Networks on chip platforms offer the opportunity to introduce a new abstraction level that defines a set of platform services with performance and power characteristics. By making the implementation of these services entirely irrelevant for system design, an effective separation of system design from component design can be achieved. We discuss the principles to formulate network-on-chip services to establish an abstract computational model that exposes all relevant properties of the platform’s functionality, performance and power consumption while hiding all irrelevant implementation details. As in many other successful abstractions, these principles are based on separating functionality from time and power aspects to allow for reasoning about these properties at the system level. As a concrete example we formulate a MoC for the Nostrum NoC. It is based on guaranteed bandwidth (GB) and best effort (BE) traffic. The MoC characterizes both GB and BE traffic in terms of closed formulas and allows for efficient composition of traffic.