For background on interface aggregation, please refer to this article.
By default, Opengear bonding mode uses active-backup link status monitoring to switch between interfaces, i.e. the backup Management LAN interface is activated only when the primary Network Interface loses link.
Alternatively, by setting Linux kernel driver parameters you may enable LACP and use the interfaces simultaneously. The upstream switch that the Opengear is connecting via must also support LACP and have its connected ports combined into a Link Aggregation Group (LAG) or Channel Group.
These driver parameters must be set via the CLI and are applied after a reboot.
To enable LACP, first enable bonding, then login to the Opengear CLI as root and run:
config -s config.system.bond.params="mode=4 miimon=100 lacp_rate=1 use_carrier=0 updelay=200" -r ipconfig reboot
To disable LACP, login to the Opengear CLI as root and run:
config -d config.system.bond.params -r ipconfig reboot
A complete list of bonding parameters can be found in the Linux kernel documentation.