Introduction
Nowadays, the Internet provides an easy way for candidates to prepare for interviews by getting answers to various queries. In the past, individuals had to go through all relevant books and materials to prepare for an interview. Currently, there is an abundance of easily accessible collections of interview questions with answers. Therefore, the process of preparing for an interview has become easier nowadays. We have handpicked the most frequently asked networking interview questions and answers for your easy understanding.
About Networking
Networking is defined as two or more devices that are connected to each other via a transmission media. A network has the potential to be built with just a handful of devices limited within a single room or scaled up to cover millions of devices spread throughout the globe. In general, networks serve as a means of setting up connectivity among nodes, which may consist of a collection of devices or computers.
This guide, networking interview questions and answers, can prove to be a valuable resource for individuals interviewing for positions at the beginner or advanced levels. It can be helpful in enhancing one’s knowledge and achieving success in the interview. Let’s get started!
Basic Networking Interview Questions and Answers
Here are the top most asked networking interview questions for freshers:
Q1. What is a Network?
A network is a collection of devices that can communicate with each other to share resources and information. Depending on its size and scope of use, a network can be of different types, such as PAN, LAN, WAN, etc.
Q2. What are the different types of networks?
Mainly there are four types of networks. These are:
1. Personal Area Network (PAN)
The Personal Area Network (PAN) is considered to be the fundamental form of computer networking. This network is limited to an individual user, meaning that the exchange of information among computer devices is limited only to the user’s personal workspace.
The PAN technology allows communication between devices within a range of 1 to 100 meters from the user. The transmission speed is relatively high, and its maintenance is simple and cost-effective.
2. Local Area Network (LAN)
LAN is a type of computer network that connects devices within a limited geographic area, such as a home, office, or school. LANs allow users to share resources, such as files, printers, and internet access, among the connected devices. One of the basic examples of Local Area Network (LAN) is a printer connected to a computer.
The maximum range of the system is 1-10 kilometers, and its transmission speed is significantly high.
3. Metropolitan Area Network (MAN)
The Metropolitan Area Network (MAN) is a network type that covers the network connection of an entire city or connection of a small area. The area covered by the network is connected using a wired network, like data cables.
This network mainly uses FDDI, CDDI, and ATM as the technology, ranging from 5km to 50km. Its transmission speed is average. It isn’t easy to maintain, and it comes with a high cost.
4. Wide Area Network (WAN)
WAN is a network that connects devices over a large geographical area, such as different cities or countries. WANs typically use public or leased telecommunication lines to transmit data. Examples of WANs are the Internet, corporate networks, and satellite networks. In most cases, the connection is established through wireless means and relies on radio towers for transmission.
WAN is a collection of Local Area Networks (LANs) that are connected with each other over a distance above 50 kilometers.
Q3. What are different network topologies?
Network topologies define how various devices are interconnected inside the network. Some of the common network topology types are:
- Star Topology
- Tree Topology
- Bus Topology
- Mesh Topology
- Ring Topology
Q4. What is latency?
Latency is the time it takes for data to make a round trip. We measure latency in milliseconds. A low number is good. A high number is bad.
You send a message and wait for a response. The time you wait is referred to as latency. It is the time for a signal to travel to a server and then come back to you.
When playing an online game, low latency is crucial. High latency causes lag. It makes the game feel slow. The same applies to video calls. High latency makes conversations difficult.
It is not the same as speed. Speed, or bandwidth, is how much data you can move at once. Latency refers to the time it takes for any piece of data to travel. You can have a fast connection with bad latency. This would feel like a big highway with a long delay at a traffic light.
Q5. What is OSI Model and why is it important?
The OSI (Open Systems Interconnection) Model is a conceptual framework that standardizes the functions of a telecommunication or computing system. It divides the network communication process into seven layers:
- Physical Layer
- Data Link Layer
- Network Layer
- Transport Layer
- Session Layer
- Presentation Layer
- Application Layer
The OSI model is important because it allows different network technologies to work together and enables troubleshooting by dividing complex network operations into manageable layers.
Q6. What is TCP/IP Model and how it differs from OSI Model?
The TCP/IP (Transmission Control Protocol/Internet Protocol) is a set of communication protocols that are used to connect network devices on the Internet. The TCP/IP model has 4 layers, unlike the 7 layers of the OSI model.
