allows you to sit at one computer and display information that resides in a web server somewhere on the Internet. The information can be in many forms, including simple text, graphics images, animation, video streams, and audio clips. Even if you’ve not heard of the term web browser, you might have heard of Internet Explorer, Netscape, Mozila Firefox which are the names of the more popular web browsers on the market today.
The browser is actually software that resides on the computer used by the end user. The browser requests a web page from a web server, and after the server responds, the web browser displays the information sent to it by a web server.
A web server consists of software that resides on the computer that is accessible to the end user via the Internet. After a browser requests a web page from a web server, the server replies by sending the contents of the web page back to the browser.
Many people refer to the actual contentthe stuff that shows up on the screen when you are using a browseras a web page. So, if you go to http://www.cisco.com, you will see a web page for Cisco Systems, the largest vendor of networking equipment. If you click other links on that web page, you’ll go to other web pages. If you do that, you will be using Cisco’s website. The term website refers to all the content in the various web pages built by that company.
The basic model revolving around web services is similar to how a new retail business works in real life. Someone has an idea about opening a store to sell something. For instance, perhaps this person wants to sell clothing for children. There’s a lot to do before opening the store, including ordering inventory, leasing and preparing the store, hiring employees, advertising, and lots of other things. Finally, the day comes, and the owner opens the store for the first time and hopes someone will show up to buy something.
Web services evolve in the same way. Someone has an idea for a website. Maybe it’s a site for this same retail children’s clothing store or for some established business, or maybe it’s just someone who has something to say. This person then builds a website that consists of multiple web pages. The website resides on a web server that is connected to the Internet. At that point, it’s like opening day at the retail storeyou hope someone shows up at the website!
The usage of the webthe combination or web servers, web browsers, and websiteshas become one of the most prolific applications in the Internet, as well as in enterprise networks. Companies, organizations, and even individuals can create their own websites on the Internet. Anyone can then ask for the content in those web pages and see the results.
Each company’s web server is inside its respective enterprise networks . Because each company has a connection to an ISP, Fred and Barney can connect to the web pages and browse the contents. To browse these web pages, Fred and Barney must each bring up the web browser software on their computers and point to the Universal Resource Locator (URL) of the website. The URL is a string of characters that uniquely identifies a particular web page. Sometimes, people refer to the URL as a web address. For instance, when Barney puts http://www.cisco.com into the right place in his browser, his browser asks for the web page of Cisco Systems.
The web browser, in conjunction with websites, represents one of the most popular network applications today. And because the main purpose of a website is to make information available to other users of the network, it relies on the existence of a network.