The Internet is a global network of interconnected computers that exchange data using standardized protocols, primarily TCP/IP. As of 2024, 5.35 billion people use the Internet, representing 64% of the global population according to the International Telecommunication Union (ITU). This guide covers the Internet’s definition, infrastructure layers, key protocols, packet routing, governance bodies, and how data moves from a browser to a server and back.
What Is the Internet?
The Internet is a worldwide system of interconnected computer networks that use the TCP/IP protocol suite to communicate. It is not owned by any single organization, government, or company. The Internet is infrastructure — a collection of physical cables, routers, switches, and data centers linked by agreed-upon communication standards.
The World Wide Web (WWW) is a service that runs on top of the Internet. The Web consists of web pages and hyperlinks delivered via HTTP/HTTPS.
The Internet also carries email (SMTP), file transfers (FTP), video streaming, voice calls (VoIP), and other services. Every device on the Internet is assigned an IP address that identifies it uniquely on the network.
Internet Infrastructure Layers
Internet infrastructure is organized into 4 tiers, each depending on the one above it to reach the global network.
- Last-mile ISPs connect end users and businesses to the Internet via DSL, cable, fiber, or mobile (4G/5G). This is the connection from the local exchange or cell tower to the customer premises.
- Regional ISPs aggregate traffic from last-mile ISPs and route it toward the backbone. Regional ISPs typically operate within a country or geographic region.
- Tier-1 backbone providers — such as AT&T, Lumen (CenturyLink), NTT, and Telia — operate global fiber networks. Tier-1 providers peer with each other at no cost under settlement-free peering agreements, giving them transit-free access to the entire Internet.
- Internet Exchange Points (IXPs) are physical locations where multiple networks interconnect and exchange traffic directly, bypassing upstream providers to reduce latency and cost. Over 1,000 IXPs operate globally. The DE-CIX in Frankfurt is the world’s largest, handling over 12 Tbps peak traffic.
Key Internet Protocols
The Internet operates through a layered protocol stack where each protocol handles a specific function.
- IP (Internet Protocol) — assigns addresses and routes packets between networks. IPv4 uses 32-bit addresses; IPv6 uses 128-bit addresses.
- TCP (Transmission Control Protocol) — provides reliable, ordered, error-checked delivery of data between applications. TCP uses a 3-way handshake (SYN, SYN-ACK, ACK) before data transfer.
- DNS (Domain Name System) — translates human-readable domain names such as example.com into IP addresses such as 93.184.216.34.
- HTTP/HTTPS (HyperText Transfer Protocol / Secure) — transfers web pages and resources between browsers and servers. HTTPS encrypts traffic using TLS (Transport Layer Security).
- SMTP (Simple Mail Transfer Protocol) — routes email between mail servers. Uses port 25 (server-to-server) and port 587 (client submission).
- BGP (Border Gateway Protocol) — routes data between Autonomous Systems (AS), the large networks operated by ISPs and enterprises. BGP is the routing protocol of the Internet.
How IP Packet Routing Works
BGP (Border Gateway Protocol) is the protocol routers use to exchange routing information between Autonomous Systems (AS) across the Internet. Each ISP or large network is assigned an Autonomous System Number (ASN) by a Regional Internet Registry (RIR).
When a packet is sent, each router along the path reads the destination IP address in the packet header and forwards it to the next router based on the routing table. The Time to Live (TTL) field in the IP header decrements by 1 at each hop.
When TTL reaches 0, the packet is discarded, preventing infinite routing loops. A typical path across the Internet traverses 15 to 25 hops between source and destination.
How Data Travels from Browser to Server
A complete web request follows this sequence from browser to server and back.
- The browser sends the domain name to a DNS resolver, which returns the server’s IP address (typically within 20–120 ms).
- The browser initiates a TCP connection with the server via a 3-way handshake (SYN → SYN-ACK → ACK).
- If HTTPS, a TLS handshake follows, negotiating encryption keys (adds 1–2 round trips).
- The browser sends an HTTP GET request for the resource (e.g., GET /index.html).
- The server (or CDN edge node) processes the request and returns an HTTP response with the HTML, CSS, or other resource.
- The browser parses the HTML and issues additional requests for linked resources (images, scripts, stylesheets).
- The TCP connection is closed or kept alive for reuse (HTTP keep-alive / HTTP/2 multiplexing).
Internet Governance
No single authority controls the Internet. Governance is distributed among several international bodies with distinct responsibilities.
- ICANN (Internet Corporation for Assigned Names and Numbers) — manages the global domain name system (DNS root zone) and coordinates IP address allocation policy. Based in Los Angeles, California.
- IANA (Internet Assigned Numbers Authority) — a function of ICANN that allocates IP address blocks to the 5 Regional Internet Registries (ARIN, RIPE NCC, APNIC, LACNIC, AFRINIC). IANA also manages protocol number assignments and the DNS root zone database.
- IETF (Internet Engineering Task Force) — publishes technical standards for Internet protocols as RFCs (Requests for Comments). RFCs are public documents — RFC 791 defines IPv4, RFC 2460 defines IPv6, RFC 7540 defines HTTP/2.
- W3C (World Wide Web Consortium) — develops standards for the World Wide Web including HTML, CSS, and accessibility guidelines.
- Regional Internet Registries (RIRs) — 5 organizations manage IP address allocation within their regions: ARIN (North America), RIPE NCC (Europe/Middle East/Central Asia), APNIC (Asia-Pacific), LACNIC (Latin America/Caribbean), AFRINIC (Africa).
Submarine Cable Infrastructure
Submarine cables carry 99% of intercontinental Internet traffic. As of 2024, over 400 submarine cable systems are in service or under construction, totaling more than 1.3 million kilometers of cable on the ocean floor. Satellites (including LEO constellations like Starlink) carry less than 1% of global Internet traffic by volume, primarily serving remote areas without cable access.
Major submarine cable routes include the Atlantic (connecting North America to Europe), the Pacific (connecting North America to Asia), and the Indian Ocean (connecting Asia to the Middle East and Africa). Cable repair ships maintain fleets globally because cables are damaged by anchors, fishing trawls, and seismic activity at an average rate of approximately 100 incidents per year worldwide.
Internet vs Intranet vs Extranet
The Internet, Intranet, and Extranet use the same TCP/IP technology but differ in access scope and purpose.
| Feature | Internet | Intranet | Extranet |
|---|---|---|---|
| Access scope | Public — anyone worldwide | Private — organization employees only | Restricted — selected external partners |
| Who controls it | Distributed (ICANN, IETF, ISPs) | Organization IT department | Organization IT + partner agreements |
| Typical use | Global communication, commerce, media | Internal HR, documents, collaboration tools | Supply chain portals, partner data sharing |
| Authentication | Generally open; services require login | Corporate credentials required | VPN or certificate-based access |
| Security boundary | Public-facing, firewall-protected services | Behind corporate firewall | DMZ or VPN tunnel to partner network |
| Example | Google, Wikipedia, YouTube | Company SharePoint, internal wiki | Supplier ordering portal, insurance broker portal |
Key Takeaways
- The Internet is infrastructure using TCP/IP. The World Wide Web is one service running on top of it.
- 5.35 billion users as of 2024 represent 64% global penetration per ITU data.
- Submarine cables carry 99% of intercontinental traffic. Over 400 systems are in service globally.
- BGP routes packets between Autonomous Systems. TTL prevents infinite routing loops.
- ICANN manages domain names; IANA manages IP blocks; IETF publishes protocol RFCs.
- A browser-to-server web request involves DNS lookup, TCP handshake, TLS handshake (HTTPS), HTTP request, and HTTP response.
Who owns the Internet?
No single entity owns the Internet. Thousands of ISPs, backbone providers, and organizations cooperatively operate it under shared protocols. ICANN coordinates naming, IANA manages IP allocation, and IETF publishes technical standards.
What is the difference between the Internet and the World Wide Web?
The Internet is the global physical and logical network infrastructure. The World Wide Web is one service running on the Internet, consisting of web pages linked by HTTP/HTTPS. Email, VoIP, and FTP are other Internet services distinct from the Web.
How many people use the Internet in 2024?
5.35 billion people use the Internet as of 2024, representing 64% of the global population, according to ITU data.
What protocol routes data between networks on the Internet?
BGP (Border Gateway Protocol) routes data between Autonomous Systems across the Internet. Within a single network or AS, protocols such as OSPF or IS-IS handle internal routing.
What percentage of intercontinental Internet traffic goes through submarine cables?
Submarine cables carry 99% of intercontinental Internet traffic. Over 400 cable systems are in service worldwide as of 2024, totaling more than 1.3 million kilometers on the ocean floor.
Last Thoughts on the Internet
The Internet is a distributed system with no single owner, controlled through international cooperation across ICANN, IANA, IETF, and 5 Regional Internet Registries. It operates through 4 infrastructure tiers — last-mile ISP, regional ISP, Tier-1 backbone, and IXPs — connected globally by over 400 submarine cable systems.
TCP/IP and BGP move data as packets across autonomous systems. The World Wide Web is one of many services running on this infrastructure alongside email, VoIP, and streaming.
