Raspbian reads files in /etc/network/interfaces.d/NNN_device in sequence at boot and upon detection event.

Configure known ip address for wired upstream connection.

• Enable wired interfaces at boot auto
• Enable wired interface when cable insertion is detected allow hot-plug
• Set interface to known static ipv4 settings iface eth0 inet static
  • address 192.168.2.9
  • netmask 255.255.255.0

	      # Enable known ethernet address at boot and plugin
	      auto eth0
	      allow hot-plug eth0
	      iface eth0 inet static
	          address 192.168.2.9
	          netmask 255.255.255.0