New CCNA Commonly asked Questions.

By | July 1, 2017

New CCNA – Basic Questions

This is an Updated commonly asked CCNA exam question (October 2016).
You might see a different IP addressing and configuration. Just try and figure out what the question actually need you to do.

Note: This Frame Relay LAB is used for demonstration only, you may come across different IP addressing, frame relay configuration and Port allocation in the real CCNA exam. But it all works the same way if you could just grasp the technique.




Question 1

Refer to the exhibit


Which of the following statements describe the network shown in the graphic? (Choose two)

A. There are two broadcast domains in the network.
B. There are four broadcast domains in the network.
C. There are six broadcast domains in the network.
D. There are four collision domains in the network.
E. There are five collision domains in the network.
F. There are seven collision domains in the network.

Answer: A F
Explanation
Routers break up broadcast domains; so in the diagram above, there are 2 broadcast domains: from e0(router interface is a broadcast domain and from e1(router interface is another broadcast domain = A is correct.
Both Router and Switch can break up collision domains so there is only 1 collision domain on the left of the router (because hubs don’t break up collision domain) and there are 6 collision domains on the right of the router (1 collision domain from e1 interface to the switch + 5 collision domains for 5 PCs in Production) -> F is correct.
So: 1 collision from router e0 to hub(hubs don’t break up collision domain)
1 collision from router e1 to switch and 5 from switch to PCs which =7 collision domain

Question 2
What is the first 24 bits in a MAC address called?
A. NIC
B. BIA
C. OUI
D. VAI

Answer: C
Explanation
Organizational Unique Identifier (OUI) is the first 24 bits of a MAC address for a network device, which indicates the specific vendor for that device as assigned by the Institute of Electrical and Electronics Engineers, Incorporated (IEEE). This identifier uniquely identifies a vendor, manufacturer, or an organization.

Question 3
Refer to the exhibit:

The technician wants to upload a new IOS in the router while keeping the existing IOS. What is the maximum size of an IOS file that could be loaded if the original IOS is also kept in flash?
A. 3MB
B. 5MB
C. 7MB
D. 4MB

Answer: D
Explanation
From the exhibit, there are 4585552 bytes (over 4MB) available so there is only enough space for an IOS file of 4MB. If a bigger file is copied then the existing IOS file will be erased (overwritten).

Question 4
Refer to the exhibit. What is the meaning of the output MTU 1500 bytes?

A. The maximum number of bytes that can traverse this interface per second is 1500.
B. The minimum segment size that can traverse this interface is 1500 bytes.
C. The minimum segment size that can traverse this interface is 1500 bytes.
D. The minimum packet size that can traverse this interface is 1500 bytes.
E. The maximum packet size that can traverse this interface is 1500 bytes.
F. The maximum frame size that can traverse this interface is 1500 bytes.

Answer: E
Explanation
The Maximum Transmission Unit (MTU) defines the maximum Layer 3 packet (in bytes) that the layer can pass onwards.




Question 5
In an Ethernet network, under what two scenarios can devices transmit? (Choose two)
A. when they receive a special token
B. when there is a carrier
C. when they detect no other devices are sending
D. when the medium is idle
E. when the server grants access

Answer: C D
Explanation
C and D are the correct answers because, The Ethernet network is a shared environment so all devices have the right to access to the medium. If more than one device transmits simultaneously, the signals collide (collision) and cannot reach the destination.
If a device detects another device is sending, it will wait for a specified amount of time before attempting to transmit.
When there is no traffic detected, a device will transmit its message. While this transmission is occurring, the device continues to listen for traffic or collisions on the LAN. After the message is sent, the device returns to its default listening mode.

Question 6
For what two purposes does the Ethernet protocol use physical addresses? (Choose two)
A. to uniquely identify devices at Layer 2
B. to allow communication with devices on a different network
C. to differentiate a Layer 2 frame from a Layer 3 packet
D. to establish a priority system to determine which device gets to transmit first
E. to allow communication between different devices on the same network
F. to allow detection of a remote device when its physical address is unknown

Answer: A E
Explanation
A is correct: Physical addresses or MAC addresses are used to identify devices at layer 2, communication on the same network.
E is correct for a full Ethernet communication on a network on same network by different devices

Question 7
A network interface port has collision detection and carrier sensing enabled on a shared twisted pair network. From this statement, what is known about the network interface port?
A. This is a 10 Mb/s switch port.
B. This is a 100 Mb/s switch port.
C. This is an Ethernet port operating at half duplex.
D. This is an Ethernet port operating at full duplex.
E. This is a port on a network interface card in a PC.

Answer: C
Explanation
CSMA/CD is a Media Access Control (MAC) protocol. It defines how network devices respond when two devices attempt to use a data channel simultaneously and encounter a data collision. So its only a half duplex connection protocol that exists on hubs and repeaters.
Modern Ethernet networks built with switches and full-duplex connections no longer utilize CSMA/CD.

Question 8
Which two locations can be configured as a source for the IOS image in the boot system command? (Choose two)
A. RAM
B. NVRAM
C. flash memory
D. HTTP server
E. TFTP server
F. Telnet server

Answer: C E
Explanation
You can use the following locations to configure as a source for the IOS image:
+ Flash (the default location)
+ TFTP server
+ ROM (can only used if no other source is found)

Question 9
A Cisco router is booting and has just completed the POST process. It is now ready to find and load an IOS image. What function does the router perform next?
A. It checks the configuration register
B. It attempts to boot from a TFTP server
C. It loads the first image file in flash memory
D. It inspects the configuration file in NVRAM for boot instructions

Answer: A
Explanation
When you turn the router on, it runs through the following boot process.
1. The Power-On Self-Test (POST) checks the router’s hardware. When the POST completes successfully, the System OK LED indicator comes on.
2. 2. The router checks the configuration register to detect where to load the IOS image from.
3. A setting of 0×2102 means that the router will use information in the startup-config file to locate the IOS image.
If the startup-config file is not found, the router will check these locations for the IOS image:
1. Flash (which should be the default location)
2. TFTP server
3. ROM (used if no other source is found)
The router then loads the configuration file into RAM.
The router can also load a configuration file from:
+ NVRAM (start-up-configuration file)
+ TFTP server
If a configuration file is missing, the router starts in setup mode.




Question 10
What is the difference between a CSU/DSU and a modem?
A. A CSU/DSU converts analog signals from a router to a leased line; a modem converts analog signals from a router to a leased line.
B. A CSU/DSU converts analog signals from a router to a phone line; a modem converts digital signals from a router to a leased line.
C. A CSU/DSU converts digital signals from a router to a phone line; a modem converts analog signals from a router to a phone line.
D. A CSU/DSU converts digital signals from a router to a leased line; a modem converts digital signals from a router to a phone line.

Answer: D