Software Defined Networking
Software-defined networking (SDN) enables programmable SDN control and management functions at a number of layers, allowing applications to control network resources or information across different technology domains, e.g., Ethernet, wireless, and optical. Current cloud-based services are pushing networks to new boundaries by deploying cutting edge optical technologies to provide scalable and flexible services. SDN combined with the latest optical transport technologies, such as elastic optical networks, enables network operators and cloud service providers to customize their infrastructure dynamically to user/application requirements and therefore minimize the extra capital and operational costs required for hosting new services.
Deploying optical-technology-based SDN in cloud environments poses new challenges owing to the various traffic flow characteristics that are presented by diverse cloud services。 Extending SDN to support interconnectivity of IT resources and storage using emerging optical transport and switching technologies, as well as existing packet networks, will enable applicationaware/service-aware traffic flow handling and routing within DCs. SDN can facilitate implementation of programmable traffic engineering and load balancing schemes within a DC by taking into account the bandwidth and latency requirements of different traffic flows of different applications, enabling on-demand mobility and migration of services. With an abstraction mechanism like OF, SDN can also simplify the complexities of handling traffic among various networking technologies.