Sunday, March 13, 2016

What Speed Should I Be Getting On My Broadband Line ?

ISPs hand out broadband connections in bits-per-second speeds. But when you download a video or a torrent, that size is measured in Bytes-per-second. Speed vs Size. It turns out that this makes a huge difference and confuses a lot of folks. Even science majors.

A Byte is essentially made up of 8 bits. Usually we use a lowercase "b" for bits and uppercase "B" to indicate Bytes.

If you have a 8Mbps connection from your ISP (PTCL for example), they should be giving you 8000 bits-per-second (or 8Mbps). But how much speed in Bytes should you theoretically get on this line ?.

Here's the math:

8 bits = 1 Byte 
1 Byte = 1/8 bit ~ 0.125 ~ 12.5% 

So to convert 8Mbps into KBps: 

 8000 Mbps = (1/8 of 8000) = (12.5% of 8000) KBps = (0.125 x 8000) KBps = 1000 KBps 

For a 4Mbps into KBps the math would be:  

4000 Mbps = (1/8 of 4000) = (12.5% of 4000) KBps = (0,125 x 4000) KBps = 500 KBps 


(Note: This is the theoretical limit of your broadband connection. If you are getting more than this speed, you are just a lucky SOB)

But most of the time, you will not get your maximum, theoretical speed. Because bandwidth is susceptible to "line losses", just like electricity and natural gas. A leakage on a connection, a leakage in your filter, etc. But ISPs should take that into account and adjust your speed accordingly.

Hope this helps you out.