Confirming APN in use

Peter Naulls peter at
Thu Oct 20 16:41:50 UTC 2022

On 10/20/22 05:06, Aleksander Morgado wrote:
> Hey Peter,

> In 4G there are 2 different sets of APNs required for a successful
> data connection: first, the initial EPS bearer settings (a.k.a. attach
> APN), which is used during modem registration phase; and second the
> data connection settings (a.k.a data APN), which is used during modem
> connection phase. These settings may be equal or different, it really
> depends on the operator. Some operators may require an attach APN that
> is by default not providing Internet access, and so a different data
> APN needs to be used if the user wants to get to the Internet. Some
> operators allow requesting no specific attach APN (i.e. using blank ""
> APN), so that the network decides which one is used.

Thanks, that was very helpful. We have decided that for our use
cases, setting the initial bearer as well is going to be the best solution.

I can set this in my monitoring script, which should be OK - check
the APN when the modem becomes available, but I don't know if there's
a better place in the MM/netifd/OpenWrt scripts where this would be
better and more reliably done?  Changing the APN might well cause
the modem to reset, which is fine, but it's worth bearing in mind.

More information about the ModemManager-devel mailing list