Improving manageability through reorganization of routing-policy configurations

As a network evolves over time, multiple operators modify its configuration, without fully considering what has previously been done. Similar policies are defined more than once, and policies that become obsolete after a transition are left in the configuration. As a result, the network configuration becomes complicated and disorganized, escalating maintenance costs and operator faults. We present a reorganization system that groups common policies by discovering a set of shared features and which uses the groupings for the configuration instead of using each individual policy. Such an approach removes redundancies and simplifies the configuration while preserving the intended behavior of the configuration. We apply the reorganization system to the routing-policy configurations from four production networks, and reduce more than 50% of configuration commands. These reduced configurations are shown to be sufficient to satisfy changes as the network evolves over a two-year period. In addition, we conduct a set of user studies involving 62 participants. These studies examine the participants' comprehension of reorganized configurations as compared to the original configurations. The studies show that our reorganization system improves both accuracy, from 60% to nearly 90%, as well as time-to-task-completion, from 24 min to 13 min.