Bandwidth Learning

Bandwidth Learning:

Bandwidth is measured in bits.(bit rate)
Bits are grouped in bytes which form words and text and other information which gets transferred from one to another computer.

If your downstream bandwidth is 768Kbps, you can download at 96 KB/sec (768Kbps / 8 Bytes)
Similarly, if it is 1.54 Mbps , your download speed 197 KB/Sec

To download a 1MB file with 768Kbps it will take you (1024KB/96 KB/sec = 10.6 secs)
1MB = 1024KB

to download a 1MB file with (full T1) 1.54Mbps it will take you (1024KB/197 KB/sec = 5.19 secs)

And to download 500MB in 768Kbps it will take (1024 x 500KB / 96KB = 88.8Mins => 1.48Hrs)
And to download 500MB in 1.54Mbps it will take (1024 x 500KB /197KB = 43.3Mins)


DSL has typically offers a bandwidth of 1.54 Mbps (Mega bits)
For example:
If you have a DSL connection to the internet, you have dedicated bandwidth between your computer and your internet provider. But your internet provider may have thousands of DSL connections to their location. All of these connection aggregate at your internet provider who then has their own dedicated connection to the internet (or multiple connections) which is much larger than your single connection. They must have enough bandwidth to serve your computing needs as well as all of their other customers. So while you have a 1.54Mb connection to your internet provider, your internet provider may have a 255Mb connection to the internet so it can accommodate your needs and up to 166 other users (255/1.54).

Upstream & Downstream:
From the user's perspective, upstream network traffic flows away from the local computer toward the remote destination. Conversely, downstream traffic flows to the user's computer. Traffic on most networks flows in both upstream and downstream directions simultaneously, and often when data flows in one direction, network protocols often send control instructions (One way to generate upstream traffic is to upload files to a server or send an email message. Conversely, downloading files and receiving email generate downstream traffic. Typical Internet users create much more downstream than upstream traffic.

Examples: The Web browser sends HTTP requests upstream to the Web server, and the server replies with downstream data usually in the form of HTML pages.

Asymmetric DSL (ADSL) services provides less bandwidth in the upstream direction in order to reserve more bandwidth for downstream traffic. generally invisible to the user) in the opposite direction.

Bandwidth and Traffic:

A very simple analogy to use to understand bandwidth and traffic is to think of highways and cars. Bandwidth is the number of lanes on the highway and traffic is the number of cars on the highway. If you are the only car on a highway, you can travel very quickly. If you are stuck in the middle of rush hour, you may travel very slowly since all of the lanes are being used up.



How Much Bandwidth Is Enough?
It depends (don't you hate that answer). But in truth, it does. Since bandwidth is a significant determinant of hosting plan prices, you should take time to determine just how much is right for you. Almost all hosting plans have bandwidth requirements measured in months, so you need to estimate the amount of bandwidth that will be required by your site on a monthly basis

If you do not intend to provide file download capability from your site, the formula for calculating bandwidth is fairly straightforward:

Average Daily Visitors x Average Page Views x Average Page Size x 31 x Fudge Factor

If you intend to allow people to download files from your site, your bandwidth calculation should be:

[(Average Daily Visitors x Average Page Views x Average Page Size) +
(Average Daily File Downloads x Average File Size)] x 31 x Fudge Factor

Let us examine each item in the formula:

Average Daily Visitors - The number of people you expect to visit your site, on average, each day. Depending upon how you market your site, this number could be from 1 to 1,000,000.

Average Page Views - On average, the number of web pages you expect a person to view. If you have 50 web pages in your web site, an average person may only view 5 of those pages each time they visit.

Average Page Size - The average size of your web pages, in Kilobytes (KB). If you have already designed your site, you can calculate this directly.

Average Daily File Downloads - The number of downloads you expect to occur on your site. This is a function of the numbers of visitors and how many times a visitor downloads a file, on average, each day.

Average File Size - Average file size of files that are downloadable from your site. Similar to your web pages, if you already know which files can be downloaded, you can calculate this directly.

Fudge Factor - A number greater than 1. Using 1.5 would be safe, which assumes that your estimate is off by 50%. However, if you were very unsure, you could use 2 or 3 to ensure that your bandwidth requirements are more than met.

Usually, hosting plans offer bandwidth in terms of Gigabytes (GB) per month. This is why our formula takes daily averages and multiplies them by 31.

Summary
Most personal or small business sites will not need more than 1GB of bandwidth per month. If you have a web site that is composed of static web pages and you expect little traffic to your site on a daily basis, go with a low bandwidth plan. If you go over the amount of bandwidth allocated in your plan, your hosting company could charge you over usage fees, so if you think the traffic to your site will be significant, you may want to go through the calculations above to estimate the amount of bandwidth required in a hosting plan.