The Business Use Cases of Software Defined Networking
Guest Post by
Saurav Kanti Chandra, Senior Technology Architect, Engineering Services, Infosys
The use case behind the invention of OpenFlow was accessing the flow and routing tables from internet routing for educational experimentations. SDN was all about OpenFlow in 2009. Today it has a much broader meaning. The wider applicability of SDN is rooted from its capability of abstracting network from topology and programming the network from a centralized management.
Following are some business use cases of SDN:
Use case 1: SDN can be used to complement network virtualization (in marketer's term Network-As-A-Service). The traditional way of configuring the physical network for virtual machines is not elastic due to limitation in VLAN extensibility. SLA configuration for security, isolation and bandwidth is not capable of scaling out due to lack of flexibility in creating firewall rules, ACLs, policies and VPNs. Although network overlay architecture and newer protocols (VXLAN, NVGRE, VCDNI, NVO3) are there to somewhat alleviate the scaling pain, SDN addresses the pain point in a lot more profound way. In a nutshell, SDN makes it really easy to slice a physical network into virtual customized pieces and make that elastic (or on-demand).
Use case 2: SDN can be used in datacenter networking and cloud hosting infrastructure. It helps in hosting a multi-tenant datacenter on a common physical network infrastructure. SDN has the capability to insert new network services, integrate with layer 4+ services, steer per tenant basis traffic, control QoS and manage security. Servers have been virtualized and the virtual entities can migrate across datacenters for workload balance. The workload mobility can be extended deep into lower layers of network with help of SDN.
Use case 3: Carriers are trying for years to provide a superior customer experience. They are making the network aware of the services offered. They are automating the monitor-action-control cycle by using deep packet inspection probes, scripted configurations and layer 4+ switches. Eventually they are extending the automation benefits to customers in terms of service fulfillment and service assurance. SDN empowers carriers to achieve the same objective in an easier way. A part of the SDN remains intrinsic to the network boxes (SDN API provider) and the other part gets used in applications (SDN API consumer). The innovative applications ensure customer experience through multiple software layers of orchestration. Steering traffic as per service requirement, optimizing the resource usages, shutting down a part of network during off-peak hours to save energy cost, elastically provisioning bandwidth are a few use cases of this. SDN can be used in the mobile access network for unifying LTE / 4G with offload ready Wi-Fi networks and in integrating technologies such as HotSpot 2.0.
Use case 4: Campus networks, especially the wireless LAN has already moved to the direction where control and access are separated. Hundreds of light weight access points are controlled and managed by a centralized controller over layer 2 or layer 3 tunnels. SDN can help in a better manageability by helping in rolling out newer services, bringing in openness from the vertically integrated and proprietary layers of network.
Finally, the timing is great. This is the time of hyper scale growth in data center usage, cloud services infrastructure, mobile broadband, mobile devices, BYOD. This is the era of "Big Data". All it means that datacenters need to utilize its assets to the fullest, network pipe bandwidth is to be used to the fullest, provisioning needs to be dynamic and a centralized management needs to tie all open ends. A careful inspection will yield a lot more use cases in all of these where SDN undoubtedly plays a bigger role.