1 High Availability

Appliances can be deployed in High Availability (HA) configuration as a pair of appliances in Active/Standby roles. There are three modes of HA deployment:

  • Parallel Inline HA
  • Serial Inline HA
  • One Arm HA

These HA deployment modes are similar to Virtual Router Redundancy Protocol (VRRP) but use a proprietary protocol called Redundant APN Control Protocol (RACP). Both Client Nodes (Clients) and Network Control Nodes (NCNs) within a Oracle Adaptive Private Network (APN) can be deployed in an HA configuration, if the selected Appliance model supports HA. The T510 and E50 do not support HA; all other appliance models do.

Note:

The NCN is the central Appliance that acts as the master controller of the APN, as well as the central point of administration for the Clients. The NCNs primary purpose is to establish and utilize Conduits with one or more Clients across the network for enterprise Site-to-Site communications.

In HA configuration, one Appliance at the Site is designated the Active appliance and is continuously monitored by the Standby appliance. Configuration is mirrored across both appliances. If the Standby appliance loses connectivity with the Active one for a defined period of time, the Standby appliance assumes the identity of the Active appliance and takes over the traffic load. Depending on the deployment mode this fast failover has minimal impact on the application traffic flowing through the Site. We will discuss the impact in more detail later in this document.

Note: For NCNs, we also support what is called Geographically-Diverse NCN redundancy. In this mode, one of the Clients is also designated as a secondary NCN. It will continuously monitor the health of the Primary NCN and if a catastrophic event occurs, it will assume the role of the NCN. The T510, T730, and E50 appliance models cannot act as NCNs

There are various technical considerations in each deployment scenario. These will be explored in the sections below.