Motorola Corporation

Sonus Networks, Inc.

John A Perreault

Stephen Schroeder

Abhay Joshi

Mete Kabatepe

Lawrence W Lloyd

Shiping Li

Shaun Jaikarran Bharrat

Mark Duffy

Jian Yang

Dennis J Picker

Katherine A Unger

Xiang Yu

Michael W Patrick

Krishnan Ramakrishnan

Ronald V Grippo

Jeffrey T Klayman

Mark Charles Miner

John Dinatale

Albert Chen

Eva Labowicz

Gary Robert McCarthy

David R Flanagan

Sunil K Menon

The invention features a computer-implemented method for playing back an announcement message to a user device. The method includes initiating, by a computing device, an announcement session in response to a user device establishing communication with the computing device and determining, by the computing device, the announcement message to be played back to the user device. The method includes loading, by the computing device, into a queue associated with the announcement session, a descriptor referencing a memory buffer on the computing device. The memory buffer includes a plurality of memory partitions, each memory partition storing at least one portion of the announcement message encoded at a different rate. The method includes the computing device scheduling play back of the announcement message, playing the announcement message to the user device at a first rate and receiving a request from the user device for playback at a second rate.

Systems and methods for playing recorded announcements

Described are computer-based methods and apparatuses, including computer program products, for identifying attackers on a network. A data packet is filtered by a multi-tiered filtering and transmission system. Data packets matching the first tier filter are discarded. Data packets matching the second tier filter are transmitted to an output module based on a criterion. Data packets in the third tier filter are hashed into bins and data packets matching an entry in the bin are transmitted to the output module based on a criterion for the bin. Data packets in the fourth tier transmission system are transmitted to the output module based on a criterion. Data packets that do not meet the criterion for transmission to the output module are transmitted to an attack identification module which analyzes the data packets to identify attacks.

Identifying attackers on a network

Described are computer-based methods and apparatuses, including computer program products, for filtering and policing for defending against denial of service attacks on a network. A data packet is filtered by a multi-tiered filtering and transmission system. Data packets matching the first tier filter are discarded. Data packets matching the second tier filter are transmitted to an output module based on a criterion. Data packets in the third tier filter are hashed into bins and data packets matching an entry in the bin are transmitted to the output module based on a criterion for the bin. Data packets in the fourth tier transmission system are transmitted to the output module based on a criterion. Data packets that do not meet the criterion for transmission to the output module are transmitted to an attack identification module which analyzes the data packets to identify attacks.

Filtering and policing for defending against denial of service attacks on a network

The apparatus (,) and method for spectrum management in a multipoint communication system controls upstream channel usage for secondary stations (,) transmitting information to a primary station (,) and downstream channel usage for secondary stations (,) receiving information from a primary station (,). The preferred apparatus (,) embodiment includes a processor arrangement (,) having a master controller (,) and a plurality of processors (,), with the processor arrangement connected to a channel interface (,). The apparatus (,) and method controls channel load balancing, channel congestion, and channel assignment in a multipoint communication system, and controls upstream channels independently from downstream channels. Factors and parameters utilized in such channel control and allocation include error parameters, channel noise parameters, transmit and receive loading factors, and congestion parameters.

Apparatus and method for spectrum management in a multipoint communication system

A system, device, and method for improving access in a hybrid contention/polling protocol maintains a list of active users, a list of recently active users, and a list of inactive users. An active user that becomes inactive is moved into the list of recently active users, and a recently active user that remains inactive is moved into the list of inactive users. A limited contention poll addressed to a number of inactive users and at least one recently active user authorizes any of the addressed users to contend for access to the shared channel. Upon detection of a collision, addressed users that are in the list of recently active users are polled individually, while the inactive users are sent a collision resolution poll which forces the inactive users to contend again for access. Users that become active are moved into the list of active users.

Hybrid contention/polling access method

An apparatus and method to implement a hybrid contention and polling protocol for a communications or computer network is disclosed. Various apparatus and method embodiments of the invention employ specific polls from a primary station for polling identified secondary stations of the network which may be in an active state, general polls to any of a plurality of secondary stations of the network which may be in an unresponsive state to initiate contention access to the network, and general polls for collision resolution in the event that a plurality of secondary stations may simultaneously contend for network access. Various embodiments may also include frequency channel allocation for transmission and reception of data and other information within the network. The various procedures and apparatus disclosed may also be used to apply various polling parameters to optimize network performance.

System for determining the frequency of repetitions of polling active

An apparatus (101, 110) and method for channel acquisition in a communication system (100) provides for selecting a channel, from a multiplicity of available channels (205), and determining whether the selected channel is the properly assigned channel for data and other information to be received by the apparatus (101, 110). The selected channel is monitored for a predetermined or adaptive energy level (210), a predetermined modulation mode (215), for a protocol signal, and for a protocol signal having an identification specifying the particular apparatus (225), such as a protocol frame containing a serial number corresponding to the apparatus. When a protocol signal having an identification specifying the particular apparatus (225) is received, the selected channel is acquired (250) for reception of data and other information. Channels are selected on the basis of searching first for those channels most likely to be assigned to the particular apparatus, such as previously assigned channels (305, 320, 325), followed by a focused search initially in the vicinity of a central channel under a particular channel plan (345, 355). The process may also be repeated utilizing a variety of channel or frequency plans (375).

