GE MDS ORBIT MCR Technical Manual page 69


Mtu - Maximum Transmission Unit in bytes - leave at the default value of 1500, unless
directed by technical support to change.

Request DNS – If enabled, the DNS servers used by the system are obtained by the DHCP
client running on this interface.

Request Routers - If enabled, default route used by the system is obtained by the DHCP
client running on this interface.
NOTE
If multiple interfaces are configured to obtain addresses using DHCP, only, one of the
interfaces should enable request-dns and request-routers parameters.

Keep Alive - The keep-alive feature allows the cellular modem to maintain connection in situations
where no traffic is passed over the cellular link for long periods of time or when the traffic is
traversing through a NAT middle box in the network and where the mobile terminated traffic can be
sent only if the NAT entries exist for corresponding mobile originated traffic. The keep-alive
mechanism sends an ICMP echo message to the configured address/name 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).

Address - This parameter specifies the address or DNS name of the destination host to which
keep-alive messages should be sent

Interval - This parameter specifies the time interval (in minutes) between keep-alive messages

Recovery on Timeout - This parameter enables the connectivity recovery mechanism to reset
the cellular modem if no response to the keep-alive messages are received up to max-num-
retries attempts. DEFAULT - true if the keep-alive feature is configured

Max Num Retries - This parameter specifies the number of keep-alive messages that are sent
before modem recovery is attempted. DEFAULT - 15 - configurable only when recovery-on-
timeout is enabled.

Service Recovery - The service recovery configuration block contains various parameters related to
service recovery feature. The service recovery mechanism is meant as a watchdog mechanism for the
cellular connection, where the cellular modem is reset by the following conditions:
- The unit is unable to register at all on the network.
- The unit is unable to register specifically to the LTE service.

General Recovery Interval - This parameter specifies the time interval after which the
cellular modem is reset if the modem-state does not transition out of the 'unknown' state.
DEFAULT - 300 sec (5 min).

Lte Recovery – For an Orbit MCR equipped with an LTE modem, this parameter enables
LTE service recovery. The LTE service recovery mechanism resets the cellular modem if it is
stuck in 3G service-state (EV-DO or UMTS) for more than the lte-recovery-interval. This is
enabled by default. This parameter affects only units with LTE capable modem.

Lte Recovery Interval - For an Orbit MCR with an LTE modem, this parameter specifies the
time interval (in sec) after which, the cellular modem is reset if the modem-state does not
transition to 'LTE' service-state. DEFAULT - 900 sec (15 min).
% set interfaces interface Cell cell-config service-recovery lte-recovery false
% commit
NOTE
The Lte Recovery mechanism should be disabled if the unit is deployed in areas that either lack
or have poor LTE coverage. Otherwise, the cellular modem and hence the cellular data
connection will be unnecessarily reset every 'lte-recovery-interval' seconds.

sim-slot - This parameter specifies the SIM slot that should be used to read the SIM card.
Orbit MCR units equipped with cell may have one or two SIM slots: SIM-A and SIM-B.
DEFAULT - SIM-A. The slots are located on the outside of the case, on the front panel. If
MDS 05-6632A01, Rev. F MDS Orbit MCR/ECR Technical Manual 69