The Basics of Computer Networks: What You Need to Know

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Computer networks are a collection of interconnected devices designed to share resources and communicate with each other. Networks can be as small as a few interconnected computers in an office or as large as the entire internet. The advantages of computer networks are numerous, including the ability to share files and resources easily, remotely access information, and improve collaboration between users. However, network security is also a critical consideration in protecting against cyber threats. With the increasing dependence on digital communication and the internet, computer networks have become an essential part of modern life.

Need of Computer Networks

A Computer network is a group of interconnected devices that are capable of exchanging information with one another. In today’s digital age, there is a growing need for computer networks for various reasons.

• The need for computer networks arises from the growing demand for information exchange. With organizations expanding their reach across the globe, it has become necessary to have a seamless communication network. Computer networks provide a platform for sharing information and resources among team members working in different locations.
• Computer networks have become essential for businesses to ensure smooth operations. With the help of computer networks, companies can monitor their operations in real-time, streamline processes and improve productivity. It also enables backup and recovery capabilities, ensuring businesses are prepared for any unforeseen circumstances.
• Computer networks have made online communication seamless and affordable. With the advent of the internet, it has become possible to interact and share information with anyone, anywhere, at any time. Computer networks have enabled online communication platforms such as email, social media platforms, and video conferencing applications.
• They facilitate e-commerce and online transactions. Online shopping and payments have become an integral part of our lives, and computer networks provide a reliable and secure platform for these transactions. It also enables organizations to reach a global audience with their products and services.
• Lastly, computer networks have enabled the development of new technologies such as the Internet of Things (IoT) and Artificial Intelligence (AI). IoT relies on a network of devices connected to the internet to exchange data, and computer networks provide the necessary infrastructure for this exchange. Similarly, AI requires access to large amounts of data, which can be collected and analyzed through computer networks.

These are some of the reasons as to why computer networks are a necessity these days.

Components of a Network

Computer networks consist of many different components, some of which work together to form the backbone of the network. In this article, we will discuss the main components of a computer network.

1. Network Devices: These are the devices that are used to connect computers and other devices on the network. Some of the network devices include routers, switches, gateways, and modems. The router is the most important device as it controls the flow of traffic between devices on the network.
2. Network Cables: These cables are used to connect the various devices on the network. There are different types of network cables, such as Ethernet cables, fiber optic cables and coaxial cables. Ethernet cables are the most commonly used cables, and they can be used to connect devices such as computers, printers, routers, and switches.
3. Network Interfaces: Network interfaces are used to connect devices to the network. They can either be built-in or external devices. An example of an external network interface is a LAN card.

4. Network Protocols: These are the communication protocols used by devices on the network to exchange data. There are different types of network protocols such as TCP/IP, HTTP, FTP, and SMTP.

5. Network Services: These are the services that are provided by the network to devices connected to it. They include services such as file sharing, email, printing, and many others. Network services are essential for the proper functioning of a network.

6. Network Operating System: This is the operating system that is used to manage the network devices and services. Some examples of network operating systems include Windows Server, Linux, and MacOS Server.

7. Security: Security is an essential aspect of any computer network. This involves protecting the network from unauthorized access, virus attacks, and other malicious activities. Some of the security measures include firewalls, routers that can block unauthorized traffic, and antivirus software.

Network Architecture

Network architecture refers to the design of a computer network, outlining how different devices and resources are connected to enable information exchange. There are different types of network architectures, with the two most common being client-server and peer-to-peer. In this post, we’ll explore the characteristics of both architectures in bulleted points.

Client-Server Architecture

• In client-server architecture, network resources are centralized in a server which sends information to clients upon request.
• The server is responsible for managing and securing the resources, ensuring the clients only access what they’re authorized to use.
• Clients rely on the server for all their needs, including file storage and processing power.
• This type of architecture is preferred when the resources on the server are crucial to the functioning of the client. For example, a web application which relies on a database.

Peer-to-Peer Architecture

• In peer-to-peer architecture, there is no central server, and resources are shared among all connected devices.
• Every device in the network is considered a “peer”, and they all have the same responsibilities and permissions.
• Peers can share both their own resources and the ones from other peers, creating a dynamic and adaptive network.
• This type of architecture is preferred when distributing large amounts of data across multiple devices, such as video streaming or file sharing.

Both architectures have their pros and cons, and choosing the right one depends on the specific needs of the network. Client-server architecture is great for centralized control and security, while peer-to-peer architecture shines in resource sharing and scalability.

Network Topology

Network topology refers to the arrangement of devices within a computer network. There are different types of network topology, each with its own characteristics and pros and cons. Now, let’s take a closer look at the various types of network topologies.

Bus Topology

In a bus topology, all devices are connected to a single cable called a bus. The bus acts as a common shared communication medium among all the devices. This type of topology is simple to set up and is cost-effective. However, it’s not very scalable or reliable. A single break in the bus can result in the entire network going down.

Star Topology

In a star topology, all devices are connected to a central device, usually a hub or a switch. The central device acts as a communication point for all connected devices. This type of topology is more reliable than a bus topology since a single device failure won’t take down the entire network. However, it is more expensive than a bus topology since you need a central device for every connected device.

Ring Topology

In a ring topology, all devices are connected in a loop formation, where data travels in only one direction. Each device is connected to two other devices, one on each side, creating a ring-like structure. This type of topology is reliable since device failure won’t take the entire network down. However, it can be slow due to the limited bandwidth and data collisions.

