On 19.02.19 01:01, JH wrote:
Sorry for asking basic questions, I am new to connman and the list,
but it seems to me that connman targets to the embedded system, a
perfect light weight network management library for the embedded
system. I am using ublox SARA LTE Cat M1 / NB1 module, EMMY-W1 WiFi
and BLE in a tiny Linux embedded system running on C / C++
applications, has anyone known if there are drivers that connman can
support those modules? Anything I need be aware of before using the
ConnMan doesn't support GSM/LTE modems directly. Instead it is using oFono for
handling all the low level interaction with modems. The same is with Bluetooth. For this
ConnMan uses BlueZ. For WiFi ConnMan is able to stear wpa_supplicant, or iwd. Though iwd
plugin needs some updates (e.g. scaning support and tethering). In short, ConnMan does
configure and maintain networking interfaces, the 'hardware' drivers are part of
I also need network switching capability, the LTE is the default
network interface, when the system detects WiFi is available, it
switches from LTE to WiFi network connection immediately which is
similar to the mobile phone to automatically switch from LTE to the
WiFi. I think the connman must has that capacity as well, but correct
me if I am wrong.
Yes, that is what ConnMan is doing. Though this depends on how good the hardware and the
Please correct me if I am wrong. The switch between LTE and Wifi is not automatic and
immediate as like in mobile phone. For example, during the system startup if I have only
cellular connectivity, Connman uses this interface(provided by ofono) for data connection.
If after sometime, wifi network is available, Connman add this interface(provided by
bluez) but in ready state and not in online state. This still means that the data
connection is still through cellular network. Connman doesn't change to wifi network
just because it's available. The switch to wifi happens, if the cellular communication
breaks completely or a manual interruption using connmanctl disconnect cellular_* and
connmanctl connect wlan_*
Thanks & Regards,
The dbus is a desktop bus as the name implies, is it mandatory that
connman has to use dbus? I heard there are problems for embedded
system to use dbus, but please correct me.
D-Bus is mandatory. I am not sure what problems you are referring. It is possible to use
also in embedded system. These days you can use a completety new reimplementation of the
D-Bus daemon which is should work way better (read resource usage)
The core of dbus-broker (the `dbus-broker` binary) has no external dependencies at all,
other than a linux kernel. It is a complete bus implementation according to the dbus
specification (see `dbus-broker(1)` man-page).
Are there any preference of Linux distribution that will be the best
for running connman? I have been thinking to use either Debian armhf
or OpenWrt, appreciate your comments.
Any distro which brings the right dependencies with it works fine.
Debian armhf will work without any problems (doing this myself). I suppose OpenWrt works
but I don't know it by fact.
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