Based on the network displayed in the exhibit, both R1 and R2 are configured as EIGRP stub
routers. If the link between R1 and R3 is down, will R3 still be able to reach 192.168.1.0/24, and
why or why not?
A.
No. R3 would remove its route to 192.168.1.0/24 through R1, but would not query R2 for an
alternate route, since R2 is a stub.
B.
No. The path through R2 would always be considered a loop at R3.
C.
Yes. When a directly connected link fails, a router is allowed to query all neighbors, including
stub neighbors, for an alternate route.
D.
Yes, because R3 would know about both routes, through R1 and R2, before the link between
R1 and R3 failed.
Explanation:
When an EIGRP stub is configured a query is actually sent to the neighbor, however, he just
replies with the prefix being unreachable. So R2 responds to the query of R3 with the prefix for
192.168.1.0/24 as unreachable. Answer A is the only good answer really.
When using the EIGRP Stub Routing feature, you need to configure the distribution and remote
routers to use EIGRP, and to configure only the remote router as a stub. Only specified routes are
propagated from the remote (stub) router. The router responds to queries for summaries,
connected routes, redistributed static routes, external routes, and internal routes with the message
“inaccessible.” A router that is configured as a stub will send a special peer information packet to
all neighboring routers to report its status as a stub router.http://www.cisco.com/en/US/docs/ios/12_0s/feature/guide/eigrpstb.html