Today, the network design process remains  ad hoc  and largely complexity agnostic, often resulting in suboptimal networks characterized by excessive amounts of dependence and commands in device configurations. The unnecessary high configuration complexity can lead to a huge increase in both the amount of manual intervention required for managing the network and the likelihood of configuration errors, and thus must be avoided. In this paper, we present an integrated top–down design approach and show how it can minimize the unnecessary configuration complexity in realizing reachability-based access control, a key network design objective that involves designing three distinct network elements: virtual local-area network (VLAN), IP address, and packet filter. Capitalizing on newly developed abstractions, our approach integrates the design of these three elements into a unified framework by systematically modeling how the design of one element may impact the complexity of other elements. Our approach goes substantially beyond the current divide-and-conquer approach that designs each element in complete isolation, and enables minimizing the combined complexity of all elements. Specifically, two new optimization problems are formulated, and novel algorithms and heuristics are developed to solve the formulated problems. Evaluation on a large campus network shows that our approach can effectively reduce the packet filter complexity and VLAN trunking complexity by more than 85% and 70%, respectively, when compared with the  ad hoc  approach currently used by the operators.
['Xin Sun', 'Geoffrey G. Xie']
An Integrated Systematic Approach to Designing Enterprise Access Control