The Talari controller provides centralized intelligence for the entire SD-WAN. Within the Talari SD-WAN, any Talari appliance can be designated as the Controller, and is referred to as the Network Control Node (NCN). The appliance designated as the Controller can be located in a data center, co-location facility or cloud, with sufficient bandwidth and connectivity to establish a connection with each Talari appliance in the network.
The Controller can be setup as a high-availability pair, with active-standby appliances. A second appliance, or high-availability pair, in a geographically separate location can also be designated as a backup Controller that will take over if a complete failure of the primary NCN pair occurs. The appliance form factor at the geo-redundant locations does not have to be the same. For example, a cloud Controller can be backed up with an on premises Controller.
These levels of redundancy ensure the Controller function is highly available. Even with these measures, it is possible to experience periods where the Controller is not accessible. However, the Talari SD-WAN is designed to continue to function, even when the NCN is temporarily unavailable.
Centralized Policy Functions
Policies that control the behavior of the Talari SD-WAN are defined within a single, centralized location. The NCN is responsible for centrally storing the application and traffic handling policies, and pushing changes to the client appliances.