Refer to the exhibit. Will redistributed RIP routes from OSPF Area 2 be allowed in Area 1?
A.
RIP routes will be allowed in Area 1 only if they are first redistributed into EIGRP.
B.
Because NSSA will discard type 7 LSAs, redistributed RIP routes will not be allowed in
Area 1.
C.
Redistributed RIP routes will be allowed in Area 1 because they will be changed into type
5 LSAs in Area 0 and passed on into Area 1.
D.
Redistributed RIP routes will be allowed in Area 1 because they will be changed into type
7 LSAs in Area 0 and passed on into Area 1.
E.
Because Area 1 is an NSSA, redistributed RIP routes will not be allowed.
Explanation:
The following are several area types that are possible on OSPF:
• Standard area – A standard area can accept link updates and route summaries.
• Backbone area (transit area) – When interconnecting multiple areas, the backbone
area is the central entity to which all other areas connect. The backbone area is always Area
0. All other areas must connect to this area to exchange route information. The OSPF
backbone has all the properties of a standard OSPF areA.
• Stub area – A stub area is an area that does not accept information about routes
external to the autonomous system, the OSPF internetwork, such as routes from non-OSPF
sources. If routers need to reach networks outside the autonomous system, they use a
default route. A default route is noted as 0.0.0.0/0.
• Totally stubby area – A totally stubby area is an area that does not accept external
autonomous system (AS) routes and summary routes from other areas internal to the
autonomous system. Instead, if the router needs to send a packet to a network external to
the area, it sends it using a 0.0.0.0/0 default route. Totally stubby areas are a Cisco
proprietary feature.
• Not-so-stubby area (NSSA) – An NSSA is an area that is similar to a stub area but
allows for importing external routes as Type 7 LSAs and translation of specific Type 7 LSA
routes into Type 5 LSAs.