3com Corporation

Cisco Technology, Inc.

Wing Cheong Chau

Wayming Daniel Tai

Tsyr-Shya Joe Sun

Xiaohu Wang

Jeffrey Kaiping Pao

Chandy Nilakantan

Tze-jian Liu

Darren Leu

Shantanu Sarkar

Dar-Ren Leu

Randall Bernard Baird

Scott S Firestone

Madhu Grandhi

Kirk Dow Sanders

Ramesh Sastry

Raffaello Pardini

Rangaraju Iyengar

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.

Measurement of round-trip delay over a network

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.

Method and apparatus for dynamic DSP resource management

A method and apparatus is described that provides for switching active data connections from one processor to another processor without significantly interfering with the transmission of the data. The data may be voice calls and the processors may be DSPs residing on a voice processing module. A DSP resource allocation algorithm may be used to load share the data by selectively moving an active voice call currently being processed on one DSP to another DSP having sufficiently available processing power, without interrupting the prevailing service. The liberated DSP may then be used to process a new active voice call. By using the DSPs to load share, the number of simultaneous active voice calls supported by a voice processing module may be increased.

Method and apparatus for hitless switchover of a voice connection in a voice processing module

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. Finally, the present invention supports authentication across multiple network access servers using a security server, by allowing the network access servers to share authentication information.

Integrated architecture to support a single system image across multiple network access servers

Architecture to support a single system image across multiple network access servers

Supporting multilink connections across multiple network access servers

Supporting load sharing across multiple network access servers

Architecture to support a single system image across multiple network

Supporting authentication across multiple network access servers

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.

Distributed signal processing for data channels maintaining channel

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Los Altos Hills, CA, United States of America

Wing Cheong Chau