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routers in stub area do not need to know about all the external destinations and The routers in stub area must send a packet to the ABR to reach the ASBR,
no type 5 external LSA
no ASBR allowed
config-router)#area 2 stub
while routers totally stub area do not need to know about all external destinations or any summary LSA from the backbone for other areas. The routers in totally stub area must send packets to the ABR to reach any destination outside the totally stub area
no type 3 summary LSA
no type 5 external LSA
no ASBR allowed
config-router)#area 2 stub no-summary
Stub area a isolated area that does not receive External LSA.
As a summary :
Stub area will have LSA type 1,2,3
Total Stubby area will have LSA type 1 and 2 and a default route
STUB: stub are only allow Type 2(Network),Type 3(Netsummary).
Totally stub:its allow only type 2 LSA and default route.
Stub areas does not receive type 4 and type 5 LSAs it is replaced by a default route to external autonomous system advertised by the area border router (ABR) , however a totally stubby area besides to that does neither receive type 3 LSAs and replaced by a default route to other areas advertised also by the ABR
Stub area can have type OSPF LSA Type 1,2,3 and 4 while Totally Stub will ONLY have Type 1,2 and Default route
Stub area is an area which donot recieve routing updates from outside of its AS so when we configure an area as a stub area ,this area will not have LSA type 5 and if we also want that this area will also donot have LSA type 3 and LSA type 4(Inter area routes) then we configure this area as a total stubby area and by default a default route is injected into stub and total stubby area.
Stub area will have LSA type 1,2,3,4.
Total Stubby area will have LSA type 1 and 2.
Ospf has specially area types called stub area
If you configure an area as stub it will block all types external LSAS . All the prefites that you redisributed into OSPF from an other routing protocol are not welcome in the sub area.
A stub area that only allows routes internal to the area and restricts Type 3 LSAs from entering the stub area is often called a totally stubby area. You can convert area 0.0.0.3 to a totally stubby area by configuring the ABR to only advertise and allow the default route to enter into the area. External routes and destinations to other areas are no longer summarized or allowed into a totally stubby area.
