Wan-load-balancing can serve two functions, increase available upstream bandwidth and provide more resilience against failure. Active/active mode increases bandwidth while providing resilience.
When using fail-over mode or active/passive traffic originating from subscribers will egress from the HSMX towards upstream over a single link, once the link perishes, the next link is used. The link weight determines the fail-over order.
In active/active mode subscriber traffic will be distributed over multiple uplinks depending on the network load and link weights. When a link fails subscriber generated network traffic will fail-over onto the remaining available WAN links.
The health of the WAN interface is by default based off the interface link state. It assumes a link either is plugged in and works or isn't and fails. This mechanism will not detect any other faults that might pose connectivity problems. WAN health can be monitored using ICMP ping commands. The target can be chosen as well as the amount of failed or succeeded tests before it is considered the link state. We recommend this mode over the default detection mechanism.
Setup the individual WAN interfaces in
Network → Network configuration, confirm their functionality. Proceed to
Network → Load-balancing to finish configuration. First Enable load balancing/ failover and click on Update. The first interface will be added by default, to add more WAN interfaces use the +-icon in the sub-menu (right top). Each interface can be configured to load-balance (active/active) or fail-over (active/passive).