NEW CCNA Routing Technologies Questions and Answers with Explanation

By | January 24, 2018

This is an Updated CCNA exam question (October 2017). You might see a different IP addressing, VLAN configuration and Port allocation and routing Configurations.
As usual, take time to read through the question so as to clearly understand what it is all about.

Note: This CCNA Routing Technologies Questions and Answers with Explanation are used for demonstration only, you will see different IP addressing, configuration and Port allocation in the real CCNA exam. But it all works the same way, try and understand what the question is all about.

        Read Routing

I suggest you use packet tracer for practice if you may.

Question 1.

Which criteria are routing decisions based upon?
A. Source IP
B. Destination IP address
C. TTL
D. Destination MAC address

Answers and Explanation
B. All routing decisions are based upon destination IP address. The router examines the IP address and routes the packet to the next closest router (this is known as a hop) for the network it belongs to.

Question 2.

Which type of routing requires network administrator intervention?
A. Link-state routing
B. Distance-vector routing
C. Static routing
D. Dynamic routing

Answers and Explanation
C. A static route is a form of routing that occurs when a router uses a manually-configured routing entry, rather than information from a dynamic routing ( RIP, EIGRP etc) traffic. Static routing requires a network administrator to intervene and create a route in the routing table.

Question 3.

When an IP address is configured on the router’s interface, what happens in the
routing table?
A. A route entry is created for the network attached to the IP address on the
interface.
B. A route entry is created for the IP address attached to the interface.
C. Dynamic routing protocols update all other routers.
D. All of the above

Answers and Explanation
D. When an IP address is configured on a router’s interface, the network is automatically created into the routing table. The IP address is also added to the routing table. When the routing table changes, this normally informs the routing protocol it should perform an update.

Question 4.

Which is a correct statement about the subnet mask?
A. The subnet mask is used by the host to determine the destination network.
B. The subnet mask is used in routing to determine the destination network.
C. The router uses its subnet mask when routing a packet.
D. The destination computer checks the subnet mask on the packet to verify that
it’s intended for that computer.

Answers and Explanation
A. The subnet mask is used by the host to determine the immediate network and the destination network. It then decides to either route the packet or try to deliver itself without the router’s help. A Subnet mask is made up of a 32-bit number that masks an IP address and divides the IP address into a network address and host address.

It is called a subnet mask because it is used to identify a network address of an IP address by performing a bitwise AND operation on the netmask.



Question 5.

What protocol does the router or host use to find a MAC address for the frame when it determines that the packet is on the local network?
A. IGMP
B. RARP
C. ARP
D. ICMP

Answers and Explanation
C. The Address Resolution Protocol (ARP) is employed by the host or router when
a packet is determined to be local on one of its interfaces.

Question 6.

When a packet is determined remote from the network of the sending host, what happens?
A. The destination IP address is changed to the router’s IP address.
B. The destination MAC address is changed to the destination host’s MAC address.
C. The destination MAC address is changed to the router’s MAC address.
D. The source IP address is changed to the router’s IP address.

Answers and Explanation
C. The destination MAC address is changed to the router’s MAC address and the destination IP address is untouched.

Question 7.

Which statement describes correctly what happens when a packet moves through a router?
A. The destination IP address is changed to the original destination.
B. The packet’s TTL is decremented.
C. The source MAC address is changed to the original source MAC address.
D. All of the above

Answers and Explanation
B. The TTL, or time to live, is decremented usually by one. When the TTL reaches zero, a packet is considered un-routable. This prevents packets from eternally routing.

Question 8.

What is the entry for the IP address in the routing table called in IOS 15 code when an interface is configured?
A. IP address route
B. Local route
C. Dynamic route
D. Static route

Answers and Explanation
B. When an IP address is configured on an interface, the entry in the routing table is called the local route. The local routes always have a prefix of /32.

Question 9.

When a packet is determined to be on the local network, what happens?
A. The destination IP address is changed to the router IP address.
B. The destination MAC address is changed to the destination host’s MAC address.
C. The destination MAC address is changed to the router’s MAC address.
D. The source IP address is changed to the router’s IP address.

