Re: [lwip-users] lwip with 4G modem

[Giuseppe Modugno]

Il 12/10/2021 11:29, Gisle Vanem ha scritto:
> Giuseppe Modugno wrote:
>
> > The serial channel for ppp/data and AT commands is single, so how can 
> > I multiplex them? Should I use CMUX?
>
> The PPP protocol handles this multiplexing itself. Using an
> escape octet "stuffing procedure" (octet 0x7d).
> Read 'https://datatracker.ietf.org/doc/html/rfc1662' for the gory
> details.

So will I be able to send AT commands (for example to make a voice call 
or read SMS) and receive/send bytes of data connection, over the same 
serial link?


> > Last question. If I have 4G modem and Ethernet PHY, is lwip able to 
> > manage two network interface at the same time?
>
> Sure.