MII monitor

The MII monitoring periodically inspects the information provided by the Media Independent Interface. If the interface reflects the failure of a certain network device, the bonding driver interprets that this particular device is down. Options related to MII monitors are:
miimon
Specifies the MII link monitoring frequency in milliseconds. The default value is 0, and this will disable the MII monitor. On Linux® on Z, it is often set to 1000.
use_carrier
Specifies whether or not miimon should use MII or ETHTOOL ioctls vs. netif_carrier_ok() to determine the link status. The default value is 1, which enables the use of netif_carrier_ok(). This is supported by the qeth device driver on Linux on Z.
updelay
Specifies the time, in milliseconds, to wait before enabling a slave after a link recovery has been detected. The updelay value should be a multiple of the miimon value.
downdelay
Specifies the time, in milliseconds, to wait before disabling a slave after a link failure has been detected. The downdelay value should be a multiple of the miimon value.
Figure 1. Example: Using the MII monitor
miimon=1000
use_carrier=1
updelay=5000
downdelay=2000