• Table Of Contents

👋Introduction

Basic terminology

<aside> 👉 Network

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Network is the interconnection of multiple devices together in a way that allows access and information flow between them.

<aside> 👉 Gateway

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A host’s way out of the local network.

<aside> 👉 Host (Node)

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• A host/ node is simply a device which sends and receive traffic.
• In a network, every node has an address.
• Nodes that provide services over a network are known as servers, they accept connections from nodes requesting some service (client), and respond to them.

Types of networks

<aside> 👉 LAN (Local Area Network)

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• Confined to a limited geographical area
• The wireless version of a LAN is known as WLAN.
• Example: WiFi, Ethernet

<aside> 👉 WAN (Wide Area Network)

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• It's a network connecting devices within a considerably large area
• The Internet is the biggest WAN in existence

<aside> 👉 CAN (Campus Area Network)

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• aka Corporate Area Network
• Larger than a LAN but smaller than a WAN
• Example: Colleges, Universities and business campuses.

<aside> 👉 PAN (Personal Area Network)

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• It's supposed to be within the operational space of our physical presence
• Here, Personal doesn't infer to private.
• PAN consists of a lot of technologies such as Bluetooth, ZigBee, NFC, RFID etc.
• Based on IEEE 802.15

<aside> 👉 MAN (Metropolitan Area Network)

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• Typically larger than LANs but smaller than WANs
• Example: Cities and govern entities

Network architecture& design

Network Architecture& Design

Groups working towards the development of the Internet

<aside> 👉 Internet Engineering Task Force (IETF)

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• It’s an open standards organisation with no formal membership that develops and promotes a wide range of Internet standards such as the TCP/IP suite, and they produce technical documentation called RFCs (Request For Comments) that define such standards
• RFCs aren’t compulsory, but they act as a guideline for those who are implementing the said technology

<aside> 👉 Internet Society (ISOC)

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• A US non-profit organisation that promotes the open development of the Internet, to benefit the people all around the world.
• The parent organisation of IETF and all RFCs are copyrighted by ISOC

<aside> 👉 International Telecommunication Union (ITU)

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A US agency responsible for coordinating the global use and access to radio spectrum and cellular networks

<aside> 👉 Internet Governance Forum (IGF)

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A global forum for the governments, private companies, and civil societies to discuss issues related to the content layer (things accessible and available over the Internet)

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Internet Research Task Force (IRTF)

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It promotes research on the evolution of the internet by doing long-term research on topics related to internet protocols, applications, architecture, and technology

<aside> 👉 Internet Architecture Board (IAB)

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Oversees the technical and engineering development of IETF and IRTF

<aside> 👉 Internet Corporation for ­Assigned Names and Numbers (ICANN)

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Does work in the IP addresses, and DNS. IANA is its baby organisation.

<aside> 👉 Institute of Electrical and Electronics Engineers (IEEE)

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Develops international standards for modern telecommunication hardware such as WiFi, Bluetooth, Ethernet, Robotics, IoT, AI etc

Network topology

Basics

A topology defines how systems are able to communicate across a network, and helps us to understand a network from the perspective of:

• How are they physically connected
• How they communicate

<aside> 👉 Physical topology

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It is a layout of how systems are connected via cables or wireless devices.

<aside> 👉 Logical topology

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After the systems are interconnected, the devices must know the rules (protocols) for sending signals to each other, which is defined by the logical topology.

Types Of physical topology

<aside> 👉 Star topology (Centralised)

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• Each node is connected to a central node (switch/ hub)
• There's a single point of failure, if the central system goes offline, the whole communication will be dead.
• A network is centralised if many clients connect through a single router.

<aside> 👉 Mesh topology

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• It's defined by overlapping connections between nodes
• A Full Mesh topology means every node is connected to every other node in the network
• No single point of failure, but it becomes a concern when the number of devices are too large.
• This type of topology is financially expensive because of the amount of wires required
• A network is decentralised if many clients connect through many routers. And a network is distributed, if all nodes are non-hierarchically connected to one another

<aside> 👉 Hybrid topology

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Collection of multiple physical topologies.

🗣️Protocols stacks

How do protocol stacks communicate - Encapsulation& De-Encapsulation

If every protocol has its own header and payload, is effective communication even possible at all?