Have you ever notice that your ISP (Internet Service Provider) advertise you Internet package in a very tricky way? One of the best way to manipulate you is with the use of technical term such as Bytes and bits. To be more brief its the term Kilobits per seconds (kbps).
However, if you would be browsing the Internet or downloading some files, you would notice that your browser is indicating the speed at Kilobytes per second (kB/s)
To be more clear, your ISP sells Internet service in terms of kilobits per seconds (kbps) whilst your browser indicates you kilobytes per seconds (kBp/s). The trap is the word b – bits and B – Bytes.
lets say you have applied for a 512 kbps.
Firstly, divide your speed by 8 and multiply by 1024 to convert from kilobits per second to bytes per second; i.e 512 x 1024/8 = 65,536 bytes per second
Then convert from bytes/s to kilobytes/s
65,535 bytes = 65,535/1000 kB/s = 65.5 kB/s
So, in brief Internet speed is what are advertised to you and what you pay for! On the other hand, what your browser download speed is What you should get!
512 kbps = 65.5 kB/s
1 Mbps = 122.1 kB/s
2 Mbps = 244.2 kB/s
10 Mbps = 1220.1 kB/s
700 x 1024 = 716800 kilobytes (convert from 700 megabytes to kilobytes)
65.5 kilobytes downloads in 1 sec (i.e 65.5kB = 1 s) then,
716800 kilobytes will download in 716800/65.5 = 5870.6 seconds
5870.597870598 / 60 = 97 minutes
This is called CIR – committed information rate. According to wikipedia, CIR is “Committed information rate or CIR in a Frame relay network is the average bandwidth for a virtual circuit guaranteed by an ISP to work under normal conditions.”
Another issue is something called PEO (Protocol Encapsulation Overhead). When you’re buying, say an ADSL link of 2 Mbps, your line is syncing with your ISP at 2 Mbps over ATM or any other backbone technology. (PPOA. PPOE). Now, the catch is that the Point to Point Protocol over ATM (PPOA), needs to be encapsulated over the ATM media. There is an overhead to do so, meaning you are not effectively getting 2 Mbps Internet Protocol connectivity.