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Rajalakshmi
Rajalakshmi

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What Is and How the Internet Works

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

Internet - nuts and bolts view

  • 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 Alt Text
    • Difference between Routers & Modem Alt Text
  • The Internet: Services view

    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

          Alt Text

          Wireless Access Networks

          Alt Text

        • Institutional access network(school, company)

          Alt Text

        • 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)

        Alt Text

  • 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

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