This 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
... [Show full abstract] 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.