[2021-New] Cisco 100-105 Dumps With Update Exam Questions (71-80)

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Q1. - (Topic 3)

What is the subnet address for the IP address 172.19.20.23/28?

A. 172.19.20.0

B. 172.19.20.15

C. 172.19.20.16

D. 172.19.20.20

E. 172.19.20.32

Answer: C

Explanation:

From the /28 we can get the following:

Increment: 16 (/28 = 11111111.11111111.11111111.11110000)

Network address: 172.19.20.16 (because 16 < 23)

Broadcast address: 172.16.20.31 (because 31 = 16 + 16 – 1)

Q2. - (Topic 2)

What does a host on an Ethernet network do when it is creating a frame and it does not have the destination address?

A. Drops the frame

B. Sends out a Layer 3 broadcast message

C. Sends a message to the router requesting the address

D. Sends out an ARP request with the destination IP address

Answer: D

Explanation:

In this case, it will send out an ARP request for MAC address of the destination IP (assuming it doesn't already have it in its table) and then address it to the destination's MAC address.

Q3. - (Topic 3)

Which IOS command is used to initiate a login into a VTY port on a remote router?

A. router# login

B. router# telnet

C. router# trace

D. router# ping

E. router(config)# line vty 0 5

F. router(config-line)# login

Answer: B

Explanation:

VTY ports are telnet ports hence command B will initiate login to the telnet port.

Q4. - (Topic 3)

Which one of the following IP addresses is the last valid host in the subnet using mask 255.255.255.224?

A. 192.168.2.63

B. 192.168.2.62

C. 192.168.2.61

D. 192.168.2.60

E. 192.168.2.32

Answer: B

Explanation:

With the 224 there are 8 networks with increments of 32 One of these is 32 33 62 63 where 63 is broadcast so 62 is last valid host out of given choices.

Q5. - (Topic 3)

Refer to the exhibit.

When running OSPF, what would cause router A not to form an adjacency with router B?

A. The loopback addresses are on different subnets.

B. The values of the dead timers on the routers are different.

C. Route summarization is enabled on both routers.

D. The process identifier on router A is different than the process identifier on router B.

Answer: B

Explanation:

To form an adjacency (become neighbor), router A & B must have the same Hello interval, Dead interval and AREA numbers

Q6. - (Topic 1)

Which three statements are true about the operation of a full-duplex Ethernet network? (Choose three.)

A. There are no collisions in full-duplex mode.

B. A dedicated switch port is required for each full-duplex node.

C. Ethernet hub ports are preconfigured for full-duplex mode.

D. In a full-duplex environment, the host network card must check for the availability of the network media before transmitting.

E. The host network card and the switch port must be capable of operating in full-duplex mode.

Answer: A,B,E

Explanation:

Half-duplex Ethernet is defined in the original 802.3 Ethernet and Cisco says you only use one wire pair with a digital signal running in both directions on the wire. It also uses the CSMA/CD protocol to help prevent collisions and to permit retransmitting if a collision does occur. If a hub is attached to a switch, it must operate in half-duplex mode because the end stations must be able to detect collisions. Half-duplex Ethernet—typically 10BaseT—is only about 30 to 40 percent efficient as Cisco sees it, because a large 10BaseT network will usually only give you 3- to 4Mbps—at most. Full-duplex Ethernet uses two pairs of wires, instead of one wire pair like half duplex. Also, full duplex uses a point-to-point connection between the transmitter of the transmitting device and the receiver of the receiving device, which means that with full-duplex data transfer, you get a faster data transfer compared to half duplex. And because the transmitted data is sent on a different set of wires than the received data, no collisions occur. The reason you don’t need to worry about collisions is because now Full-duplex Ethernet is like a freeway with multiple lanes instead of the single-lane road provided by half duplex. Full-duplex Ethernet is supposed to offer 100 percent efficiency in both directions; this means you can get 20Mbps with a 10Mbps Ethernet running full duplex, or 200Mbps for FastEthernet.

Q7. - (Topic 5)

Refer to the exhibit.

A network technician is asked to design a small network with redundancy. The exhibit represents this design, with all hosts configured in the same VLAN. What conclusions can be made about this design?

A. This design will function as intended.

B. Spanning-tree will need to be used.

C. The router will not accept the addressing scheme.

D. The connection between switches should be a trunk.

E. The router interfaces must be encapsulated with the 802.1Q protocol.

Answer: C

Explanation:

The proposed addressing scheme is on the same network. Cisco routers will not allow you to assign two different interfaces to be on the same IP subnet.

Q8. - (Topic 3)

Refer to the exhibit.

Which two statements are true about the loopback address that is configured on RouterB? (Choose two.)

A. It ensures that data will be forwarded by RouterB.

B. It provides stability for the OSPF process on RouterB.

C. It specifies that the router ID for RouterB should be 10.0.0.1.

D. It decreases the metric for routes that are advertised from RouterB.

E. It indicates that RouterB should be elected the DR for the LAN.

Answer: B,C

Explanation:

A loopback interface never comes down even if the link is broken so it provides stability for the OSPF process (for example we use that loopback interface as the router-id) -The router-ID is chosen in the order below:

The highest IP address assigned to a loopback (logical) interface.

If a loopback interface is not defined, the highest IP address of all active router’s physical interfaces will be chosen. -> The loopback interface will be chosen as the router ID of RouterB -

Q9. - (Topic 3)

On a live network, which commands will verify the operational status of router interfaces? (Choose two.)

A. Router# show interfaces

B. Router# show ip protocols

C. Router# debug interface

D. Router# show ip interface brief

E. Router# show start

Answer: A,D

Explanation:

Only two commands “show interfaces” and “show ip interface brief” reveal the status of router interfaces (up/up, for example).

Q10. - (Topic 3)

Which two statements describe characteristics of IPv6 unicast addressing? (Choose two.)

A. Global addresses start with 2000::/3.

B. Link-local addresses start with FE00:/12.

C. Link-local addresses start with FF00::/10.

D. There is only one loopback address and it is ::1.

E. If a global address is assigned to an interface, then that is the only allowable address for the interface.

Answer: A,D