As data center designs focus on East-West traffic and move toward leaf-spine, or full-mesh, architectures, systems using Multi-fiber Push On (MPO) connectors and Quad Small Form-factor Pluggable (QSFP), ports are becoming more predominate. While MPO connectivity and QSFP transceivers are not new, the ability to use them as a single port which then can break out to multiple lanes of slower speeds creates more of a challenge in the physical layer. This article will review data center architecture trends, appl­ications and transmissions standards utilizing MPO connectivity; some of the different options available when deploying MPO infrastructure; and finally, the testing of MPO connectivity.