A. Hot-Standby mode and Active-Standby mode in High Availability

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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 lost 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 introduces High Availability in 4 parts:

A. Hot-Standby method and Active-Standby method B. Advanced parameters

C. Configuration for High Availability Hot-Standby scenario D. Configuration for High Availability Active-Standby scenario

A. Hot-Standby mode and Active-Standby mode in High Availability

Hot-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 cannot have different configurations 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.

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Active-Standby mode:

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.

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B. Advanced Parameters

1._{Redundant Method:}

a._{Hot-Standby: The secondary Vigor3900 remains idle until detecting the malfunction} of the Primary Vigor3900.

b._{Active-Standby: Primary Vigor3900 and the Secondary Vigor3900 can work} simultaneously.

2._{Config Synchronization Role: Only for Hot-Standby mode. The secondary Vigor3900 will} synchronize the configurations from the Primary Vigor3900 automatically.

3._{Config Synchronization IP: The IP address of the Primary Vigor3900.}

4._{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.

5._{Advance Preemption Mode: For Hot-Standby mode only. User can choose it so the} Primary Vigor3900 takes back the Master role once it is up again.

a._{Automatic: Primary Vigor3900 will take back the Master role once it is up from the} last failure.

b._{Automatic Delayed: Add the delay before the Primary Vigor3900 takes back the} Master role.

c._{Manual: The Primary Vigor3900 won’t take back the Master role automatically until} administrator re-actives it manually.

6._{LAN Port Detection Mode:}

a._{At Least One UP: Primary Vigor3900 will detect if the LAN Port Members in HA LAN} Profiles are up, and will do HA while detecting none of the LAN Port Members is up.

b. _{All Must Be UP: Primary Vigor3900 will detect if all the LAN Port Members in HA LAN}

Profiles are up, and will do HA while detecting any LAN Port Member is down. While selecting this mode, it is necessary to remove the LAN ports (for example: the LAN port3/ fiber LAN port.) that are not used from the LAN profile members in LAN >>

Switch.

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• DO NOT connect Primary Vigor3900 and Secondary Vigor3900 to the same switch before

finishing all configurations. It is essential to prevent the auto configuration synchronization work before all configurations are done.

• The Primary Vigor3900 and the secondary Vigor3900 should have the LAN profiles with the

exact same name (for example: lan1, lan2 and lan3) and the same VLAN ID.

And the LAN profile IP of the Primary Vigor3900 and the secondary Vigor3900 must NOT be the same.

1. _{Configurations on the Primary Vigor3900}

a._{Open Applications >> High Availability >> High Availability Profile Setup, and} click Add. Input the Profile name, HA LAN Profile, Virtual IP for Gateway, VHID and Role Primary then click Apply.

VHID: VHID is for identifying group. The VHID of the corresponding HA LAN profile of the Primary and the Secondary Vigor3900 should be the same.

Virtual IP for Gateway: The Virtual Gateway IP for LAN hosts.

b._{Open Applications >> High Availability >> High Availability General Setup.} Redundant Method: Hot-Standy

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LAN Port Detection Mode: At_Least_One_Up Click Apply.

2._{Configurations on the Secondary Vigor3900}

a._{Open Applications >> High Availability >> High Availability Profile Setup, and} click Add. Input the Profile name, HA LAN Profile, Virtual IP for Gateway, VHID and Role as Secondary, and click Apply.

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b._{Open Applications >> High Availability >> High Availability General Setup.} Redundant Method: Hot-Standy

Config Synchronization Role: Secondary

Config Synchronization IP: The Primary Vigor3900’s LAN IP

Priority ID: 1 (Priority ID means the backup priority for the secondary. There can be several secondary Vigor3900 to back up one primary Vigor3900. ID 1 means the secondary Vigor3900 will have the highest priority.)

LAN Port Detection Mode: At_Least_One_Up Enable High Availability

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3._{After above settings are done, please connect the Primary Vigor3900 and the Secondary} Vigor3900 to the same LAN switch for High Availability.

4._{Open Applications >> High Availability >> High Availability Profile Setup for checking} the HA status.

We can see which Vigor3900 is acting as Master and the failed reason of the Primary Vigor3900.

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D. Configurations High Availability in Active-Standby method

1._{Configurations on the Primary Vigor3900}

a._{Open Applications >> High Availability >> High Availability Profile Setup then} click Add. Input the Profile name, HA LAN Profile, Virtual IP for Gateway, VHID and Role Primary then click Apply.

VHID: VHID is for identifying group. The VHID of the corresponding HA LAN profile of the Primary and the Secondary Vigor3900 should be same.

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b._{Open Applications >> High Availability >> High Availability General Setup.} Redundant Method: Active-Standy

Tick Enable High Availability Click Apply.

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2. _{Configurations on the Secondary Vigor3900}

a._{Open Applications >> High Availability >> High Availability Profile Setup then} click Add. Input the Profile name, HA LAN Profile, Virtual IP for Gateway, VHID and Role as Secondary then click Apply.

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b._{Open Applications >> High Availability >> High Availability General Setup.} Redundant Method: Active-Standy

Tick Enable High Availability Click Apply.

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c._{Select and Edit the s1 HA profile via Applications >> High Availability >> High}

Availability Profile Setup.

Change the role to Backup and fill in the Master IP and the Priority ID. Click Apply.

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3._{Open Applications >> High}_{Availability >> High Availability Profile Setup for checking} the HA status.

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We can see which Vigor3900 is acting as Master.