"NetworkManager was created by Red Hat and is used today in
Fedora, Ubuntu, OpenSUSE, and many other distros. It provides a
background service that manages devices and connections; it also
has a user interface front-end that is accessible through the
desktop notification area. The functionality provided by the
NetworkManager background service is exposed through D-Bus, which
makes it easy for third-party software developers to get
information about connection availability and network device
status.
"The NetworkManager user interface gives users the ability to
toggle connection status, select wireless networks, and perform
other basic configuration tasks without having to use the command
line or to manually edit configuration files. There are several
custom NetworkManager user interfaces, including one for KDE that
is built with Plasma. NetworkManager supports ethernet, WiFi,
mobile broadband, and VPN connections.
"ConnMan was created by Marcel Holtmann of Intel's Open Source
Technology Center. Holtmann is probably best known for his works as
the maintainer of BlueZ, the Linux Bluetooth stack. During a
presentation at the Linux Collaboration Summit, he explained
ConnMan and discussed some of the problems he encountered with
NetworkManager that compelled him to build an alternative."