NetworkManager provides a sophisticated and intuitive user interface which enables users easily to switch their network environment. However, NetworkManager is not a suitable solution in the following cases:
You want to use more than one provider for dial-up for one interface.
Your computer is a router for your network.
Your computer provides network services for other computers in your network, for example, it is a DHCP or DNS server.
Your computer is a Xen server or your system is a virtual system inside Xen.
You want to use SCPM for network configuration management. To use SCPM and NetworkManager at the same time, disable the network resource in SCPM configuration.
You want to use more than one active network connection simultaneously.