NETEMBED: A Network Resource Mapping Service for Distributed Applications

Emerging configurable infrastructures such as large-scale overlays and grids, distributed testbeds, and sensor networks comprise diverse sets of available computing resources (e.g., CPU and OS capabilities and memory constraints) and network conditions (e.g., link delay, bandwidth, loss rate, and jitter) whose characteristics are both complex and time-varying. At the same time, distributed applications to be deployed on these infrastructures exhibit increasingly complex constraints and requirements on resources they wish to utilize. Examples include selecting nodes and links to schedule an overlay multicast file transfer across the Grid, or embedding a network experiment with specific resource constraints in a distributed testbed such as PlanetLab. Thus, a common problem facing the efficient deployment of distributed applications on these infrastructures is that of "mapping" application-level requirements onto the network in such a manner that the requirements of the application are realized, assuming that the underlying characteristics of the network are known. We refer to this problem as the network embedding problem. In this paper, we propose a new approach to tackle this combinatorially-hard problem. Thanks to a number of heuristics, our approach greatly improves performance and scalability over previously existing techniques. It does so by pruning large portions of the search space without overlooking any valid embedding. We present a construction that allows a compact representation of candidate embeddings, which is maintained by carefully controlling the order via which candidate mappings are inserted and invalid mappings are removed. We present an implementation of our proposed technique, which we call NETEMBED – a service that identify feasible mappings of a virtual network configuration (the query network) to an existing real infrastructure or testbed (the hosting network). We present results of extensive performance evaluation experiments of NETEMBED using several combinations of real and synthetic network topologies. Our results show that our NETEMBED service is quite effective in identifying one (or all) possible embeddings for quite sizable queries and hosting networks – much larger than what any of the existing techniques or services are able to handle.National Science Foundation (CNS Cybertrust 0524477, NSF CNS NeTS 0520166, NSF CNS ITR 0205294, EIA RI 0202067

ANALYSIS AND DEVELOPMENT OF A MATHEMATICAL STRUCTURE TO DESCRIBE ENERGY CONSUMPTION OF SENSOR NETWORKS

Collections of several hundred, thousands, or even millions of small devices scattered or placed throughout an area monitoring the environment called sensor networks have several useful applications. Until recently, the economic cost of development, manufacture, and deployment limited the use of sensor networks to military and government applications. Recent advances in technology provide a means for economical development, deployment, and manufacture of sensor networks.Current methodology designs, then implements and simulates the sensor network, then goes back and redesigns to better meet the specifications. The model developed in this dissertation provides an early indication of what types of solutions will meet the requirements and what types of solutions will not. With this ability, the time required for simulation and proof of concept is reduced, allowing more time and money for design and testing of the real world system. The model developed characterizes the energy consumption of a sensor or RFID network as a whole is extremely beneficial and is needed. The model provides a means to benchmark different types of sensor networks (i.e. different protocols, hardware, software) and to determine which type is the better solution. A model such as this removes the requirement to develop a simulation to compare different types. Using the model reduces the time (and save money) needed to verify the solution and helps with development as multiple designs can be quickly tested and compared possibly at a much earlier stage in the development cycle allowing a thorough investigation of different design alternatives

A Quantitative Analysis of Performance in a Multi-Protocol Ad Hoc 802.11b-based Wireless Local Network

The popularity of the Internet and the growing demand for ubiquitous connectivity accelerate the need for viable wireless local area network (WLAN) solutions. As a consequence, increasing number of manufacturers have adopted the Institute of Electrical and Electronic Engineers (IEEE) 802.11a/b/g set of WLAN standards and produced inexpensive wireless products to expand capabilities of existing LANs. IEEE 802.11 b wireless products are widely accepted. Mobile ad hoc networks, a variant of the 802.11 standards, exist without the requirement for a wired infrastructure or host to provide routing, connectivity, and maintenance services. Because of the high variability of environments in which ad hoc networks operate, numerous routing protocols are proposed. Research indicates that these protocols are unsuited for efficient operation in multiple environments. In this investigation, the author examined the effect of multiple protocols on throughput and end-to-end delay in simulated ad hoc networks. The author selected the ad hoc on-demand distance vector (AODV) and dynamic source routing (DSR) routing protocols for this research. The outcomes from the simulations conducted indicated increased end-to-end delay and reduced packet throughput as a result of the mixed populations of the AODV and DSR ad hoc routing protocols. The results also indicated that increasing node density and velocity improved packet throughput and reduced end-to-end delay

ABSTRACT Lowering the Barrier to Wireless and Mobile Experimentation

The success of ns highlights the importance of an infrastructure that enables efficient experimentation. Similarly, Netbed’s automatic configuration and control of emulated and live network environments minimizes the effort spent configuring and running experiments. Learning from the evolution of these systems, in this paper we argue that a live wireless and mobile experimental facility focusing on ease of use and accessibility will not only greatly lower the barrier to research in these areas, but that the primary technical challenges can be overcome. The flexibility of Netbed’s common abstractions for diverse node and link types has enabled its development from strictly an emulation platform to one that integrates simulation and live network experimentation. It can be further extended to incorporate wireless and mobile devices. To reduce the tedium of wireless and mobile experimentation, we propose automatically allocating and mapping a subset of a dense mesh of devices to match a specified network topology. To achieve low-overhead, coarse repeatability for mobile experiments, we outline how to leverage the predictability of passive couriers, such as PDA-equipped students and PC-equipped busses. 1