178
3.
If one device fails, the other device can take over the services by using VRRP or a dynamic routing
protocol (such as OSPF) to avoid service interruption.
In this document, the stateful failover feature supports backing up portal, and DHCP services.
Figure 48
Network diagram for stateful failover
Introduction to stateful failover states
The stateful failover states include:
•
Silence: Indicates that the device has just started, or is transiting from synchronization state to
independence state.
•
Independence: Indicates that the silence timer has expired, but no failover link is established.
•
Synchronization: Indicates that the device has completed state negotiation with the other device
and is ready for service backup.
Figure 49
Stateful failover state relations