- Network Interface Layer
- Internet Layer
- Transport Layer
- Application Layer
The key difference is that TCP/IP is the actual protocol suite used in the real world, while the OSI model serves as a conceptual guideline.
Q7. Define IP Address and Its Types.
An IP (Internet Protocol) address is a unique identifier assigned to each device on a network. There are two types of IP Addresses:
- IPv4: IPv4 addresses are 32-bit addresses written in dotted decimal format. It approximately allows 4.3 billion unique addresses. Example: 192.168.1.1
- IPv6: IPv6 addresses are 128 bits and are represented in hexadecimal format. It enables a vast number of unique addresses to meet future demands. Example: 2001:0db8:85a3:0000:0000:8a2e:0370:7334
Q8. What is Subnet?
A subnet is a logical subdivision of an IP network. It allows a single network to be divided into smaller segments, each with its own range of IP addresses and network settings. It can improve network performance, security, and scalability.
Q9. What is DNS?
DNS is known as the phonebook that helps in translating the domain into a computer-readable IP address. DNS allows users to access websites without having to memorize long strings of numbers.
For example, instead of typing 104.26.10.228, you can type pynetlabs.com, and DNS will find your corresponding IP address.
Q10. What happens when you type a website address into your browser?
Your browser starts by looking up the website’s real address. The name you type is not the actual location. DNS servers translate this name into a numerical IP address.
Next, your browser creates a connection to that server. It utilizes the TCP protocol to establish a secure pathway for data transfer. This happens through a three-way handshake process. Your browser then requests the webpage. It sends an HTTP message requesting specific content from the server. This message includes details about what your browser can handle.
The server handles this request, and it responds by transmitting the webpage files. The latter consists of HTML, CSS, JavaScript code, and graphics. The files flow back to your device via the internet.
Your browser receives all of these components. It reads the code, applies the styling, and executes the scripts, displaying all on your screen as one whole web page.
Q11. What are clients and servers in a network?
The client is the component responsible for initiating communication and requesting a network service, such as retrieving a web page, transferring a file, or transmitting an email.
The server is the component responsible for responding to client requests and delivering the requested service, such as transmitting a webpage, file, or email.
Computer application uses the client-server model.
Q12. What is a MAC address?
The Media Access Control (MAC) address holds significant importance in computer networking, similar to that of an IP address. It is also known as a physical, hardware, or burned-in address.
It is a 12-digit hexadecimal number divided into six octets. The first three octets indicate the organization that issued the address, and the last three identify the specific device.
MAC addresses direct data packets to the correct destination on a local network.
Q13. What is the role of ARP?
ARP translates a known IP address into a physical MAC address.
Devices on a local network need a MAC address to communicate directly. ARP is the protocol used to discover it. When a device needs to send data, it knows the destination IP address. It uses an ARP request to ask the network for the matching MAC address.
The device with that IP address sends an ARP reply. This reply contains its MAC address.
The requesting device can now send its data. ARP is an essential process for discovering addresses on a local network.
Q14. What is the difference between unicast, multicast, and broadcast traffic?
Unicast: It involves a one-to-one transmission. One sender sends the data to a single and specific receiver. It can be described as direct communication between two devices.
Multicast: A one-to-many transmission is multicasting. Data is sent by one sender to multiple interested receivers.
Broadcast: It is a one-to-all transmission. One sender sends data to every device on the entire local network. All devices receive the data, whether they need it or not.
Q15. What is SD-WAN?
SD-WAN stands for Software-Defined Wide Area Network. It is a solution based on SDN architecture for simplifying WAN management. It separates the control and data planes to optimize application performance and reduce costs.
Q16. What are the benefits of SD-WAN?
Here are some benefits of SD-WAN:
- It simplifies WAN Management.
- It reduces WAN costs.
- Provides more security.
- Increased Bandwidth and efficiency.
- It provides easier network management.
Q17. What are Nodes and Links?
Two or more computers form a network when some wire or fiber optics physically links them. In this configuration, the computers are referred to as nodes, and the link is the actual medium of communication, i.e., the physical medium.
Q18. Explain the concept of a VLAN
Virtual local area network, also known as VLAN divides a large network into smaller independent sections. A device in one VLAN communicates with another device in the same VLAN, as though it is in its own bubble, despite existing in the same physical system. This makes things neat and safe. When a problem, such as a virus, occurs in one VLAN, it remains there and does not propagate. It also decreases network congestion; data travels at a higher rate. VLANs simplify management of networks without additional hardware or cables requirements. They are an intelligent means of managing devices, improving security and keeping things going effortlessly.
