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QID:N2C67 - If RT1 is an ABR why is it injecting a type 7 default into own table
#1
Hello,

Your answer makes no sense to me.  If RT1 is an ABR why would it inject a type 7 default route into its own routing table.  It doesn't do that.  Instead it injects a type 7 default route into the routing table of other routers in the area.  So this means the answer needs to be:

The default route is learned from an OSPF neighbor.

That is the correct answer.

11. (QID:N2C67) Refer to the exhibit. On the basis of the information presented, which statement is true?
Exhibit:

RT1# show ip route ospf
O IA     6.0.0.0/8 [110/65] via 5.0.0.2, 00:00:18, Serial2/1/0
O* N2   0.0.0.0/0 [110/1] via 5.0.0.2, 00:00:18, Serial2/1/0

Network 6.0.0.0/8 was learned from an OSPF neighbor within the area.
The default route is learned from an OSPF neighbor.
OSPF router 5.0.0.2 is an ABR.
A default route is configured on the local router.

Correct Answer: OSPF router 5.0.0.2 is an ABR.

Explanation:
It looks like the OSPF area is an NSSA Totally Stubby Area, a Cisco proprietary feature. When the ABR is configured with the area 1 nssa no-summary command, it works exactly the same as the totally stubby technique. A single default route replaces both inbound-external (type 5) LSAs and summary (type 3 and 4) LSAs into the area. The NSSA ABR, automatically generates the O*N2 default route into the NSSA area with the no-summary option configured at the ABR.

http://www.cisco.com/warp/public/104/nssa.html
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#2
The question doesn't say thay the show ip route ospf command was issued on 5.0.0.2 though. It must have been issued on a router behind 5.0.0.2.

HTH,
Gary
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#3
Oh yeah.. ok now I see.  Yeah I must have been tired that day.  I took and passed my BSCI already so it worked out ok.

But yes this question makes perfectly good sense now.  The answer is that 5.0.0.2 is an ABR for sure.
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