - San Jose CA
Wayming Daniel Tai - Cupertino CA
Xiaohu Wang - Milpitas CA

Assignee:

3Com Corporation - Santa Clara CA

International Classification:

H04L 1266

US Classification:

370352

Abstract:

The present invention provides a modular architecture for connecting a plurality of telephone lines to a computer network. The invention binds a plurality of network access servers together so that they form a single system image to clients dialing into the plurality of network access servers. The invention operates by providing a tunneling mechanism for communication between the network access servers. The tunneling mechanism facilitates packet re-forwarding so that a call dialed into a physical port in a network access server can be re-forwarded through a logical port in another network access server. This allows a call to be routed through a physical port in a network access server even if no logical port is available in the network access server. Packet re-forwarding also allows multilink connections through physical ports in multiple network access servers to be routed through a single logical port in a network access server. Packet re-forwarding also provides support for spoofing; if the telephone line is torn down during spoofing, the logical port is maintained so that the connection may be reestablished through a physical port in another network access server.

US Patent:

6256305, Jul 3, 2001

Filed:

Jun 8, 1999

Appl. No.:

9/328191

Inventors:

Wing Cheong Chau - Los Altos Hills CA
Darren Leu - San Jose CA
Chandy Nilakantan - Cupertino CA
Jeffrey Kaiping Pao - San Jose CA
Wayming Daniel Tai - Cupertino CA
Xiaohu Wang - Milpitas CA

Assignee:

3Com Corporation - Santa Clara CA

International Classification:

H04L 1202

US Classification:

370352

Abstract:

The present invention provides a modular architecture for connecting a plurality of telephone lines to a computer network. The invention binds a plurality of network access servers together so that they form a single system image to clients dialing into the plurality of network access servers. The invention operates by providing a tunneling mechanism for communication between the network access servers. The tunneling mechanism facilitates packet re-forwarding so that a call dialed into a physical port in a network access server can be re-forwarded through a logical port in another network access server. This allows a call to be routed through a physical port in a network access server even if no logical port is available in the network access server. Packet re-forwarding also allows multilink connections through physical ports in multiple network access servers to be routed through a single logical port in a network access server. Packet re-forwarding also provides support for spoofing; if the telephone line is torn down during spoofing, the logical port is maintained so that the connection may be reestablished through a physical port in another network access server.