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- CCNA Routing and Switching 200-105
111.
Two routers, R1 and R2, are configured to be part of an HSRP group. R1’s configuration includes the standby 1 priority 1 command, and R2’s configuration includes the
standby 1 priority 2 command. R1 powers up. An hour later, R2 powers up. Which
of the following answers is true about which router is now the HSRP active router?
- A.R2 is active regardless of other configuration settings.
- B.R1 is active regardless of other configuration settings.
- C.R2 is active only if R2 is also configured with standby 1 preempt.
- D.R1 is active only if R1 is also configured with no standby 1 preempt.
- Answer & Explanation
- Report
Answer : [C]
Explanation :
Explanation :
| R2 has a better priority because the priority value is higher. However, because R1 comes up first, R1 becomes HSRP active before R2 boots. R2 must then have preemption configured, otherwise it will not preempt R1 to become active. As for the wrong answers, R1’s preemption setting does not matter in this case. The other two wrong answers state that a router is active regardless of other settings, and the answer is dependent on other configuration. |
112.
Another engineer has configured HSRP on two routers that connect to the same LAN.
You connect to the console of one of the routers, and see this log message:
*Mar 12 17:18:19.123: %IP-4-DUPADDR: Duplicate address 10.2.2.2 on GigabitEthernet0/0, sourced by 0000.0c9f.f002Which of the answers list an HSRP configuration mistake that would cause the router to list this message? (Choose two answers.)
- A.The two HSRP routers are configured with different HSRP group numbers.
- B.The local router is filtering all incoming HSRP messages.
- C.The two HSRP routers are configured with different HSRP version numbers.
- D.The two HSRP routers have configured different virtual IP addresses.
- Answer & Explanation
- Report
Answer : [A and C]
Explanation :
Explanation :
|
Two HSRP misconfigurations cause both HSRP routers to attempt to use the
same virtual IP address (VIP), at the same time, because both routers believe that they
should be active. With a correct configuration other than mismatched group numbers, the two routers act independently, both using the VIP, resulting in the duplicate
address message. The same kind of logic applies when the two routers have correct
configuration other than a mismatched HSRP version: they do not act together, but
act independently, both use the address, and then detect the duplicate use of the
address. As for the incorrect answers, an ACL that prevents a router from even receiving the HSRP messages will prevent that router from noticing the duplicate use of the VIP, so it does not list the duplicate address log message. Finally, if the configuration mistake is that the two routers configure two different VIPs, then they are using different addresses, so there is no need to issue a message about using duplicate addresses. |
113.
Which of the following are differences between OSPFv2 and OSPFv3? (Choose two
answers.)
- A.OSPFv2 uses neighbor relationships, while OSPFv3 does not.
- B.OSPFv2 uses an SPF algorithm, while OSPFv3 uses the DUAL algorithm.
- C.OSPFv2 uses LSAs, while OSPFv3 uses LSAs but with differences.
- D.OSPFv2 is a link-state protocol, while OSPFv3 is an advanced distance vector protocol.
- E.OSPFv2 can advertise IPv4 routes, while OSPFv3 can advertise both IPv4 and IPv6 routes.
- Answer & Explanation
- Report
Answer : [C and E]
Explanation :
Explanation :
| OSPFv2 and OSPFv3 are both link-state protocols that use the SPF algorithm to calculate the best routes. They both use the concept of being enabled on an interface, and then discovering neighbors on those interfaces by using Hello messages. One key difference between the two is that OSPFv3 introduces some new link-state advertisement (LSA) types. The other key difference, of course, is that OSPFv3 supports the advertisement of IPv6 routes. |
114.
An engineer wants to set the OSPFv3 router ID for Router R1. Which of the following answers could affect R1’s choice of OSPFv3 router ID?
- A.The ipv6 address command on interface Gigabit0/0
- B.The ip address command on interface Serial0/0/1
- C.The ospf router-id command in OSPFv3 configuration mode
- D.The ipv6 address command on interface loopback2
- Answer & Explanation
- Report
Answer : [B]
Explanation :
Explanation :
| OSPFv3 uses the exact same rules for choosing its router ID (RID) as does OSPFv2, even choosing the 32-bit RID value based on IPv4 addresses, and not based on the IPv6 addresses. The two answers that mention the ipv6 address command have no impact on the OSPFv3 RID. For the other incorrect answer, the ospf router-id command does not exist; instead, the command is simply the router-id command. Only the answer with the ip address interface subcommand can impact a router’s choice of OSPFv3 RID. |
115.
Router R1 has a Serial0/0/0 interface with address 2001:1:1:1::1/64, and a G0/0 interface with address 2001:2:2:2::1/64. The OSPFv3 process uses process ID 1. Which of
the following OSPFv3 configuration commands enables OSPFv3 on R1’s G0/0 interface and places it into area 0?
- A.A network 2001:1:1:1::/64 1 area 0 command in router configuration mode
- B.An ipv6 ospf 1 area 0 command in G0/0 interface configuration mode
- C.A network 2001:1:1:1::/64 1 area 0 command in router configuration mode
- D.An ospf 1 area 0 command in G0/0 interface configuration mode
- Answer & Explanation
- Report
Answer : [B]
Explanation :
Explanation :
| OSPFv3 does not use a network command in OSPFv3 router configuration mode, ruling out two of the answers. It does use an interface subcommand that both refers to the OSPFv3 by process ID and defines the area number. The correct answer lists that interface subcommand with the correct syntax. |
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