High Availability Terminology

High Availability Terminology

Active	The operative condition of a hardware unit. The Active identifier is a logical role that can be assumed by either a Primary or Secondary hardware unit.
Failover	The actual process in which the Standby unit assumes the Active role following a qualified failure of the Active unit. Qualification of failure is achieved by various configurable physical and logical monitoring facilities described in Configuring High Availability.
HA	High Availability: non-stateful, hardware failover capability.
HA Control Interface	The interface that carries HA control communication, such as heartbeats, between the two firewalls.
HA Data Interface	The interface that carries stateful synchronization data between the two firewalls.
Active/Active DPI	An HA mode in which the Standby firewall inspects offloaded traffic while the Active firewall forwards all traffic.
Active/Active DPI Interface	The dedicated interface that carries offloaded DPI traffic between the two firewalls.
PPP	Point-to-point protocol that provides a standard method for transporting multi-protocol datagrams over point-to-point links.
PPPoE	A method for transmitting PPP over ethernet.
PPPoE HA	HA PPPoE support function without state synchronization.
Preempt	Applies to a post-failover condition in which the Primary unit has failed, and the Secondary unit has assumed the Active role. Enabling Preempt causes the Primary unit to seize the Active role from the Secondary after the Primary has been restored to a verified operational state.
Primary	The principal hardware unit itself. The Primary identifier is a manual designation and is not subject to conditional changes. Under normal operating conditions, the Primary hardware unit operates in an Active role.
Secondary (Backup)	The subordinate hardware unit itself. The Secondary identifier is a relational designation and is assumed by a unit when paired with a Primary unit. Under normal operating conditions, the Secondary unit operates in a Standby mode. Upon failure of the Primary unit, the Secondary unit assumes the Active role.
Standby	The passive condition of a hardware unit. The Standby identifier is a logical role that either a Primary or a Secondary hardware unit can assume. The Standby unit assumes the Active role when the Active unit fails.