NetworkManager - Debian Wiki
Using NetworkManager | Reference | openSUSE Leap 42.3 NetworkManager is the ideal solution for laptops and other portable computers. It supports state-of-the-art encryption types and standards for network connections, including connections to 802.1X protected networks. 802.1X is the “ IEEE Standard for Local and Metropolitan Area Networks—Port-Based Network Access Control ”.With NetworkManager, you need not worry about configuring network networkmanager - Where does Network Manager store settings Any configuration changes you make through NetworkManager will be saved using the keyfile plugin instead. SuSE apparently used to have ifcfg-suse, but it seems to be deprecated. Other distributions may have their own plugins. Re: Reload from Config File NetworkManager 0.9 and later try to be better team players in the system, and will read the existing configuration from a network interface on startup and use that as a "runtime" connection. Which is why your restart didn't apply that changed configuration, because NM picked up the interface's existing configuration.
Ubuntu Manpage: NetworkManager.conf - NetworkManager
You can select an interface, and NetworkManager displays the required credentials providing automatic connection after the reboot process. NetworkManager can configure network aliases, IP addresses, static routes, DNS information, and VPN connections, as well as many connection-specific parameters. NetworkManager.conf: NetworkManager configuration file NetworkManager.conf is the configuration file for NetworkManager. It is used to set up various aspects of NetworkManager's behavior. The location of the main file and configuration directories may be changed through use of the --config, --config-dir, --system-config-dir, and --intern-config argument for NetworkManager, respectively. NetworkManager: NetworkManager Reference Manual
NetworkManager.conf(5) — network-manager — Debian jessie
NetworkManager is a dynamic network control and configuration system that attempts to keep network devices and connections up and active when they are available. NetworkManager consists of a core daemon, a GNOME Notification Area applet that provides network status information, and graphical configuration tools that can create, edit and remove connections and interfaces.