Milan: Middleware Linking Applications and Networks

Current trends in computing include increases in both distribution and wireless connectivity, leading to highly dynamic, complex environments on top of which applications must be built. The task of designing and ensuring the correctness of applications in these environments is similarly becoming more complex. The unified goal of much of the research in distributed wireless systems is to provide higher level abstractions of complex low-level concepts to application programmers, easing the design and implementation of applications. This is also the goal of the proposed Milan middleware platform, but Milan’s unique feature is its ability to continuously control the network functionality with respect to the application’s changing demands. Applications targeted by Milan are characterized by their ability to adapt to changing sets of available components, and their need to further constrain the active components for applicationperformance reasons. Physical resources (e.g., transmission distance, bandwidth) and minimum application performance limit the input to certain subsets of available components. It is the job of Milan to identify these feasible sets and determine which set optimizes the tradeoff between application performance and network cost (e.g., energy dissipation). Milan must then configure the network so that components in the selected feasible set are linked to the application. A key feature of Milan is the separation of the policy for managing the network, which is defined by the application, from the mechanisms for implementing the policy, which is effected within Milan. This report describes the initial design of Milan as well as our plans for future research.