Kiran Nagaraja

Peer-to-Peer Computing

The term “peer-to-peer” (P2P) refers to a class of systems and applications that employ distributed resources to perform a critical function in a decentralized manner. With the pervasive deployment of computers, P2P is increasingly receiving attention in research, product development, and investment circles. This interest ranges from enthusiasm, through hype, to disbelief in its potential. Some of the benefits of a P2P approach include: improving scalability by avoiding dependency on centralized points; eliminating the need for costly infrastructure by enabling direct communication among clients; and enabling resource aggregation. This survey reviews the field of P2P systems and applications by summarizing the key concepts and giving an overview of the most important systems. Design and implementation issues of P2P systems are analyzed in general, and then revisited for each of the case studies described in Section 6. This survey will help people understand the potential benefits of P2P in the research community and industry. For people unfamiliar with the field it provides a general overview, as well as detailed case studies. It is also intended for users, developers, and information technologies maintaining systems, in particular comparison of P2P solutions with alternative architectures andPeer-to-peer (P2P) technology, or peer computing, is a paradigm that is viewed as a potential technology for redesigning distributed architectures and, consequently, distributed processing. Yet the scale and dynamism that characterize P2P systems demand that we reexamine traditional distributed technologies. A paradigm shift that includes self-reorganization, adaptation and resilience is called for. On the other hand, the increased computational power of such networks opens up completely new applications, such as in digital content sharing, scientific computation, gaming, or collaborative work environments. In this book, Vu, Lupu and Ooi present the technical challenges offered by P2P systems, and the means that have been proposed to address them. They provide a thorough and comprehensive review of recent advances on routing and discovery methods; load balancing and replication techniques; security, accountability and anonymity, as well as trust and reputation schemes; programming models and P2P systems and projects. Besides surveying existing methods and systems, they also compare and evaluate some of the more promising schemes. The need for such a book is evident. It provides a single source for practitioners, researchers and students on the state of the art. For practitioners, this book explains best practice, guiding selection of appropriate techniques for each application. For researchers, this book provides a foundation for the development of new and more effective methods. For students, it is an overview of the wide range of advanced techniques for realizing effective P2P systems, and it can easily be used as a text for an advanced course on Peer-to-Peer Computing and Technologies, or as a companion text for courses on various subjects, such as distributed systems, and grid and cluster computing.

MobilityFirst: a robust and trustworthy mobility-centric architecture for the future internet

This paper presents an overview of the MobilityFirst network architecture, currently under development as part of the US National Science Foundations Future Internet Architecture (FIA) program. The proposed architecture is intended to directly address the challenges of wireless access and mobility at scale, while also providing new services needed for emerging mobile Internet application scenarios. After briefly outlining the original design goals of the project, we provide a discussion of the main architectural concepts behind the network design, identifying key features such as separation of names from addresses, public-key based globally unique identifiers (GUIDs) for named objects, global name resolution service (GNRS) for dynamic binding of names to addresses, storage-aware routing and late binding, content- and context-aware services, optional in-network compute layer, and so on. This is followed by a brief description of the MobilityFirst protocol stack as a whole, along with an explanation of how the protocol works at end-user devices and inside network routers. Example of specific advanced services supported by the protocol stack, including multi-homing, mobility with disconnection, and content retrieval/caching are given for illustration. Further design details of two key protocol components, the GNRS name resolution service and the GSTAR routing protocol, are also described along with sample results from evaluation. In conclusion, a brief description of an ongoing multi-site experimental proof-of-concept deployment of the MobilityFirst protocol stack on the GENI testbed is provided.

MobilityFirst future internet architecture project

This short paper presents an overview of the MobilityFirst network architecture, which is a clean-slate project being conducted as part of the NSF Future Internet Architecture (FIA) program. The proposed architecture is intended to directly address the challenges of wireless access and mobility at scale, while also providing new multicast, anycast, multi-path and context-aware services needed for emerging mobile Internet application scenarios. Key protocol components of the proposed architecture are: (a) separation of naming from addressing; (b) public key based self-certifying names (called globally unique identifiers or GUIDs) for network-attached objects; (c) global name resolution service (GNRS) for dynamic name-to-address binding; (d) delay-tolerant and storage-aware routing (GSTAR) capable of dealing with wireless link quality fluctuations and disconnections; (e) hop-by-hop transport of large protocol data units; and (f) location or context-aware services. The basic operations of a MobilityFirst router are outlined. This is followed by a discussion of ongoing proof-of-concept prototyping and experimental evaluation efforts for the MobilityFirst protocol stack. In conclusion, a brief description of an ongoing multi-site experimental deployment of the MobilityFirst protocol stack on the GENI testbed is provided.

MobilityFirst: a mobility-centric and trustworthy internet architecture

MobilityFirst is a future Internet architecture with mobility and trustworthiness as central design goals. Mobility means that all endpoints -- devices, services, content, and networks -- should be able to frequently change network attachment points in a seamless manner. Trustworthiness means that the network must be resilient to the presence of a small number of malicious endpoints or network routers. MobilityFirst enhances mobility by cleanly separating names or identifiers from addresses or network locations, and enhances security by representing both in an intrinsically verifiable manner, relying upon a massively scalable, distributed, global name service to bind names and addresses, and to facilitate services including device-to-service, multicast, anycast, and context-aware communication, content retrieval, and more. A key insight emerging from our experience is that a logically centralized global name service can significantly enhance mobility and security and transform network-layer functionality. Recognizing and validating this insight is the key contribution of the MobilityFirst architectural effort.

