Marcel Holtmann wrote:

quoted

...
CAIFSO_CHANNEL is used for specifying the physical interface to use
for the CAIF Channel. You can select the type of interface to use by
setting link_selector: CAIF_PHYPREF_LOW_LAT will typically be used
for AT (or other control traffic), and CAIF_PHYPREF_HIGH_BW for IP
traffic. 
When the CAIF interfaces registers itself it will inform about their
type, (low-latency or high-bandwidth). This approach assumes that you
have only one modem, but multiple links to it (e.g. USB and UART).

But you can also specify interface by name using link_name. In this
case you specify the name of the interface to use. I think this would
support your use case with multiple modems attached.

sounds good, but why using a socket option and not allowing to just
use bind(). Maybe it is just my personal preference, because I am
used to do it like this for TCP and Bluetooth.  

We actually considered this when designing the interface,
but I don't feel bind() fits in this case. bind() would normally bind
an address to the client socket. An interface did not seem
like a client socket address to us, so we decided to use sockopt instead.
Conceptually I don't think CAIF has a client address at all, it only
connects to a server side address.

BR/Sjur