Designing Core Layer in Campus Network Using Software-Defined Networking

An IMRAD digest of an SDN-based campus backbone design leveraging RouteFlow, OSPF, and OpenFlow over a Mininet/Open vSwitch testbed

Iwan Setiawan; Azis Wisnu Widhi Nugraha; Sauqi Asrorul Zaza· 2026· DOI 10.48550/arXiv.2608.25373

The core problem

The core layer, or backbone, of a campus network is responsible for interconnectivity and routing between internal and external networks, including other campus networks and the Internet. Because this layer must be highly available, its design is a high priority. The authors propose using the software-defined networking (SDN) paradigm to design the campus core layer, applying best practices of network topology and routing protocol at that layer, with a use case of a university campus network core. The design employs RouteFlow as the SDN platform to support a traditional routing protocol, Open Shortest Path First (OSPF), over an OpenFlow (OF) network infrastructure. The central research question is whether an SDN-based core layer can deliver reliable interconnectivity and shortest-path routing using OSPF implemented on top of the SDN platform.

Interconnectivity tests using ping succeeded for all OF switches in the topology and for hosts connected to the switches. This confirms that the SDN-based core layer can establish basic reachability across the emulated campus backbone. Traffic monitoring with tcpdump on all switch interfaces verified that packets traversed the expected paths. The results indicate that OSPF, implemented in the virtual network on top of the SDN platform, correctly computed and installed shortest-path routes. The two-VM testbed, with Open vSwitch in Mininet on the data plane and RouteFlow with POX on the control plane, proved capable of supporting the designed core layer functions. No packet loss or misrouting was reported during the evaluation, supporting the viability of the approach for campus core layer design.

The core layer, or backbone, of a campus network is responsible for interconnectivity and routing between internal and external networks, including other campus networks and the Internet. Because this layer must be highly available, its design is a high priority. The authors propose using the software-defined networking (SDN) paradigm to design the campus core layer, applying best practices of network topology and routing protocol at that layer, with a use case of a university campus network core. The design employs RouteFlow as the SDN platform to support a traditional routing protocol, Open Shortest Path First (OSPF), over an OpenFlow (OF) network infrastructure. The central research question is whether an SDN-based core layer can deliver reliable interconnectivity and shortest-path routing using OSPF implemented on top of the SDN platform.

The experimental testbed consists of two virtual machines (VMs). The first VM acts as the SDN/OF data plane, running Open vSwitch inside the Mininet network emulator. The second VM represents the SDN control plane, comprising RouteFlow with a POX controller. This separation allows the data plane to forward packets while the control plane manages routing decisions. The design is evaluated by testing interconnectivity using ping for the OF switches in the topology and for hosts connected to the switches. Packet routes are tracked by monitoring traffic passing through all network interfaces of the switches using tcpdump. This evaluation ensures that packets are routed along the shortest path from source to destination using OSPF implemented in the virtual network on top of the SDN platform. The architecture can be summarized as follows:

The study demonstrates that combining SDN with a traditional routing protocol such as OSPF is feasible for a campus core layer. By using RouteFlow, the design preserves the familiarity and robustness of OSPF while gaining the programmability of OpenFlow. The separation of control and data planes across two VMs mirrors real-world SDN deployments and allows for centralized routing decisions. The use of Mininet and Open vSwitch provides a flexible, reproducible testbed. However, the evaluation is limited to a virtual environment with a small topology; scalability, latency, and failure recovery were not tested. Future work could extend the testbed to larger topologies, incorporate high-availability mechanisms, and compare performance against traditional core layer designs. The taxonomy candidates for this work include Architecture, Cybersecurity, Network, and Cryptography, reflecting its focus on network design and security-relevant infrastructure.

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