In a Versa Secure SD-WAN solution, the hub controller plays a multifaceted role that is crucial for the efficient and secure operation of the network. Three of the primary functions of a hub controller include CPE lifecycle management, acting as a control plane node, and providing visibility and control.

CPE Lifecycle Management (A): The hub controller is instrumental in managing the lifecycle of Customer Premises Equipment (CPE). This includes tasks such as configuration, maintenance, updates, and troubleshooting. This management capability ensures that the CPEs are always operating with the latest security patches, configurations, and software versions, thereby maintaining the security and efficiency of the network.

Control Plane Node (B): The hub controller also serves as a control plane node. It is responsible for maintaining the routing information and ensuring the efficient distribution of this information across the network. This includes handling BGP routes toward VPNsand tenants, distributing security association (SA) information, and enabling IPsec connectivity between branches without the overhead of maintaining a full mesh of IKE keys among all branches​​.

Visibility and Control (D): Finally, the hub controller provides visibility and control over the network. This includes monitoring the network's health, traffic management, and implementing security policies. By offering a centralized point of visibility and control, the hub controller enables network administrators to effectively manage and secure the network.

The hub controller's role as a data plane node (C) is not explicitly mentioned among its primary functions, as it is more involved in the control and management aspects of the network rather than direct data forwarding. Similarly, acting as a staging server (E) is not listed as one of its primary roles in the documentation reviewed.