Question 5 of 7: HTTP, WWW, and URL

Question 5: HTTP, WWW, and URL (20 marks)

Question text not reproduced: the examination questions are © Engineers and Geoscientists BC. Open the official past paper (linked at the top of this page) to read the question, then follow the worked solution below.

(a) What HTTP stands for

HTTP stands for HyperText Transfer Protocol.

(b) What WWW is

The WWW (World Wide Web) is not the Internet itself but an application built on top of it: a distributed, interlinked collection of hypertext and hypermedia documents (pages, images, video) hosted on servers worldwide, connected to one another by hyperlinks, and each identified/located by a URL. It was proposed by Tim Berners-Lee at CERN around 1989–1991 as a way to let researchers share and cross-reference documents without needing to know in advance where every document physically resided.

(c) How HTTP relates to WWW

The WWW is the content and information space — hyperlinked documents identified by URLs — while HTTP is the specific application-layer protocol used to retrieve and transfer that content between a client (a browser) and a server. HTTP defines the request-response message exchange (typically carried over TCP) by which a client asks for a named resource and a server returns it. Without HTTP, or a functionally similar protocol, there would be no standard way to fetch WWW content, but the Web as an idea — hyperlinked documents named by URLs — is conceptually distinct from the protocol used to move its bytes; indeed other protocols (e.g. FTP) can also serve resources named by a URL.

(d) What a URL is

A URL (Uniform Resource Locator) is a structured, human-readable address that identifies where a specific resource lives and how to fetch it, generally of the form scheme://host[:port]/path[?query][#fragment] — for example https://www.example.com:443/docs/page.html?id=5#section2. The scheme names the access protocol (http, https, ftp, mailto…), the host names the server (usually resolved via DNS), the path locates the resource on that server, and the optional query/fragment refine or pinpoint content within it.

(e) The process of locating information in the WWW

1. The user supplies a URL — by typing it, clicking a hyperlink, or opening a bookmark.
2. The browser parses the URL into its scheme, hostname, port, path, and query components.
3. The browser resolves the hostname to an IP address via DNS.
4. The browser opens a transport connection (TCP, preceded by a TLS handshake if the scheme is https) to that IP address on the given port.
5. The browser sends an HTTP request (e.g. GET /path) naming the requested resource by its path.
6. The server processes the request and returns an HTTP response: a status line (e.g. 200 OK), headers (content type/length, caching), and the resource body (e.g. an HTML document).
7. The browser renders the returned content. If that content references further resources (images, stylesheets, scripts) or contains hyperlinks, each is itself a URL, and steps 2–7 repeat for it — this is what lets a user browse the whole "web" of interlinked documents just by following links, without needing to know or type every address directly.