Interfaces
Wireless Wide Area Networks (WWANs)
IX14 User Guide
66
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:
n
A cellular modem.
n
Several networking parameters for the WAN, such as firewall configuration and IPv4 and IPv6
support.
n
Several parameters controlling failover.
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 IX14 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 IX14 device to regularly probe connections through the
modem to determine if the modem connection has failed.
Required configuration items
n
Enable SureLink.
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 IX14
device to automatically recover the modem in the event that it cannot obtain an IP address.
See
Configure a Wireless Wide Area Network (WWAN)
for details about
SIM failover
.
n
The type of probe test to be performed, one of:
l
Test another interface's status: Used to create a failover or coupled relationship between
two interfaces. Requires the name of the alternate interface, the IP version to be tested,
and the expected status of the alternate interface (either up or down).
l
Ping: Requires the hostname or IP address of the host to be pinged.
l
DNS query: You can perform a DNS query to a named DNS server, or to the DNS servers
configured for the WAN.
l
HTTP test: Requires the URL of the host to be tested.
l
Test DNS servers configured for this interface: Tests communication with this interface's
DNS servers that are either provided by DHCP, or statically configured.
l
Interface status: Determines if the interface has an IP address assigned to it, that the
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
n
The behavior of the IX14 device upon test failure:
l
The default behavior, which is to restart the
Modem
interface.
l
SIM switching (also enabled by default).
