Basics of Computer Networking

Last Updated : 15 Feb, 2025

A computer network is a collection of interconnected devices that share resources and information. These devices can include computers, servers, printers, and other hardware. Networks allow for the efficient exchange of data, enabling various applications such as email, file sharing, and internet browsing.

Basic Terminologies of Computer Networks

Network: A network is a collection of computers and devices that are connected together to enable communication and data exchange.

Nodes: Nodes are devices that are connected to a network. These can include computers, Servers, Printers, Routers, Switches, and other devices.

Protocol: A protocol is a set of rules and standards that govern how data is transmitted over a network. Examples of protocols include TCP/IP, HTTP, and FTP.

Topology: Network topology refers to the physical and logical arrangement of nodes on a network. The common network topologies include bus, star, ring, mesh, and tree.

Service Provider Networks: These types of Networks give permission to take Network Capacity and Functionality on lease from the Provider. Service Provider Networks include Wireless Communications, Data Carriers, etc.

IP Address: An IP address is a unique numerical identifier that is assigned to every device on a network. IP addresses are used to identify devices and enable communication between them.

DNS: The Domain Name System (DNS) is a protocol that is used to translate human-readable domain names (such as www.google.com) into IP addresses that computers can understand.

Firewall: A firewall is a security device that is used to monitor and control incoming and outgoing network traffic. Firewalls are used to protect networks from unauthorized access and other security threats.

How Does a Computer Network Work?

Basics building blocks of a Computer network are Nodes and Links. A Network Node can be illustrated as Equipment for Data Communication like a Modem, Router, etc., or Equipment of a Data Terminal like connecting two computers or more. Link in Computer Networks can be defined as wires or cables or free space of wireless networks.

The working of Computer Networks can be simply defined as rules or protocols which help in sending and receiving data via the links which allow Computer networks to communicate. Each device has an IP Address, that helps in identifying a device.

What do Computer Networks do?

Computer networks first developed in 1950 for military and defense purpose. At that time they are mainly used to send data through telephone lines and had limited use in business or science.

Today computer networks are essential for businesses also. Modern networks offer more than just connecting devices. They play a key role in helping businesses adapt to the digital world and succeed. These networks have become more flexible, automated, and secure, making them even more important in today’s business environment.

Modern computer networks can:

Work Virtually: The physical network can be divided into smaller virtual networks. In these virtual networks, devices are connected and can send data through multiple physical routes. For example, many business networks use the internet this way.

Connect on a Large Scale: Modern networks link many smaller, spread-out networks into one big, powerful system. Automation and monitoring tools help manage and adjust the network as needed, allowing it to grow or shrink based on demand.

Adapt Quickly: Many networks are controlled by software, so changes can be made quickly through a digital dashboard. This allows traffic to be managed easily.

Keep Data Secure: Built-in security features like encryption and access control protect data. Additional protections like antivirus software, firewalls, and malware protection can be added to strengthen network security.

Computer Networking

Types of Enterprise Computer Networks

LAN: A Local Area Network (LAN) is a network that covers a small area, such as an office or a home. LANs are typically used to connect computers and other devices within a building or a campus.

WAN: A Wide Area Network (WAN) is a network that covers a large geographic area, such as a city, country, or even the entire world. WANs are used to connect LANs together and are typically used for long-distance communication.

Cloud Networks: Cloud Networks can be visualized with a Wide Area Network (WAN) as they can be hosted on public or private cloud service providers and cloud networks are available if there is a demand. Cloud Networks consist of Virtual Routers, Firewalls, etc.

These are just a few basic concepts of computer networking. Networking is a vast and complex field, and there are many more concepts and technologies involved in building and maintaining networks. Now we are going to discuss some more concepts on Computer Networking.

Open system: A system that is connected to the network and is ready for communication.
Closed system: A system that is not connected to the network and can’t be communicated with.

Types of Computer Network Architecture

Computer Network falls under these broad Categories:

Client-Server Architecture: Client-Server Architecture is a type of Computer Network Architecture in which Nodes can be Servers or Clients. Here, the server node can manage the Client Node Behaviour.

Peer-to-Peer Architecture: In P2P (Peer-to-Peer) Architecture, there is not any concept of a Central Server. Each device is free for working as either client or server.

Network Devices

An interconnection of multiple devices, also known as hosts, that are connected using multiple paths for the purpose of sending/receiving data or media. Computer networks can also include multiple devices/mediums which help in the communication between two different devices; these are known as Network devices and include things such as routers, switches, hubs, and bridges.

Network Devices

Network Topology

The Network Topology is the layout arrangement of the different devices in a network. Some types of network topologies are:

Bus Topology: In bus topology all devices are connected to a single central cable called a bus. Data is sent along this cable and all devices share the same connection. Simple and cheap to set up but if the main cable fails the whole network goes down.

