Understanding Web Performance and Bandwidth          
by Brian D. Chmielewski

No one wants to wait around for a Web page that loads slowly, or fails to load completely. If your site does not respond quickly, you are likely to lose visitors to more responsive sites. Performance is key to the success of a site. There are many factors that influence performance on the World Wide Web, but due to the cooperative nature of the Internet, most of them are not in any single entity's control. You can, however, stack the deck in your favor by designing your pages carefully, and by choosing your Web presence provider wisely. Here is how to ensure that your pages have the best chance of loading quickly on a consistent basis:

The Client Side
The client side consists of the end user's computer, modem, Web browser and connection to the Internet. You can't influence the quality and speed of the user's Internet connection, but you can lower the time that it takes for your pages to load. Spend a little time thinking about your page layout, and ask these questions:

• How many simultaneous colors are you using?
Reduce the number of colors as much as possible. A 24-bit color (~65,000 simultaneous colors) image looks great, but will cause your images to be much larger than if you dither your graphics down to 8-bits of color (256 simultaneous colors) or less.


• Are you using the most efficient format for each image?
JPEG is typically good for photographs and other images, while GIF is well suited to less complex images like logos and line art. Determine which format produces the smallest file size for each image on your page. Are you using graphics where text would suffice? Consider varying the size and color of text using HTML tags instead of creating your copy with graphics.


• Do you need so many images?
People often create pages with many unnecessary images. This can result in a 'busy' look, which makes it hard to read. Just as importantly, it greatly increases the time it takes to load the page. Evaluate each image based on its contribution ('How important is this image?') vs. its cost ('How large is this image?').

The Server Side
The server side consists of the hardware, software and Internet connection of the machine serving your site. You can exercise a great deal of control over this aspect of performance-by choosing a good Web presence provider. It is important to consider many points when evaluating a Web hosting service.

• The speed of their Internet connection.
The size of the average Web page continues to increase. Large graphics and multimedia files can quickly saturate an Internet link, so it is very important that your provider have a sufficiently large pipe to the net. The minimum size connection to consider would be a T1 line (1.544 Mb/s), but this does not give your provider much room to grow. Keep in mind that it's not just your site that is being hosted, but many others as well. It is not difficult for a single 'popular' site to overwhelm the capabilities of a T1. Depending on the provider's size, a better choice would be to find one with a T3 line (44.736 Mb/s). This will ensure that they will not be running out of bandwidth at peak traffic times.


• The underlying transport of the connection.
Setting up an Internet link can be a very expensive proposition. Web presence providers often cut corners and use an inexpensive frame relay network, or other public type of network, for their 'local-loop'. This means that your data is sharing communication lines with many other users before it ever gets to the Internet. It is not unlikely to experience packet loss due to this type of connection. Make sure that your provider is connected to the net via a dedicated circuit for their local loop.


• Number of hops to the backbone.
Traffic on the Internet consists of packets being transmitted from one router to the next before eventually reaching its destination. It is not unusual for a packet to be handled by 20 or more routers before it ends up where it is destined. Each hand-off from one router to another is called a 'hop' and it has a performance cost. To reduce the number of hops choose a provider that is as close as possible to the backbone (the highest bandwidth routes that carry most of the Internet's traffic). Providers directly connected (1 hop) to the backbone typically outperform those who are connected further down stream (multiple hops). Be sure to ask exactly how many hops away from the backbone your provider is connected. You could also determine this yourself by using a 'traceroute' program.

You can read the remainder of this article at CapitalSites, an authorized dealer of RapidSite, at http://www.capitalsites.com.

First published in WebPromote's Jan. 1998, Vol. 5 newsletter.