Top Networking Interview Questions and Answers

This page covers a networking questionnaire prepared by experienced specialists in the networking domain. These top 10 networking interview questions and answers help engineers seeking networking jobs to crack the interview with ease. These questions are also asked in college vivas. This networking FAQ is useful for various networking-related jobs such as network administrator, network engineer, etc.

Question -1: What is the difference between the OSI stack and the TCPIP stack?

Answer -1: The OSI stack has 7 layers, while TCPIP has 5 layers. Presentation and session layers do not exist in the TCPIP stack.

The idea here is to understand the functions of each of these layers. Let me briefly explain the main functions of each layer:

• Layer-1 (Physical Layer): Takes care of providing a reliable wired or wireless connection. A wired connection will have voltage and current specifications, while a wireless connection will have forward error correction and modulation techniques.
• Layer-2 (Data Link or MAC Layer): Takes care of providing peer-to-peer reliable connections using the addition of checksums or CRC. It also incorporates the Ethernet or MAC header with destination and source addresses, as well as the length of the packet. It handles re-transmission of erroneous packets.
• Layer-3 (IP Layer): Takes care of routing the packet using IP addresses.
• Layer-4 (TCP or UDP Layer): Takes care of multiplexing and demultiplexing multiple applications. TCP is used for connection-oriented systems, and UDP is used for connectionless systems. It manages the sequencing of received out-of-order packets.
• Layer-5 (Session Layer): Establishes, maintains, and terminates connections. Helps in billing.
• Layer-6 (Presentation Layer): Used to communicate between systems with different syntaxes, such as EBCDIC and ASCII.
• Layer-7 (Application Layer): Used to provide service to more than one application with the help of assigning unique port addresses of size 16 bits. For example, FTP has been assigned 23, and HTTP has been assigned 8080.

Question -2: Explain protocol fields present in the Ethernet header and IP header parts.

Answer -2:

Ethernet Header = {source ethernet address, destination ethernet address, type} IP header = {source ip address, destination ip address, … }

Question -3: Explain the difference between a Hub and a Switch.

Answer -3: A Hub works at layer-1, while a Switch works at layer-2 or layer-3.

Question -4: What is the difference between wired LAN and Wireless LAN?

Answer -4: Wired LAN uses wired Ethernet devices such as hubs, switches, and routers, while Wireless LAN uses wireless devices (WLAN routers, MiFi routers, etc.). WLAN devices follow IEEE 802.11 based protocols.

Question -5: What is the difference between a router and a gateway?

Answer -5: Both routers and gateways work at layer-3, i.e., the networking layer of the OSI stack. A Gateway interfaces with two different sets of protocols, while a Router interfaces with the same set of protocols.

Question -6: What is the function of TCP and UDP in IP packets?

Answer -6: As mentioned above, TCP is short for Transmission Control Protocol and is a connection-oriented protocol. UDP is short for User Datagram Protocol and is a connectionless protocol. The Protocol field in the IP header is set to 6 for TCP and 17 (decimal) for UDP.

Question -7: Explain the difference between RIP and OSPF routing protocols.

Answer -7: Both of these are routing protocols.

Question -8: What are IP addresses and Ethernet Addresses, and what are their sizes?

Answer -8: An IP address is a logical address, and an Ethernet address is a MAC address or physical address. There will be only one Ethernet address, which will be fixed. Any IP address can be assigned to a system as per IPV4 or IPV6.

For IPV4, the IP address is 32 bits in size, while for IPV6, it is 128 bits in size. The Ethernet address is 48 bits in size and is manufacturer-specific.

Question -9: What are the functions of ARP and RARP?

Answer -9:

Question -10: What is the difference between the internet and an intranet?

Answer -10: The interconnection of computers in an organization is known as an intranet. The interconnection of computers throughout the world is known as the internet.

Question-11: What is networking?

Answer -11: Networking is a very vast field. It is basically the connection of people or things using networks known as the internet. All the devices should have an IP address to communicate with peers in the network. People use various social networking tools and applications to communicate with one another over the internet using smart IP devices.

Question-12: How to set up a Cisco router or any other router?

Answer -12: It is very easy to install any router. As installation varies based on routers from different manufacturers, one has to follow the manual provided by the supplier or manufacturer in order to set up the router.

Question-13: What is the difference between NAT and PAT?

Answer -13: The full form of NAT is Network Address Translation, and the full form of PAT is Port Address Translation.

Question-14: What is the difference between FTP and HTTP?

Answer -14: FTP is used as a file transfer protocol. With this, a file can be sent or received. HTTP is used for internet browsing. They have unique port numbers assigned.

Question-15: How many hosts are accommodated in IPV4? What is the difference between IPV4 and IPV6?

Answer -15: In class-C IPV4, there are 8 bits reserved for hosts, and hence there will be $2^8 = 256 - 2 = 254$ hosts that can be assigned unique IP addresses. We have subtracted 2 as one is reserved for the broadcast address (all 1’s), and the other one (all 0’s) for loopback testing.

Networking is a very vast field wherein many types of jobs are available across the world. Following are a few of the networking-related job positions:

• Network Administrator
• Network Engineer
• Network Analyst
• Networking technician
• Information System Administrator
• Webmaster
• Systems Analyst
• Network security specialist
• Computer programmer
• Computer repair specialist

These top 10 networking FAQs are very useful for all the above networking job positions.

There will be questions on the following topics also, which we have not covered:

• Operating systems (Windows, Unix, Linux)
• Security aspects (such as firewalls, etc.)
• Backup or system recovery
• Wireless networking such as WLAN