Internet - Service Protocols

The Internet uses a number of different service protocols. We will look at the following, more commonly used, service protocols:


•   HTTP
•   FTP
•   POP/SMTP.

Service protocols deal with identifying which service is needed to display the contents of each packet.


HTTP (HyperText Transfer Protocol)


HTTP is the service protocol that allows users to receive information from the World Wide Web.


HTTP protocol identifies and downloads web page resources. Web resources typically contain the following:


•   coding (HTML tags, including anchors and hyperlinks)
•   content (text).

HTML tags


HTML stands for HyperText Markup Language. It is a set of codes and script that allows web pages to be formatted and designed. The codes are known as tags. When a document with HTML is processed by a browser, it interprets the tags and displays the document accordingly. HTML tags are scripted instructions: special pieces of text that browser software can interpret. HTML tags are contained inside “<” and “>” signs.


<HTML>

<HEAD>
<TITLE>My Home Page</TITLE>
</HEAD>

<BODY>
Welcome to my home page<BR>
Hope you enjoy my web site<BR>
</BODY>
</HTML>


Anchors


An anchor is an HTML code (tag) that allows a piece of text or a graphic on a web page to become interactive – when clicked on by the user, the anchor ‘jumps’ the display to another location – that being determined by the script (or attribute) associated with the anchor.

Anchors may take you to another place on the same web page, to another page, to another website, or even to an image file or another application (e.g. e-mail software).

Typically, anchors displayed as text appear in a different colour and are underlined; the cursor changes to a pointing hand on mouse rollover.

Links

 

 

A hyperlink is the HTML attribute of an anchor that allows for a jump to a new location. HTTP needs the information to make the jump requested. For example, the hyperlink information needed to create a jump to Yahoo would be “href = http://www.yahoo.com”


The Internet user cannot normally see the hyperlink, but if the user ‘hovers over’ the anchor, a yellow box will pop up displaying the hyperlink.


Links can also be used to launch graphics, sound and video files. For example, “IMG SRC=http://mywebpage.com/face.gif” would link to an image file which would be downloaded and displayed in the browser window.


The terms anchor and hyperlink are often used interchangeably.

Now click the link below - Start learning HTML now!  Work through each example in turn.

http://www.w3schools.com/html/default.asp

 

Download and complete Worksheet 4.

 

 

 

 



 

Intermediate II Home
Database | Using Information | Internet | NAB/Coursework| Revision
Log into Glow | School Website | Contact Us