Apparatus and method for channel acquisition in a communication system

A plurality of secondary stations (10.sub.a through 10.sub.n) are coupled to a primary station (8) by way of a shared communication medium (15, 16). The secondary stations (10.sub.a through 10.sub.n) sends information to the primary channel on the upstream channel. The primary station sending information to the secondary stations (10.sub.a through 10.sub.n) on a downstream channel. The power level of a secondary station (10.sub.n) is set at the power level stored in secondary station memory (55). The secondary station (10.sub.n) transmits a message to the primary station on the upstream channel. The primary station (8) receives the message, determines the power level of the received message, and sets the power level of the secondary device to the nominal power level.

Method for transmit power control in a communication system

A control station (8) is coupled to a plurality of tributary devices (20, 16, 18) by way of at least one high speed broadcast downstream data channel and more than one shared lower speed upstream data channels. The control station (8) broadcasts data to all the tributary devices (20, 16, 18) and selects a channel for a specific tributary device (20, 16, 18) to respond to a poll. After polling, the tributary device (20, 16, 18) changes the tributary device transmitter (42) to the frequency of the selected channel. The tributary device (20, 16, 18) either sends data to send to the control station (8) or sends a negative acknowledge to the control station (8). If a negative acknowledgment was transmitted, the control station (8) notifies the control station transmitter that the channel is idle.

Method, device and data communication system for multilink polling

An apparatus and method to implement a hybrid contention and polling protocol for a communications or computer network is disclosed. Various apparatus and method embodiments of the invention employ specific polls from a primary station for polling identified secondary stations of the network which may be in an active state; limited contention polls to an identified individual secondary station which may be in an idle state or to an identified subset of a plurality of secondary stations which may be in an idle state to initiate limited contention access to the network; limited contention polls for collision resolution in the event that a plurality of secondary stations in an idle state may have simultaneously contended for network access; general polls to any of a plurality of secondary stations of the network which may be in an unresponsive state to initiate contention access to the network; and general polls for collision resolution in the event that a plurality of secondary stations may simultaneously contend for network access. Various embodiments may also include frequency channel allocation for transmission and reception of data and other information within the network.

Method and apparatus for a hybrid limited contention and polling protocol

An apparatus (110, 101), method, system (100) and system method provide for distributed internetwork routing of information in a communication system (100). The communication system (100) is characterized by a topology having a primary node connected to a first network, such as the Internet, and connected via an intermediate network to a mulitplicity of secondary nodes, which are further connected via a secondary network to a plurality of terminals, such as personal computers. The apparatus (110, 101), method, system and system method provide for routing of information between the primary node and the terminals independently of and transparently to any internetwork address of a secondary node. The apparatus (110, 101), method, system and system method conserve internetwork addresses by utilizing internetwork addresses only for a primary node and for terminals.

Apparatus, method, system and system method for distributed routing in a

An apparatus (101, 110) and method provide for memory utilization and management which may expand the number of write operations for limited write memories, such as non-volatile memory, to provide for more optimal performance of systems such as computer or communication systems. Such memory utilization, in accordance with the present invention, includes allocating portions of the limited write memory, as a memory structure, for an ordinal or parameter designation. Upon system initialization or start up, comparison of adjacent ordinal designations may then be utilized to precisely locate the area of memory into which data or other information was previously written, indicating the current memory locations for current read operations, and to precisely locate the area of memory into which data or other information is to be written next, in order to provide the proper memory location for a subsequent write operation. The ordinal designation also provides for tracking the number of write operations performed in a given memory location, to prevent overuse of a given memory location and concomitant potential loss of data. In the preferred embodiment, the apparatus includes a processor (150) and memory (155), which includes a working memory and a limited write memory.

Apparatus and method for utilization of limited write memory

An apparatus (101, 110) and method for adaptive forward error correction in a data communication system (100) provides for dynamically changing forward error correction parameters based upon communication channel conditions, such as noise levels or error rates. In the method embodiment of the invention, data having a current degree of forward error correction is received (305), and a channel parameter is monitored (310), such as packet or bit error rates. A threshold level for the channel parameter is determined (315), and the monitored channel parameter is compared to the threshold level (320). When the channel parameter is not within a predetermined or adaptive variance of the threshold level, a revised forward error correction parameter having a greater or lesser degree of forward error correction capability is selected (330, 340, 350, 360), and the revised forward error correction parameter is transmitted (370). The device receiving the revised forward error correction parameter, such as a secondary station (110), then transmits data encoded utilizing the revised error correction parameter (425).

Apparatus and method for adaptive forward error correction in data

The system and method provide for efficiently resolving collisions in an environment where a transmitting device cannot hear collisions without a headend control station/control device, i.e., master, repeating transmission of all upstream frames in the downstream direction. This invention also prevents additional collisions from occurring between a device that is retransmitting and a device that is transmitting a packet for the first time. Further, the present invention allows continued utilization of a channel by other devices while contending devices are processing collision resolution procedures.

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Hopkinton, MA, United States of America

John A Perreault