Service Clouds : A Distributed Infrastructure for Composing Autonomic Communication Services ∗

This paper proposes Service Clouds, a distributed infrastructure designed to facilitate rapid prototyping and deployment of autonomic communication services. The Service Clouds infrastructure combines dynamic software configuration methods with overlay network services in order to support both crosslayer and cross-platform cooperation. The Service Clouds architecture includes a collection of low-level facilities that can be either invoked directly by applications or used to compose more complex services. The architecture is designed for extension: developers can plug in new modules, at different layers of the architecture, and use them in constructing additional services. We have implemented a prototype of Service Clouds atop the PlanetLab Internet testbed. After describing the Service Clouds architecture, we present results of two experimental case studies conducted on PlanetLab. In the first we use Service Clouds to implement a service in which an overlay node is dynamically selected and configured as a TCP relay for bulk data transfers; experiments demonstrate that the Service Clouds approach often produces better performance than using native IP routes. In the second we use Service Clouds to deploy and evaluate a multipath protocol that dynamically establishes a high-quality secondary path between a source and destination. The secondary path supports a “shadow” transmission of the data stream in order to mitigate transient delays and failures on the primary path.