Abstract: Providing power management to sensing nodes in a sensor network may include a plurality of sensing nodes, each sensing node connected through a power management device to an external power source, such as a powered node of another network, for managing power from the external power source to the sensing node. Multiple power management devices allow for a sensor network of fixed or mobile wireless sensing nodes or sensor gateways to make use of power from an external source such as an another network. An intelligent power management device connected to at least one of the sensing nodes may provide for power policy management.

Abstract: Algorithms and data structure are described for constructing and maintaining a clock distribution tree (“CDT”) for timing loop avoidance. The CDT algorithms and data structure allows a node to make an automated and unattended path switch to the most desirable clock source in the network. In response to a network topology change, a clock root node distributes new clock paths to all nodes in the network. In particular, the root node calculates a new clock path for each affected node by building a clock source topology tree, and identifying from that tree a path to the network node from a clock source of higher or equal stratum relative to that network node. The root node then sends a network message to each node indicating the new path that the node should use. Each node receives the message and compares the new path with the existing path. If the paths are different then the node acquires the new path just received in the message. If the paths are the same then the node does nothing and discards the message.

Abstract: Secure access to inventory data concerning a supplier's product located at a seller's premises is provided by tagging units of product with a supplier identifier and a product identifier. The identifiers may be embedded in RFID tags or EPC labels. A secure VPN tunnel is established between a supplier and a seller. The VPN tunnel is associated with a particular supplier identifier such that only inventory data associated with the supplier identifier that matches the supplier is transmitted on the VPN tunnel, and inventory data associated with supplier identifiers that do not match the supplier are filtered out. Hence, the seller can provide the supplier with access to inventory data without exposing sensitive information related to the seller and other suppliers.

Abstract: A traffic controller is provided which integrates black-box tests of unauthorized applications to extract application characteristics from associated Internet traffic, exploits the networking information learned by host clients, actively scans and controls hosts on the corporate network, and dynamically configures a corporate firewall to block traffic to and from critical application network elements. As a result, the traffic controller effectively manages unauthorized applications and their associated traffic in a corporate environment.

Abstract: The present invention relates to a system and method for providing power management to sensing nodes in a sensor network. A system may include a plurality of sensing nodes, each sensing node connected through a power management device to an external power source, such as a powered node of another network, for managing power from the external power source to the sensing node. Beneficially, a plurality of power management devices allow for a sensor network of fixed or mobile wireless sensing nodes or sensor gateways to make use of power from an external source such as an another network e.g. an existing emergency lighting system or other similar powered building system. Thus for example, a sensor or group of sensing nodes and their associated power management devices may be integral with or co-located in proximity to powered nodes of these other networks.

Abstract: Secure access to inventory data concerning a supplier's product located at a seller's premises is provided by tagging units of product with a supplier identifier and a product identifier. The identifiers may be embedded in RFID tags or EPC labels. A secure VPN tunnel is established between a supplier and a seller. The VPN tunnel is associated with a particular supplier identifier such that only inventory data associated with the supplier identifier that matches the supplier is transmitted on the VPN tunnel, and inventory data associated with supplier identifiers that do not match the supplier are filtered out. Hence, the seller can provide the supplier with access to inventory data without exposing sensitive information related to the seller and other suppliers.

Abstract: A traffic controller is provided which integrates black-box tests of unauthorized applications to extract application characteristics from associated Internet traffic, exploits the networking information learned by host clients, actively scans and controls hosts on the corporate network, and dynamically configures a corporate firewall to block traffic to and from critical application network elements. As a result, the traffic controller effectively manages unauthorized applications and their associated traffic in a corporate environment.

Abstract: A timestamp-based clock synchronization technique is employed for CES in packet networks. The technique is based on a double exponential filtering technique and a linear process model. The linear process model is used to describe the behavior of clock synchronization errors between a transmitter and a receiver. The technique is particularly suitable for clock synchronization in networks where the transmitter and receiver are not driven from a common timing reference but the receiver requires timing reference traceable to the transmitter clock.

Abstract: The invention includes a technique for clock recovery in a network having master and slave clocks in respective Time Division Multiplexing (“TDM”) network segments which are interconnected by a non-TDM segment. Master clock timestamps are sent to the slave. The slave measures a master clock timestamp inter-arrival interval, and sends slave clock timestamps to the master. The master measures a slave clock timestamp inter-arrival interval, and sends that slave clock timestamp inter-arrival interval to the slave. The slave then calculates an error signal based at least in-part on the difference between the master clock timestamp inter-arrival interval and the slave clock timestamp inter-arrival interval, and employs the difference to recover the first service clock in the second TDM segment.

Abstract: A technique for adaptively load balancing connections in multi-link trunks is disclosed. The present invention provides an adaptive load balancing algorithm that utilizes relative link quality metrics to adjust traffic distribution between links. Link quality metrics may include short-term averages of an observed packet drop rate for each member link in a bundle. The present invention may dynamically adjust the number of flows on each link in proportion to available bandwidth. In addition, link quality metrics may be equalized, such that no link is more lossy than the others.

Abstract: A computer network processes data packets in the event of a network link failure. The network includes a plurality of routers that deliver data packets to the network via a plurality of links. At least one router includes a protection cycle manager. The protection cycle manager has a protection cycle packet identifier and a protection cycle packet processor. The protection cycle packet identifier identifies, as protection cycle packets, data packets having a specific protection cycle format. The protection cycle packet processor processes protection cycle packets to determine whether the packet destination corresponds to the routing node, and if the packet destination corresponds to the routing node, the protection cycle packet is treated by the routing node as a data packet received from the packet source via the failed link. Otherwise, if the packet destination does not correspond to the routing node, the protection cycle packet is sent to a protection cycle node for the routing node.

