Roland's blog

If you are like most people you probably have seen that 802.11g standard routers advertise bandwidths of 54Mbps, and of course that's in bits per second. So ho many MiB (1 Mega Bytes = 1024x1024 bits) per second is that?

1 Byte = 8 Bits

54 Mbps = 54/8 = 6.75 MiByes (Mega bytes per second)

So really, you are expected to transfer a maximum of 6 MB per second over a wireless link. That's quite not true either.

The bandwidth to one node 1/3 of that if you consider noise from other neighbors or maybe bad implementation of your drivers. Who knows?

So, really when you a 54 Mbps router will help you transfer about 2 MB per second to your router.

This is very frustrating especially if you are transferring a large amount of such as streaming recorded DVRMS files to your laptop, which are multiples of gigabytes in size.

On the other hand, this sort of overestimation has been around since the days of dial up. A 92kbps dialup line could at most deliver about 8KB/s download, which meant you couldn't do anything else but load one webpage at a time.

Also, your laptop hard drive can barely process more than 4 MB/s (depending on DMA this can be as high as 6MB/s) so you really can't transfer more than your drive can read or write either. So, what's the point of having a 50Mbps bandwidth DSL/Cable connection when the bottleneck is in your link? Well, the only reasonable answer I can think of, you can have more 3 people using the link to saturate that bandwidth. That's still very restrictive.

What's interesting is that media file size has increased over time and capacity to transfer those files have increased, however the speed of transferring the data in comparison has progressed much slower. So a large file in the past (which as a few MB) takes just as long of transferring a large file today (several MB or GB).