Star Topology: In star topology all devices are connected to a central node called hub or switch. The hub controls the flow of data between devices. If one device fails the rest of the network is unaffected. But, if the central hub fails the whole network stops working.

Ring Topology: In ring topology devices are connected in a circular loop with each device connected to two others. Data travels in one direction (or sometimes both) passing through each device until it reaches its destination. A failure in one device can affect the whole network.

Mesh Topology: In mesh topology every device is connected to every other device in the network. It provides multiple paths for data so if one path fails another can take over.

Tree Topology: Tree topology is the combination of star and bus topology. Tree topology is good for organizing large networks and allows for easy expansion.

Hybrid Topology: Hybrid topology is the combination of two or more different topologies (like star and mesh). It is flexible and can be customized based on the network’s specific needs.

Network Topology

OSI Model

OSI stands for Open Systems Interconnection. It is a reference model that specifies standards for communications protocols and also the functionalities of each layer. The OSI has been developed by the International Organization For Standardization and it is 7 layer architecture. Each layer of OSI has different functions and each layer has to follow different protocols. The 7 layers are as follows:

Network Protocols

A protocol is a set of rules or algorithms which define the way how two entities can communicate across the network and there exists a different protocol defined at each layer of the OSI model. A few such protocols are TCP, IP, UDP, ARP, DHCP, FTP, and so on.

Transmission Control Protocol/Internet Protocol (TCP/IP): TCP/IP is the foundational protocol suite of the internet, enabling reliable communication. TCP Ensures data is delivered reliably and in order and IP routes data packets to their destination based on IP addresses.
Hypertext Transfer Protocol (HTTP) and HTTPS: HTTP and HTTPS protocols used for transmitting web pages. In HTTP communication is unsecured and in HTTPS secured communication using SSL/TLS encryption.
Simple Mail Transfer Protocol (SMTP): SMTP protocol used to send email. SMTP protocol works with other protocols like POP3 and IMAP for email retrieval.
File Transfer Protocol (FTP): FTP protocol used for transferring files between computers. Includes commands for uploading, downloading, and managing files on a remote server.
Dynamic Host Configuration Protocol (DHCP): DHCP protocol automatically assigns IP addresses to devices on a network. Reduces manual configuration and IP address conflicts.
Domain Name System (DNS): DNS Translates human-friendly domain names into IP addresses. Ensures seamless navigation on the internet.

Unique Identifiers of Network

Hostname: Each device in the network is associated with a unique device name known as Hostname. Type “hostname” in the command prompt(Administrator Mode) and press ‘Enter’, this displays the hostname of your machine.

HostName

IP Address (Internet Protocol address): Also known as the Logical Address, the IP Address is the network address of the system across the network. To identify each device in the world-wide-web, the Internet Assigned Numbers Authority (IANA) assigns an IPV4 (Version 4) address as a unique identifier to each device on the Internet. The length of an IPv4 address is 32 bits, hence, we have 2³² IP addresses available. The length of an IPv6 address is 128 bits.

In Windows Type “ipconfig” in the command prompt and press ‘Enter’, this gives us the IP address of the device. For Linux, Type “ifconfig” in the terminal and press ‘Enter’ this gives us the IP address of the device.

MAC Address (Media Access Control address): Also known as physical address, the MAC Address is the unique identifier of each host and is associated with its NIC (Network Interface Card). A MAC address is assigned to the NIC at the time of manufacturing. The length of the MAC address is: 12-nibble/ 6 bytes/ 48 bits Type “ipconfig/all” in the command prompt and press ‘Enter’, this gives us the MAC address.

Port: A port can be referred to as a logical channel through which data can be sent/received to an application. Any host may have multiple applications running, and each of these applications is identified using the port number on which they are running.

A port number is a 16-bit integer, hence, we have 2¹⁶ ports available which are categorized as shown below:

Port Types	Range
Well known Ports	0 – 1023
Registered Ports	1024 – 49151
Ephemeral Ports	49152 – 65535

Number of ports: 65,536
Range: 0 – 65535
Type “netstat -a” in the command prompt and press ‘Enter’, this lists all the ports being used.

List of Ports

Socket: The unique combination of IP address and Port number together is termed a Socket.

Other Related Concepts

DNS Server: DNS stands for Domain Name System. DNS is basically a server that translates web addresses or URLs (ex: www.google.com) into their corresponding IP addresses. We don’t have to remember all the IP addresses of each and every website. The command ‘nslookup’ gives you the IP address of the domain you are looking for. This also provides information on our DNS Server. \

Domain IP Address

ARP: ARP stands for Address Resolution Protocol. It is used to convert an IP address to its corresponding physical address(i.e., MAC Address). ARP is used by the Data Link Layer to identify the MAC address of the Receiver’s machine.

