CCNA Interview Questions and Answers

CCNA Interview Questions

CCNA is an associate level IT certification from Cisco. With the help of this certification, IT professionals can endorse their knowledge of understanding, contouring, operating and troubleshooting medium level routed and switched networks. Engineers with a background in networking are highly considered in the IT Industry and acquiring a certification of this level will enhance their chances of landing a nicely- paid job. There are a variety of CCNA courses available as per the needs of the candidates.

Cisco along with its partners offer a plethora of training methods that include the books that are published by Cisco Press and courses that are available online as well as offline. The topics under CCNA include how to connect to a WAN, network media, how to implement network security, network types and a lot many more technicalities. It teaches you what routing is, what the purpose of the data link is when network congestion can occur and also whether a bridge divides a network into smaller sections.

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CCNA Interview Questions

In full duplex, both the devices, the one that is transmitting and the other that is receiving at the same time, can communicate together. This means that both the devices, the one transmitting and the other receiving, can receive and transmit at the same time. On the other hand, in case of half duplex, a device cannot transmit while it is receiving and vice versa.
Firstly, there is unicasting, which refers to one-on-one communication. Multicasting, on the other hand, means a one-to-many chain of communication. In multicasting, however, there must be at least one device that is not receiving the file. Broadcasting, on the other hand, means one-to-all communication. In case of broadcasting, every device receives packets. Lastly, anycast is one-to-nearest communication. It works on IPv6.
In a broadcast domain, if a broadcast frame is forwarded, every device becomes alert and pays attention to receive the data. In a collision domain, the chances of data colliding are huge. Just as in Hub, if more than one sends traffic at the same instant, data will collide mid-way, and no one will receive data.
A Window is that segment that is sent from the source to destination before an acknowledgment is sent.
A link is a logical or a physical component of a network to interconnect nodes or devices. The job of a data link layer is to check whether the messages are being sent to the right device or not. One of its other functions is framing.
We use straight cable to connect two different layer devices like router-pc, router switch as well as the switch pc while the cross cable is used for connecting two same layer devices like a switch with a switch, a router with router and pc with pc. Color-coding for both the cables is different. However, if the color-coding on the end of the cable is same, then it is a straight cable. Whereas, if 2<->6, 1<-> three is used then it is a cross cable used for data transfer.
Routing is a simple process of trading route information from one router to another. In the absence of routing it is not possible to connect two or more networks located at same or different geographical areas. It is more or less the process of finding a path through which data can pass from source to destination. Routing is done using routers. Routers are network-layer devices that forward data packets along a network.
In total there are seven different layers of the Open Systems Interconnection model. These are Data Link Layer, Transport Layer, Physical Layer, Network Layer, Presentation Layer, Session Layer and Application Layer.
When you have to route globally over the internet, public IP addresses are used. They are provided to different websites and companies for access over the Internet. Once connected to the internet, they become unique worldwide. On the other hand, private IP addresses are for personal and local use. You cannot route them over the internet. Private IP addresses can be the same in different organizations.
Data encapsulation is the process of adding header and trailer information in the data. Whenever data is being passed from one layer to another, the layers add some extra information to the data. This is known as a header. The next layer processes the data and adds its own header. As the data further moves on through layers, the same process continues until the data is placed on the physical media. This entire process is called encapsulation. In contradiction to this, removing the trailer information and the header from the data is called data decapsulation.
When you are using a Cisco Router, the User mode is being used for the regular task. For instance, it is used to connect to remote devices, to see system information; it is also used to check the status of the router. On a different note, the Privileged mode includes all options that are there for the user mode and more. This mode can also be used for making any changes in the configurations on the router including debugging and making various tests.
To configure a Cisco router for routing IPX, the first thing to do is to enable IPX routing by using the command, ‘IPX Routing.’ Each interface that’s used in the IPX network is then configured with a number for the network and an encapsulation method. There are two kinds of IPX access list- Standard and Extended. Standard Access List can filter only the source or the destination IP address. On the other hand, an extended access list uses the source and destination IP address, socket, protocol and port while filtering a network.
RIP depends on the number of hops for finding out the best route to a network. Meanwhile, IGRP takes into consideration some things before determining the best route. It considers bandwidth, MTU, reliability as well as the hop count.
The steps of conversion for data encapsulation are:
  • First, Second and Third layer (Application/session/presentation)- the alphanumeric input from the user is converted into data
  • Fourth Layer (Transport)- data is yet converted into small segments
  • Fifth Layer (Networking)- data is now converted to little packets of datagrams, and the network header is added
  • Sixth Layer (Data Links)- Packets or datagrams are built into frames
  • Seventh Layer (Physical)- frames are finally converted into bits
LLC stands for Logical Link Control. It provides optional services to an application developer. One way to provide flow control to the network layer is by using stop or start codes. It can also provide error correction.

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