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Use High Availability in Hot-Standby Mode

Published On: Oct 24, 2017 

High Availability (HA) is a feature that allows the network administrator to another router to the network for hardware redundancy. In Hot-Standby Mode, The primary and secondary router share the same WAN source; however, usually, only the primary is online. When the primary router goes down, the secondary comes up, dial up the same WAN line, and continue to provide Internet service to LAN clients.

For DrayOS models, the two Vigor Router working in HA hot-standby mode can share the same WCF license key, and the configuration made on the primary will automatically sync to the secondary one. This article is going to demonstrate how to set up two routers in HA Hot-Standby Mode and create a group on MyVigor to share the WCF license key.

a network topology

Configuration of the Primary Router

1. On the primary router, go to Application >> High Availability,

  1. Group ID: The routers with the same number will be in the same HA group. The default value is 1, we may leave it as default here.
  2. Priority ID: In a HA group, the router with the largest number will be the primary one.
  3. Authentication Key: All the HA members should have the same key.
  4. Management Interface: the packets for communication between members will send over the selected interface. To have the best communication and for security purpose, we recommend to choose an interface that has less interruption. In our scenario, we reserve LAN 1 for High Availability only and put all other LAN clients in LAN2~LAN5.
  5. Update DDNS: for dynamic WAN IP users, enable this function so once the secondary router becomes primary and dials up the WAN, it will also update its new WAN IP address to the same DDNS profile, so your network will be accessible with the same DDNS domain.
  6. Syslog: enable to show all the High Availability relative logs in syslog.
  7. Enable the LAN Subnet to join High Availability. Hardware redundancy will only apply to the selected LAN subnets. Virtual IP is the IP which will be used as LAN client's gateway IP.

2. Go to Config Sync tab, check Enable Config Sync to update the configuration to the secondary router periodically.

a screenshot of DrayOS HA settings

3. LAN IP Configuration at LAN >> General Setup,

  • IP Address: It has to be different from the Virtual IP. If the HA peers have the same Priority ID, the one has the smaller number for LAN IP will be the primary one, so we suggest using an IP with a lower number on the Primary one.
  • Gateway IP: should is the same as LAN IP, and the note indicates that the actual gateway IP provided to DHCP clients will be the Virtual IP.

a screenshot of DrayOS LAN IP configuration

For the Secondary Router

4. Go to Application >> High Availability, and have a similar HA configuration except for Priority ID. Priority ID should be lower than the primary router.

a screenshot of DrayOS HA configuration

5. Go to LAN >> General Setup for LAN IP Configuration. Mind that the IP should be different from (better larger) than that of the primary router.

a screenshot of DrayOS LAN IP configuration

If you have more than one LAN, every LAN should have a different IP Configuration on primary and secondary routers to avoid IP conflict.

  Subnet Primary Router Secondary Router Virtual IP
LAN1 192.168.1.0 192.168.1.2 192.168.1.3 192.168.1.1
LAN2 192.168.2.0 192.168.2.2 192.168.2.3 192.168.2.1
LAN3 192.168.3.0 192.168.3.2 192.168.3.3 192.168.3.1
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LANx 192.168.x.0 192.168.x.2 192.168.x.3 192.168.x.1

6. After all the functions are set up correctly, we link up the management interface LAN so both routers can start communicating with each other, deciding which one should be the primary and syncing the configuration.
NOTE: Be sure to link the routers on a port that is a port member of the management LAN subnet. You can confirm this from LAN >> VLAN. In this example, we can use port 5.

a screenshot of DrayOS VLAN configuration

7. We may check the High Availability status by visiting the Status page. For the first time the two routers link up, we can see they are syncing the configuration from the primary to the secondary (showing "Progressing" on the secondary router).
TIPS: Click "Renew" to update the information of remote router, click "Refresh" to update the information of local router.

a screenshot of DrayOS HA Status

8. When the routers have the same configuration, it will show the "Equal" at Config Sync Status.
TIPS: Router will check if there's any un-synced modification when it reaches the time interval we set in step 2. We may force to sync by clicking the "Sync" button. The secondary router will reboot after the config sync.

a screenshot of DrayOS HA status

9. We may also check the Details page.

 a screenshot of HA Status Details
Sharing the WCF License

10. Now the routers are set, if you have WCF license, you may create a group on MyVigor so these routers can share the same license. First, log in to myvigor.draytek.com, find High Availability Settings and click Add New.

a screenshot of MyVigor

11. Give a Group Name, select the same HA Group ID as router's HA settings, and select the member routers in the HA Device drop-down menu.
NOTE: Only the devices registered under this MyVigor account will be listed. The HA peers should be registered to the same account.

a screenshot of MyVigor

12. Save the profile, and we can see the group entry.

a screenshot of MyVigor
a network topology

Before configuring High Availability, we need to set up LAN profiles and the VLAN ID configurations on each router by the following rules:

1. The LAN profile name and VLAN ID of the corresponding LAN between different routers must be the SAME.
2. Routers MUST own the DIFFERENT IP addresses on the HA Management LAN.
3. Router MUST own the SAME IP address on the non-HA Management LAN.

