On the stability of adaptive Service Level Agreements

We consider some implications of non-linear feedback, due to policy combinatorics, on policy-based management of networked services. We pay special attention to the case where the monitoring of certain aspects of Service Level Agreements is used to alter future policy dynamically, according to a control feedback scheme. Using two simple models, we show that nonlinear policies are generally unstable to service provision, i.e. provide no reliable service levels (QoS). Hence we conclude that automated control by policy-rule combinatorics can damage quality of service goals.