Q19. What is VPN?
VPN stands for Virtual private network.
- It is considered VIRTUAL because it establishes a digital pathway, without needing a physical cable, between the user’s device and the VPN server.
- It is considered PRIVATE due to its ability to encrypt user data and conceal their Internet Protocol (IP) address.
- It is considered a NETWORK due to its ability to connect various computing devices, namely the user’s device and the VPN server.
Virtual Private Networks simplify the transmission of all network traffic to a virtual network, thus allowing users to access local network resources remotely and bypass Internet censorship. The majority of operating systems have built-in VPN support.
VPNs were initially designed to connect separate corporate networks over the internet securely or to provide remote access to a company’s network.
Q20. What is a firewall and how does it work?
Firewalls are a kind of network security technique used to restrict unauthorized access to the network. A device or program that is capable of filtering both incoming and outgoing data within a private network, applying a predefined set of regulations to identify and prevent cyber threats. They serve as an essential element of network security.
The majority of operating systems are equipped with a rudimentary integrated firewall. However, the utilization of a firewall application from a third-party source offers enhanced protection measures.
Working: Firewalls are used to monitor and control the flow of network traffic. It evaluates and determines what traffic to allow or restrict on a specific set of regulations. The firewall can be understood as a guard placed at the entry of a computer system, carefully allowing entry only to authorized sources or IP addresses within the network.
The regulations are derived from various factors as specified by the packet data, such as their origin, destination, and other relevant attributes. In order to prevent cyberattacks, traffic originating from suspicious sources is blocked.
Q21. What is the difference between Hub, Switch, and Router?
Here is a table explaining the difference between Hub, Switch, and Router –
| Device | Layer (OSI Model) | Function | Example |
| HUB | It works on Layer 1 i.e., Physical Layer | Connects multiple devices on a single network and broadcasts data to all ports. | A hub can be used to connect four computers in a small office network. |
| Switch | It works on Layer 2 i.e., Data Link Layer | Connects multiple devices on one or more networks and forwards data to the destination port based on MAC address. | A switch can be used to create VLANs and reduce broadcast traffic. |
| Router | It works on Layer 3 i.e., Network Layer | Connects two or more networks and routes data based on IP address. | A router can be used to connect a home network to the internet and provide firewall protection. |
Q22. What is Bandwidth?
Bandwidth is a measurement that indicates the highest possible data transmission capacity of a wireless or wired communication channel within a network connection during a specific time frame.
Higher bandwidth means more data can be sent and received faster and with fewer errors.
Q23. What do you understand by NIC?
The full form of NIC is the Network Interface Card, which is a peripheral card connected to the PC to link to the network, and each NIC has its own MAC address that locates PCs over the network. It provides a wireless connection to a local area network and is allowed on desktop computers.
Q24. What is DHCP and how does it function?
DHCP (Dynamic Host Configuration Protocol) is a protocol that automatically assigns IP addresses to network devices. When a device joins the network, the DHCP server assigns it an IP address, gateway, and other network parameters, simplifying network management.
Q25. Explain the TCP three-way handshake.
The three-way handshake happens as:
- SYN: The client sends a synchronization request to start a connection.
- SYN-ACK: The Server acknowledges and sends a synchronization request.
- ACK: The client acknowledges the server’s request and completes the handshake.
Advanced Networking Interview Questions and Answers
Here are some of the most asked advanced networking Interview Questions with their answers.
Q26. What is the difference between the ipconfig and ifconfig?
ipconfig stands for Internet Protocol Configuration, whereas ifconfig stands for Interface Configuration. The two have similar functions, except that the ipconfig command is used with the Windows operating system, while the ifconfig command is used on Linux and Mac computers.
Both commands display network information. They display your IP address, network mask, and gateway information.
However, `ifconfig` is not limited to displaying information. `ifconfig` allows you to modify network settings directly. You can enable or disable network interfaces. You can also assign new IP addresses through this command. `ipconfig` is more limited in what it can do. It mainly shows network details. Its main extra feature is refreshing your network connection.
Many Linux users now prefer the newer `ip` command. It has replaced `ifconfig` in some newer distributions. But `ifconfig` is still commonly used and understood.