Mesh Topology

In a mesh topology, each device is connected to multiple devices, creating a redundant path for data to travel. This type of topology is highly reliable, as multiple paths mean that a single device failure won’t affect the entire network. However, it is also expensive due to the high number of connections required.

Hybrid Topology

A hybrid topology is a combination of two or more types of topology. This type of topology offers the benefits of both types of topology, such as the reliability of a star topology and the efficiency of a mesh topology. However, it is also complex to set up and requires more hardware.

Basic Network Terminologies

• IP: Internet Protocol, a unique numerical identifier assigned to each device connected to a network.
• DNS: Domain Name System, a system that translates easy to remember domain names (like google.com) into IP addresses.
• Router: A networking device that forwards data packets between different computer networks, either within a single network or between multiple networks.
• Gateway: A device that provides a bridge between different networks or subnetworks.
• Firewall: A security system that monitors and controls incoming and outgoing network traffic based on pre-defined security rules.
• LAN: Local Area Network, a group of devices connected together within a small geographical area, like an office or a home.
• WAN: Wide Area Network, a group of geographically dispersed devices connected together, typically using internet technologies like fiber optics or satellite communication.
• TCP/IP: Transmission Control Protocol/Internet Protocol, a set of networking protocols used for communication between devices on the internet.
• Port: A specific numerical identifier used to differentiate between different types of traffic on a single network or device.

Enterprise Networks

LAN Networks:

• Stands for Local Area Network.
• Connects devices within a limited geographical area like an office building, campus, or company building.
• Often configured with Ethernet or Wi-Fi technologies for data transmission.
• Usually managed and secured by an on-premise IT team.
• Provides reliable access to company resources and applications, improving overall productivity.

WAN Networks:

• Stands for Wide Area Network.
• Connects devices over a larger geographical area, like different cities, states, or countries.
• Often configured with technologies like leased lines, VPNs, or the Internet for data transmission.
• Managed and secured by an IT team, either in-house or outsourced.
• Enables remote workers to access company resources, improving collaboration and flexibility.

Cloud Networks:

• Stands for Cloud Computing Network.
• Uses remote servers accessible via the internet to store, manage, and process data.
• Managed and secured by a cloud provider like Azure, Amazon Web Services (AWS), or Google Cloud.
• Enables easy access to resources and applications by remote workers and third-party applications.
• Offers scalability and flexibility for businesses.

OSI Model

The OSI model, short for the Open Systems Interconnection model, is a conceptual framework used to standardize communication between different systems. The model is divided into seven layers, each with its own specific purpose and role in communication.

Here are the seven layers of the OSI model, explained in detail:

1. Physical Layer – The Physical Layer is the first layer of the OSI model. It deals with the physical characteristics of the actual communication medium, such as the connection types, cables, and connectors. It describes the electrical and physical representation of the data being transmitted over the network.
2. Data Link Layer – The Data Link Layer is responsible for transmitting data between adjacent network nodes. This layer deals with the framing of data packets and error detection. It provides error-free communication between two nodes on the same network segment.

3. Network Layer – The Network Layer deals with the logical addressing and routing of data. It is responsible for creating packets and forwarding them to their destination. The Network Layer transmits data between different network segments.

4. Transport Layer – The Transport Layer ensures reliable end-to-end communication between different devices. This layer is responsible for sequencing, error checking, and flow control between hosts. It is responsible for providing error-free communication between processes on different devices.
5. Session Layer – The Session Layer is responsible for establishing, maintaining, and terminating sessions between devices. It provides for synchronization, security, and checkpointing of the session management. This layer allows multiple applications to run on a single connection.
6. Presentation Layer – The Presentation Layer is responsible for data representation and code formatting. It deals with the translation of data to ensure that data from one system can be understood by another system. This layer also deals with compression and encryption of data.

7. Application Layer – The Application Layer is the topmost layer of the OSI model. This layer provides application services for end-users such as file transfer, email, and remote login. It is the communication interface between the user and the network.

Network Protocols

Network protocols are a crucial element of modern computer networking, allowing devices to communicate with each other over a network. Here are some of the most common protocols:

1. TCP/IP: Transmission Control Protocol/Internet Protocol is the most widely used protocol on the internet. It’s responsible for sending data packets between devices and ensuring they arrive safely.
2. HTTP/HTTPS: Hypertext Transfer Protocol is used to transfer data between web servers and clients. HTTPS is a secure version of HTTP, providing encryption of data in transit.
3. DNS: Domain Name System is used to translate domain names into IP addresses. This allows users to type in a website address rather than having to remember its numerical IP address.
4. FTP: File Transfer Protocol is used for transferring files between devices over a network. It’s commonly used for website maintenance, allowing files to be uploaded to servers.
5. SMTP: Simple Mail Transfer Protocol is used for sending email messages between servers. It’s responsible for routing messages to their intended recipients.
6. POP3/IMAP: Post Office Protocol and Internet Message Access Protocol are used for retrieving email messages from servers. They both allow users to download messages onto their own devices.
7. SSH: Secure Shell is a secure protocol used for remote access to servers. It allows users to log into a server and execute commands, all while encrypting the communication.

This was the introduction to computer networks. All of the above-mentioned concepts (IP address, DNS etc.) will be covered in the upcoming posts. Stay tuned!

Access the OSI and TCP/IP Models (Next post in Networking) by clicking HERE

Access the complete DevOps series by clicking HERE