Quantifying the performability of cluster-based services

In this paper, we propose a two-phase methodology for systematically evaluating the performability (performance and availability) of cluster-based Internet services. In the first phase, evaluators use a fault-injection infrastructure to characterize the services behavior in the presence of faults. In the second phase, evaluators use an analytical model to combine an expected fault load with measurements from the first phase to assess the services performability. Using this model, evaluators can study the services sensitivity to different design decisions, fault rates, and other environmental factors. To demonstrate our methodology, we study the performability of a multitier Internet service. In particular, we evaluate the performance and availability of three soft state maintenance strategies for an online bookstore service in the presence of seven classes of faults. Among other interesting results, we clearly isolate the effect of different faults, showing that the tier of Web servers is responsible for an often dominant fraction of the service unavailability. Our results also demonstrate that storing the soft state in a database achieves better performability than storing it in main memory (even when the state is efficiently replicated) when we weight performance and availability equally. Based on our results, we conclude that service designers may want an unbalanced system in which they heavily load highly available components and leave more spare capacity for components that are likely to fail more often.

Network service abstractions for a mobility-centric future internet architecture

The increasing composition of mobile devices and mobile applications in the Internet requires us to revisit the traditional principles of fixed, host-centric communications, when designing a next-generation architecture. To support this major shift, we define in this paper a set of basic service abstractions that should be afforded by a future Internet that is centered upon the notion of self-certifying globally unique IDs (GUID) for all network principals - hosts, content, services, etc. alike. We followup with a specific set of network service APIs that provide full access to the proposed abstractions, and implement these on Linux and Android hosts that connect to an instantiation of the future Internet architecture proposal - MobilityFirst [5]. Using performance benchmarks and the implementation of representative use cases we show that the API is flexible and can enable efficient and robust versions of present and future applications.

Power-aware data management for small devices

Pervasive computing devices such as Personal Digital Assistants (PDAs) and laptop computers are becoming increasingly ubiquitous. The future promises even more advanced devices such as digital watches, jewelry, and even clothing. However, as pervasive devices become more widely used for more advanced applications, their resource limitations are becoming more apparent. In this work, we focus on data management and power limitations. We investigate the benefit of using power-aware schemes to automatically manage content across a collection of devices and prolong data availability. We monitor the available energy supply on each device and migrate content from devices that are in danger of dying. In our simulated environment, we have found that, using intelligent techniques for data management can increase the amount of time a collection of devices remains usable by over 2 times. Furthermore, our techniques can perform autonomously, independent of user intervention.

A Mobile Phone Based WSN Infrastructure for IoT over Future Internet Architecture

Large-scale wireless sensor network (WSN) deployment is a major challenge for Internet of Things (IoT) to connect physical world through sensors or tags at the scale of billions of objects. Todays WSNs normally use dedicated gateways to bridge sensors and IP networks. The installation and maintenance of such a WSN infrastructure are expensive and non-scalable. As the number of smart phone users grows exponentially every year, a powerful mobile computing platform could be used as an alternative WSN infrastructure, which is ubiquitous and scalable. This paper studies the major challenges of using mobile phones as spontaneous gateways of WSNs in IoT systems. The challenges include (1) matching the throughput of mobile phone gateways and sensor data rate at hotspot locations, (2) securing sensor data access and (3) providing accounting records of gateway the service offered by mobile phones. In this paper, we show that using a name-based future Internet architecture (FIA), such as Mobility First, these challenges can be overcome effectively though its native networking layer functions. A proof-of-concept prototype system demonstrates the feasibility of proposed solution. The system delivers a temperature sensor data from an Android phone directly to multiple applications via in-network multicast over an Mobility First network test bed.

Compiler-directed program-fault coverage for highly available Java internet services

We present a new approach that uses compiler- directed fault-injection for coverage testing of recovery code in Internet services to evaluate their robustness to op- erating system and I/O hardware faults. We define a set of program-fault coverage metrics that enable quantifica- tion of Java catch blocks exercised during fault-injection experiments. We use compiler analyses to instrument appli- cation code in two ways: to direct fault injection to occur at appropriate points during execution, and to measure the resulting coverage. As a proof of concept for these ideas, we have applied our techniques manually to Muffin, a proxy server; we obtained a high degree of coverage of catch blocks, with, on average, 85% of the expected faults per catch being experienced as caught exceptions.

Supporting efficient machine-to-machine communications in the future mobile internet

Machine-to-machine (M2M) communication represents an important new class of applications for the future “Internet of Things (IoT)”. The IoT scenario requires scalable connectivity to billions of embedded devices such as sensors, RFIDs and machines. Current sensor networking solutions involve the use of gateways for hierarchical access to sensor devices, but this approach leads to specialized M2M systems which are not visible to the vast majority of Internet devices and applications. The MobilityFirst future Internet architecture provides a new framework for efficiently supporting sensor net and M2M scenarios through the use of an identity naming system for all network attached objects using the concept of a “globally unique identifier (GUID)”. The use of GUID results in a “flat” network where sensors and other embedded devices are visible to all applications and devices on the Internet. In addition, GUID names make it possible to introduce context and content-aware services which are well suited for M2M scenarios where attributes such as location or type of content are more important than physical address for establishing network connectivity. This paper presents a discussion of how M2M service scenarios are supported in the MobilityFirst architecture, introducing the protocol layers and APIs as they apply to sensors and embedded devices. A proof-of-concept prototype implementation is discussed and an application to a sensor scenario is described.