5.7 Cellular Operation
When set up as a console ser ver the 3G cellular mod em can be set up to connect t o the carrier in either:
- Failover mode. In this case a dial-out cellular connection is only established i n event of a ping failure
- OOB mode. In this mode the dial-out con nection to the car rier cellular netwo rk is always on - awaiting
any incoming acces s (from a remote site want ing t o access to the cons ol e server or att ached serial
consoles/network hosts)
- Cellular router mode. Again in this case the dial-out c onnection to the carri er cellular netwo rk is always
on, but IP traffic is routed between the c el lul ar connected net work and the cons ol e server’s local
network ports
- Circuit Switch ed Dat a (CSD) mode. In this dial-in mode t he cellular modem can receive incoming calls
from remote modems who dial a special Dat a Terminating numb er
5.7.1 OOB access set up
Out-of-band acce ss is enabled by defaul t and the cellular mo dem connection is always on. However to be
directly accessed the console server needs to have a Public IP address and it must not have SSH access
firewalled.
Almost all carrier s of fer corporate mobile data service/ plans with a Public (st atic or dynamic) IP address.
These plans often have a service fee attached.
If you have such a st atic Public IP add ress plan you can also now try accessing t he console
server using the Public IP Address provided by t he carrier. However by def aul t only HTTPS
and SSH access is enabl ed on the OOB connect i on. So you can brow se t o the console
server, but you cannot ping it
If you have a dynamic Public IP addre ss plan then a DDNS serv ice will need to be confi gured
to enable the remote a dm i nistrator to init i ate incoming acce ss. Once this is done you can
then also try acce ssi ng t he console server usi ng the allocated domain name
By default most provi ders offer a consumer grade service w hi ch provides dynami c Private IP address
assignments to 3G devices. This IP address is not visible across the Internet but generally it i s adequate
for home and general business use.
With such a plan the Failover& Out-of-Band tab on the Status: Statistics shows will identify that
your carrier has allo cated you a Private IP Address (i.e. in t he range 10.0.0.0 – 10.255.255.255,
172.16.0.0 – 172. 31.255.255 or 192.168.0.0 – 192.168.255.255
In out of band access mode the internal cellular modem will continually stay connected. The alternative is
to set up Failover mode on the console serve r as detailed in the next section.
5.7.2 Cellular failover setup
Once you have configured carrier connection, the cellular modem can be configured for failover.
This will tell the cellular connection to re m ai n i dl e i n a low power state. I f the primary and secondary probe
addresses are not available it will bring up the cellular connection and connect back to the c el l ul ar carrier.
Navigate back to the Network Interface on the System:IP menu specify Internal Cellular
modem (cell modem 01) as the Failover Interface to be used when a f aul t has been detecte d
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