[mjd26]

When aiming to obtain the maximum connection speed on an ADSL2+ connection there are a significant number of things to consider, many of them are not within your control but others are.
This guide focuses mainly on the things you can do / check to obtain the highest possible sync speed and then to ensure that you're getting the best possible throughput for your sync speed.

Getting Started
Almost all ISPs which offer ADSL2+ have a function known as a "Performance Profile" or a "Profile Manager" or something like that, this is a section (normally of their members area) which allows you to adjust your connection speed at the telephone exchanges.
Most ISPs have a structure of "profiles" which range from restrictive ADSL1 profiles to very high speed ADSL2+ profiles with no interleaving. If you don't know if your ISP has such a feature, or don't know how to use it, you are best served by speaking directly with them as they will in almost all cases have the ability to do it themselves if you don't, but it will make your some aspects of your experimenting a little trickier.

As a general rule, a medium profile is best for almost all connections. Only those who live very close to the telephone exchange will generally benefit from the higher, more agressive profiles without excessive loss of connection stability.

Ready for testing?
For the purpose of testing, you want to be on a profile which will probably be called something along the lines of "Resilient", if in doubt, ask your ISP if they have a profile which is ADSL1 up to 8Mbps and targets an SNR of around 15 - 16db. If they do, that's the one you want. This profile will normally lower your speeds, but give you a much bigger differentiation of speed when you eliminate a source of noise. Quite literally and absolutely, when on Resilient, more noise = less speed. So if during testing you see higher speeds, you know what you've changed / done has had an impact (this is very much instantaneous confirmation of a fix). This whole process will also work (reasonably well) for dropouts as the less noise there is on your line the less prone your connecion will be to dropping out.

You will also need a way to view what physical connection speed you have to the telephone exchange. Those ISPs which have a Profile Manager will generally also show your connection speed in the same place.
If they don't have a profile manager or don't show the speeds then all modem's will let you see the speed if you log into them. Each modem is different for viewing the connection speed, I can provide instructions in later posts for some specific models if needed.

Now that you (hopefully) know about the profile changer and the speed it shows you, note done your current starting speed before you start doing anything, this is your benchmark for how you're going. Then it's time for the real fun to begin:

Find your telephone sockets
First; Identify how many telephone sockets you have throughout the premises, whether (or not) they are in use. This really does mean EVERY SINGLE SOCKET IN THE PREMISES. Remember to include:
Alarm system sockets, foxtel (digital) sockets (or equivalent pay TV that uses your phone line), sockets in your garage / shed, sockets in the attic / basement, ALL OF THEM!

- If there are 5 or more sockets in total, you will likely need a central splitter to obtain the optimal connection at your premises, having so many sockets increases line noise and line resistance significantly and in so doing decreases potential speed greatly.

Find your telephone devices
Next; identify all of the telephone devices which are connected at your premises.
You must include:
Telephones, answering machines, cordless telephones, fax machines, dialup modems, foxtel digital, monitored alarm systems, alarm systems which are capable of being monitored (even if not actually being monitored), caller ID units.
ANYTHING which connects to the telephone line for any purpose.
- If there are 5 or more, you will almost definately need a central splitter, the load caused by them will attenuate the ADSL signal on your line so heavily as to potentially reduce your speed a lot.

Are your telephone devices filtered correctly?
Once those items above have been identified, establish whether (or not) they currently have ADSL microfilters. Any that do currently have a microfilter on them, ensure that it is correctly oriented (the end labelled "Line" towards the wall and the end labelled "phone" towards the actual telephone), some people will say / think "but they can only go in one way". This is incorrect, any ADSL filter can potentially be installed backwards and it's a surprisingly common occurance.

