SDN/NFV-based scalable mobile service integration for gradual network evolution

The coexistence of heterogeneous networks is becoming increasingly more common with the evolution towards 5G, increasing the complexity and cost of deploying and managing these networks. Network operators consequently need to find efficient ways of flexibly constructing and operating networks within a heterogeneous network environment in order to reduce operational expenditure (OPEX) and capital expenditure (CAPEX). One possible way to meet this requirement is the accommodation of previous legacy network services in the newly-deployed network while gradually reducing the reliance on physical legacy networks. Software-defined transitional network (SDTN) architecture is a strong candidate to achieve this. In the SDTN, the software-defined networking and the networkf function virtualization (SDN/NFV) plays a key role in integrating legacy network services into the newly-deploying network. This paper proposes an SDTN architecture and presents an example of its deployment in a mobile network evolution scenario in which 3G mobile services are integrated into a 4G network. The unified mobility management, in which 3G mobile services are integrated into a 4G access networks based on SDN/NFV is described. The network nodes for legacy mobility management services are virtualized at the control plane and accommodated into the SDTN architecture. As a result, the mobility management is interoperable between the virtualized legacy network service functions and the underlying 4G network. In order to support various heterogeneous services integration into the 4G mobile network, scalable edge switches are proposed for protocol mapping between incoming heterogeneous service traffic and 4G data. The proposed SDTN approach can be applied to the future deployment of 5G networks by accommodating various pre-existing legacy services in newly-deploying networks.