Answers and Explanation
B. When a packet is determined to be local to the sending host, ARP is used to resolve the MAC address for the IP address of the destination host, and the frame is sent directly to the host.

Question 10.

How does the sending host know if the destination is local or remote in respect to its immediate network?
A. The host compares the IP address to its internal routing table.
B. The host performs ANDing on its subnet mask and the destination IP address comparing the result to its own network address.
C. The host performs ANDing on the destination subnet mask and the destination IP address, comparing the result to its own network address.
D. The IP address is verified to be local to its network via ICMP.

Answers and Explanation
B. The sending host ANDs its subnet mask against the destination IP address, then against its IP address, and this give a frame of reference for where it needs to go and where it is.



Question 11.

What is the current method Cisco routers use for packet forwarding?
A. Process switching
B. Fast switching
C. Intelligent packet forwarding
D. Cisco Express Forwarding

Answers and Explanation

D. The current method of packet forwarding used by Cisco routers is Cisco Express Forwarding (CEF). CEF creates several cache tables used for determining the best route for the destination network.

Question 12.

What is the process called at layer 2 when a packet hops from router to router and eventually to the host?
A. IP routing
B. Frame rewrite
C. Packet hopping
D. Packet switching

Answers and Explanation

B. The layer 2 process is called frame rewrite. When a packet hops from router to router, the destination frame is rewritten for the next destination MAC address.

Question 13.

When a host sends an ARP request packet out, what is the destination address of the frame?
A. The router’s MAC address
B. The host’s MAC address
C. The MAC address is in the form of a broadcast.
D. The MAC address is in the form of a multicast.

Answers and Explanation

C. When a MAC address is unknown for the destination IP address or the default gateway, the ARP request is sent in the form of a broadcast.

Question 14.

What does every network device use to limit the amounts of ARP packets?
A. ARP cache
B. IP multicasting
C. Frame casting
D. IP cache

Answers and Explanation

A. Every host contains an ARP cache. This cache allows for lookups of MAC addresses for destination IP addresses when the host frequently sends packets to the destination. Therefore, there are fewer ARP packets.

Question 15.

Which statement describes what happens when a packet enters a router?
A. The router accepts all incoming frames regardless of their destination MAC address.
B. The router decapsulates the packet and inspects the destination IP address.
C. Routers do not need to decapsulate packets to inspect the destination IP address.
D. Routers make routing decisions first by examining the source MAC address.

Answers and Explanation

B. After the frame is verified to be addressed to the router and the FCS has been checked, the router decapsulates the packet and strips off the frame.



Question 16.

Which command will display the router’s ARP cache?
A. Router#show arp
B. Router#show arp table
C. Router#show arp cache
D. Router#show ip arp

Answers and Explanation

D. The command to display the router’s ARP cache is show ip arp.

Question 17.

What is the default time an entry will live in the ARP cache?
A. 180 seconds
B. 240 seconds
C. 300 seconds
D. 600 seconds

Answers and Explanation

B. By default, all entries have a time to live, or TTL, of 240 seconds. They will be removed after that period if not used during the 240 seconds.

Question 18.

What is the relevance of the default gateway address on a host?
A. The destination IP address is replaced with the default gateway when the destination is remote.
B. The host sends the default gateway packets that are deemed remote via a broadcast.
C. The host sends an ARP packet for the default gateway when the destination is remote.
D. The host creates a dedicated connection with the default gateway for remote traffic.

Answers and Explanation
C. When traffic is remote to the immediate network, the host sends an ARP packet for the IP address of the default gateway. This determines the destination MAC address for the frame.

Question 19.

Which command will display the router’s routing table?
A. Router#show ip route
B. Router#show route
C. Router#show route table
D. Router#show routes

Answers and Explanation
A. The command to view the routing table is show ip route.

Question 20.

Which type of routing allows for routers to share their routing tables with other routers in the network?
A. Default routing
B. Stub routing
C. Static routing
D. Dynamic routing

Answers and Explanation
D. Dynamic routing allows for the population of routing tables from advertisements of other routers. There are several dynamic routing protocols, such as, for example, EIGRP, RIP, OSPF.