25..Introduction To Bandwidth

Bandwidth is the amount of data (files located on your domain that are viewed by visitors, email, ftp) that can be send/received by your web server. You can understand how important this factor is when buying a web hosting plan or leasing a web server. Generally speaking, the more bandwidth you have, the more visitors can visit your web site.

Determining how much bandwidth is needed
To determine how much bandwidth you need per month, you will need to have a look at your web site statistics. Visitors per month times avg. data transferred per month per user = Amount of Bandwidth used per month. Bandwidth is usually measured in MB or GB. It is not very important to get the exact number of visitors. An approximate number will be sufficient for calculating the monthly bandwidth usage.

Whereas the accuracy of the numbers in the first part of the calculation was a rather unimportant factor it plays a big role in the second part of the calculation.

Finding the average files transferred can be difficult if your web site is very large, since it has to be done for every single page. To find the size, add up the size of every image on the page and the size of the page of every single page on your web site. To make life a little easier for you it is recommended to use the following loading time test tool. Once you've obtained that number add 25%-33% to that number to give your web site room and allow it to grow.

Here is an example calculation:

Page 1: 15.000 visitors per mo. x 125KB of data = 1875000KB = ~1875 MB = ~1,875GB / mo.
Page 2: 15.000 visitors per mo. x 100KB of data = 1500000KB = ~1500 MB = ~1,500GB / mo.
Page 3: 10.000 visitors per mo. x 85KB of data = 850000KB = ~850 MB = ~0,850GB / mo.

Total data transferred per month: ~1,875GB + ~1,500GB + ~0,850GB = ~4,225GB. Adding 25%-33% to that amount will give us a result of 5,28GB - 5,62GB. So it would be recommended getting a plan with 5.5GB or 6GB bandwidth per month.

Please note that: 1024 Bytes = 1 KB, 1024 KB = 1 MB and 1024 MB = 1 GB

How can bandwidth be saved?
There are a number of ways to save bandwidth. A general advice is to keep all files on your web site as small as possible. (Sounds logic doesn't it?) To reduce the size of your pages you have to remove unnecessary tags from your code. WYSIWYG (What You See Is What You Get) programs like Dreamweaver have a clean HTML function.

CSS (Cascading Style Sheets) is also an effective way to save bandwidth. It is designed to reduce HTML file size by attributing values for any HTML element/command at the beginning of the document.

Once that is done you have to go to the next step, optimizing all graphics and pictures. It is important to know that graphics (vectors) have to be saved as .gif files and pictures as .jpeg files. If you don't own a picture program like Fireworks or PhotoShop then you can optimize your pictures for free at NetMechanic.com.

Your dial-up visitors will thank you for optimizing all your web pages.

Preventing bandwidth theft
Linking to images of another web site in your img src tag without permission is considered as bandwidth theft. As unethical as it may be, it is a reality many webmasters have to deal with on a daily basis.

The most effective and unfortunately also very time-consuming method of preventing bandwidth theft is scanning your web site logs. By analyzing your logs you can find out who is using your images without your permission. Once you have located the offending party, you can either contact them or replace the hotlinked file with a picture that says "Please Do NOT Hotlink Our Images", along with the URL of your web site. This way all their web site visitors will see the webmaster hotlinked your pictures.