Network Engineer Interview Question and Answers

Network Engineer Interview Question and Answers

Best Networking Online TrainingThe Network Engineer supervises and administers the configuration, installation and maintenance of IT network systems in organization. They ensure the efficient operation of the network selecting cost-effective network components, such as: servers, software and other IT technologies and IP solutions.

1. What is OSI model?

ANS: OSI is Open System Interconnection Reference Model. It is an abstract model for layered communications and computer network protocol design. There are seven layers of OSI model which, from top to bottom, are the Application, Presentation, Session, Transport, Network, Data-Link, and Physical Layers.

2. How many layers are in OSI model? Name them

ANS: There are seven layers of OSI model. The layers are:

Application layer
Presentation layer
Session layer
Transport layer
Network layer
Data link layer
Physical layer

3. What is the difference between a repeater, bridge, router?  Relate to OSI model?

ANS: Repeaters, bridges, and routers are devices used to link individual LANs together to form larger internet works. Each one operates within a specific layer of the OSI model.

Repeaters operate at the Physical Layer of the OSI model. They simply listen to all network traffic on one port and send it back out through one or more ports, extending smaller networks into a larger, single network.

Bridges operate at the Data Link Layer. They use the Data Link Layer and its physical addressing to join several networks into a single network efficiently.

Routers operate at the Network Layer of the OSI model. The Network Layer provides addressing for internet works, and routers use this addressing information to determine how to pass along packets of data.

4. What is ping? Why you use ping?

ANS: PING Stands for Packet Internet Gopher. PING is used for connectivity checking of any network or any host or device of any or other networks.

5. What is a gateway?

ANS: A gateway acts a door for the packet to reach the ‘outside’ of the internal network.

6. How can you check the connectivity of any network?

ANS: By using ping command.

7. Name a device which can operate at physical layer of OSI model.

ANS: Hub.

8. What are the difference between TCP and UDP?

ANS: TCP: Connection oriented protocol, acknowledged one, Point to point communication.

UDP: Connection less protocol, unreliable, less traffic

9. Which three layers of OSI model is treated as “Media Layers”?

ANS: Physical layer, data link layer and network layer are treated as “Media Layers”.

10. What is deadlock?

ANS: Deadlock is a situation when two or more processes are waiting indefinitely for an event that can be caused by only one of the waiting processes. The implementation of a semaphore with a waiting queue may result in this situation.

11. What is the functionality or ARP?

ARP refers to Address Resolution Protocol. ARP is a computer networking protocol for determining a network host’s link layer or hardware address when only its Internet Layer (IP) or Network Layer address is known.

12. How DHCP works?

DHCP works by four-steps: (1) IP request, (2) IP offer (3) IP selection and (d) Acknowledgement.

13. What is the difference between TCP and IP ?

ANS: Transmission control protocol is the set of protocol which is responsible for the delivery of the data to the correct destination over the network and it is the connection oriented protocol. and IP is the set of rules which is used to communicate two host on the network or we can say that ip is the logical address of the particular machine of the network.

14. What is the range of class A address?

ANS: 0-127 is the range of class A address.

15. What is the major differences between a router and a switch?

ANS: A router can divide the broadcast domain and collision domain. But a switch can only divide the collision domain. Router can communicate among different networks where as the switch can not communicate different networks.

16. Hub operates at which layers of OSI model? Is it wise to use a hub for huge networks? Why or why not?

ANS: Hub operates at only physical layer of OSI model.

No, it’s not so wise to use hub for a huge network.

Hubs can’t divide the broadcast domain or the collision domain. So, if we use hubs then there creates huge broadcast domain. When there are huge broadcast, the network gets problem time to time. So, it’s not wise to use hubs to support a huge network.

17. Why do you need to use a router?

ANS: Router can easily divide the broadcast domain and collision domain. So, to communicate among several networks, routers are used.

18. What is the data unit of Data Link layer?

ANS: Frame

19. Why do you need subnet mask?

ANS: Subnet mask is required to divide a large network into several small networks.

DNS: Domain Name System
FTP: File Transfer Protocol

20. Describe UDP and TCP and the differences between the two.

ANS: UDP is much faster, used for streaming video and audio files on the net. TCP is slower, because it contains the main factor UDP does not have, which is flow/error control.

TCP is used by most users on the net because data transferred needs to be verified. Error correction allows data to be effectively received.

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