Prithviraj Patil

Voronoi-based placement of road-side units to improve dynamic resource management in Vehicular Ad Hoc Networks

Vehicular Ad-hoc Networks (VANETs) illustrate mobile P2P networks, which hold significant promise in improving traffic safety and alleviating traffic congestion. Reliable VANETbased services require dynamic resource management due to limited and often fluctuating network connectivity of VANETs that stem from the wireless and mobile nature of vehicleto-vehicle (V2V) communications. To address these needs, a collaboration with Road-Side Units (RSU) have been proposed to complement V2V communication by providing event and data brokering capability in the form of Vehicle-to-Infrastructure (V2I) communications. Deploying RSUs involves upfront investment and maintenance costs, and hence solutions are needed that maximize the benefit of RSUs by placing them effectively in accordance to existing and projected traffic density, and the types of services planned for VANETs. To address these challenges, this paper proposes a novel Voronoi diagram-based algorithm for the effective placement of RSUs using packet delay and loss as a criteria. This approach has two-fold advantages: a significant reduction in the number of RSUs required to cover a geographic region, and increase in the logical coverage area of each RSU irrespective of the dynamic vehicular traffic conditions thereby improving reliability of communications. This algorithm has been evaluated in the context of a road network and traffic conditions for an urban area. When compared with other baseline placement algorithms, communication reliability stemming from our Voronoi diagram-based placement algorithm results in less packet delay and lesser packet loss both of which are important to realize the different VANET-based services.

Maximizing Vehicular Network Connectivity through an Effective Placement of Road Side Units Using Voronoi Diagrams

Vehicular Ad-hoc Networks (VANETs) are increasingly used to support critical services that improve traffic safety and alleviate traffic congestion. Developing VANET-based services and applications, however, is hindered due primarily to limited and often fluctuating communication capacity of VANETs that stem from the wireless and mobile nature of vehicle-tovehicle (V2V) communications. To address this limitation, Road- Side Units (RSU) have been proposed to complement V2V communication by providing event and data brokering capability in the form of Vehicle-to-Infrastructure (V2I) communications. This paper proposes a novel Voronoi network-based algorithm for the effective placement of RSUs which when deployed forms Voronoi networks in terms of the amount of delay incurred by data packets sent over the RSUs.

PADS: Design and Implementation of a Cloud-Based, Immersive Learning Environment for Distributed Systems Algorithms

As distributed systems become more complex, understanding the underlying algorithms that make these systems work becomes even harder. Traditional learning modalities based on didactic teaching and theoretical proofs alone are no longer sufficient for a holistic understanding of these algorithms. Instead, an environment that promotes an immersive, hands-on learning of distributed systems algorithms is needed to complement existing teaching modalities. Such an environment must be flexible to support the learning of a variety of algorithms. The environment should also support extensibility and reuse since many of these algorithms share several common traits with each other while differing only in some aspects. Finally, it must also allow students to experiment with large-scale deployments in a variety of operating environments. To address these concerns, we use the principles of software product lines and model-driven engineering, and adopt the cloud platform to design an immersive learning environment called the Playground of Algorithms for Distributed Systems (PADS). A prototype implementation of PADS is described to showcase use cases involving BitTorrent Peer-to-Peer file sharing, ZooKeeper-based coordination, and Paxos-based consensus, which show the benefits of rapid deployment of the distributed systems algorithms. Results from a preliminary user study are also presented.

Enabling Software-Defined Networking for Wireless Mesh Networks in smart environments

Wireless Mesh Networks (WMNs) serve as a key enabling technology for various smart initiatives, such as Smart Power Grids, by virtue of providing a self-organized wireless communication superhighway that is capable of monitoring the health and performance of system assets as well as enabling efficient trouble shooting notifications. Despite this promise, the current routing protocols in WMNs are fairly limited, particularly in the context of smart initiatives. Additionally, managing and upgrading these protocols is a difficult and error-prone task since the configuration must be enforced individually at each router. Software-Defined Networking (SDN) shows promise in this regard since it enables creating a customizable and programmable network data plane. However, SDN research to date has focused predominantly on wired networks, e.g., in cloud computing, but seldom on wireless communications and specifically WMNs. This paper addresses the limitations in SDN for WMNs by allowing the refactoring of the wireless protocol stack so as to provide modular and flexible routing decisions as well as fine-grained flow control. To that end, we describe an intelligent network architecture comprising a three-stage routing approach suitable for WMNs in uses cases, such as Smart Grids, that provides an efficient and affordable coverage as well as scalable high bandwidth capacity. Experimental results evaluating our approach for various QoS metrics like latency and bandwidth utilization show that our solution is suitable for the requirements of mission-critical WMNs.

Bootstrapping Software Defined Network for flexible and dynamic control plane management

To improve reliability and performance of Software Defined Networking (SDN) architectures, a number of recent efforts have proposed a logically centralized but physically distributed controller design that overcomes the bottleneck introduced by a single physical controller. Despite these advances, two key problems still persist. First, the task of controlling the host network and the task of controlling the control-plane network remain tightly intertwined, which incurs unwanted complexity in the controller design. Second, the task of deploying the distributed controllers continues to be performed in a manual and static way. To address these two problems, this paper presents a novel approach called InitSDN to bootstrapping the distributed software defined network architecture and deploying the distributed controllers. InitSDN makes the SDN control plane design less complex, makes coordination among controllers flexible, provides additional reliability to the distributed control plane.

