The Cellular Modem Link Recovery feature is used to check whether the modem functions properly and bring back the modem to normal operation state if the modem is in inoperative state. When an inoperative state is identified, the modem is reset (the cellular modem is power cycled). The link recovery feature is enabled by default, and can be disabled using Cisco IOS CLI.
There are four configurable parameters to adjust the behavior of cellular link recovery. The default values have been optimized for the best performance of the feature and changing it is not recommended unless advised by Cisco.
The following table explains the cellular modem link recovery parameters.
Table 6 Cellular Modem Link Recovery Parameters
This parameter defines the RSSI value below which the link recovery feature triggers additional scrutiny to look for potential issues and take action if needed. The range of this parameter can be set from -90 dBm to -125 dBm. The recommended and default value is -110 dBm.
This parameter determines how often link recovery looks for potential issues. The default value for this parameter is 20 seconds which means, link recovery feature will be triggered every 20 seconds and look at certain parameters to determine if there is a potential issue. You can configure the monitor-timer range between 20 to 60 seconds. Increasing the monitor timer value above 20 seconds will increase the response time of the feature.
wait-timer and debounce-count
The wait-timer parameter is used in conjunction with the debounce-count parameter to perform more frequent, additional checks, once the link recovery feature has identified a potential issue that needs to be recovered from, with a modem power-cycle. The default value for wait-timer is 10 seconds and the default value for debounce- count is 6. With this setting, once link recovery has identified an inoperative modem state, it performs additional checks every 10 seconds, up to 6 times, to determine if the issue has been resolved without a modem reset. Reducing the debounce-count and the wait-timer makes faster link recovery, while reducing them may increase the time for recovery. The configurable range for wait-timer is 5-60 seconds. The configurable range for debounce-count is 6-20 seconds.