What Is and How the Internet Works

#webdev #computerscience #network #discuss

Hi Devs! If you are a developer before putting our hands-on code it's better to know how the Internet works and if you are experienced you can brush up on the concepts.

Without delay let's Dive in

Different Views of Internet

The Internet: Nuts And Bolts view
- Computer Network → (Example: Connection between two computers through LAN cable)
- Internet → Network of Networks

In Packet Switches
circle → Routers
square → Switch
Router → Connects devices across multiple networks . Finds the shortest path for a packet. Network Layer
Switch → Connects various devices in a network . Data Link Layer.
Modem → Connects various devices such as PC, Desktop to the Internet. Data Link Layer.
- Difference between Routers & Switch
- Difference between Routers & Modem
The Internet: Services view
- Example for Using the Internet as a Service in applications
  - Streaming Video from Datacenter (content Provider network) to mobile network
  - Using HTTP protocol from Datacenter (content Provider network) to enterprise network
  - Skype calls between mobiles use the Internet
Internet Structure
- Network edge → Clients & Servers
  
  Clients → end-user requesting www.google.com
  
  Server → serving www.google.com page (often in data centers)
- Access network & Physical Media → wired, wireless communication links
  
  The connection between our mobile, laptop to the routers(end host to Router(ISP))
  - To connect end systems to edge router(router at the edge of our network)
    - Residential access nets
      
      Access Networks: Home Networks
      
      Wireless Access Networks
    - Institutional access network(school, company)
    - Mobile access networks(WiFi, 4G/5G)
- Network core → mesh of interconnected routers, ISP's, network of networks
  - Connection between multiple routers
  - Packet-switching ⇒ Hosts break the application layer messages into packets
    
    Network forwards packets from one router to next, across links on a path from source to destination(here algorithms are used to find the best path)
Internet Flow when we hit www.google.com in our browser

Flow from our host to google data center (Content Provider) which is in the US

Host ⇒ Router ⇒ ISP ⇒ Network of Regional ISPs ⇒ Network of global ISP's ⇒ content Provider Datacenter