Is the modem sharing its telephone socket?
Identify whether (or not) your modem shares a telephone socket with another telephone device. If so, stop it unless it is completely unavoidable.
If you absolutely must share the telephone socket that the modem is connected to, then it is incredibly important that it is connected in the following way:
Get an ADSL inline filter-splitter.
Connect the side labelled "line" straight into the wall via the shortest peice of cable possible (it should come with a roughly 3" long one; use that)
Into the other end, plug your telephone device into the side labelled "phone" and plug the modem into the other side labelled "ADSL" or "Modem".

Once it has been established that the modem is connected into its own socket, or has been connected in the way as outlined above you can move on.

Telephone extension cables?
Establish whether you have any telephone extension cables on any of the telephone devices you found earlier. If any of them have extension cables, eliminate them. If it is impossible to eliminate it, then ensure that the ADSL microfilter is connected on the wall side of the extension cable.
IE.
Wall socket > tiny short cable > adsl filter > longer cable > device

It is very important that the modem does not use an extension cable. It should use the telephone cable that came in the box with the modem when first purchased.
If you can't reach that cable to the modem and the ethernet cable to the computer then you must buy a new ethernet cable, most electronics / computer shops stock them.
You can NOT have a telephone extension cable on your modem and still acheive maximum speed and stability.

Theoretically, just with these steps checked you should already be seeing some improvement. In some cases where your setup was really bad the improvement will be significant. In other cases it's only marginal. You're still not done yet though.

The isolation test
An isolation test is where you eliminate every other telephone device in your house to see if any of them are interfering. The most common causes for interference are cordless phones, but anything can do it, especially if the filter it is on has failed or wasn't working correctly from the factory (frighteningly common).
1. Unplug every telephone device (including filters) throughout your premises (except for the modem). If the modem was sharing a socket, remove the filter / splitter, double adapter (etc).
2. Take note of your (hopefully) new speed without any devices connected.
If a significant change is found, plug devices back in [/one by one/] until the problem device(s) is found. Stop using that device OR try "double filtering" it.
Double filtering is:
Wall socket into "line" of filter 1
from "phone" of filter 1 into "line" of filter 2
from "phone" of filter 2 into telephone device.
This may or may not work and you might actually have to get rid of the problematic device.

Trying different sockets
With the above all checked, it's time to try out all the other sockets around the house. If wireless, this is easy for you, if cabled it's a bit of a painful process.
The simple reason for doing this test is that not all internal phone cabling is equal, it is quite common in many premises to have poor quality joins in the roof / walls and to have quite different line characteristics from socket to socket. So:

Take the modem, with power cable and telephone cable. You don't need the ethernet cable / computer if you're wireless, but if you don't have wireless, you're going to need to have the ethernet cable as well.

Unplug every other telephone device around the premesis (as per the isolation test)
Now, work your way around the premises from socket to socket seeing what speed you get on each and every one. If there are significant differences found, note them down, whether they are up or down it's still useful.
It is always worth doing a couple of samples per socket to be certain of the results:
Eg.
Plug in and turn on > Wait until connected > check speed (note down).
turn off. Wait 1 minute > turn on > wait until connected > check speed (note down).
Repeat this process if it fluctuates heavily from time to time.
Perhaps even average the samples.

With all that done, you should now know which socket around your premises delivers the highest connection speed. The more differentiation there is between sockets, the worse your internal wiring is. If there is very little differentiation that can actually be both a good sign and a bad sign. If you're approaching your theoretical speed limits (look further down) and there's little variation, that's good. If you're WAY off your theoretical limits and there isn't much variation, that's bad. It implies that there is some seriously dodgy wiring in your roof effecting all sockets. Getting a technician in to look at it (and perhaps install that central splitter mentioned earlier) is a good idea.

[mjd26]

Now to work out what speed you should get.

