通過策略路由完成控制， 比如：
ospf 1
default-route-advertise type 1
import-route static route-policy import-static
area 0.0.0.0
network x.x.x.x 0.0.0.3
route-policy import-static permit node 10
if-match ip-prefix permit-static
#
ip ip-prefix permit-static index 10 permit 192.168.x.x 24 //靜態路由指定的網段