Unlocking the Cloud: A Glimpse into Computer Network Essentials for Seamless Cloud Computing

Why Computer Networks are Important ?

1. Enabling Communication : Connects people and organization globally
2. Data Sharing and Resource Access : Networks allow sharing , productivity and collaboration of data
3. Supporting Online Services : Eg - Net Banking
4. Driving Business and Innovation : Enable Cloud , AI , IoT etc
5. Connecting the World

History of Networks

1960's - ARPANET - Researchers developed the first host-to-host protocols, which eventually evolved into the Transmission Control Protocol (TCP) and Internet Protocol (IP) stack.

1970's - Ethernet and LAN [Local Area Network]

1980's - WAN [Wide Area Network]

1990's - Internet Revolution [ World Wide Web ]

2000's - Wireless Network and Mobile Connectivity

2010's - Cloud Computing and Virtualization

2020's - 5G & IoT and Network Expansion

What is Computer Network ?

A computer network is a collection of interconnected devices, such as computers, servers, routers, switches, and other hardware, that are linked together to enable communication and resource sharing.

The main reason to create a Network is to share Data so loss of data don't occur and also the resources used would be less. Resource Sharing, Communication , Data Transfer and Storage, Remote Access and Mobility, Centralized Management and Control, Cost Efficiency, Internet Access and Connectivity, Entertainment and Media Sharing, Research and Innovation are the key features.

Network Components and Terminologies

Some of the network-related terminologies you will have to encounter is as follows:

1. Routers: Devices that forward data packets between computer networks. Routers operate at the network layer of the OSI model and make decisions about how to send data based on IP addresses. A router is like a traffic director for your internet connection. It takes the internet signal from your internet service provider (ISP) and splits it into smaller signals that each of your devices can understand.
2. Switches: Device that connect devices within a local area network (LAN). Switches operate at the data link layer and use MAC addresses to determine where to send data.
3. Hubs: Basic networking devices that connect multiple computers in a network. Unlike switches, hubs do not intelligently manage data traffic and simply broadcast data to all connected devices.
4. Firewalls: Security devices or software that control and monitor incoming and outgoing network traffic based on predetermined security rules. They provide a barrier between trusted and untrusted networks.
5. Protocols: Set of rules and conventions that govern how data is transmitted and received over a network. Examples include TCP/IP (Transmission Control Protocol/Internet Protocol), HTTP (Hypertext Transfer Protocol), and FTP (File Transfer Protocol).
6. Data Packets: Units of data that are transmitted over a network. Data packets contain the actual data being sent along with information about the source, destination, and other control information.
7. Bandwidth: The amount of data that can be transmitted over a network in a given amount of time. It is usually measured in bits per second (bps), kilobits per second (Kbps), megabits per second (Mbps), or gigabits per second (Gbps).
8. Latency: The time delay between the transmission of data from the source to its reception at the destination. Low latency is important for real-time applications like video conferencing and online gaming.
9. TCP/IP: The foundational suite of protocols that powers the Internet. It includes protocols like IP (Internet Protocol) for addressing and routing, and TCP (Transmission Control Protocol) for reliable data transmission.
10. LAN (Local Area Network): A network of computers and devices located within a limited geographical area, such as a home, office, or campus.
11. WAN (Wide Area Network): A network that spans a larger geographical area, typically connecting multiple LANs. The Internet itself is a massive WAN.
12. IP Address: A unique numerical label assigned to each device connected to a network, allowing it to be identified and communicate with other devices.
13. MAC Address: A unique identifier assigned to the network interface of a device. It operates at the data link layer and is used for local addressing within a network segment.
14. DNS (Domain Name System): A system that translates human-readable domain names (like www.example.com ) into IP addresses that computers use to identify each other on a network.
15. VPN (Virtual Private Network): A secure and encrypted connection that allows users to access a private network over a public network (like the Internet). It's commonly used for remote access and enhancing security.

