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- CCNA Routing and Switching 200-105
101.
Router 1 has a Fast Ethernet interface 0/0 with IP address 10.1.1.1. The interface
is connected to a switch. This connection is then migrated to use 802.1Q trunking.
Which of the following commands could be part of a valid configuration for Router
1’s Fa0/0 interface? (Choose two answers.)
- A.interface fastethernet 0/0.4
- B.dot1q enable
- C.dot1q enable 4
- D.trunking enable
- E.trunking enable 4
- F.encapsulation dot1q 4
- Answer & Explanation
- Report
Answer : [A and F]
Explanation :
Explanation :
| Of all the commands listed, only the two correct answers are syntactically correct router configuration commands. The command to enable 802.1Q trunking is encapsulation dot1q vlan_id. |
102.
Router R1 has a router-on-a-stick (ROAS) configuration with two subinterfaces of
interface G0/1: G0/1.1 and G0/1.2. Physical interface G0/1 is currently in a
down/down state. The network engineer then configures a shutdown command when
in interface configuration mode for G0/1.1, and a no shutdown command when in
interface configuration mode for G0/1.2. Which answers are correct about the interface state for the subinterfaces? (Choose two answers.)
- A.G0/1.1 will be in a down/down state.
- B.G0/1.2 will be in a down/down state.
- C.G0/1.1 will be in an administratively down state.
- D.G0/1.2 will be in an up/up state.
- Answer & Explanation
- Report
Answer : [B and C]
Explanation :
Explanation :
| Subinterface G0/1.1 must be in an administratively down state due to the shutdown command being issued on that subinterface. For subinterface G0/1.2, its status cannot be administratively down, because of the no shutdown command. G0/1.2’s state will then track to the state of the underlying physical interface. With a physical interface state of down/down, subinterface G0/1.2 will be in a down/down state in this case. |
103.
A Layer 3 switch has been configured to route IP packets between VLANs 1, 2,
and 3 using SVIs, which connect to subnets 172.20.1.0/25, 172.20.2.0/25, and
172.20.3.0/25, respectively. The engineer issues a show ip route connected command
on the Layer 3 switch, listing the connected routes. Which of the following answers
lists a piece of information that should be in at least one of the routes?
- A.Interface Gigabit Ethernet 0/0.3
- B.Next-hop router 172.20.2.1
- C.Interface VLAN 2
- D.Mask 255.255.255.0
- Answer & Explanation
- Report
Answer : [C]
Explanation :
Explanation :
|
The configuration of the Layer 3 switch’s routing feature uses VLAN interfaces.
The VLAN interface numbers must match the associated VLAN ID, so with VLANs 1,
2, and 3 in use, the switch will configure interface vlan 1, interface vlan 2 (which is
the correct answer), and interface vlan 3. The matching connected routes, like all connected IP routes, will list the VLAN interfaces. As for the incorrect answers, a list of connected routes will not list any next-hop IP addresses. Each route will list an outgoing interface, but the outgoing interface will not be a physical interface, but rather a VLAN interface, because the question states that the configuration uses SVIs. Finally, all the listed subnets have a /25 mask, which is 255.255.255.128, so none of the routes will list a 255.255.255.0 mask. |
104.
An engineer has successfully configured a Layer 3 switch with SVIs for VLANs 2 and
3. Hosts in the subnets using VLANs 2 and 3 can ping each other with the Layer 3
switch routing the packets. Next week, the network engineer receives a call that those
same users can no longer ping each other. If the problem is with the Layer 3 switching function, which of the following could have caused the problem? (Choose two
answers.)
- A.Six (or more) out of ten working VLAN 2 access ports failing due to physical problems
- B.A shutdown command issued from interface VLAN 4 configuration mode
- C.VTP on the switch removing VLAN 3 from the switch’s VLAN list
- D.A shutdown command issued from VLAN 2 configuration mode
- Answer & Explanation
- Report
Answer : [C and D]
Explanation :
Explanation :
|
First, for the correct answers, a Layer 3 switch will not route packets on a
VLAN interface unless it is in an up/up state. A VLAN interface will only be up/up
if the matching VLAN (with the same VLAN number) exists on the switch. If VTP
deletes the VLAN, then the VLAN interface moves to a down/down state, and routing in/out that interface stops. Also, disabling VLAN 2 with the shutdown command
in VLAN configuration mode also causes the matching VLAN 2 interface to fail,
which makes routing on interface VLAN 2 stop as well. As for the incorrect answers, a Layer 3 switch needs only one access port or trunk port forwarding for a VLAN to enable routing for that VLAN, so nine of the ten access ports in VLAN 2 could fail, leaving one working port, and the switch would keep routing for VLAN 2. A shutdown of VLAN 4 has no effect on routing for VLAN interfaces 2 and 3. Had that answer listed VLANs 2 or 3, it would definitely be a reason to make routing fail for that VLAN interface. |
105.
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, G0/2, and
G0/3 in the channel. Which of the following are true about SW1’s configuration to
make the channel be able to route IPv4 packets correctly? (Choose two answers.)
- A.The ip address command must be on the port-channel 1 interface.
- B.The ip address command must be on interface G0/1 (lowest numbered port).
- C.The port-channel 1 interface must be configured with the no switchport command.
- D.Interface G0/1 must be configured with the routedport command.
- Answer & Explanation
- Report
Answer : [A and C]
Explanation :
Explanation :
| With a Layer 3 EtherChannel, the physical ports and the port-channel interface must disable the behavior of acting like a switch port, and therefore act like a routed port, through the configuration of the no switchport interface subcommand. (The routedport command is not an IOS command.) Once created, the physical interfaces should not have an IP address configured. The port-channel interface (the interface representing the EtherChannel) should be configured with the IP address. |
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