While open source SDN controllers were some of the first to emerge, a number of vendors have begun to offer commercial SDN controllers as part of their programmable networking portfolios.
As with open source controllers, it's still the early days for commercial controllers, said Andrew Lerner, research director at Gartner.
"We would estimate there are less than 1,000 mainstream production SDN deployments globally," Lerner said. The most well-known commercial controllers to date include platforms that manage SDN overlays, as well as those that control hardware and software network switches.
Lerner added that when considering controllers, it's important to recognize the amount of "SDN-washing" in the market -- or vendors referring to non-SDN concepts as SDN. "Orchestration, agility and dynamic provisioning are all fantastic and solve real problems but by themselves are not SDN."
We rounded up five key commercial SDN controllers.
1. Cisco Application Policy Infrastructure Controller (APIC) is considered a distributed system implemented as a cluster of controllers. Within Cisco's Application Centric Infrastructure (ACI), APIC acts as a single point of control. It provides a central API, a central repository of global data and a repository of policy data. The controller can automatically apply application-centric network policies and functions with data model-based declarative provisioning. The primary goal of APIC is to provide policy authority and policy resolution mechanisms for Cisco ACI devices to optimize application performance and network efficiency. Automation is said to occur as a direct result of policy resolution and of rendering its effects onto the ACI fabric.
There are ACI spine and leaf switch nodes that APIC communicates with. By doing so, it is able to distribute policies and deliver a number of administrative functions. By not having the controller involved directly in data plane forwarding, a cluster won't lose any data center functionality if there is a disconnect of APIC components.
2. HP Virtual Application Networks (VAN) SDN Controller controls policy and forwarding decisions in an SDN network running OpenFlow-enabled switches in the data center or campus infrastructure. HP is also working with Verizon and Intel to develop an app used for WAN bandwidth provisioning using the VAN controller.
The controller also enables centralized control and automation. Within an HP SDN environment, the VAN controller delivers integration between the network and business system. It uses programmable interfaces that enable the orchestration of application and automation of network functions. The controller also provides control of the network, including functions such as network topology discovery.
The VAN controller can also be clustered, allowing a controller to take over the functions of another if one fails. In regards to security, the controller uses authentication and authorization methods. In turn, SDN applications can interact with the controller, while unauthorized applications aren't able to gain network access. The southbound connections between the OpenFlow switches and the HP controller are also secured and encrypted.
3. NEC ProgrammableFlow PF6800 Controller is at the center of NEC's ProgrammableFlow OpenFlow-based Network Fabric. It provides a point of control for physical and management for virtual and physical networks. The controller is considered programmable, as well as standardized. It integrates with both OpenStack and Microsoft System Center Virtual Machine Manager for added network management and orchestration. The controller also includes NEC's virtual tenant network technology, which allows for isolated, multi-tenant networks.
4. Nuage Networks Virtualized Services Controller (VSC) allows for the full view of a per-tenant network and service topologies while externalizing network service templates defined through Nuage Networks' Virtualized Services Directory. The service directory is a policy engine that uses network analytics and rules to allow role-based permissions. The VSC sends messages using those rules to Nuage's Virtual Routing and Switching platform. The platform senses either the creation or deletion of a virtual machine and then asks the SDN controller if there is a policy in place for that tenant. If there is a rule, network connectivity is established immediately.
5. VMware NSX Controller is considered a distributed state management system that controls virtual networks and overlay transport tunnels. It is the central control point for all logical switches within a network. The controller maintains information of virtual machines, hosts, logical switches and VXLANs, while using northbound APIs to talk to applications.
When working with the controller, the applications communicate what they require, and the controller programs all vSwitches under NSX control in a southbound direction to meet those requirements. The controller could run two ways within NSX: either as a dismissed cluster of virtual machines in a vSphere environment, or in physical appliances for those with mixed hypervisors.