What are the area types of OSPF?

Backbone area (area0) Standard area Stub area Totally stubby area Not-so-stubby area (NSSA)

1) Common Area: OSPF areas are common areas by default.
Common areas include standard areas and backbone areas.
A backbone area connects all the other OSPF areas.
It is usually named Area0.2) Stub Area3) Totally Stub Area4) NSSA (Not So Stuby Area)5) Totally NSSA (Totally Not So Stuby) Area

Area Types: (1) Standard Area - Default OSFP area type (2) Stub Area - External link (type5) LSAs are replaced with a default route (3) Totally Stubby Area - Type3,4 and5 LSAs are replaced within a default route (4) Not So Stubby Area (NSSA) - A stub area containing an ASBR; type5 LSAs are converted to type7 within the area

Totaly three types of area,

1. Intra area 

2. Inter area 

3.Stub Area, Totally stub area

4.NSSA, Totally NSSA