Types of Networks

Based on Geographical Area

Networks can be named and classified into following types :

1. Local Area Network (LAN): LANs are commonly found in homes, offices, and schools, where devices are connected within a small area. For instance, a small office might have a LAN connecting computers, printers, and servers to facilitate local communication and resource sharing.
2. Metropolitan Area Network (MAN): A city-wide Wi-Fi network providing free internet access across public areas like parks, squares, and government buildings is an example of a MAN. Citizens and tourists can connect to this network for online activities within the city limits.
3. Wide Area Network (WAN): The global Internet is the most prominent example of a WAN. People and organizations across the world can communicate and share data seamlessly, regardless of their geographical locations.
4. Campus Area Network (CAN): A university campus might have a CAN connecting different departments and buildings. Students and faculty members can access resources and collaborate effectively across various locations on the campus.
5. Global Area Network (GAN): Multinational corporations often use GANs to connect their offices and facilities worldwide. For instance, a large retail chain may have a GAN connecting its headquarters in one country to its stores in multiple other countries, facilitating centralized management and communication.
6. Home Area Network (HAN): A smart home setup could involve a HAN where devices like smart thermostats, lights, and security cameras are interconnected and controlled from a single smartphone app.
7. Personal Area Network (PAN): Consider a scenario where you connect your smartphone to wireless headphones using Bluetooth. This forms a PAN, allowing you to listen to music or take calls without physical cables.
8. Wireless Local Area Network (WLAN): Coffee shops, airports, and libraries often provide public Wi-Fi services for users to connect their devices while on the premises. These WLANs offer internet access without the need for physical connections. The largest WAN we use is the Internet.
9. Virtual Private Network (VPN): While not tied to a specific geographical location, VPNs are used to securely access resources over the internet from remote locations. An employee working from home can connect to their company's internal network using a VPN, ensuring a secure connection for sensitive data.

Based on the host role

Network can be classified into 2 types namely,

1. Client-Server Network:

• Clients: These are devices (computers, smartphones, etc.) that request and consume services from servers.
• Servers: These are devices that provide services to clients. They respond to client requests and fulfill them. Examples include web servers, email servers, and database servers.

2. Peer-to-Peer (P2P) Network:

• Peers: All devices in the network are considered equal. They can act as both clients and servers, sharing resources and services directly with one another. P2P networks are often used for file sharing, collaboration, and communication.

3. Workgroup Network:

• Workstations: These are individual computers used by end-users for their tasks. They might share files and printers within a small group or department.
• No central server: Resources are shared directly between workstations without a dedicated server. It's a simple form of networking often found in small businesses or home offices.

4. Domain Network:

• Domain Controller: A central server that manages user accounts, authentication, and access control within a Windows domain. It provides a centralized security and management framework.

5. Clientless Network:

• Devices: These could be IoT devices, sensors, or other network-enabled objects that communicate without the need for traditional clients or servers.
• Communication without traditional client-server architecture: These devices might use protocols like MQTT (Message Queuing Telemetry Transport) for lightweight, efficient communication.

6. Hybrid Network:

• Combines different roles: A network can combine various roles, such as having both client-server and P2P elements. Cloud services might also be integrated into the network architecture.

7. Centralized Network:

• Central Controller: All communication and data flow through a central controller, which manages and directs traffic and resources. This is often used in industrial control systems or smart grids.

8. Decentralized Network:

• No single central controller: Devices communicate directly with each other, making decisions collectively. Blockchain networks are an example of decentralized networks.

Network Topology and Types

Network topology refers to the way devices are connected in a computer network. The choice of topology depends on factors like the size of the network, the reliability needed, and the cost involved. Network topology can be classified into two main categories: physical topology and logical topology. They are as follows :

1. Physical Topology:

Physical topology refers to the actual physical layout or arrangement of devices and cables in a network. It describes how devices are physically connected to each other and how data flows between them.Common types of physical topologies include:

• Bus Topology: Devices are connected in a linear fashion along a single cable. Example: A small office network where computers are connected to a single Ethernet cable.
• Star Topology: Devices are connected to a central hub or switch. Example: Imagine a home network where all devices (computers, printers, smartphones) connect to a central Wi-Fi router.
• Ring Topology: Devices are connected in a circular chain. Example: A simple token ring network where computers are connected in a circular manner, passing data from one to the next.
• Mesh Topology: Devices are interconnected in a mesh-like manner, creating redundant paths. Example: An advanced communication system for emergency services, where multiple communication devices are interconnected for seamless and reliable communication.
• Tree Topology: Devices are organized in a hierarchical structure with a main root and secondary branches.Example: A corporate network with a main server (root) connected to departmental servers (secondary) which are further connected to individual computers (end devices).