In this scenario, we use LAN1 as the HA Management LAN, so the IP addresses of each router on LAN1 should be different. And the IP addresses on other non-HA Management LAN should be the same. So, the IP addresses settings will be:
- Vigor3900_Master: LAN1 (HA-LAN) - 192.168.10.1, LAN2 - 192.168.20.254
- Vigor3900_Slave: LAN1 (HA-LAN) - 192.168.10.2, LAN2 - 192.168.20.254

Master Router Setup

1. Go to Applications >> High Availability >> Hot-Standby Profile Setup,

  • Select "lan1" for HA LAN Profile.
  • Input Priority ID as 1, which is the highest priority.
  • Input Virtual IP 192.168.10.254 for Gateway. Virtual IP should be an IP in the lan1 network
  • Input Group ID 1 (The other router should have same Group ID)
  • Click Apply.
a screenshot of Vigor3900 HA configuration

2. Go to Applications >> High Availability >> High Availability Global Setup:

  • Check Enable High Availability
  • Select "Hot-Standby" for Redundant Method
  • Input Authentication Key (The other router should have same Authentication Key; otherwise, the config synchronization will fail.)
  • Select "Immediate" for Advance Preemption Mode
  • Select "Enable" for WAN Connection Status Detection
  • Select "At Least One Up" for LAN Port Status Detection
a screenshot Vigor3900 HA configuration
Slave Router Setup

3. Go to LAN >> General Setup >> lan1 profile (the HA-LAN profile) to change the IP Address first, the LAN IP should be different from the master router.

a screenshot of Vigor3900 HA Configuration

NOTE: Only set the Master and Slave routers to different IP addresses on the management interface, the IP addresses of the rest of the LANs should be the same on both routers. Here is the example, which takes LAN1 as management interface:

  Subnet Master Router Slave Router
LAN1
Management Interface
192.168.1.0 192.168.1.1 192.168.1.2
LAN2 192.168.2.0 192.168.2.254 192.168.2.254
LAN3 192.168.3.0 192.168.3.254 192.168.3.254
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LANx

192.168.x.0

192.168.x.254

192.168.x.254

4. Go to Applications >> High Availability >> Hot-Standby Profile Setup, and

  • Select lan1 for HA LAN Profile
  • Input Priority ID as 2, since we already have the other Vigor3900 configuring with Priority ID 1
  • Input Virtual IP 192.168.10.254 for Gateway (Virtual IP should be the same as the Virtual IP set up on the other router)
  • Input Group ID 1 (should be same as the Group ID on the other router)
  • Click Apply.
a screenshot of Vigor3900 HA configuration

5. Go to Applications >> High Availability >> High Availability Global Setup,

  • Check Enable High Availability
  • Select Hot-Standby for Redundant Method
  • Input Authentication Key (The Authentication Key should be the same as the other router.)
  • Select "Immediate" for Advance Preemption Mode
  • Select "Disable" for WAN Connection Status Detection (Because in Hot-Standby mode, Master and Slave router share the same Internet connection, so this is to ensure Slave device will keep Inter-LAN working when WAN connection is failed.)
  • Select "Disable" for LAN Port Status Detection
a screenshot of Vigor3900 HA setup

6. After completing the configurations above, we can connect the LAN of both router, then configuration synchronization will start. The Slave router will backup and restore the whole Master configurations except for the LAN IP, HA configurations, Administrator Password, and Router Name. Please do not connect the WAN on the Slave router at this moment.

7. After config synchronized, Slave router will restart. We can check HA Status from Applications >> High Availability >> HA Status.

a screenshot of Vigor3900 HA status

By clicking Detail, we can see more device information.

a screenshot of Vigor3900 HA status

8. When Master meets WAN or LAN Fail Event, or be powered off, the router with Priority ID 2 will become the new Master.

a screenshot of Vigor3900 HA status

9. When upgrading the firmware of the Master router, the Slave router will upgrade to the same firmware version automatically. The process is:

  1. Master reboots for applying new firmware.
  2. Master is up and exchanges HA information with the backup router.
  3. Slave router finds the firmware version is different.
  4. Slave router will download the firmware from the Master router, and then upgrade itself automatically
a screenshot of firmware upgrade success message

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