In /etc/config/network:
config route
option interface 'xxx'
option target '0.0.0.0'
option netmask '0.0.0.0'
option gateway 'xxx.xxx.xxx.xxx'
In /etc/config/network:
config route
option interface 'xxx'
option target '0.0.0.0'
option netmask '0.0.0.0'
option gateway 'xxx.xxx.xxx.xxx'