What download speed should I actually get?
The speed in the performance profile section of most ISPs as well as that in most modems is in kbps or "kilobits per second"
Eg. My current speed:
20,405 kbps
To work out the speed in kilobytes per second (what your downloads are measured in), factoring in overheads etc, you should divide by (roughly) 9.
So in my case, my theoretical speed should be:
20405 / 9 = 2267.2 KBps (kilo BYTES per second)

In order to find out what speed your connection can actually download at you do not want to use an online browser based test, they have a bad habit of fluctuating and producing lower than realistic results.
It is strongly recommended you download a large file from a known high speed server. Microsoft is a good example and the FTP host of your own ISP is normally a good one.
A quick test of my download speed using a 120mb download from my ISPs FTP server showed my speed to be 2090KBps.
I would consider this an acceptable variance. It's less than a 10% margin for error.

If the download speed presented to you by your FTP client or browser (or whatever you're using to do the download test) is fluctuating significantly, that's a bad sign. What it tells you is that your line is "running errors". This probably means you've gone a little bit too hard with the connection speed. A lower speed profile may be for you. If you're on your ISPs "resillient" (or similar) profile then you could be in trouble and may actually need to lodge a line fault with your ISP.

So, if your speed on the resilient profile was (for example)
4,720kbps
I would expect a download speed of
524KBps give or take roughly 10%.
So I would accept as "right" anywhere from 470 to 570.

If your speed does not fall into that range (or close to) then there is the possibility that your line is producing errors or that something else is coming into play. If there are errors on the line your ISP should be able to log those errors over a period of time and see if they are "acceptable" or not. If it's not errors, then it could be something at your end.

Here are some non-sync-speed related causes for lower than anticipated speeds:

Eliminate wireless (just in case)
If you're currently using wireless then, I would eliminate that as a possible cause first up.
Connect via ethernet. And disable the wireless ideally within the modem itself (just in case your neighbour is using it too), but on your computer if that's too hard. This will ensure that it doesn't interfere. Re-run the download speed test as you did earlier. Note down the results.

For the purpose of torrenting, wireless is a bad idea. While the theoretical speeds of wireless are well above the sync speed of ADSL2+ (54Mbps vs 24Mbps), the increased latency and issues with multiple simultaneous connections cause it to be far less than ideal.

Using "netstat" to find out what your PC is really doing on the net
We want to check to see what on your PC is using the net at any one moment moment as if there are a number of programs using it that you (potentially) weren't aware of then they could be decreasing your effective speed. To do this; you could download any one of several programs which list active internet connections or you could use the really quite simple tool built in to windows. This is a command line (dos prompt) tool called "netstat".
To access this command:
Start > run > type in:
cmd
> ok.

You are presented with the black box with white writing (command prompt).
Type in EXACTLY:
netstat -b
Then hit return / enter.
You should be presented with a table similar to this:
[` [(C:Documents and SettingsMatt>netstat -b
Active Connections
Proto Local Address Foreign Address State PID
TCP bob:1118 localhost:1119 ESTABLISHED 3124
[FIREFOX.EXE]
TCP bob:1119 localhost:1118 ESTABLISHED 3124
[FIREFOX.EXE]
TCP bob:4672 by1msg5146408.phx.gbl:1863 ESTABLISHED 3236
[msnmsgr.exe]
TCP bob:1197 filer-1.filearena.net:ftp CLOSE_WAIT 1380
[Explorer.EXE]
TCP bob:3739 infotrain.mg.unisa.edu.au:ftp CLOSE_WAIT 1380
[Explorer.EXE]
TCP bob:4675 a202-6-138-118.deploy.akamaitechnologies.com:http CLOSE_WAIT 3236
[msnmsgr.exe]
TCP bob:4676 a202-6-138-118.deploy.akamaitechnologies.com:http CLOSE_WAIT 3236
[msnmsgr.exe]
TCP bob:1185 po-in-f147.google.com:http TIME_WAIT 0
[FIREFOX.EXE])]`]

What does all that mean!?!?
So, now that you've got the list, what does it all mean?
Any line which currently says "Established" is a current; active internet connection. Below it you will see what program is using that connection inside the [square brackets]. In my case I've got one up to my university through explorer, a couple of MSN ones, a couple of firefox sessions and other things like that.
If your list is particularly long, or contains programs you didn't expect to see in there, then you're probably going to need to kill off those programs. They may be P2P programs (like uTorrent etc.) or they could possibly be viruses, or even windows updates (etc).
Once you've cleared that list out, you should be able to get it down to nothing (or very close to). Try your speed test again at that point.

