Network has both Wan (ethernet) and mobile.
Wan set to 1st priority, mobile 2nd priority.
(TCR100 tested using 9.03 and 9.04)
Case 1
Wan: Failover not set ; Mobile: Failover not set;
1 If both wan and mobile enabled,
traffic goes via the wan for preference.
2 If disconnect only the wan, traffic goes via the mobile network
even though failover not enabled
3 if disconnect only the mobile network, traffic continues to go via the wan.
Case 2
Wan: Failover set ; mobile: Failover set;
1 If both Wan and Mobile enabled,
traffic goes via the Wan for preference.
2 If disconnect only the Wan, traffic goes via the mobile network
3 if disconnect only the Mobile network, traffic continues to go via the Wan
So case 1 & 2 seems the same!
Is there some difference I have missed?
Is the difference that:
If failover off for both, traffic may go via Mobile if the Wan is congested.
If Failover on for both, traffic will only go via Mobile if Wan is really down?
When failover or load balancing is not enabled, only the WAN connection with the highest priority (lowest metric) will be used. You can confirm this by prioritizing the WAN connection and checking your IP address, which will reflect only the active WAN source. If you want to utilize multiple WAN sources, either failover or load balancing must be configured. Without these settings, the additional WAN connections won’t be used unless the main one fails.
Of course i have read Failover and Load Balancing on TCR100 already.
I tried many times to understand the implications,
and have done many tests over many hours to see what happens in each scenario.
But please see Case 2, Point 2 above:
“2 If disconnect only the wan, traffic goes via the mobile network
even though failover not enabled”
So even though Failover is not enabled,
it still sends traffic to the Mobile if the Wan/ethernet goes down.
So this seems the same whether Failover is enabled or not??
I noted you wrote:
“Without these settings, the additional WAN connections won’t be used unless the main one fails.”
but if without Failover the additional connection is used if the main one fails,
what additional does setting Failover in both of them do?
I did further testing, now on 7.10
and I can confirm your first sentence might not be accurate.
You say:
When failover or load balancing is not enabled, only the WAN connection with the highest priority
(lowest metric) will be used.
If Failover is disabled, and i have 2 interfaces, and I disconnect the highest priority interface
(pull the cable out!)
traffic goes via the lower priority interface.
Further, the switch is immediate - this lower prioity interface is online.
If Failover is on, and I disconnect the higher priority device,
the switch to mobile takes a few seconds as the lower prioity device is in “Standby”.
So I think the difference is:
If Failover off for both, traffic may go via Mobile if the Wan is congested.
If Failover on for both, traffic will only go via Mobile if Wan is really down.
Grateful if you could confirm that this is correct.
You’re correct that when failover is not enabled, and the higher priority interface (e.g., WAN with metric 1) is disconnected, it is removed from the IP routing table, and the lower priority interface (e.g., mobile WAN with metric 3) takes its place immediately, as it now has the highest metric. This happens seamlessly without the delay caused by failover standby mode.
Regarding your statement: “If Failover is off for both, traffic may go via Mobile if the WAN is congested,” I have verified that when failover is disabled, all traffic will always go through the higher priority (lower metric) WAN interface, regardless of congestion. Failover only takes effect when the higher priority connection is down, not simply due to congestion.
In brief, failover works by sending pings to a host to check connectivity. If no response is received, it means the WAN connection through that interface is no longer functional, and it switches to the backup, even if the cable is still connected and the interface status shows as up.
Especially it is very useful to know:
“I have verified that when failover is disabled, all traffic will always go through the higher priority
(lower metric) WAN interface, regardless of congestion.
Failover only takes effect when the higher priority connection is down, not simply due to congestion.”
Thank you very much for verifying that !!
So I was wondering why I would bother to use Failover.
The answer is:
“If no response is received, it means the WAN connection through that interface is no longer functional, and it switches to the backup, even if the cable is still connected and the interface status shows as up.”