RARP: RARP stands for Reverse Address Resolution Protocol. As the name suggests, it provides the IP address of the device given a physical address as input. But RARP has become obsolete since the time DHCP has come into the picture.

The Domain Name System (DNS) is a critical component of computer networking. It converts easily recognizable domain names, such as www.example.com, into numerical IP addresses that computers use to identify each other on the network.

How DNS Works?

DNS works efficiently, translating user-friendly domain names into IP addresses, allowing seamless navigation on the internet. Below step by step working of DNS:

User Input: When a user enters a domain name in a browser, the system needs to find its IP address.
DNS Query: The user’s device sends a DNS query to the DNS resolver.
Resolver Request: The DNS resolver checks its cache for the IP address. If not found, it forwards the request to the root DNS server.
Root DNS Server: The root DNS server provides the address of the TLD (Top-Level Domain) server for the specific domain extension (e.g., .com).
TLD DNS Server: The TLD server directs the resolver to the authoritative DNS server for the actual domain.
Authoritative DNS Server: The authoritative DNS server knows the IP address for the domain and provides it to the resolver.
Response to User: The resolver stores the IP address in its cache and sends it to the user’s device.
Access Website: With the IP address, the user’s device can access the desired website.

Network Security

Ensuring the security of a network is crucial to protect data and resources from unauthorized access and attacks. Key aspects of network security include:

Firewalls: Devices or software that monitor and control incoming and outgoing network traffic based on security rules.
Encryption: The process of encoding data to prevent unauthorized access. Commonly used in VPNs, HTTPS, and secure email.
Intrusion Detection Systems (IDS): Tools that monitor network traffic for suspicious activity and potential threats.
Access Control: Mechanisms that restrict access to network resources based on user identity and role.
Regular Updates and Patching: Keeping software and hardware up to date to protect against vulnerabilities.

Why Use Computer Networks?

Computer network play a important role in modern life. Here are some key benefits of computer networks:

Fast and Easy Communication: Networks enable all types of digital communication, like emails, messaging, file sharing, video calls, and streaming.

More Storage Space: Suppose if we don’t have a cloud storage then we have to store data in physical files that will consume a physical space so computer network provide a storage for storing data.

Easier Sharing of Information: Networks make it simpler for users and teams to share resources and information. Teams can collaborate more easily, and users get faster response from network devices.

Better Security: Well designed networks are more reliable and give businesses more options for keeping data safe. They come with built-in security features like encryption and access controls to protect sensitive information from cyber threats.

Conclusion

Understanding the basics of computer networking is essential in today’s interconnected world. Networks enable the seamless exchange of information, support countless applications, and underpin the functionality of the internet. From different types of networks and their components to protocols and security measures, a solid grasp of these concepts is foundational for anyone working in or with technology. As technology evolves, so too will the complexity and capabilities of computer networks, making continuous learning and adaptation crucial.

Frequently Asked Questions on Basics of Computer Networking – FAQs

What is an IP address?

An IP (Internet Protocol) address is a unique identifier assigned to each device on a network. It allows devices to locate and communicate with each other. There are two types of IP addresses: IPv4 (e.g., 192.168.1.1) and IPv6 (e.g., 2001:0db8:85a3:0000:0000:8a2e:0370:7334).

What is the difference between TCP and UDP?

TCP (Transmission Control Protocol): A connection-oriented protocol that ensures reliable and ordered delivery of data. It is used for applications where data integrity is critical, like web browsing and email.

UDP (User Datagram Protocol): A connectionless protocol that does not guarantee delivery or order. It is used for applications where speed is more important than reliability, like streaming and gaming.

What is a firewall?

A firewall is a network security device or software that monitors and controls incoming and outgoing network traffic based on predefined security rules. It acts as a barrier between a trusted internal network and untrusted external networks like the internet.

What is a subnet mask?

A subnet mask is used in IP addressing to divide the network into sub-networks, or subnets. It helps determine which portion of an IP address is the network address and which part is the host address.

What is NAT (Network Address Translation)?

NAT is a method used by routers to translate private IP addresses within a local network to a public IP address before sending data over the internet. This helps to conserve IP addresses and add a layer of security by hiding internal network addresses.

What is a MAC address?

A MAC (Media Access Control) address is a unique identifier assigned to a network interface card (NIC) for communication on a physical network segment. It is a hardware address that is unique to each network device..

What is latency in networking?

Latency is the time it takes for data to travel from the source to the destination across a network. It is usually measured in milliseconds (ms) and can affect the performance of networked applications.