- Home
- Networking
- CCNP Routing 300-101
56.
A router has been configured with the commands router ospf 9 , network 172.16.1.0
0.0.0.255 area 8 and network 172.16.0.0 0.0.255.255 area 9 , in that order. No
other OSPF-related commands have been configured. The answers list the IP
addresses that could be assigned to this router's Fa0/0 interface. Which answers list
an IP address/prefix length that would cause the router to put Fa0/0 into area 9?
(Choose two.)
- A.172.16.0.1/23
- B.172.16.1.1/26
- C.172.16.1.1/24
- D.172.16.0.255/23
- E.None of the other answers is correct.
- Answer & Explanation
- Report
Answer : [A and D]
Explanation :
Explanation :
| The wildcard mask is used for matching the prefix only, and not the prefix length. As such, 172.16.1.0 0.0.0.255 matches all addresses that begin with 172.16.1, and 172.16.0.0 0.0.255.255 matches all addresses that begin 172.16. Also, OSPF reviews the network command with the most specific wildcard masks (wildcard masks with the most binary 0s) first, so an interface IP address beginning with 172.16.1 matches the command that references area 8. |
57.
Which of the following is true about an OSPF area border router (ABR)?
- A.The ABR must have multiple interfaces connected to the backbone area
- B.An ABR is a router with two interfaces, each connected to a different nonbackbone area.
- C.The only requirement to be considered an ABR is at least one interface connected to the backbone area
- D.An ABR must have at least one interface in the backbone area plus at least one other interface in a nonbackbone area.
- Answer & Explanation
- Report
Answer : [D]
Explanation :
Explanation :
| ABRs, by definition, connect the backbone area to one or more nonbackbone areas. To perform this function, a router must have at least one interface assigned to the backbone area and at least one interface assigned to a nonbackbone area. |
58.
Which of the following can either directly or indirectly identify all the interfaces for
which 1) OSPF has been enabled and 2) OSPF is not passive? (Choose two.)
- A.show ip ospf database
- B.show ip ospf interface brief
- C.show ip protocols
- D.show ip route ospf
- E.show ip ospf neighbors
- Answer & Explanation
- Report
Answer : [B and C]
Explanation :
Explanation :
|
First, for the two correct answers: show ip ospf interface brief explicitly
lists all OSPF-enabled interfaces that are not passive. show ip protocols lists either
the details of the configured network commands, or if configured using the ip ospf
area command, it lists the interfaces on which OSPF is enabled. This command also
lists the passive interfaces, so armed with interface IP address information, the list of
OSPF-enabled nonpassive interfaces could be derived. Of the three wrong answers, show ip ospf database does not list enough detail to show the OSPF-enabled interfaces. show ip route ospf lists only routes learned with OSPF, so if no routes use a particular OSPF-enabled interface as an outgoing interface, this command would not indirectly identify the interface. Finally, an interface might be OSPF-enabled but with no neighbors reachable on the interface, so the show ip ospf neighbor command might not identify all OSPF-enabled interfaces. |
59.
Router R1 directly connects to subnet 10.1.1.0/24 with its Fa0/0 interface. R1 can
ping four other working OSPF routers in that subnet. R1 is neither the designated
router (DR) nor backup DR (BDR). OSPF is working correctly on all five routers.
Which of the following are true on R1? (Choose two.)
- A.The show ip ospf neighbors command lists two neighbors off Fa0/0.
- B.The show ip ospf neighbors command lists four neighbors off Fa0/0.
- C.The show ip ospf neighbors command lists two neighbors off Fa0/0 in the FULL state.
- D.The show ip ospf neighbors command lists two neighbors off Fa0/0 in the DISCO state.
- Answer & Explanation
- Report
Answer : [B and C]
Explanation :
Explanation :
| On a LAN, the non-DRs form fully adjacent neighborships with only the DR and BDR, giving R1 two neighbors in the FULL state. The other two neighbors settle into the 2-Way state. |
60.
Routers R1 and R2 are OSPF neighbors using their Fa0/0 interfaces, respectively,
using default settings for all timers. An engineer adds the ip ospf hello-interval 6
command to R1's Fa0/0 configuration. Which of the following are true regarding the
results from this change? (Choose two.)
- A.The show ip ospf neighbor command on R1 lists the revised Hello timer.
- B.The show ip ospf interface brief command on R1 lists the revised Hello timer.
- C.The R1-R2 neighborship fails because of Hello timer mismatch.
- D.The show ip ospf interface command on R1 lists the revised Hello timer.
- Answer & Explanation
- Report
Answer : [C and D]
Explanation :
Explanation :
| The show ip ospf interface command displays a router's OSPF Hello Interval setting for each enabled interface. The other listed commands do not display the timer. Also, OSPF routers do need to have matching Hello timers to become neighbors, so the neighborship would fail. |
|
|
||||||||||||||||||||||||||||