Q27. What is Piggy Backing?
The network is the communication between two nodes that are interconnected by each other to share resources and data. But when we think about acknowledgment in between two-way communications there were several issues are raised, in that network needs to utilize a lot of bandwidth, and there again needed solutions for the same.
So, there is a thing which is Piggybacking, which is used when we want to transfer data in two-way communication, and there is no need to send special acknowledgment with the frame.
Q28. What is CIDR?
CIDR is Classless Inter-Domain Routing. It is a way of assigning IP addresses in a more efficient manner compared to older ones.
Before CIDR, IP addresses were divided into fixed classes. This wasted many addresses because organizations often got more than they needed. CIDR solved this problem by allowing flexible network sizes.
CIDR uses a slash notation to show network size, i.e., 192.168.1.0/24. The number after the slash will indicate the number of bits utilized by the network portion. The remaining bits are for individual device addresses.
This system allows networks to be any size needed. Small networks can get just a few addresses. Large networks can get thousands. This reduces the amount of information that routers must store and process. CIDR also helps routers work more efficiently. It allows them to group multiple networks together in a single routing table. This reduces the amount of information routers need to store and process.
Modern internet infrastructure cannot survive without the system. It helps control the scarcity of IPv4 addresses and is also expected to aid in the development of internet-enabled devices.
Q29. What is a trunk port?
A trunk port is a network link that carries data for many VLANs over a single connection. Its main job is to connect switches, allowing VLANs to stretch across multiple devices.
Trunk ports handle traffic from many different VLANs. Trunk ports add a special tag to each piece of data. This tag identifies which VLAN the data belongs to. The receiving switch reads the tag to send the data to the correct destination. This system makes the network more efficient and flexible.
Q30. What is the difference between TCP and UDP?
Below, we have presented the difference between TCP and UDP based on different factors.
| Factors | TCP (Transmission Control Protocol) | UDP (User Datagram Protocol) |
| Connection | Connection-oriented | Connectionless |
| Reliability | Reliable | Unreliable |
| Ordering | Preserve the order of packets | Does not preserve the order of packets |
| Congestion Control | Have a congestion control mechanism | Does not have a congestion control mechanism |
| Header size | 20 bytes | 8 bytes |
| Speed | Slower than UDP | Faster than TCP |
| Application | Web browsing, email, and file transfer | Streaming media, online gaming, voice-over IP |
Q31. What is 10Base2?
10BaseT defines the data transfer rate, i.e., 10Mbps, where Base is the “Baseband” and T defines the cable type.
The IEEE 802.3a standard defines 10Base2, which includes data transmission rates of 10Mbps and a maximum segment length of 185 meters through the utilization of RG-58 coaxial cable. The 10Base2 protocol is characterized by a physical bus topology and employs BNC connectors that are equipped with 50-ohm terminators at both ends of the cable. It is necessary to ground one of the physical ends of every segment.
Q32. What is Kerberos?
Kerberos is a network security protocol initially developed by MIT (Massachusetts Institute of Technology) that is specifically utilized for authenticating service requests among multiple trusted hosts over an untrusted network, such as the Internet.
It works via various crucial elements. These are:
- Client: The individual attempting to establish a connection with a particular service.
- Server: The server is responsible for hosting the service.
- Authentication Server (AS): Verifies the identity of the user. Upon successful client authentication, a Ticket Granting Ticket (TGT) is generated as evidence of the client’s authenticity.
- Ticket Granting Server (TGS): A server application that generates and delivers service tickets.
- Key Distribution Center (KDC): A server that hosts AS, database, and TGS.
Q33. What is MPLS, and how does it improve network traffic flow?
MPLS, or Multiprotocol Label Switching, is a method for directing traffic on a network. It uses labels to forward data instead of long network addresses. This makes the process simpler and faster. Once data enters an MPLS network, it gets a label. Then the data is sent rapidly by network devices using this shorter label along an already established path. This eliminates the need for complicated routing choices at each step. Through this, a more efficient and reliable network is achieved, which can be helpful to businesses that require high-quality connections to run their applications. MPLS improves traffic flow in several ways:
- It uses labels for faster forwarding decisions.
- It creates predictable paths for data to follow.
- It reduces the work routers have to do.
- It allows for prioritizing important traffic.