Abstract: A method and system for allocating bandwidth of a wireless channel to different types of traffic includes partitioning the bandwidth of the wireless channel into a plurality of contention periods. Traffic flows are associated with access categories, and one or more of the access categories are assigned to each contention period. During at least one of the contention periods, traffic flows associated with a proper subset of the access categories contend for access to the wireless channel.

Abstract: A timestamp-based all digital phase locked loop is utilized for clock synchronization for Circuit Emulation Service (“CES”) over packet networks. The all digital phase locked loop at a CES receiver includes a phase detector, a loop filter, a digital oscillator and a timestamp counter. The all digital phase locked loop enables the CES receiver to synchronize a local clock at the receiver with a clock at a CES transmitter, where indications of transmitter clock signals are communicated to the receiver as timestamps. The phase detector is operable to compute an error signal indicative of differences between the timestamps and a local clock signal. The loop filter is operable to reduce jitter and noise in the error signal, and thereby produce a control signal. The digital oscillator is operable to oscillate at a frequency based at least in-part on the control signal, and thereby produce a digital oscillator output signal.

Abstract: A system, method and apparatus synchronize protocol events in a distributed communication network. The network includes a plurality of nodes. Each node in the network includes a time source which maintains a clock signal synchronized with each other node time source in the network. An announcement of a protocol event is sent to at least one node. The announcement includes a predetermined time for implementing the protocol event. The protocol event is acted upon at the predetermined time.

Abstract: Network elements may be synchronized over an asynchronous network by implementing a master clock as an all digital PLL that includes a Digitally Controlled Frequency Selector (DCFS), the output frequency of which may be directly controlled through the input of a control word. The PLL causes the control word input to the master DCFS to be adjusted to cause the output of the master DCFS to lock onto a reference frequency. Information associated with the control word is transmitted from the master clock to the slave clocks which are also implemented as DCFSs. By using the transmitted information to recreate the master control word, the slaves may be made to assume the same state as the master DCFS without requiring the slaves to be implemented as PLLs. The DCFS may be formed as a digitally controlled oscillator (DCO) or as a Direct Digital Synthesizer (DDS).

Abstract: A method and apparatus for designing a PLL enables initial component characteristics and design specifications of the PLL to be specified. Time constants for a loop filter that would be required to create a PLL having the desired design specifications and component characteristics are then computed. The performance or behavior characteristics of the PLL may then be computed for the PLL given the time constants and the initial set of components, to determine whether the performance of the PLL would be considered satisfactory. For example, PLL design software may determine whether a PLL would be sufficiently stable if it was to be created using the particular selected components given the required design specifications. Where the PLL does not meet particular behavior characteristics, the PLL design software may provide guidance as to what component characteristics would improve performance of the PLL. Designed PLLs may be used for timestamp based clock synchronization.

Abstract: A first level of control over operation of slave Digitally Controlled Frequency Selectors (DCFSs), such as DCOs or DDSs, may occur by periodic transmission of control words from the master clock to the slave clocks. To allow enhanced control over the output of the slave clocks, the frequency of the local oscillator used to generate the synthesized output of the master clock may also be conveyed to the slave clocks to allow a second level of control to take place. The second level of control allows the local oscillators at the slave clocks to lock onto the frequency of the master local oscillator to thereby allow the slave local oscillators to operate the slave DCFSs using the same local oscillator frequency. The first level of control synchronizes operation of the DCFSs while the second level control prevents instabilities in the local oscillators from causing long term drift between the slave and master clock outputs. Timestamps may be used to synchronize the master and slave local oscillators.

Abstract: A computer network processes data packets in the event of a network link failure. The network includes a plurality of routers that deliver data packets to the network via a plurality of links. At least one router includes a protection cycle manager. The protection cycle manager has a protection cycle packet identifier and a protection cycle packet processor. The protection cycle packet identifier identifies, as protection cycle packets, data packets having a specific protection cycle format. The protection cycle packet processor processes protection cycle packets to determine whether the packet destination corresponds to the routing node, and if the packet destination corresponds to the routing node, the protection cycle packet is treated by the routing node as a data packet received from the packet source via the failed link. Otherwise, if the packet destination does not correspond to the routing node, the protection cycle packet is sent to a protection cycle node for the routing node.

Abstract: A novel beacon-based position location technique for efficient location discovery of untethered clients in packet networks is disclosed. The position location technique utilizes the time-difference-of-arrival (“TDOA”) of a first signal transmitted by a beacon of known location and a second signal transmitted by an untethered client. The TDOA of these two signals is measured locally by at least three non-collinear signal receivers. For each of the receivers, the TDOA is used to calculate a perceived distance to the client. A circle is then calculated for each receiver, centered on the receiver and having a radius equal to the perceived distance. At least two lines defined by points of intersection of the calculated circles are then calculated. The point of intersection of the lines represents the location of the client. To facilitate operation, the signal receivers may be arranged on vertices which define a convex polygon as viewed from above.

Abstract: Where a common network clock is available at both a TDM receiver and a TDM transmitter which communicate via a packet network, differential clock recovery can be accomplished by matching the number of service clock pulses in a network reference clock period at the transmitter and receiver. In one embodiment the transmitter need only send a counter value from a counter that is clocked and reset, respectively, by the service clock and network reference clock, thereby allowing use of different types of oscillators, both analog and digital, to be implemented at the transmitter and receiver. The technique is also general enough to be applied in a wide variety of packet networks including but not limited to IP, MPLS and Ethernet. In an alternative embodiment, a faster derived network clock fdnc drives both the transmitter and receiver counters, which in turn are reset, respectively by the slower transmitter service clock fsc and slower receiver service clock frc.