MDS 05-6628A01, Rev. B
MDS Orbit MCR-4G Technical Manual
31
LTE Recovery
The cellular modem used inside the unit may occasionally remain in a 3G (EVDO-REV A) service state and
not transition to 4G LTE. The firmware incorporates a recovery mechanism to recover from this condition.
If the cellular modem has been in 3G coverage for more than 15 minutes, the firmware resets the modem to
bring it back into LTE service state. LTE recovery is enabled by default. This mechanism should be disabled
if the unit is deployed in areas that either lack or have poor LTE coverage. Otherwise, the cellular modem
will unnecessarily reset every 15 minutes.
Keep Alive
This feature allows the cellular modem to maintain a connection in situations where no traffic is passed over
cellular link for long periods of time, which would otherwise cause disruption. The keep alive mechanism
sends an ICMP echo message to the configured address/host at the configured interval. This feature should
be used only if an application is passing data very infrequently over a cellular connection (
i.e.
, if data is
passed at a rate of less than once per hour).
The commands for setting 3G/4G operation are as follows:
4G Operation
– Default programming.
% set interfaces interface Cell cell-config service-recovery lte-recovery true
% commit
3G Operation
– Turn off the LTE Recovery Mode to allow continual 3G mode operation without periodic
disconnection for 4G service search.
% set interfaces interface Cell cell-config service-recovery lte-recovery false
% commitKeep Alive
NOTE:
The Verizon network can disconnect the cellular connection if any packets get routed from LAN
to Cellular interface without undergoing masquerading (Source Network Address Translation
(NAT) before exiting the cellular interface. Therefore, always configure masquerading on the
cellular interface. Refer to the “Firewall and NAT” section in this manual for more information
on NAT configuration.
Monitoring
Ensure the CLI is in Operational mode. Follow the example below to view the cellular interface state and
statistics:
admin@(none) 16:23:34> show interfaces interface Cell
interfaces interface Cell
if-index 6
status mac-address 00:a0:c6:00:00:00
status mtu 1500
status link up
status ipv4 address [ 172.18.175.131/29 ]
status ipv6 address [ fe80::2a0:c6ff:fe00:0/64 ]
status counters collisions 0
status counters multicast 0
status counters rx_bytes 50574
status counters rx_compressed 0
status counters rx_crc_errors 0
status counters rx_dropped 0
status counters rx_errors 0
status counters rx_fifo_errors 0
