Efficient Mobile Data Collection with Mobile Collect

WISENET (NES)PromosCONE

Do Sensor Networks need Mobile MAC Protocols?

WISENET (NES)SSFCNSCONETPromo

Tools and methods for evaluation of overlay networks

Overlay networks is a popular method to deploy new functionality which does not currently exist in the Internet. Such networks often use the peer-to-peer principle where users are both servers as well as clients at the same time. We evaluate how overlay networks performs in a mix of strong and weak peers. The overlay system of study in this thesis is Bamboo, which is based on a distributed hash table (DHT). For the performance evaluation we use both simulations in NS-2 and emulations in the testbed PlanetLab. One of our contributions is an NS-2 implementation of the Bamboo DHT. To simulate nodes joining and leaving, NS-2 is modified to be aware of the identity of overlay nodes. To control experiments on PlanetLab we designed Vendetta. Vendetta is both a tool to visualize network events and a tool to control the individual peer-to-peer nodes on the physical machines. PlanetLab does not support bandwidth limitations which is needed to emulate weak nodes. Therefore we designed a lightweight connectivity tool called Dtour. Both the NS-2 and PlanetLab experiments indicate that a system like Bamboo can handle as much as 50% weak nodes and still serve requests. Although, the lookup latency and the number of successful lookups suffer with the increased network dynamics

Tools and methods for evaluation of overlay networks

Overlay networks is a popular method to deploy new functionality which does not currently exist in the Internet. Such networks often use the peer-to-peer principle where users are both servers as well as clients at the same time. We evaluate how overlay networks performs in a mix of strong and weak peers. The overlay system of study in this thesis is Bamboo, which is based on a distributed hash table (DHT). For the performance evaluation we use both simulations in NS-2 and emulations in the testbed PlanetLab. One of our contributions is an NS-2 implementation of the Bamboo DHT. To simulate nodes joining and leaving, NS-2 is modified to be aware of the identity of overlay nodes. To control experiments on PlanetLab we designed Vendetta. Vendetta is both a tool to visualize network events and a tool to control the individual peer-to-peer nodes on the physical machines. PlanetLab does not support bandwidth limitations which is needed to emulate weak nodes. Therefore we designed a lightweight connectivity tool called Dtour. Both the NS-2 and PlanetLab experiments indicate that a system like Bamboo can handle as much as 50% weak nodes and still serve requests. Although, the lookup latency and the number of successful lookups suffer with the increased network dynamics

Experimental Challenges in Wireless Sensor Networks — Environment, Mobility, and Interference

Wireless sensor networks are used to collect sensor data in different applications such as environmental monitoring, smart building control, and health care applications. Wireless sensor nodes used are typically small, low-cost, and battery powered. The nodes are often hard to access after deployment, for example when they are in remote  locations. Another property of wireless sensor networks is that their operation is dependent on the environment they operate in, both due to the specific sensor readings but also due to the effects on communication by factors such as fading and radio interference. This makes it important to evaluate a wireless sensor network in its intendent target environment before final deployment. To enable experiments with wireless sensor networks in their target environment, we have designed and implemented a testbed called Sensei-UU. It is designed to allow WSN experiments to be repeated in different locations, thus exposing effects caused by the environment. To allow this, the testbed is designed to be easily moved between experimental sites. One type of WSN applications Sensei-UU is aimed to evaluate is protocols where nodes are mobile. Mobile testbed nodes are low-cost robots which follow a tape track on the floor. The localization accuracy of the robot approach is evaluated and is accurate enough to expose a protocol to fading phenoma in a repeatable manner. Sensei-UU has helped us develop a lightweight interference classification approach, SoNIC, which runs on standard motes. The approach only use information from a standard cc2420 chipset available when packets are received. We believe that the classification accuracy is good enough to motivate specific transmission techniques avoiding interference.WISENE

Tools and methods for evaluation of overlay networks

Overlay networks is a popular method to deploy new functionality which does not currently exist in the Internet. Such networks often use the peer-to-peer principle where users are both servers as well as clients at the same time. We evaluate how overlay networks performs in a mix of strong and weak peers. The overlay system of study in this thesis is Bamboo, which is based on a distributed hash table (DHT). For the performance evaluation we use both simulations in NS-2 and emulations in the testbed PlanetLab. One of our contributions is an NS-2 implementation of the Bamboo DHT. To simulate nodes joining and leaving, NS-2 is modified to be aware of the identity of overlay nodes. To control experiments on PlanetLab we designed Vendetta. Vendetta is both a tool to visualize network events and a tool to control the individual peer-to-peer nodes on the physical machines. PlanetLab does not support bandwidth limitations which is needed to emulate weak nodes. Therefore we designed a lightweight connectivity tool called Dtour. Both the NS-2 and PlanetLab experiments indicate that a system like Bamboo can handle as much as 50% weak nodes and still serve requests. Although, the lookup latency and the number of successful lookups suffer with the increased network dynamics

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bandwidth study of a DHT in a heterogeneous environmen