Fifth-generation (5G) mobile networks require a significant redesign of transport networks to accommodate increasingly bandwidth-intensive radio access networks and to leverage the performance and cost efficiencies gained from integrating backhaul and fronthaul segments over a unified transport infrastructure, as well as incorporating cloud RAN architectures. The 5G-Crosshaul project addresses this challenge by proposing a transport network architecture that enables multi-tenancy through network slicing. This architecture is designed to allow simultaneous use by various tenants, such as mobile virtual network operators (MVNOs), over-the-top (OTT) providers, and vertical industries, thereby enhancing usage and cost efficiency. A key component of this architecture is an SDN/NFV-based control plane, which facilitates the flexible and efficient allocation of transport network resources to multiple tenants.