Other SDN/programmability/network virtualization players say SDNs and the applications they enable can relieve VLAN exhaustion, facilitate data center interconnect and disaster recovery, allow for granular, policy-based security, network isolation, service interposition, deterministic application performance and customization, among others. Policy-based security is particularly important to the BYOD trend; as the ONF notes, enterprise IT is under pressure to accommodate personal devices in a fine-grained manner while protecting corporate data and intellectual property, and meeting compliance mandates.
Service providers need SDNs for agile service delivery, proponents say. SDNs and network programmability can enable policy-based control and analytical data capture to help optimize and monetize service delivery, they say. Cloud service providers and webscale companies like Google, Facebook and Yahoo to ease or automate network configuration and reconfiguration, and quickly add more functionality without manually touching each and every switch or router in the network.
Such companies can use OpenFlow and SDNs to reroute traffic, balance traffic loads, provide bandwidth on demand for peak requirements, execute policies to scale and segregate the networks of different data center or cloud tenants, and connect subscribers to content and services. Cloud providers in particular require programmability to support scalable multi-tenant environments through automated provisioning and virtualization overlays that abstract complicated and distributed physical infrastructures from function.
From an IT perspective, deployment of and access to cloud services can be facilitated by SDNs that enable "elastic scaling" of compute, storage and network resources using a common suite of tools from a common viewpoint, according to the ONF. This is particularly important as organizations stress increased security, compliance, and auditing in cloud environments, or when abrupt changes emerge as businesses reorganize, consolidate or merge.
Massively scalable data centers are said by Cisco to require network flow management enabled through customization using programmatic APIs to provide deep insight into network traffic. And academia and research require network "slicing," or partitioning to separate experimental network use -- i.e., to investigate applicability of OpenFlow or SDNs -- from production networks.