The physical topology determines factors such as the length of cables, the number of connections, and the overall layout of the network.

2. Logical Topology:

Logical topology refers to how data flows in a network from one device to another, regardless of the physical layout. It focuses on the path that data takes as it travels between devices.Common types of logical topologies include:

• Point-to-Point: Direct communication between two devices.
• Broadcast: Data is sent from one device to all other devices in the network.
• Token Passing: Devices take turns sending data in a circular manner.
• Mesh (Full Mesh, Partial Mesh): Logical paths for data between devices, irrespective of physical connections.
• Star: Data is sent through a central hub or switch to reach other devices.

Logical topology determines how devices communicate and share data. It may involve protocols and rules that dictate how data is transmitted and received.

Server and its various types

A server is like a central hub that serves information or resources to other devices in a network. It responds to requests from clients, which can be computers, smartphones, or other devices, by providing them with the data or services they need. It's like a waiter at a restaurant taking orders from customers and bringing them the food they asked for.

Different Types of Servers:

There are several types of servers, each designed to perform specific tasks or provide particular services. Here are a few common types:

1. Web Server: A web server stores and delivers websites and web applications to users when they enter a URL in their web browser. It processes requests for web pages and sends the appropriate content to the requesting devices.
2. File Server: A file server stores and manages files, documents, and data that can be accessed and shared by authorized users on a network. It acts as a centralized storage location.
3. Database Server: This type of server manages and stores databases, allowing clients to access, manipulate, and retrieve data from those databases. It's commonly used for applications that require structured data storage.
4. Mail Server: A mail server handles email communication by sending, receiving, and storing emails. It manages the flow of emails between different users and domains.
5. Print Server: A print server manages printing requests from clients, allowing them to send print jobs to network-connected printers.
6. Game Server: Game servers host online multiplayer games, enabling players to connect, interact, and play together over the internet.
7. DNS Server: A Domain Name System (DNS) server translates human-readable domain names (like www.example.com ) into IP addresses that computers use to locate each other on the internet.
8. Proxy Server: A proxy server acts as an intermediary between clients and other servers, helping to improve security, privacy, and performance by caching and filtering content.
9. Application Server: An application server hosts and manages software applications, providing a platform for running and managing various applications for multiple users.
10. FTP Server: An FTP (File Transfer Protocol) server allows users to upload and download files to and from a remote server over a network.

Address and its various types

In a computer network, an address is a unique identifier assigned to a device or resource to enable proper communication and data exchange. Addresses play a crucial role in ensuring that data reaches the intended destination within the network. There are different types of addresses used in networking, each serving a specific purpose :

1. MAC Address (Media Access Control Address) :

A MAC address is a hardware address assigned to a network interface card (NIC) of a device. It is a globally unique identifier that identifies the device's physical connection on a local network. MAC addresses are used at the data link layer of the OSI model and are primarily associated with Ethernet networks.

Example: Suppose you have a laptop with a MAC address like "00:1A:2B:3C:4D:5E." This address uniquely identifies your laptop's network adapter on the local network.

2. IP Address (Internet Protocol Address) :

An IP address is a numerical label assigned to each device connected to a network that uses the Internet Protocol for communication. IP addresses allow devices to be located and identified on a network or the internet. There are two main types of IP addresses: IPv4 (32-bit) and IPv6 (128-bit).

Example: An IPv4 address like "192.168.1.10" identifies a device within a local network, while an IPv6 address like "2001:0db8:85a3:0000:0000:8a2e:0370:7334" provides a more extensive addressing space for the internet.

3. Domain Name :

A domain name is a human-readable address used to identify resources on the internet. Domain names are used to translate user-friendly names (like www.example.com) into IP addresses, allowing users to access websites and services.

Example: The domain name "www.google.com" is used to access Google's search engine. When you enter this domain name in a web browser, it is translated to the corresponding IP address to reach the Google server.

