Static - The route is configured over Static IP.
This route is written to configuration files.
Dhcp - The route is Configured by DHCP
(received as part of DHCP configuration)
This route IS NOT written to configuration files
Default - The route is Configured by default system config
exists till any other configuration is applied.
Icmp - The route is Configured by ICMP protocol either by
router advertisements or to be advertised in router
advertisements .