Peer-to-peer (P2P) networks have recently emerged as an attractive solution to enable large-scale content distribution without requiring major infrastructure investments. Recent developments have led to a significant maturity increase of peer-to-peer technologies, which are currently available as tools for performing core tasks in virtual and networked organizations.
Key Terms in this Chapter
Peer-to-Peer File Sharing: File distribution based on peer-to-peer architectures. P2P file sharing systems have become the single most popular class of end-user Internet application in this decade and have attracted a lot of attention to peer-to-peer architectures. Some P2P file sharing software offers a larger user base and greater numbers of files to choose from. Some software better handles network resources. Also, some P2P file sharing programs are increasing in popularity while others are declining.
Peer-to-Peer (P2P): A class of network applications and services that eliminates the need for servers and allows computers to communicate, collaborate and share resources as equals. In P2P networks and architectures, each node has similar capabilities and responsibilities, in contrast with client/server architectures, in which some nodes are specialized to serve the others.
High Availability: A processing and communications system that can quickly recover and hide the failure of one of its components. As opposed to fault tolerant systems, high available systems can have a short downtime period, but processing and communications will continue; also called reliability, availability, serviceability (RAS) as well as fault resilient.
Overlay Network: Overlay networks combine and share the resources owned by nodes distributed around the Internet, which are normally relegated to the role of clients. Examples of such technologies include peer-to-peer systems and grids, but in general, any large-scale distributed system characterized by decentralization and sharing of resources can benefit from an overlay-based approach.
JXTA: An open source peer-to-peer platform created by Sun Microsystems, defined as a set of XML-based protocols that allow any node in a network to exchange messages and collaborate while abstracting the network topology. JXTA is the most mature P2P framework currently available and was designed to allow a wide range of devices, from mainframes to PDAs, to communicate in a decentralized manner.
Request-Based Virtual Organization (RBVO): A B2B value network which is dynamically constituted upon demand in order to meet identified business opportunities. This approach offers a number of advantages over the traditional B2B marketplace approach where an intermediate entity establishes particular marketplace policies, provides infrastructure and ensures the virtual presence of the participants in the community.
Service-Oriented Architecture (SOA): A software architecture that defines the use of services to support the requirements of software users. In an SOA, nodes make resources available to other participants in the network as independent services that the participants access in a standardized way. Most definitions of SOAs employ Web services. SOAs aim at providing loosely coupled and highly interoperable services.
Web Service: A software system designed to support interoperable machine-to-machine interaction over a network. A Web service has an interface that is described in a machine-processable format. Other systems interact with the Web service in a manner specified by its interface via messages which are usually conveyed using the HTTP protocol. Software applications written in various programming languages and running on various platforms can use Web services to exchange data over a computer network. OASIS and W3C are the main standard bodies responsible for the architecture of Web services.
Business-to-Business (B2B): Relations between two or more enterprises as opposed to relations between enterprises and other groups (public administration or consumers). B2B electronic commerce is typically an automated process between trading partners and is performed in a much higher volume than business-to-consumer (B2C) commerce. B2B can also encompass marketing activities between businesses, and not just the final transactions that result from marketing.
Content Delivery: The process of copying data resources to dispersed nodes in a network, which also involves dynamically identifying and serving content from the closer data provider to a requester when a request for data is performed; also referred to as content distribution and content caching.