Developing and deploying a carrier-class sdn-centric network management system for a tier 1 service provider network

Software-defined networking (SDN) has considerably shaken the telecommunications industry, with almost every major vendor upgrading their product portfolio and all providers building use cases to inculcate the SDN concept. Significant collaborative activity is underway toward a common set of SDN standards. However, with a huge amount of existing network gear, one question remains: How should providers adopt SDN given the existing infrastructure? To this end, we have developed a well-standardized technology with minor tweaks and created a hardware paradigm whose forwarding plane conforms to carrierclass standards, but whose control plane caters to the SDN philosophy. This paper discusses our experience building such a control plane and its subsequent deployment. We describe the design and implementation of a network management system (NMS) for carrier-class networks using carrier Ethernet manifestations. The management system subscribes to the SDN philosophy, thereby facilitating user-control-based provisioning and service definitions. A centralized controller communicates with carrier Ethernet switch routers (CESRs) that provision services based on multiple identifiers such as IPv6, IPv4, MAC, CTAG/STAG, and port-based identifiers. In this paper, we describe the design of the controller in the NMS and the control state-machine in the CESR, as well as their interactions. The paper details the concepts underlying the SDN system as well as its module-level and service-level implementation aspects. Our key contribution is that the CESR we built along with the SDN NMS is put to the test in a tier 1 provider network, thereby facilitating real network performance measurement. A citywide network was built and we present its results in this paper.