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- CCNA Routing and Switching 200-105
106.
A LAN design uses a Layer 3 EtherChannel between two switches SW1 and SW2,
with port-channel interface 1 used on both switches. SW1 uses ports G0/1 and G0/2
in the channel. However, only interface G0/1 is bundled into the channel and working. Think about the configuration settings on port G0/2 that could have existed
before adding G0/2 to the EtherChannel. Which answers identify a setting that could
prevent IOS from adding G0/2 to the Layer 3 EtherChannel? (Choose two answers.)
- A.A different STP cost (spanning-tree cost value)
- B.A different speed (speed value)
- C.A default setting for switchport (switchport)
- D.A different access VLAN (switchport access vlan vlan-id)
- Answer & Explanation
- Report
Answer : [B and C]
Explanation :
Explanation :
|
With a Layer 3 EtherChannel, two configuration settings must be the same on
all the physical ports, specifically the speed and duplex as set with the speed and
duplex commands. Additionally, the physical ports and port-channel port must all
have the no switchport command configured to make each act as a routed port.
So, having a different speed setting, or being configured with switchport rather
than no switchport, would prevent IOS from adding interface G0/2 to the Layer 3
EtherChannel. As for the wrong answers, both have to do with Layer 2 configuration settings. Once Layer 2 operations have been disabled because of the no switchport command, those settings related to Layer 2 that could cause problems on Layer 2 EtherChannels do not then cause problems for the Layer 3 EtherChannel. So, Layer 2 settings about access VLANs, trunking allowed lists, and STP settings, which must match before an interface can be added to a Layer 2 EtherChannel, do not matter for a Layer 3 EtherChannel. |
107.
R1 and R2 attach to the same Ethernet VLAN, with subnet 10.1.19.0/25, with
addresses 10.1.19.1 and 10.1.19.2, respectively, configured with the ip address interface subcommand. Host A refers to 10.1.19.1 as its default router, and host B refers
to 10.1.19.2 as its default router. The routers do not use an FHRP. Which of the following is a problem for this LAN?
- A.The design breaks IPv4 addressing rules, because two routers cannot connect to the same LAN subnet.
- B.If one router fails, neither host can send packets off-subnet.
- C.If one router fails, both hosts will use the one remaining router as a default router.
- D.If one router fails, the host that uses that router as a default router cannot send packets off-subnet.
- Answer & Explanation
- Report
Answer : [D]
Explanation :
Explanation :
| With this design, but no FHRP, host A can send packets off-subnet as long as connectivity exists from host A to R1. Similarly, host B can send packets off-subnet as long as host B has connectivity to router R2. Both routers can attach to the same LAN subnet, and basically ignore each other in relation to their roles as default router, because they do not use an FHRP option. When either router fails, the hosts using that router as default router have no means by which to fail over. |
108.
R1 and R2 attach to the same Ethernet VLAN, with subnet 10.1.19.0/25, with
addresses 10.1.19.1 and 10.1.19.2, respectively, configured with the ip address interface subcommand. The routers use an FHRP. Host A and host B attach to the same
LAN and have correct default router settings per the FHRP configuration. Which of
the following statements is true for this LAN?
- A.The design breaks IPv4 addressing rules, because two routers cannot connect to the same LAN subnet.
- B.If one router fails, neither host can send packets off-subnet.
- C.If one router fails, both hosts will use the one remaining router as a default router.
- D.If one router fails, only one of the two hosts will still be able to send packets offsubnet.
- Answer & Explanation
- Report
Answer : [C]
Explanation :
Explanation :
| The use of an FHRP in this design purposefully allows either router to fail and still support off-subnet traffic from all hosts in the subnet. Both routers can attach to the same LAN subnet per IPv4 addressing rules. |
109.
R1 and R2 attach to the same Ethernet VLAN, with subnet 10.1.19.0/25, with
addresses 10.1.19.1 and 10.1.19.2, respectively, configured with the ip address interface subcommand. The routers use HSRP. The network engineer prefers to have R1
be the default router when both R1 and R2 are up. Which of the following is the
likely default router setting for hosts in this subnet?
- A.10.1.19.1
- B.10.1.19.2
- C.Another IP address in subnet 10.1.19.0/25 other than 10.1.19.1 and 10.1.19.2
- D.A hostname that the FHRP mini-DNS will initially point to 10.1.19.1
- Answer & Explanation
- Report
Answer : [C]
Explanation :
Explanation :
| HSRP uses a virtual IP address. The virtual IP address comes from the same subnet as the routers’ LAN interfaces, but is a different IP address than the router addresses configured with the ip address interface subcommand. As a result, the hosts will not point to 10.1.19.1 or 10.1.19.2 in this design. The other wrong answer lists an idea of using Domain Name System (DNS) to direct hosts to the right default router; although this idea exists in some other forms of network load balancing, it is not a part of any of the three FHRP protocols. |
110.
The following text lists output taken from Router R3, which is using HSRP. Subnet
10.1.12.0 uses mask 255.255.255.0. Based on the output of this command, which of
the following answers is true?
R3# show standby brief Interface Grp Pri P State Active Standby Virtual IP Gi0/0 1 105 Active local 10.1.12.1 10.1.12.2
- A.Hosts with a default router setting of 10.1.12.1 are sending their packets to Router R3.
- B.Hosts with a default router setting of 10.1.12.2 are sending their packets to Router R3.
- C.Router R3 has an ip address 10.1.12.2 255.255.255.0 command configured on its G0/0 interface.
- D.Router R3 has an ip address 10.1.12.1 255.255.255.0 command configured on its G0/0 interface.
- Answer & Explanation
- Report
Answer : [B]
Explanation :
Explanation :
| The command, taken from R3, lists R3 as HSRP active. That means R3 currently takes on the role of the router with the virtual IP address, listed as 10.1.12.2. R3 will send back Address Resolution Protocol (ARP) Reply messages when hosts send ARP messages looking for 10.1.12.2, and process packets sent to the matching virtual MAC address. The 10.1.12.1 IP address is the interface IP address of the other router in the HSRP group, the one that is standing by to take over for Router R3. Finally, R3 does not configure the virtual IP address with the ip address interface command, but instead with the standby group ip virtual-address interface subcommand. |
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