Other computers using your bandwidth?
If you still don't have success, consider other computers connected to your network.
Normally, this will just be your own computers connected in assorted places around the premises.
With wireless, these might not be your own computers. It could be your neighbours, the guys across the road, or the 2 geeks sitting in the Corona out in the street.
Each wireless modem has a way to check the current wireless connections, you will need to check yours to see if there are unexpected connections in there. If so, get someone to help you re-secure your wireless.

Hopefully with all this your connection speed is about as good as it can be. At this point you should be able to start bringing your profile back up to the higher, more agressive profiles. It is well worth doing all of the actual speed tests at each and every step because a higher sync speed does NOT always equate to a higher download speed.

Theoretical maximum connection speeds
When connecting with ADSL2+ the single biggest determinant of your connection speed to the exchange is the distance between you and the exchange. The further you are from the exchange the slower your connection speed will be.
A major Australian ISP has been kind enough to provide a graph which shows estimates of what speed you should get based on your distance to your local telephone exchange.
In my experience this graph is too optimistic at the top (between roughly 900M and 2300M) and too pessimistic beyound about 3700M, it does however still give you some idea.
The graph can be found here:
http://www.internode.on.net/media/images/i...dsl2-dist07.jpg
For those not familiar with meters as a preffered unit of measure, please make use of the google conversion utility:
http://www.google.com.au/search?hl=en&safe...nG=Search&meta=
http://www.google.com.au/search?hl=en&safe...nG=Search&meta=

If anyone has any questions, don't hesitate to ask.

Good luck.

[n3g4t1v3]

That is quite interesting. I used to have DSL when i lived with my parents, but have cable out here at the college.

But yeah... great work!

[vicky_black]

thanks
interesting topic and very usefull

[mjd26]

Quote

But yeah... great work!

Thankyou.

Quote

thanks
interesting topic and very usefull

Not a problem at all. If you come up with any questions, or have trouble with any specific parts, let me know.

[Caracul]

Thats a very clear, very thorough tutorial. Logical to the extreme, thanks!

[aussie33]

Great tutorial very helpful.

[Dusty666]

Thanks for the info. My adsl+2 is running sweet now, except the dropouts. all of a suden my net started getting dropouts before i did the above. I have two computers running through a router thats plugged into my modem and both drop out at same time. I have called my isp and they sent someone out to the exchange and my house to check the lines and came back fine?? I am running avast antivirus and it didn't find anything unusual on either computers?

[qiqi1021]

Dusty666, on Feb 2 2009, 03:01 AM, said:

Thanks for the info. My adsl+2 is running sweet now, except the dropouts. all of a suden my net started getting dropouts before i did the above. I have two computers running through a router thats plugged into my modem and both drop out at same time. I have called my isp and they sent someone out to the exchange and my house to check the lines and came back fine?? I am running avast antivirus and it didn't find anything unusual on either computers?

I used to get the exact same problem until I bought a proper ADSL2+ certified filter. ADSL1 filters are generally fine to use but they cause dropouts all the time, and especially when a call comes in. FYI your computers cannot cause dropouts, only what goes on between the phone socket and your modem matters.

[Dusty666]

qiqi1021, on Feb 2 2009, 05:13 PM, said:

I used to get the exact same problem until I bought a proper ADSL2+ certified filter. ADSL1 filters are generally fine to use but they cause dropouts all the time, and especially when a call comes in. FYI your computers cannot cause dropouts, only what goes on between the phone socket and your modem matters.

Thanks. will try that once i get into town and purchase some.