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A key concept of software-defined networking (SDN) is separation of the control and data plane. This idea provides several benefits, including fine-grained network control and monitoring, and the ability to deploy new services in a limited scope. Unfortunately, it is often cost-prohibitive for enterprises (and universities in particular) to upgrade their existing networks to wholly SDN-capable networks all at once. A compromise solution is to deploy SDN capabilities incrementally in the network. The challenge then is to take full advantage of SDN-based services throughout the network, in an integrated fashion rather than in a few "islands" of SDN support. At the University of Kentucky, SDN has been integrated into the campus network for several years. In this paper, we describe two aspects of this challenge, along with our solution approaches. One is the general reluctance of campus network administrations to allow novel or experimental (SDN-based) services in the production network. The other is how to extend such services throughout the legacy part of the network. For the former, we lay out a set of principles designed to ensure that the production service is not harmed. For the latter, we use policy based routing and a graph database to extend our previously-described VIP Lanes service. Our simulation results in a campus-like topology testbed show that we can provide a host with custom path service even if it is connected to a legacy router. 

Network security devices intercept, analyze and act on the traffic moving through the network to enforce security policies. They can have adverse impact on the performance, functionality, and privacy provided by the network. To address this issue, we propose a new approach to network security based on the concept of short-term on-demand security exceptions. The basic idea is to bring network providers and (trusted) users together by (1) implementing coarse-grained security policies in the traditional way using conventional in-band security approaches, and (2) handling special cases policy exceptions in the control plane using user/application-supplied information. By divulging their intent to network providers, trusted users can receive better service. By allowing security exceptions, network providers can focus inspections on general (untrusted) traffic. We describe the design of an on-demand security exception mechanism and demonstrate its utility using a prototype implementation that enables high-speed big-data transfer across campus networks. Our experiments show that the security exception mechanism can improve the throughput of flows by trusted users significantly.