4. Port Number :

A port number is a 16-bit address used to identify specific processes or services running on a device within a network. Port numbers allow data to be directed to the appropriate application or service on a device.

Example: In a web browser, when you enter "https://www.example.com:80," the ":80" part refers to the port number. Port 80 is commonly used for HTTP (Hypertext Transfer Protocol) traffic, which is used for web communication.

5. URL (Uniform Resource Locator) :

A URL is a web address used to identify and access resources on the internet. It typically includes the protocol (such as "http" or "https"), the domain name, and often a path to a specific resource.

Example: The URL "https://www.openai.com/blog/introducing-gpt-3-5-turbo/" points to a specific blog post on OpenAI's website.

6. E-mail Address :

An e-mail address is used to identify a recipient's mailbox within an email system. It consists of a user name and a domain name.

Example: "[email protected]" is an e-mail address where "jeevi.m" is the user name, and "example.com" is the domain.

These various types of addresses help devices and services communicate effectively within a network and across the internet, ensuring that data is correctly routed to its intended destination.

More about OSI Model Layers , DoD Model and TCP/IP Address

Certainly, let's delve into these networking concepts: the OSI model layers, the DoD model, and TCP/IP addresses.

1. OSI Model Layers :

The OSI (Open Systems Interconnection) model is a conceptual framework that standardizes networking functions and divides them into seven layers. Each layer has a specific role and interacts with adjacent layers to facilitate communication between devices in a network. The layers, from bottom to top, are:

Physical Layer : Deals with the physical medium of transmission, such as cables and connectors. It handles electrical signals and their physical characteristics.

Data Link Layer : Focuses on data framing, error detection, and MAC (Media Access Control) addressing. Ethernet switches operate at this layer.

Network Layer : Provides routing and logical addressing (IP addresses). Routers operate at this layer to forward packets between different networks.

Transport Layer : Ensures end-to-end communication, flow control, and error checking. TCP (Transmission Control Protocol) and UDP (User Datagram Protocol) operate here.

Session Layer : Manages sessions and dialog control between applications, establishing, maintaining, and terminating connections.

Presentation Layer : Deals with data translation, compression, and encryption to ensure compatibility between different systems.

Application Layer : Provides network services directly to end-users and applications, like web browsing, email, and file transfer.

2. DoD Model :

The DoD (Department of Defense) model, also known as the Internet protocol suite, is a four-layer networking model used in the early days of the ARPANET (precursor to the internet). The layers are:

Network Interface Layer : Similar to the OSI's Physical and Data Link layers, this layer handles hardware addressing and framing.

Internet Layer : Corresponds to the OSI's Network layer and focuses on routing and logical addressing (IP addresses).

Transport Layer : Equivalent to the OSI's Transport layer, this layer ensures reliable communication and data flow control.

Application Layer : This layer covers everything from session to application in the OSI model, handling user-level applications and services.

3. TCP/IP Address :

TCP/IP (Transmission Control Protocol/Internet Protocol) is the foundational suite of protocols that powers the internet. It uses IP addresses to identify devices and facilitate data exchange. IP addresses come in two main versions: IPv4 and IPv6.

IPv4 Address : An IPv4 address consists of four groups of numbers separated by periods, like "192.168.0.1." Each group represents an 8-bit segment, resulting in a total of 32 bits. IPv4 addresses were the initial standard and are still widely used, but they are becoming scarce due to the growth of devices on the internet.

IPv6 Address : With the exhaustion of IPv4 addresses, IPv6 was introduced. IPv6 addresses are 128 bits long, represented as eight groups of hexadecimal digits separated by colons, such as "2001:0db8:85a3:0000:0000:8a2e:0370:7334." IPv6 provides a significantly larger address space to accommodate the expanding number of devices connected to the internet.

TCP/IP addressing allows devices to locate and communicate with each other across networks and the internet. IP addresses, along with other TCP/IP protocols, form the backbone of modern networking.

In conclusion, this article has provided you with a comprehensive understanding of computer networks. Armed with this knowledge, you are well-equipped to explore further and delve into more specialized aspects of computer networking. Happy networking!

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