Please explain – Stub vsNSSAvs Totally Stub vs Totally NSSA?

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OSPF has multiple Area types: 

Stub: LSA 5 + Lsa 4 are filtered in this area from ABR. 

         Automatic Default Route Is Generated by ABR.

        Stub area can not have an ASBR.

 

Totally Stub: Same as above, along with the filtering of LSA 3.

 

NSSA: LSA 5+ LSA 4 are filtered in this area on ABR.

           This area can have ASBR. But the external routes are injected in this area by ASBR in the form of LSA 7, which is again converted

            into LSA 5 while leaving area boundry on ABR.

           Default Route is also generated manually.

 

Totally NSSA:  LSA 3 / LSA 5 / LSA 4 are filtered on ABR.

            Automatic default route is present.

           External routes are injected in this area by ASBR in the form of LSA 7, which is again converted into LSA 5 while leaving area     

           boundry on ABR.