About QMI-PROXY

[Aleksander Morgado]

Hey,

> I am looking into the QMICLI manual and some examples on the internet about these commands. I am wondering if this flag is mandatory when we want to start/stop data connection on the modem:
>
> --device-open-proxy
>
> I am trying to understand the pros and cons.

If you use the flag, all the qmicli commands will go through the
qmi-proxy, which is the process that talks to the QMI port. By running
the proxy, you can run multiple qmicli commands in parallel, or even
have another long-running process like ModemManager talking to the QMI
proxy through the port at the same time. The key point to understand
is, if you use the proxy, ALL other programs in the system must also
use the proxy. If you don't use the proxy, you MUST make sure no other
program (not even another qmicli call) is trying to access the QMI
port.

On a standard GNU/Linux distribution you may already have ModemManager
running in the system, and ModemManager forces everyone else to use
the proxy.

Using the proxy or not doesn't have a direct relationship with the
actual data connection setup. A key point to consider when setting up
the data connection using qmicli is that you MUST make sure the WDS
client is not released after the Start Network, i.e. you must run
--wds-start-network always with --client-no-release-cid, and then
reuse the WDS client cid (with --client-cid=CID) in every other qmicli
WDS command for that connection setup, even in the --wds-stop-network.

-- 
Aleksander
https://aleksander.es