Wireless Wide Area Networks (Wwans); Configure Surelink Active Recovery To Detect Modem Failures - Digi IX10 User Manual

Interfaces

Wireless Wide Area Networks (WWANs)

A Wireless Wide Area Network (WWAN) provides connectivity to the internet or a remote network
through a cellular connection. A WWAN configuration consists of the following:
A cellular modem.
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Several networking parameters for the WAN, such as firewall configuration and IPv4 and IPv6
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support.
Several parameters controlling failover.
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Configure SureLink active recovery to detect modem failures

Problems can occur beyond the immediate modem connection that prevent some IP traffic from
reaching its destination. Normally this kind of problem does not cause the IX10 device to detect that
the modem has failed, because the connection continues to work while the core problem exists
somewhere else in the network.
Using Digi SureLink, you can configure the IX10 device to regularly probe connections through the
modem to determine if the modem connection has failed.
Required configuration items
Enable SureLink.
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SureLink can be enabled for both IPv4 and IPv6 configurations. By default, SureLink is enabled
for IPv4 for the preconfigured Modem interface. It is disabled for IPv6.
When SureLink is configured for Wireless WANs, SureLink tests are only run if the cellular
modem is connected and has an IP address. Use the SIM failover options to configure the IX10
device to automatically recover the modem in the event that it cannot obtain an IP address.
See Configure a Wireless Wide Area Network (WWAN)
The type of probe test to be performed, either:
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Ping: Requires the hostname or IP address of the host to be pinged.
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DNS query: You can perform a DNS query to a named DNS server, or to the DNS servers
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configured for the WAN.
HTTP or HTTPS test: Requires the URL of the host to be tested.
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Interface status: Determines if the interface has an IP address assigned to it, that the
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physical link is up, and that a route is present to send traffic out of the network interface.
The preconfigured Modem interface is configured by default to use SureLink to both test the
interface status and perform a test DNS query.
Additional configuration items
The behavior of the IX10 device upon test failure:
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The default behavior, which is to restart the Modem interface.
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Reboot the device.
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The interval between connectivity tests.
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The number of probe attempts before the Modem interface is considered to have failed.
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The amount of time that the device should wait for a response to a probe attempt before
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considering it to have failed.
IX10 User Guide
Wireless Wide Area Networks (WWANs)
for details about SIM failover.
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