- It helps manage network congestion better.
Q34. What is NAT?
NAT stands for Network Address Translation. The process of NAT involves converting a specific range of private IP addresses to a single public IP address linked to a gateway device. The network address translation process allows a single device to act as an intermediary or agent between a private, localized network and a public network, such as the Internet.
The main focus of NAT is to conserve public IP addresses.
Q35. What is an Anycast address?
Anycast address is a single IP address utilized by a set of servers at different sites. When one directs any request to an Anycast address, the address is redirected to the nearest server. This will improve the speed and consistency of network services since the distance the information needs to travel is reduced. It is also able to help manage heavy traffic at the same time.
How it works:
- The same IP address is used for many servers.
- The network finds the closest server to you.
- Your request is sent to that server automatically.
- If one server fails, traffic is redirected to the next closest server.
Q36. What is the difference between synchronous and asynchronous transmission?
Here are some differences between synchronous and asynchronous transmission –
| Synchronous transmission | Asynchronous transmission |
| Data is sent in blocks or frames | Data is sent in bytes or characters |
| Requires synchronization between sender and receiver | Does not require synchronization between the sender and receiver |
| Fast and efficient for large amounts of data | Slow and economical for small amounts of data |
| Uses timing signals to coordinate data transfer | Uses start and stop bits to indicate data boundaries |
| Examples: Telephonic conversations, video conferencing, online gaming | Examples: Email, file transfer, online forms |
Q37. What is ICMP?
The Internet Control Message Protocol (ICMP) is designed for reporting errors and information related to network connectivity issues to the origin of the failed transmission. It is primarily utilized by network administrators to diagnose and resolve issues related to Internet connectivity.
The ICMP protocol operates by generating and transmitting messages to the originating IP address, signaling the inability to access an Internet gateway for the purpose of delivering packets. The process involves the transmission of datagrams that comprise an IP header, which encapsulates the ICMP data.
Error messages such as:
- Destination unreachable
- Source quench message
- Redirection message
- Time exceeded message
- Parameter problem
Q38. What is SNMP?
SNMP stands for Simple Network Management Protocol. SNMP is a network protocol that allows data collection, organization, and transmission among network devices. SNMP is a prevalent tool in network management, utilized to configure various network devices such as hubs, servers, routers, printers, and switches.
Critical components of SNMP are:
- Management Information Base (MIB)
- SNMP Manager
- SNMP Agent
- Managed device
Q39. What is anonymous FTP?
It is used to allow users to receive files on a public server. In other words, Anonymous FTP allows users to get data into these servers without having to verify themselves but rather by logging in as anonymous guests.
Q40. Can IP multicast be load-balanced?
No, because the IP multicast multipath command separates traffic, not balances traffic. Traffic coming from a source will be allowed only one way, even if the traffic far exceeds traffic coming from other sources.
Q21. Can a routing table contain two entries with the same destination address in a datagram network?
No, a routing table cannot have two entries with the same destination address in a datagram network because either the destination address or the receiver address is unique.
Q42. Define the term OFDM.
OFDM stands for Orthogonal Frequency Division Multiplexing, which is also a multiplexing technique used in analog systems. In OFDM, a guard band is not necessary, and the spectral efficiency of OFDM is high, which negates FDM. Additionally, an individual data source connects all the sub-channels in it.
Q43. What do you understand by Sneakernet?
It is the earliest form of networking where data is physically transferred through removable media.
Q44. Define the functionality of the OSI session layer.
The OSI session layer provides the protocol and means for two devices on the network to communicate with each other by keeping a session. It is responsible for session establishment, management of session time information exchange, and tear-down process based on session termination.
Q45. Explain the term Jitter.
Jitter refers to a “packet delay variance,” which is a problem when multiple packets of data encounter multiple delays in the network, and the data at the acceptor application is time-critical, i.e., audio or video data. It is calculated in milliseconds and is described as interference with the normal process of sharing data packets.
These are all the important networking interview questions and answers for both fresher and experienced candidates.
Conclusion
In this blog, we have covered some of the basic networking interview questions and answers you may encounter. Whether you are applying for a network engineer or any other role, these questions will help you demonstrate your knowledge and skills in computer networks. We hope that this blog has given you some insights into the networking interview questions that you can expect in your interviews.
Remember to prepare well, practice your answers, and be confident. Good luck with your networking career!
