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

Reference - Computer networking - A Top-Down Approach by Kurose Ross