74 Copyright © 2012, IGI Global. Copying or distributing in print or electronic forms without written permission of IGI Global is prohibited. Chapter 5 INTRODUCTION P2P networks have traditionally been considered too transient in nature to perform useful compu- tations for real-world applications, leave aside the formulation of a viable QoS framework. The only mature application that P2P networks successfully cater to, are those related to content sharing, where the sheer scale of P2P networks along with strategies for content-caching and replication enable content to be located and downloaded in a time-bound manner. Gummadi Ankur Gupta Model Institute of Engineering and Technology, India Lalit K. Awasthi National Institute of Technology, India Toward a Quality-of- Service Framework for Peer- to-Peer Applications ABSTRACT P2P networks have caught the imagination of the research community and application developers with their sheer scalability and fault-tolerance characteristics. However, only content-sharing applications based on the P2P concept have reached the desired level of maturity. The potential of the P2P concept for designing the next-generation of real-world distributed applications can be realized only if a com- prehensive framework quantifying the performance related aspects of all classes of P2P applications is available. Researchers have proposed some QoS (Quality-of-Service) parameters for content-sharing P2P applications based on response time and delay, but these do not cover the gamut of application domains that the P2P concept is applicable to. Hence, this chapter proposes an early QoS framework covering various classes of P2P applications; content distribution, distributed computing and com- munication and collaboration. Early results from the prototype implementation of the Peer Enterprises framework (a cross-organizational P2P collaborative application) are used as a basis for formulation of the QoS parameters. The individual performance measures which comprise the QoS framework are also discussed in detail along with some thoughts on how these can be complied with. The proposed framework would hopefully lead to quantifable Service-Level Agreements for a variety of peer-to-peer services and applications. DOI: 10.4018/978-1-4666-0906-8.ch005