Heather Yu

Handbook of Peer-to-Peer Networking

The Handbook of Peer-to-Peer Networking is a comprehensive and unified repository of the various models, applications, methodologies, trends, and challenges of peer-to-peer computing, making it an essential reference for researchers and proffesionals alike. This handbook addresses current issues as well as emerging concepts and applications, including P2P architectures, search and queries, incentive mechanism, multimedia streaming, service- oriented architectures, collaboration to share non-storage resources, mobile P2P, theory and analysis, and P2P databases. In addition, it covers practical perspectives such as traffic characteristics and trends of P2P applications, and E-business models in P2P applications.

UP2P: a peer-to-peer overlay architecture for ubiquitous communications and networking

Approaches to building an intelligent consumer-friendly network have evolved over time from centralized switch-based to router- and server-based Internet architectures. We propose to drive this evolution further with a new highly scalable architecture that provides features to users derived from the computational and networking capabilities of very large populations of sophisticated terminals. This architecture relies on emerging peer-to-peer overlay technology. We describe a peer-to-peer overlay design that addresses requirements crucial for consumer applications, including overlay federation, peer heterogeneity, peer mobility, and service discovery. In addition, we introduce the concept of an overlay operator and describe the requirements for managed overlays. We have designed and implemented both a middleware and a peer-topeer platform that illustrates these concepts.

Peer-to-peer streaming for networked consumer electronics [Peer-to-Peer Multimedia Streaming]

Applications such as multimedia communications and entertainment make media streaming a key feature for peer-to-peer (P2P) technology embedded in networked consumer electronics. In this article, we discuss some key issues that are relevant to enabling peer-to-peer streaming in networked consumer electronics and address possible technical solutions to the issues of interoperability, NAT/firewall traversal, and codec inflexibility. We also address how to improve overall system performance by introducing a notion of node coordinates into the discovery of services on a P2P network and confirm the effectiveness of our approach using simulation. We conclude with a discussion of our prototype CE-oriented P2P streaming system.

Chapter 13 – Mobility and Heterogeneity

Increasingly portable electronic devices are providing functionality previously restricted to desktop computers. Such devices can connect to the Internet using broadband wireless network interfaces. Using mobile devices as peers in an overlay introduces the possibility of increased churn due to frequent roaming transitions that such devices experience. Possible solutions are discussed in this chapter, which include using mobility support in the native layer, virtualizing such support in the overlay itself, or restricting the role of mobile devices as peers. In addition, mobile devices and other networked consumer electronics introduce a degree of resource heterogeneity into the peer population. Adaptability to heterogeneous peer conditions is the scope of another category of P2P overlays called variable-hop overlays, which are discussed here. As mobile ad hoc networks (MANETs) and sensor networks proliferate, there is likely to be significant value in integrating such networks into P2P overlays; proposals for doing so are discussed at the end of the chapter.

Peer-to-Peer Content Delivery

This chapter provides an overview of peer-to-peer content delivery. P2P technologies offer a new approach to content delivery networks that combines improved system scalability with low implementation cost. P2P content delivery is thus, an important technique for commercial systems, such as IPTV. This chapter highlights the design issues of P2P content delivery networks, including topology, delivery path selection, push versus pull, and control strategy for content flow. In addition, various approaches for content caching are discussed and some example systems are used to illustrate the approaches. The chapter concludes with a discussion of hybrid P2P-CDN designs. Classification of P2P content delivery schemes, topology constraints, categories of data topology and delivery path, P2P caching, and so on is reviewed. Caching is a well-known strategy in many networked applications. It provides the capability to reduce origin server load and bandwidth requirement, reduce network bandwidth usage, and reduce client-side latency that leads to improved scalability and performance with lower cost.

Peer-to-Peer Concepts

This chapter provides an overview on peer-to-peer concepts. P2P encompasses mobile and other consumer electronics devices. Then it discusses the principles of P2P overlays, such as self-organization and peer autonomy. It provides a sequence of sections giving various perspectives on the P2P model, including a graph theoretic perspective, a design space perspective, a routing performance perspective, and an implementation perspective. There are a number of ways to look at P2P overlays, from user to application developer, system designer, and researcher. Similarly, there are a variety of relevant conceptual, theoretical, and implementation perspectives to consider. A peer-to-peer overlay is a distributed collection of autonomous end-system computing devices called peers that form a set of interconnections called an overlay to share resources of the peers such that peers have symmetric roles in the overlay for both message routing and resource sharing.

Chapter 3 – Unstructured Overlays

Publisher Summary nThis chapter provides a review on unstructured overlays. Most deployed P2P applications have used unstructured topologies. Here the chapter highlights important classes of overlay in detail, starting with the basic routing mechanisms. Then it describes the theory of various types of unstructured graphs, such as random graphs, power-law random graphs, and scale-free graphs. Influential designs, such as Gnutella, Freenet, Fastrack, and Gia are then explained. Ideas from social networks, especially the small-world phenomenon, are related to unstructured topologies, and an overview of social overlays follows. This chapter also looks at the way file and similar information sharing works when the P2P application does not impose much if any structure on the interconnection of the peers. Such approaches are classified as unstructured overlays. An important observation about the nature of information sharing in P2P applications compared to information delivery via the World Wide Web is that P2P involves primarily individuals as both information publishers and users. Thus, there is a social dimension to P2P information sharing that is derived from the social relationships between the individuals who comprise the P2P system.

Chapter 15 – Managed Overlays

Publisher Summary nThis chapter provides a review on managed overlays. Physical networks are managed by their operators to assure that network services perform as expected. Although overlays are self-organizing, experience with deployed overlays indicates that additional management mechanisms are needed in some cases. This chapter compares the traditional network management functions with the requirements for managing large-scale overlays and outlines a general approach for integrating an external management agent with an overlay. In addition, we review current trends in addressing the impact of P2P traffic on ISP networks.

Chapter 11 – Service Overlays

Publisher Summary nThis chapter highlights service overlays. Service orientation is growing in importance as a fundamental architecture in distributed enterprise computing. In the P2P context, an overlay can be used by multiple applications, as opposed to a dedicated overlay for each type of P2P application. The advantage is that a common mechanism, such as routing, naming, search, and security is shared across multiple applications. Using the P2P overlay as a service delivery platform can also accelerate the delivery of new services. Overlays have also been used to deliver services traditionally built into the network layer. An overlay designed to provide a network service, such as selecting an alternate routing path, multicast delivery, or session establishment is referred to as a service overlay. In addition, the application of principles of service-oriented architectures to P2P overlays is of growing interest. Three concepts—resource virtualization, service orientation, and devices as peers—unify the two categories of service overlay and are described in this chapter. For network services it provides an example, such as delivering DNS records from a DHT, resilient overlay networks, and QoS-aware overlays. Then it discusses service discovery, replication, and load balancing in the context of service-oriented service overlays. The chapter concludes with some examples of service composition.

Women in communications technology [The President's Page]

Central to the ComSoc 2.0 framework, presented in the January 2008 Presidents column, is the concept of a global ComSoc community. This community ideally includes all members regardless of where they are on the planet (or beyond). In line with this, one of the initiatives due for discussion is a brand new women in communications technology program at ComSoc to encourage and inspire woman engineers in the communications and related disciplines worldwide.