Network function virtualization (NFV) is the concept of implementing network services in software using commodity hardware. Services include forwarding, learning, and firewalling, among others. Modular NFV (MNFV) was introduced as a methodology for designing virtualized network functions (VNFs), precisely and ultimately compiling them to an open platform. This thesis applies the methodology to rigorously design a 2-port relay switch from reusable behaviors with features found in commercial switches. A potential implementation of the 2-port relay using Intel’s open platform called the Data Plane Development Kit (DPDK) is investigated.