The Web Is Not The Internet and HTTP for Dummies
The Web Is Not The Internet
Tim Berners-Lee invented the World Wide Web (or simply the web) around 1989 when he was working at CERN which is headquartered in Geneva. The web is the dominant Internet application since mid 1990s.
Please keep in mind that the web is not the Internet. The Internet is a network of networks (an internetwork) that is connected by routers, switches, fiber cables, copper wires etc. The web came after the Internet and is an application of the Internet. The web helps people to browse and find information on the Internet. Other applications of the Internet includes Email, instant messaging, DNS etc.
What Are Hypertext And Hyperlink?
Hypertext is text that contains links to other web pages. Hypertext is ususally underlined. Hyperlink is the link that is embeded into hypertext. Through hyperlinks (or simply links), information on the web are linked to each other.
The Internet vs. The Web
The following points help you differentiate between the Internet and the web.
- The Internet is a web of networks which connects computers. The web is a web that links information on the same computer and information on other computers.
- The smallest unit on the Internet is a computer, a phone, a tablet. The smallest unit on the web is a text file, an image, a video, etc which resides on the Internet.
- The Internet is connected by routers, switches, fiber cables, copper wires etc. The web is linked by hyperlinks.
- The Internet is a physical infrastructure. The web is digital.
Web 2.0 is a participatory web where user can modify the content on the web such as user-generated content on social media, forums, discussion boards. In web1.0, the visitor can only view the content published by webmasters.
The Deep Web
Websites and webpages that can’t be indexed by search engines are known as the deep web. There’re more websites that resides on the deep web than websites that are indexed by search engines. You must be shocked by this fact. We’re just surfing on the surface on the web.
The web mainly consists of three components: web browsers, HTTP protocol and web servers. HTTP is the protocol that is used by browsers and servers to talk to each other. HTTP stands for Hyper Text Transfer Protocol.
HTTP rides above TCP
HTTP protocol uses TCP as the transport layer protocol and as you may know TCP is a connection-oriented protocol which means a connection must be established before two hosts can send data to each other. So in HTTP, the web browser aka user agent must establish a TCP connection before it can send the first request to the server. The TCP connection costs a round trip time
HTTP has been around since the beginning of the web. HTTP is the basis of the modern web. The first version we used is HTTP 0.9.
In HTTP/1.0, every request costs one connection. First the browser and the server establish a connection and then the browser send a request, then the server response. After the reponse the connection is closed. If the browser wants to send a new request, it must establish a new connection so the page load time (PLT) is adversely affected.
HTTP/1.1 enables the browser to use an existing TCP connection to send a new request (persistent connection) eliminating the need to establish a separate connection to send new requests. Page load time is improved but the browser must receieve a response to the previous request before it can send a new request. This is known as head-of-line blocking.
Then a feature called HTTP pipelining was added to HTTP/1.1. If both the browser and server support pipelining, then the browser can send multiple requests at once and wait for the server to send back multiple responses. The drawback is that the server is required to response to requests in the order they arrived. If a the first request asks for dynamic content then it takes more time for the server to process the first request and response. The server might have completed processing other requests that asks for static content. But the server have to send the response to the first request. This delays all other response. This is also a head-of-line blocking.
HTTP/2 is standardized in 2015. In HTTP/2 the browser can send multiple requests at any time on a single connection reducing lots of round trip time. The server can send responses at whatever order it likes. This is a true multiplexing.
What is a Domain Name Label
A domain name lable is any text in a domain name that is separated by dot. For example, in www.linuxbabe.com, www is a domain name lable, linuxbabe is a domain name lable, com is also a domain name lable.
A single lable domain is a domain that has no www lable or com lable. Single domain name lable is only vaild inside a local network. They can not be used on the Internet. For example, linuxbabe is single lable domain, but you can not access www.linuxbabe.com by typing linuxbabe in the browser address bar.
It’s common for web developers to set up a local website on their own computer and usually they can visit this local website by typing localhost in browser address bar. localhost is a single lable domain that is pointed to 127.0.0.1 which is the IP address of their own computer.