Industrial 4g with sim slot router’s OSPF stub area

If the number of industrial routers increases, it means the increase of LSA. Sometimes, in a stub network, a lot of routing information is redundant and does not need to be advertised, because all industrial routers in an OSPF area can pass through the area. ABR goes to other OSPF areas or external networks other than OSPF. Since industrial wireless routers in an area only need to know where they are going to ABR, they can go to networks outside the area, so the industrial 4g with sim slot router wireless routers outside the area can be filtered out to enter a certain Area, such an area is called OSPF stub area (Stub Area); although all routers in a stub area can go from the ABR to the network outside the area, there must still be a route to the ABR on the router, so the industrial 4G router in the stub area Only the default route is needed, and no detailed industrial-grade 3G router routes are required to communicate with networks outside the area. Different industrial 3G router routes outside the area are filtered out according to the stub area.

Under Not-so-Stubby Area (NSSA), ABR will filter out all external routes into the stub area, and also allow routes from other OSPF areas (Inter-Area Route) to enter the NSSA area, and routers can also redistribute external routes Enter the OSPF process, that is, the industrial full Netcom router in the NSSA area can become an ASBR. Since it can redistribute the industrial-grade full network router routes of the external network into the OSPF process, the ABR will not automatically send a message to itself in the NSSA area. The default route, but you can manually send the default full Netcom industrial router route to the NSSA domain, and you can only send the default route on the ABR.