How does the INTERNET work? | ICT #2

How Does the Internet Work?

The Journey of Data

• The video you are watching has traveled from a Google Data Center to your device, illustrating the complex journey of data.

• While satellites could transmit signals, they introduce significant latency due to their distance (22,000 miles above Earth), making them unsuitable for most internet applications.

Optical Fiber Cables

• Instead of satellites, data is transmitted through a network of optical fiber cables connecting data centers to devices like mobile phones and laptops.

• Videos are stored in solid-state devices (SSDs) within servers at data centers, which act as powerful computers providing requested content.

Understanding IP Addresses

• Every internet-connected device has a unique identifier known as an IP address, similar to a home address that ensures information reaches its destination.

• Domain names (e.g., youtube.com) simplify access to websites by corresponding with IP addresses, making it easier for users to remember them.

DNS: The Internet's Phone Book

• A server can host multiple websites; thus, additional information called host headers is used for identification when accessing these sites.

• The Domain Name System (DNS) functions like a phone book for the internet, translating domain names into IP addresses upon request.

Data Transmission Process

• When you enter a domain name in your browser, it requests the corresponding IP address from the DNS server before forwarding it to the appropriate server.

• Data travels in digital format via optical fiber cables as light pulses over long distances and through challenging terrains.

Infrastructure and Signal Conversion

• Global companies maintain optical cable networks that lay cables undersea using specialized ships and plows creating trenches on the seabed.

• Routers convert light signals into electrical signals for transmission via Ethernet cables or cellular towers depending on how users connect to the internet.

Management of Internet Resources

• An organization called ICANN manages essential aspects of the internet such as IP address assignments and domain name registrations.

Efficiency of Data Transfer

Understanding Data Packet Transmission

Structure of Data Packets

• Each data packet consists of six bits, along with a sequence number and the IP addresses of both the server and the receiving device (e.g., your phone).

• Packets do not necessarily follow the same route; each packet independently selects the best available path to reach its destination.

Packet Reassembly and Loss Management

• Upon arrival at your phone, packets are reassembled based on their sequence numbers.

• If any packets fail to arrive, an acknowledgment is sent from your phone requesting those lost packets to be resent.

Comparison with Postal Systems

• The process is likened to a postal network where improper addressing can prevent letters from reaching their intended destinations.

Role of Protocols in Data Management