[Vigor3900] What is High Availability (HA)?
Support Model : Vigor3900
High Availability (HA) is the feature that ensures the business continuity for your organization. IT staff can take HA as a simple solution for the disaster recovery. DrayTek utilizes the Common Address Redundancy Protocol (CARP) to avoid the system downtime, which could stop the normal operation and then causes considerable loss of the entire organization.
As enabling the HA feature, the network administrator can set another Vigor3900(s) as the backup device(s) to deliver full routing services during the downtime of the main Vigor3900. The network administrator can use the Virtual IP (e.g., 192.168.39.3) for both master device and backup device HA configurations. During the system uptime, the master device (e.g., 192.168.39.1) would offer services and act as the Virtual IP. When the master device is temporarily out-of-service, the backup device(s) (e.g., 192.168.39.2) acts the Virtual IP and delivers all routing functions.
This document will introduce the difference between Hot-Standby mode and Active-Standby mode and the parameters in HA settings. (For HA on Vigor2925 and Vigor2860 series, please refer to the article here.)
Hot-Standby mode and Active-Standby mode
The primary and the secondary devices use the same public IP address for Internet Access. The secondary device will auto-synchronize the configurations from the primary device and the configuration can not be different from the primary device. The secondary device is always idle when the primary device is operating. When the primary device is down or is detecting no active switch port of its LAN or WAN interface, the secondary device will be up and take over the primary role.
The primary and the secondary devices use different public IP address for Internet Access. The secondary device uses its own configuration which can be different from the primary device. The secondary device is also operating while the primary device is up and running.
Hot-Standby: The Secondary Router remains idle until detecting the malfunction of the Primary Router.
|Config Synchronization Role||Only for Hot-Standby mode. The Secondary Router will synchronize the configurations from the Primary Router automatically.|
|Config Synchronization IP||The IP address of the Primary Router.|
|Authentication Key|| The key to encrypt the HA session. It prevents the HA system get stopped by attacks from fake HA control packets.
Members in the same HA Group/VHID should have the same Authentication Key.
|Advance Preemption Mode||
For Hot-Standby mode only. User can choose it so the Primary Router takes back the Master role once it is up again.
|LAN Port Detection Mode||
At Least One UP: Primary Router will detect if the LAN Port Members in HA LAN Profiles are up, and will do HA while detecting none