Cisco CAB-L400-20-TNC-N= Manuel D’Utilisation
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Antenna Guide for ISR and CGR with Verizon Wireless 4G LTE
Q) My connection is showing 3G and it won’t return to 4G/LTE. Why?
A) The radio access technology (RAT) chosen by an LTE device is based on 3GPP specification
and the radio signal reception of the device’s LTE modem. The RAT value can be seen from the
ISR “
and the radio signal reception of the device’s LTE modem. The RAT value can be seen from the
ISR “
show cell x radio
” enable-mode command. LTE 3G-to-4G reselection requires the
connection to be dormant for 7-10 seconds in the Verizon LTE network. For a mobile phone,
return to LTE is feasible. For a router with multiple devices behind it, the user traffic, keep-
alives, and normal protocol messages may keep a dormancy period from occurring for hours or
days. Another factor is that even a transient condition can cause the LTE modem to choose 3G.
Below are two options to mitigate this situation:
return to LTE is feasible. For a router with multiple devices behind it, the user traffic, keep-
alives, and normal protocol messages may keep a dormancy period from occurring for hours or
days. Another factor is that even a transient condition can cause the LTE modem to choose 3G.
Below are two options to mitigate this situation:
- Confirm that the ISR is at a stationary location and has consistently acceptable LTE signal. If
so, lock the connection to LTE (IOS enable-mode command “
so, lock the connection to LTE (IOS enable-mode command “
cellular x lte tech lte
”). The modem
will only connect to LTE. If there’s no LTE signal, no connection will be made. This setting is
permanent (until overridden by using the above command to set “tech” back to “auto”).
- Either manually or via EEM, check RAT. If on 3G, power off/on the modem’s radio. This will
cause a brief disconnect (IOS config: “
permanent (until overridden by using the above command to set “tech” back to “auto”).
- Either manually or via EEM, check RAT. If on 3G, power off/on the modem’s radio. This will
cause a brief disconnect (IOS config: “
controller cell x
”, “
lte radio off
”, “
no lte radio off
”).