Ethernet SureLink settings

You can configure the SureLink settings to run a selected test that examines the functional integrity of the network connection, and take action to recover the connection in the event that it is lost.

Link test enable

Enables or disables the SureLink feature and the specified link integrity monitoring tests. The default is off (disabled).

Test interval

The interval, in seconds, when the selected test is initiated (repeated). A new test starts every N seconds while the mobile connection is established. You must specify a valid value between 10 and 65535 seconds. The default is 240. Only the Ping, TCP Connection Test, and DNS Lookup Test options use this setting. The Device Cloud Connection Test option does not use this setting.

If the configured interval is less time than it takes a test to complete, the next test will not be initiated until the previous (current) test has completed.

Test only if link is idle

Use the test repeat interval (above) as an idle period interval. That is, initiate the selected link integrity test only after receiving no data for the specified interval of time. This changes the behavior of the test in that the test interval varies according to the presence of other data received from the mobile connection. Only the Ping, TCP Connection Test, and DNS Lookup Test options use this setting. The Device Cloud Connection Test option does not use this setting.

Although using this idle option may result in less data exchanged over the mobile connection, it also prevents the link integrity tests from running as often to verify the true bi-directional state of that connection.

Number of consecutive failures to cause recovery action

The mobile connection will be disconnected and reestablished after the configured number of consecutive link integrity test failures. This value must be between 1 and 255. The default is 3. The “consecutive failures” counter resets to zero when the mobile connection is reestablished.

If the mobile connection disconnects for any reason (including not as a result of a link integrity test failure), the consecutive failures count resets to zero when the mobile connection is reestablished.

Host List

These settings apply to Ping, TCP Connection, and DNS Lookup tests only. Two hostnames may be configured for the link integrity monitoring test. You can specify hostnames in the form of domain names or IP addresses. If the first hostname fails to reply, the same test is sent to the second hostname. The test fails if no reply is received for either hostname. The primary and secondary DNS names must be fully qualified domain names. Note that the reverse lookup of an IP address is possible, but that is usually unlikely to succeed in returning a name. You can still use a reverse lookup to demonstrate the integrity of the mobile connection.

Test type

Several tests are available. For details about each type, see Link integrity test options.

Link failure action

The action to be performed when a link failure is detected: