1.4 E-Commerce Infrastructure

E-commerce sits on a three-layer technology foundation:

   ┌─────────────────────────────────┐
   │   E-Commerce Applications       │  ← Amazon, Flipkart, etc.
   ├─────────────────────────────────┤
   │   World Wide Web (WWW)          │  ← HTTP, HTML, browser
   ├─────────────────────────────────┤
   │   Internet                      │  ← TCP/IP, routing, DNS
   ├─────────────────────────────────┤
   │   Physical Network              │  ← Fibre, mobile, satellite
   └─────────────────────────────────┘

1. Internet — the foundation

The Internet is a global network-of-networks connected by the TCP/IP protocol suite.

Key Internet protocols (5-layer view)

Key Internet components

Internet vs Intranet vs Extranet

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2. World Wide Web — the application layer

The WWW (Tim Berners-Lee, CERN, 1989) is a system of interlinked hypertext documents accessed over the Internet.

Web building blocks

Web architecture — request flow

Web evolution — Web 1.0, 2.0, 3.0

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3. Mobile applications — the third leg

Mobile e-commerce dominates Indian commerce by transaction volume. The mobile stack has two delivery channels:

Mobile-specific technologies

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Internet Infrastructure components for E-Commerce

A complete e-commerce site uses these infrastructure pieces:

   ┌─ Customer ───────────────────────────────────────────┐
   │ Browser / Mobile App                                 │
   └────────────────────────────────┬─────────────────────┘
                                    │ HTTPS
                                    ▼
   ┌─ CDN (Cloudflare / Akamai / CloudFront) ────────────┐
   └────────────────────────────────┬─────────────────────┘
                                    │
                                    ▼
   ┌─ Load Balancer ──────────────────────────────────────┐
   └────────────────────────────────┬─────────────────────┘
                                    │
            ┌───────────────────────┼───────────────────────┐
            ▼                       ▼                       ▼
       ┌────────┐             ┌────────┐             ┌────────┐
       │ Web    │             │ Web    │             │ Web    │
       │ Server │             │ Server │             │ Server │
       └───┬────┘             └───┬────┘             └───┬────┘
           └─────────┬──────────────┘──────────────────┘
                     ▼
            ┌──────────────────┐
            │   Application    │
            │   Servers        │
            └────────┬─────────┘
                     ▼
       ┌─────────────┼─────────────┐
       ▼             ▼             ▼
   Database      Cache         Search
   (Postgres,    (Redis,       (Elasticsearch)
    MySQL)        Memcached)

Key e-commerce infrastructure components

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Cloud Computing — the modern e-commerce platform

Most modern e-commerce runs on the cloud — outsourced infrastructure provided as a service.

Cloud service models

Cloud providers

• AWS (Amazon) — market leader, ~32% share
• Microsoft Azure — ~22% share
• Google Cloud — ~11% share
• Indian providers — Jio Cloud, Tata Cloud, Yotta

Why e-commerce loves cloud

• Elastic scale — handle Big Billion Day traffic without buying servers
• Pay-as-you-go — no upfront capex
• Global reach — deploy in any region in minutes
• Built-in services — DB, cache, queue, AI/ML as services
• Resilience — multi-AZ, multi-region failover

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Mobile Infrastructure for India

India's mobile internet is unique in scale and price:

This infrastructure made Bharat (tier-2/3/4 India) addressable for e-commerce — the entire Meesho / DealShare model relies on cheap mobile data.

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Web Technologies for E-Commerce

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Key Terms — Lesson 1.4

This lesson is heavy with networking and infrastructure vocabulary. These are the terms you must be able to define and contextualise — most appear in PYQs every cycle.

Internet — A worldwide network of interconnected networks that uses the TCP/IP protocol suite to exchange data. The Internet is decentralised (no single owner), packet-switched (data is broken into small pieces routed independently), and best-effort (no quality-of-service guarantee at the IP layer). It is the foundation on which the Web, email, mobile apps, and all of e-commerce ride.

World Wide Web (WWW or Web) — An application layer built on top of the Internet, invented by Tim Berners-Lee at CERN in 1989. The Web uses three core technologies: URLs (addressing), HTTP/HTTPS (transport), and HTML/CSS/JavaScript (content). Confusingly, "Internet" and "Web" are often used interchangeably — they are not the same. The Internet is the road network; the Web is one (very large) set of vehicles that drive on it.

TCP/IP — The protocol stack on which the Internet runs. IP (Internet Protocol) handles addressing and routing — each device gets an IP address; routers forward packets toward the destination. TCP (Transmission Control Protocol) sits on top of IP and adds reliability — guaranteed delivery, in-order packets, retransmission of lost data. Most e-commerce traffic is TCP; real-time video calling uses UDP (faster but unreliable).

HTTP (HyperText Transfer Protocol) — The application-layer protocol the Web speaks. A browser sends an HTTP request (GET /product/12345); a server sends back an HTTP response with a status code (200 OK, 404 Not Found, 500 Server Error) and a body (HTML, JSON, image). HTTP is stateless — each request stands alone; cookies and sessions are how e-commerce remembers the user across requests.

HTTPS (HTTP Secure) — HTTP wrapped inside an SSL/TLS encrypted tunnel. Anyone snooping the connection sees only ciphertext. HTTPS is mandatory for any e-commerce site today: browsers mark plain HTTP as "Not Secure", Google ranks HTTPS sites higher, and most payment gateways refuse to load on insecure pages. The familiar lock icon in the address bar indicates HTTPS.

Domain Name System (DNS) — The Internet's distributed "phone book" that converts human-readable names (flipkart.com) into machine-routable IP addresses (e.g., 52.207.13.190). A DNS lookup happens before every fresh HTTP request and typically takes 20–100 ms — which is why DNS caching (at the browser, OS, and ISP) is the single most-used performance optimisation in computing.

ISP (Internet Service Provider) — The company that connects a household or business to the Internet — Reliance Jio Fiber, Airtel Xstream, ACT, BSNL, Hathway. ISPs run the last-mile fibre or wireless, allocate IP addresses to their customers, and peer with other ISPs to exchange traffic. India has 100+ licensed ISPs but four operators (Jio, Airtel, BSNL, Vi) carry over 90% of consumer traffic.

Backbone Network — The high-capacity, long-haul core of the Internet: undersea cables crossing oceans, intercity fibre routes, large peering exchanges (NIXI in Mumbai/Delhi). In India, Reliance Jio, Tata Communications, and BSNL operate the major backbones. A packet from your phone to a server in California may traverse 4–8 backbone networks before arriving.

Intranet vs Extranet — An intranet is a private TCP/IP network used by a single organisation for internal collaboration (HR portal, internal wiki). An extranet extends an intranet to selected outside parties — suppliers, partners, large customers — using authentication and VPN. Many B2B portals (Walmart's supplier portal, Cisco's partner portal) are technically extranets.

Web Server — Software that listens for HTTP requests and returns static files (HTML, CSS, images) or proxies the request to an application server. The two dominant web servers are Nginx and Apache HTTP Server; both can also act as reverse proxies and load balancers.

Application Server — Software that runs the business logic behind a web request — looks up products in the database, computes cart totals, charges the card, writes the order. Examples: a Node.js process (Express, Next.js), a Java JVM (Spring Boot, Tomcat), a Python WSGI/ASGI app (Django, FastAPI), a .NET app, or a Ruby on Rails server.

Content Delivery Network (CDN) — A globally distributed network of edge caches (servers near users) that store and serve static content — images, JavaScript bundles, video — without round-tripping to the origin server. Akamai, Cloudflare, Amazon CloudFront, and Fastly are the major CDNs. CDNs are usually the single largest performance lever for an e-commerce site: a 100 ms latency cut typically produces a 1–2% conversion lift.

Load Balancer — A device or software that distributes incoming requests across multiple application servers, both to handle higher traffic and to provide failover when one server goes down. Common load balancers include Nginx, HAProxy, AWS Application Load Balancer (ALB), and Google Cloud Load Balancer.

Cache — A fast, usually in-memory data store that holds frequently-read data so repeat requests do not hit the slower database. Redis and Memcached are the workhorses; product catalogues, session data, and inventory counts are all common cache contents. A typical e-commerce read pattern is ~90% cache hits, ~10% database hits.

Cloud Computing — On-demand access to computing resources (servers, storage, databases, networking) over the Internet, billed by usage rather than by capex. The three core service models are IaaS (raw VMs and storage — AWS EC2, Azure VMs), PaaS (managed runtime — Heroku, AWS Elastic Beanstalk, Vercel), and SaaS (complete applications — Shopify, Salesforce, Google Workspace). Cloud is what makes Big Billion Day economics possible: you rent 10× capacity for 24 hours and release it.

Mobile Commerce (M-Commerce) — E-commerce conducted on mobile devices. India is now mobile-first: ~85% of Flipkart orders, ~95%+ of Meesho orders, and 100% of UPI transactions happen on mobile. M-commerce relies on 4G/5G connectivity, app stores (Google Play, Apple App Store) for distribution, and mobile-money rails (UPI, wallets, in-app purchase) for payment.

Wireless / 4G / 5G — Cellular technologies that deliver internet over radio rather than cable. 4G LTE brought reliable mobile broadband (~10–50 Mbps), enabling video streaming and modern e-commerce; 5G (deployed in 700+ Indian cities by 2024) offers ~10× higher throughput and ~10× lower latency, enabling new use cases (AR shopping, live commerce at scale, IoT commerce).

Latency vs Bandwidth — Two distinct performance metrics often confused. Latency is the round-trip time for a single packet (Delhi to Mumbai: ~30 ms; Delhi to California: ~250 ms). Bandwidth is throughput — bits per second. You can have high bandwidth and high latency (satellite Internet) or low bandwidth and low latency (a slow but local link). E-commerce performance is usually latency-bound, not bandwidth-bound, which is why CDNs help so much.

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Study deep

1. The TCP/IP stack is invisible but foundational. A user adding to cart on Amazon triggers ~50 HTTP requests, each involving DNS lookup, TCP handshake, TLS negotiation, HTTP request/response, and packet routing through 10–20 routers. All in <1 second.

1. HTTPS is not optional any more. Modern browsers flag plain HTTP sites as "Not Secure." Google ranks HTTPS sites higher. SSL/TLS adds ~30ms per page load but secures customer data — required for any e-commerce.

1. CDN matters more than you think. A 100ms latency increase reduces conversion by 7% (Amazon study). CDNs (Cloudflare, Akamai) cache static assets at 200+ global edges, cutting latency by 70%+ for distant users.

1. The mobile-first transition is complete in India. Almost no Indian e-commerce now designs "desktop-first" — UX, payments, performance all assume a smartphone with 4G. Flipkart was browser-first in 2007, app-first by 2015, app-only briefly in 2015, then learned and re-added browser.

1. Cloud-native architecture changes economics. Pre-cloud, scaling for Big Billion Day required buying physical servers (capex). Cloud allows ramping up 10× capacity for 24 hours and scaling back — pay only for what's used. This makes massive sales events economically possible.

PYQ pattern: "Describe the technological building blocks / infrastructure of e-commerce." — Three layers (Internet → Web → Mobile), explain TCP/IP, HTTP, HTML, mobile app technologies, common infrastructure components (CDN, load balancer, DB, cache, search).

PYQ pattern: "Differentiate Internet, Intranet and Extranet." — Three-row table (access, purpose, example).