The disclosed embodiments include system and method for routing communications over a communications network. In one embodiment, a determination is made as to whether to establish a communication along a communication path based on network performance information. The disclosed embodiments provide several alternatives for establishing the communication and improving communications along the communication path in response to a determination that at least one network node along the communication path is impaired or congested.

System and method for routing data on a packet network

A system for monitoring and optimizing network performance to a wireless device including a wireless router in communication with the wireless device for transmitting and receiving RF signals between the wireless router and the wireless device, the wireless router configured to determine network performance information of the wireless network; concatenate the network performance information into data packets; a packet network switch in communication with the wireless router for communicating the data packets between the wireless router and the packet network switch; and a network management device in communication with the packet network switch for instructing the packet network switch to route the data packets to the wireless router based on the network performance information to optimize the network performance to the wireless device. A method for monitoring and optimizing network performance to a wireless device is also included.

System and method for monitoring and optimizing network performance to a wireless device

A system and method for tracking application resource usage. Network performance information of a communications network is gathered using performance information packet data packets. The network performance information is communicated to an application. Instructions in the application are executed in response to receiving the network performance information.

System and method for tracking application resource usage

A re-programmable non-volatile memory system, such as a flash EEPROM system, having its memory cells grouped into blocks of cells that are simultaneously erasable is operated to perform memory system housekeeping operations in the foreground during execution of a host command, wherein the housekeeping operations are unrelated to execution of the host command. Both one or more such housekeeping operations and execution of the host command are performed within a time budget established for executing that particular command. One such command is to write data being received to the memory. One such housekeeping operation is to level out the wear of the individual blocks that accumulates through repetitive erasing and re-programming.

Scheduling of housekeeping operations in flash memory systems

A system for adjusting the window size of a TCP packet on a packet network including a sending network element in communication with a receiving network element for transmitting and receiving data packets between the sending network element and the receiving network element on the packet network, wherein at least one of the sending network element and the receiving network element is configured to determine network performance information of the packet network; concatenate the network performance information into the data packets; and adjust the window size of the TCP packet based on the network performance information. A method for adjusting the window size of a TCP packet on a packet network is also included.

System and method for adjusting the window size of a tcp packet through network elements

A method and apparatus dynamically control data traffic, such as multimedia streams, needing a guaranteed Quality of Service (QoS) and normal data traffic, according to a variable communication environment. The method of dynamically controlling traffic in a wireless station includes reading header information of a packet received from an upper layer and determining a type of the packet, setting a priority according to the type of the packet, adjusting a size of a variable buffer by performing appropriate dynamic buffering according to the type of the packet, enqueuing the packet in a fixed buffer if the priority is high and enqueuing the packet in the variable buffer if the priority is low, and transmitting the packet enqueued in the fixed buffer to a destination station prior to the packet enqueued in the variable buffer.

Method and apparatus for dynamically controlling traffic in wireless station

Wireless sensor networks (WSNs) are subject to significant resource constraints. Particularly, routing protocols for low-rate WSNs suffer from maintaining routing metrics and stable links of paths. Even though opportunistic routing protocols are well-suited to WSNs, they have some weaknesses for supporting real-time data and low power consumption. This paper proposes a new routing protocol called opportunistic real time routing (or ORTR) that guarantees delivery of data under time constraints with efficient power consumption. In order to satisfy time requirements, an area where real-time data must be delivered is defined with effective transmission power and a relay node within the area is selected for the purpose of balancing overall energy levels. We compare existing routing protocols against ORTR through a set of simulation experiments. Our simulation results illustrate that ORTR provides guaranteed real-time service with optimal transmission power without degrading the energy balance.

Opportunistic real-time routing in multi-hop wireless sensor networks

In this paper, we conduct a systematic study of human-initiated cascading failures in three critical inter-dependent societal infrastructures due to behavioral adaptations in response to a crisis. We focus on three closely coupled socio-technical networks here: (i) cellular and mesh networks, (ii) transportation networks and (iii) mobile call networks. In crises, changes in individual behaviors lead to altered travel, activity and calling patterns, which influence the transport network and the loads on wireless networks. The interaction between these systems and their co-evolution poses significant technical challenges for representing and reasoning about these systems. In contrast to system dynamics models for studying these interacting infrastructures, we develop interaction-based models in which individuals and infrastructure elements are represented in detail and are placed in a common geographic coordinate system. Using the detailed representation, we study the impact of a chemical plume that has been released in a densely populated urban region. Authorities order evacuation of the affected area, and this leads to individual behavioral adaptation wherein individuals drop their scheduled activities and drive to home or pre-specified evacuation shelters as appropriate. They also revise their calling behavior to communicate and coordinate among family members. These two behavioral adaptations cause flash-congestion in the urban transport network and the wireless network. The problem is exacerbated with a few, already occurring, road closures. We analyze how extended periods of unanticipated road congestion can result in failure of infrastructures, starting with the servicing base stations in the congested area. A sensitivity analysis on the compliance rate of evacuees shows non-intuitive effect on the spatial distribution of people and on the loading of the base stations. For example, an evacuation compliance rate of 70% results in higher number of overloaded base stations than the evacuation compliance rate of 90%.

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Human initiated cascading failures in societal infrastructures.

We present a distributed transactional memory (TM) scheduler called Bi-interval that optimizes the execution order of transactional operations to minimize conflicts. Bi-interval categorizes concurrent requests for a shared object into read and write intervals to maximize the parallelism of reading transactions. This allows an object to be simultaneously sent to nodes of reading transactions (in a data flow TM model), improving transactional makespan. We show that Bi-interval improves the makespan competitive ratio of the Relay distributed TM cache coherence protocol to O(log(n)) for the worst-case and Θlog(n - k) for the average-case, for n nodes and k reading transactions. Our implementation studies confirm Bi-interval's throughput improvement by as much as 200% ∼ 30%, over cache-coherence protocol-only distributed TM.

On transactional scheduling in distributed transactional memory ystems

A method for wireless LAN communication using multiple channels is provided An ATIM containing channel information is generated when there is data to be sent, and the ATIM is transmitted via a main channel after a predetermined period of time When a station loses a channel reservation competition, the station generates and transmits via the main channel another ATIM containing channel information regarding another channel to be used from data transmission The station then performs channel switching to the other channel corresponding to the channel information, transmits the data via the other channel, and switches the channel back to the main channel at the time of a subsequent beacon

Junwhan Kim

Papers

Method and apparatus for dynamically controlling traffic in wireless station

Opportunistic real-time routing in multi-hop wireless sensor networks

Human initiated cascading failures in societal infrastructures.

On transactional scheduling in distributed transactional memory ystems

Method for wireless local area network communication using multiple channels