Towards Reliable Communication in Intelligent Transportation Systems

Cyber physical systems (CPS) are increasingly seen as a way to provide solutions for societal benefits. For these systems to become widely adopted, reliability of these systems is a key requirement because CPS appear in safety- and mission critical applications. To bring about the reliability challenges and the scientific principles behind developing solutions for CPS reliability, I am focusing on two CPS domains: intelligent transportation system and reconfigurable conveyor systems. Intelligent transportation system is a system where vehicles collaborate together to improve road safety, alleviate congestion thereby helping the environment, and providing a better travel experience. Reconfigurable conveyor systems represent a class of systems in advanced manufacturing that will make manufacturing agile while reducing the operating costs. This report presents an overview of recent work that highlights the challenges we face and their possible solutions in making communication in ITS reliable. It also discusses the reliability issues in reconfigurable conveyor systems. We then outline the future directions.

Cyber Foraging and Offloading Framework for Internet of Things

Computation offloading or cyber foraging is a key capability required to achieve effective resource utilization in mobile cloud computing. It enables the dynamic offloading of computations to either neighboring mobile nodes or remote cloud based servers, retrieve results from the offloaded computations, and thereafter continue execution of the mobile business logic. A number of computational mobility solutions have emerged recently for mobile cloud computing involving smartphones and tablets. However, these solutions incur limitations in the context of Internet of Things (IoT) due to the significant heterogeneity illustrated by the range of objects involved in IoT and the fact that existing solutions tend to be tightly coupled to their underlying frameworks, which makes it hard to seamlessly adapt these solutions to the IoT scenarios. To address these concerns, this paper makes three contributions. First, it presents a novel modular and highly configurable framework for providing seamless computational mobility in the IoT realm. Second, it provides implementation details for key capabilities of this framework. Third, it provides qualitative evaluation of the frameworks capabilities.

A Cloud-Based Immersive Learning Environment for Distributed Systems Algorithms

As distributed systems become more complex, understanding the underlying algorithms that make these systems work becomes even harder. Traditional learning modalities based on didactic teaching and theoretical proofs alone are no longer sufficient for a holistic understanding of these algorithms. Instead, an environment that promotes an immersive, hands-on learning of distributed system algorithms is needed to complement existing teaching modalities. Such an environment must be flexible to support learning of a variety of algorithms. Moreover, since many of these algorithms share several common traits with each other while differing only in some aspects, the environment should support extensibility and reuse. Finally, it must also allow students to experiment with large-scale deployments in a variety of operating environments. To address these concerns, we use the principles of software product lines (SPLs) and model-driven engineering and adopt the cloud platform to design an immersive learning environment called the Playground of Algorithms for Distributed Systems (PADS). The research contributions in PADS include the underlying feature model, the design of a domainspecific modeling language that supports the feature model, and the generative capabilities that maximally automate the synthesis of experiments on cloud platforms. A prototype implementation of PADS is described to showcase a distributed systems algorithm illustrating a peer to peer file transfer algorithm based on BitTorrent, which shows the benefits of rapid deployment of the distributed systems algorithm.

Scalable and Adaptive Software Defined Network Management for Cloud-hosted Group Communication Applications

Group communications form the primary communication pattern for many cloud-hosted applications and cloud infrastructure management services, such as system health monitoring, multimedia distribution, collaborative applications and distributed databases. Although IP multicast has been used to support group communication semantics in diverse Internet-based distributed applications, its deployment in cloud Data Center Networks (DCNs) has been limited due to its higher resource consumption, scalability, and stability issues, which in turn degrades the utility of the cloud. Software Defined Networking (SDN) has enabled the re-engineering of multicast capabilities to overcome these limitations. To that end, this paper presents an autonomous, dynamic and flexible middleware solution called SDN-based Multicast (SDMC), which provides both network load-aware and switch memory-efficient group communication semantics in DCNs. Thus, SDMC improves DCN resource utilization while allowing applications to remain agnostic to the underlying group communication semantics by efficiently toggling between unicast and multicast in accordance with changing network bandwidth and switch memory usage. Empirical studies comparing SDMC with traditional IP multicast shows up to 60% better latency performance for different DCNs topologies, and up to 50% better performance in the switch memory utilization for multicast groups exceeding size 30.

Software-defined Adaptive Resource Management for Cloud-hosted Group Communication Applications: Poster

Many cloud-hosted applications and cloud infrastructure management services with publish/subscribe semantics rely heavily on the use of group communications. Although multicast is useful for efficient group communications, traditional IP multicast has seen very low adoption in cloud data center networks (DCNs) due to issues with its stability and scalability. The introduction of Software-defined Networking (SDN) in DCNs has provided new opportunities for re-engineering and effectively utilizing multicast capabilities that can overcome existing impediments to the adoption of IP multicast. To that end this paper presents an adaptive and flexible middleware solution called SDN-based Multicast (SDMC), which provides group communication capabilities in DCNs in a way that is both network load-aware and switch memory-efficient. Applications using SDMC remain agnostic to the underlying group communication semantics, which SDMC provides efficiently by dynamically adapting between unicast and multicast in accordance with changing network bandwidth and switch memory usage.