What are the basics of the TNA-300 series failover feature?
As of firmware v1.11.2, all TNA-300 series devices operating in Station or PTP-slave modes can be configured to use an alternative upstream data path via a device attached to the eth1 port.
Instead of replying on a low-quality, built-in 5GHz radio for failover, you can use whatever radio you'd like - it can even be pointed to a different site completely!
Under what conditions will the TNA use the alternative data path?
The alternative data path will be used under the following circumstances:
- The station is not currently associated to an AP, or
- The RSSI of the wireless link drops below the pre-configured RSSI threshold (see the web UI guide for more details about these settings).
Under what conditions will the TNA resume normal operation?
The device will switch back to the wireless uplink data path once two conditions are met:
- The station is connected to the access point at an RSSI that's above the pre-configured failover threshold, and
- The RSSI of the link has been above the failover threshold for the amount of time defined in the "Flap protection time (sec)" field under the failover settings.
You can view the current failover status from the station dashboard. It will be updated once the device's wireless signal is back within a normal range, and the flap timer is counting down. More status details are available under the ETH1 settings of the dashboard:
Why can't I see any failover settings in the UI?
Your device must be running 1.11.2 or later firmware, be operating in station mode, and not have data VLAN enabled. Data VLAN is not currently supported when failover is enabled.
How many pings can I expect to lose once the data path is switched over to the failover data path?
There are a couple of different factors that could affect ping loss during failover state changes (like how long it takes for ARP to switch over), but generally only a few pings will be lost.
Real world use case:
- The Ethernet 1 graph on the right shows the traffic over a TNA-301 AP and the Ethernet 3 graph shows the traffic over the 5GHz failover AP.
- A laptop connected to the TNA-302 client is streaming a 4k UHD video.
- The TNA-301 AP was rebooted to simulate an outage on the primary link and then recovery once it boots back up.
- There were no issues with the video stream and pings showed a single drop to the internet.
How often is the wireless signal checked once failover is enabled?
It is checked once a second.
Can I use the 2.5G eth0 port for failover?
At this time, only the 1G eth1 port can be configured for use in failover.
How will I know if my device has failed over in the past?
Activity events, log entries, and SNMP traps are all created whenever the device's failover state changes:
Failover status is also available via the SNMP:
What happens if there is no link on the eth1 device?
Failover is automatically disabled if there is no active connection on the eth1 port. This will be indicated by a message at the top of the station dashboard, as well as under the eth1 status:
