For those less experienced I dare say that­:

internet line can be compared to a sort of pipe and connection speed is the water passing from that pipe.

For this reason:

1. our provider doesn’t supply us with water but he just provides us with a pipe and we just pay for our pipe real capacities (the real amount of water that can pass through it);
2. the source of our water is not our ISP but it comes from another tab (the server we are connected to).

That is to say that all online programs measuring our line speed usually send us a file showing the download program speed (in practice they deliver into our tab a certain amount of water so that we can estimate the real quantity passing through our tab at the same time).

The first real trouble to run reliable tests is the following:

• Is the speed showed by servers during these tests lie or truth? And is it the same one as for any pc? In other words, are the figures real ones?
• If so, does this speed correspond to my computer one?

So you must check if the visualized download speed is not an invention.

To verify our speed we can install a program testing our band and it will show us the data entry speed that should correspond to the one visualized in any test site. I found a free and nice one, Netmeter. You can install and start it during your ADSL speed test so that you can do a comparison of all figures (the ones showed to you and also your pc ones). Then you will be showed a window like this one:

Make a supposition of your ADSL speed from different test results

It might even sound like a silly doubt, but it is not. In case my ADSL speed test server supplies my tab with a quantity of water smaller than its capacity, its speed will be a correct one but it will never correspond to my line real speed.

Here you have different download speeds reported during speed test programs I personally ran using these devices:

• CPU dual core – WinXP Pro Notebook
• Router Wifi Zyxel 660 HW
• Wlan Connection 802.11 b/g (up to 54 Mbps)

Even if they are very variable, I had confirmation during all tests by my Net Meter that these data are reliable ones. So, how to know my real connection speed?

If thinking about the comparison of water and tab, with reliable figures, my ADSL speed nearest result certainly is the highest one (4.492 by zdnet.com.au). All the others had lower results for the following reasons:

• They sent less data than my line could really support (less water than my tab capacities);
• Maybe the net was engaged (a water waste during the flowing and so its incoming quantity is less than my tab capacities).

The main difference between Wifi and Ethernet cable connections

Of course, we are not dealing with the same 10Mbps I am paying money for, but I feel lucky in comparison to other people facing some sort of never ending stories. Anyway, I didn’t want to be content with that, so I had the care of repeating all tests again, this time connecting my notebook to the router by an Ethernet cable and not a Wifi connection.

Then a doubt arose, as I already knew that Ethernet cables guarantee a better performance on the same line in comparison to wlan 802.11 b/g, but I didn’t know how much.

Give a glance to all the same line and same conditions results, using an Ethernet cable to the router.

Connecting by a cable the notebook to the router, I obtained that my ADSL ran at an incredible higher speed! Then I had the possibility to confirm that all these tests are reliable even when new cable measurements show homogeneous and substantial differences among all ADSL speed tests in comparison to wireless ones.

I even had a strong waste of time trying to improve my wifi connection. I did so working on my router settings, but I didn’t get to any consistent improvement. Then, as for wireless connection, I was already in a sort of pole position.

Anyway, in this occasion too, I had the chance of making new discoveries, that sooner I’ll have the pleasure to share with you all.

Many are DSL operators inefficiencies, and sometimes you just need a little bit more knowledge to avoid any useless stress. Here you can get some further information in order to verify whether your ADSL is really a slow one or you just made a possible wrong estimation.

Photo Credit: cerae

Differences between asynchronous (ADSL) and synchronous (SDSL) DSL

Asymmetric Digital Subscriber Line is a wide band line with an upload speed lower than its download one. For private and not business use ADSL is the most common one as there is no need to send too many data, for there are many more incoming data than outgoing ones. On the contrary symmetric DSL (SDSL) guarantees you the same speed, for both kind of data.

Megabit and Megabyte: how to understand lines real speed

For a 4 Mbps (Megabit per second) line people think of a 4 Mb/sec (Megabyte per second) download speed. Be careful: one byte corresponds to 8 bits; one kilobyte corresponds to 1024 bytes; one megabyte corresponds to 1024 kilobytes. Such a high quantity of speed measures variables usually generates a sort of confusion, created on purpose by the commercial system.

Here you have a list of an hypothetical 4Mbps line, which is translated in bit, bytes and megabytes:

• A Mbps line downloads no more than:

• • 4 Megabit per second
  • 500 Kbyte per second
  • 0,5 MegaByte per second

So, a 100 Mb file, with a 4 Mbps line, should need 200 seconds time download, with a browser indicating a 500kb/sec download speed.

The minimum guaranteed band

Therefore, all operators guarantee a really minimum speed much lower than the one in force in all commercial networks. For a more detailed idea of ADSL lines performances, you must calculate as done before, considering the minimum guaranteed band and not the commercialized speed.

Anyway, take care: the minimum guaranteed band is often indicated in kilobit! But your PC can show a kilobyte speed where 1 kilobyte corresponds to 8 kilobit. Is that clear? You should divide the minimum guaranteed band for 8 and the result will be the value that should be then shown in your PC during the download (in case it shows it in kilobytes).

Let’s take a 10Mb file, that must be downloaded on a PC, and let’s give a glance to the maximum download speed supposed to be as the guaranteed band varies:

• 128 Kilobit/sec.-> 11 minutes download at the maximum, with a transfer speed of 16 Kilobyte/sec.
• 256 Kilobit/sec.-> 5,5 minutes download at the maximum, with a transfer speed of 32 Kilobyte/sec.
• 512 Kilobit/sec.-> 2,5 minutes download at the maximum, with a transfer speed of 64 Kilobyte/sec.

How to calculate your real ADSL download speed

1. Connect here and check your line download speed
2. Mark Kbps (kilobit per second) speed
3. Check which is the minimum speed guaranteed specified in your subscription and, first of all, if it is in Kilobit (it should be so)
4. Connect here, insert your value in the text box and then the speed is converted in other measurements standards (Kilobyte, Megabyte, etc).

In conclusion: too many people are still confused by kilobit and kilobytes, as there is no clearness on the subject.

I hope I didn’t do any serious mistake…if so…please tell me !!!