Health monitor

Monitor WAN connectivity and configure recovery actions.

Health Monitor

The Health Monitor continually monitors the network connectivity and system state of each Hera WAN interface. If the network performance changes, the Health Monitor can:

• Seamlessly switch WAN interfaces to maintain connectivity
• Stop and restart the affected WAN interface
• Reset the cellular connection
• Change to a different SIM profile
• Monitor status files or execute test applications (for example, the Health Monitor can activate Shell scripts)
• Perform a system reboot if required

General settings – Global Health Monitor

Health Monitor Architecture

The Health Monitor system on the HERA Router operates across multiple levels to ensure robust data connectivity monitoring and recovery.

Global Health Monitor

• Operates at the highest level of the monitoring hierarchy.
• Executes connectivity tests at configurable periodic intervals.
• Serves as the central controller for overall health status.
• Global monitor runs across all interfaces when multiple interfaces are configured.
• Global actions are only performed if all interfaces are down.

#	Field name	Value	Explanation
1	Interface Prioritization	Enabled/Disabled	Used for devices with multiple WAN Interfaces – Not relevant here
2	- with this value of metric shift	Number between 1-9	Used to switch Route Priority when multiple Default Routes are used. The effect is that the Secondary Route will temporarily become the Primary Route during the detected connectivity outage.
3	Time (in seconds) between system polls	Value in seconds	Determines the periodic frequency of the health monitor connectivity test
4	Restart WAN interface	Enabled/Disabled	Determines the action to take when a health monitor failure is detected. This action forces the WAN interface to be administratively forced 'down' then 'up'.
5	- after this number of failed system polls	Number between 1-10	Determines how many consecutive failed polls are required before the WAN interface is restarted.
6	Reboot Router	Enabled/Disabled	Determines the action to take when a health monitor failure is detected. This action reboots the Router.
7	- after this number of failed system polls	Number between 1-10	Determines how many consecutive failed polls are required before the router is rebooted.
8	Method for choosing the best WAN interface	Priority, Round Trip Time or both.	Priority will take actions depending on interface failures. Round Trip Time will take link quality into account.

General Settings – Interface Monitors

Interface-Level Health Monitors

• One or more lower-level monitors can be configured for each active WAN interface.
• Each monitor runs independently and has its own interval settings.
• These monitors provide granular visibility and control over individual WAN connections.

1) For interface tests that fail.

These actions will be performed for each interface that fails.

#	Field name	Value	Explanation
1	Restart Interface	Enabled/Disabled	Determines the action to take when an interface test fails. This action forces the WAN interface to be administratively forced 'down' then 'up'.
2	- after this number of failed interface tests.	Number between 1-9	Number of consecutive failed tests required to initiate action.
3	Restart interface with a new profile	Enabled/Disabled	Determines the action to take when an interface test fails. This action switches to the next available cellular profile.
4	- after this number of failed system polls	Number between 1-10	Determines how many consecutive failed polls are required before a new profile is selected.
5	Reset Interface	Enabled/Disabled	Determines the action to take when an interface test fails. This action resets the WAN interface.
6	- after this number of failed system polls	Number between 1-10	Determines how many consecutive failed polls are required before the WAN interface is reset.

2) For interface tests that receive zero packets.

In addition to ping testing, the interfaces are also monitored for the presence of data packets. If no data packets are determined on a monitored interface for consecutive polls, then a failure is determined.

#	Field name	Value	Explanation
1	Restart Interface	Enabled/Disabled	Determines the action to take when an interface receives zero packets. This action forces the WAN interface to be administratively forced 'down' then 'up'.
2	- after this number of zero packet interface tests.	Number between 1-9	Number of consecutive failed tests required to initiate action.
3	Restart interface with a new profile	Enabled/Disabled	Determines the action to take when an interface receives zero packets. This action switches to the next available cellular profile.
4	- after this number of zero packet interface tests	Number between 1-10	Determines how many consecutive zero packet tests are required before a new profile is selected.
5	Reset Interface	Enabled/Disabled	Determines the action to take when an interface test receives zero packets. This action resets the WAN interface.
6	- after this number of zero packet interface tests.	Number between 1-10	Determines how many consecutive zero packet interface tests are required before the WAN interface is reset.

General Settings Miscellaneous

An interface or global health monitor failure is determined by the below settings. A single unanswered ping is not necessarily deemed a failure at the health monitor level, as congestion or latency could cause a dropped/unanswered ping during a normal data session.

#	Field name	Value	Explanation
1	Ping Requests - Timeout	Value in seconds	Determines how long to wait before an unreturned ping response is deemed a ping fail
2	Number of unanswered before failure	Default 3	Determines how many consecutive unreturned pings are required to be determined as a failed interface test.
3	DNS Requests - Timeout	Value in seconds	Determines how long to wait before an unreturned dns response is deemed a fail.
4	Number of unanswered before failure	—	Determines how many consecutive unreturned dns requests are required to be determined as a failed interface test

Settings for each WAN interface

Additional parameters to configure each independent health monitor interface.

#	Field name	Value	Explanation
1	Priority	Integer	When multiple interfaces are present, the priority value determines which interface should be used for the primary default route.
2	Interface	cellpri/ethwan	The interface name that the health monitor test is running on.
3	Ping Address	Comma separated list of IP addresses	This is the address of the ping server. If a list is present, then the health monitor will always try the first server in the list. The 2nd server is only tried if the first server does not respond.
4	DNS Lookup	Domain Name	The DNS name to be looked up to determine DNS is working correctly.
5	Time between interface tests	Time in seconds	This is the periodic interval between interface polls. Typically, an interface test runs more frequently than a global poll.
6	Enabled	Enabled/Disabled	Enable or Disable the interface Health Monitor.

Note: New interfaces will only appear in this section when an accompanying physical interface is created.

Overrides for each WAN interface

These are used in scenarios where multiple interfaces are used. It allows for each interface to be configured independently from each other. Use the General settings sections above for reference.