Using a Netgear 4G modem with Netgear D6400 router

[spon]

Hi,

I'm looking to purchase a Netgear 4G modem (NETGEAR LB2120-100UKS) to use as a back-up internet connection with an existing Netgear D6400. The D6400 is used for fibre connection in the UK. The existing router has an onboard modem and it's not clear how/if this would need to be disabled if the unit was working with the 4G modem.

The 4G modem purchase information suggests that it is "plug and play" with existing routers but I don't want to spend £120 on it without fully understanding how it should be connected and configured as a back-up.

Any guidance appreciated please.  We run a business from a home office and need a back-up solution should our fibre connection fail. The 4G modem may be ideal. The alternative is a complete new 4G router (Huawei or similar) but if I can plug the Netgear modem into the existing system it would be a smoother changeover.

Thanks

spon

[antinode]

> [...] The existing router has an onboard modem and it's not clear
> how/if this would need to be disabled if the unit was working with the
> 4G modem. [...]

   A better way to look at the question might be to ask how the router
decides between the DSL modem and the Ethernet WAN/Internet port.  In
the D6400 User Manual, there's a section, "Change the Physical WAN
Connection Preference" which says:

      The modem router can autodetect the type of WAN connection.
      However, you can also set the WAN connection preference manually
      to either the DSL port or the Ethernet WAN port.

   I don't know what "autodetect" actually means, so I would not bet
that the router would automatically switch between the two WAN
connections when the (fiber) DSL link dies and re-awakens.  I haven't
tried it on my D7000, so I know nothing, but my guess would be that an
Ethernet connection would be preferred over a DSL connection.  (But what
do I know?)

   I suspect that you could use the D6400 either way, but you might need
to switch it manually between the two WAN interface choices (ADVANCED >
Setup > WAN Setup : WAN Preference).  I haven't looked, but I'd also
guess that there are more sophisticated (industrial-grade) routers which
can be configured to do what you want (automatically).

[spon]

Thanks for the helpful reply. I'm not so worried about auto failover as this is more a contingency if the main fibre falls over. I've purchased a Netgear 4G modem which looks like it should work but I'll know more when Amazon deliver tomorrow. I did ask for help from Netgear presale support but seems that new order enquiries aren't a priority as no response 😞
Fingers crossed and thanks for your advice.
spon