Extensible adaptation via constraint solving

This paper presents the design, implementation, and evaluation of a simple programming language for expressing scheduling policies for transmission of multiple objects across a shared network connection. A key design component of our language is the ability to express constraints among the objects to be transmitted. A policy can make ordering constraints such as "all text objects are transmitted before any image objects" or a policy might express rules on the the relative bandwidth allocations across objects of different types or it can reserve certain amount of bandwidth for an object. Because it is possible to express contradictory constraints, our system finds suitable approximate solutions when no precise solution is available.