SDN orchestration and virtualization of heterogeneous multi-domain and multi-layer transport networks: The STRAUSS approach

SDN proposes a logically centralized architecture where the control entity (SDN controller) is responsible for providing an abstraction of network resources through Application Programming Interfaces (API). This abstraction enables SDN to perform network virtualization, that is, to slice the physical infrastructure and create multiple co-existing network slices (virtual networks) independent of the underlying wireless or optical technology and network protocols. Ideally, the SDN architecture is based on a single control domain comprising multiple network nodes featuring diverse technologies provided by different vendors that are controlled through standard interfaces. However, transport network operators usually fragment their networks into multiple domains to cope with administrative and regional organizations. Each domain can be provided by a different vendor with its own control plane technology (SDN/OpenFlow with some proprietary extensions, legacy GMPLS/PCE, MPLS control, etc.). This paper presents the architecture of SDN orchestration and virtualization proposed in the STRAUSS project. The proposed architecture provides a unified transport network operating system allowing the composition, at a an abstracted level, of end-to-end virtual transport networks as well as end-to-end provisioning services across multiple domains with heterogeneous control and transport technologies.