Radial Architecture: Enterprise Networks Towards Hybrid SDN Deployment

Today's enterprise/campus networks are growing into complex link topologies. The management of these networks in the traditional paradigm presents numerous operational challenges. The operators of these network infrastructures should execute policy changes, administer scheduled maintenance resource allocation, troubleshoot swiftly and accurately without introducing faults and network downtime. SDN came into the picture promising a harmonized approach to address certain challenges of network management operations. But its adoption has a significant challenge due to budget and other constraints. Therefore, a problem arises on how enterprise/campus networks infrastructures can realize benefits from incrementally deployable SDN while addressing the contradiction of performance and costs. This paper presents Radial architecture, a systematic and cost-effective approach to operate a hybrid network. The architectural solution reveals legacy SDN candidate ports to a logical SDN for policy implementation in a partially upgraded network by a property called Pathway Enforcement. Moreover, a planning tool to assure cost of deployment within budget. The tool also provides a couple of greedy heuristics to strategically leverage the number of SDN candidate ports. In the evaluation, almost 50% of the legacy ports can be SDN governed for policy enforcement, with just 12% deployment of SDN switches at the distribution layer under a safe resource utilization. Hence, Radial architecture realizes cost-effective incremental deployment of SDN for policy enforcement and enables operators to run hybrid networks as a nearly fully deployed SDN.