Router data

[Rossian]

What info can be gleaned from the details from the router?

F'rinstance at the moment the line attenuation figures on mine are: up/down 31.5/61dB (is this an indicator of likely speed of connection? can I use this in any way?)

What are FEC/CRC/HEC errors (ie a straight decode) and what use are they to me?

The Ancient Mariner

Generalised questions I know but I'm trying to build a case for an upgrade to the electric string that connects me to the exchange, so I need to have a firm idea of what I'm talking about in some detail. At the moment BT say talk to your ISP it's their problem and the ISP says it's BT's problem take your case to them. Where's a handy Kalshnikov when you need one?

[Saab Dastard]

This is a good place to start:

thinkbroadband :: The UK's largest independent Broadband / ADSL comparison & review website (http://www.thinkbroadband.com/)

Also, use Wikipedia to research those elements that your router manual doesn't explain properly (or at all).

SD

[Mike-Bracknell]

What info can be gleaned from the details from the router?

F'rinstance at the moment the line attenuation figures on mine are: up/down 31.5/61dB (is this an indicator of likely speed of connection? can I use this in any way?)

What are FEC/CRC/HEC errors (ie a straight decode) and what use are they to me?

The Ancient Mariner

Generalised questions I know but I'm trying to build a case for an upgrade to the electric string that connects me to the exchange, so I need to have a firm idea of what I'm talking about in some detail. At the moment BT say talk to your ISP it's their problem and the ISP says it's BT's problem take your case to them. Where's a handy Kalshnikov when you need one?


Probably the most useful indicator in this instance is the "noise margin". This tells you how much dB margin you have between the current 'sync'ed rate of the ADSL line, and the maximum possible on the line in your situation.

An important thing to understand is that ADSL "self trains" over the first 10 days of it's connection, in order to get the fastest, stable connection possible given the circumstances.

This URL is useful in understanding what's going on ::. Kitz - How DSLMax works .:: (http://www.kitz.co.uk/adsl/maxdsl2.htm) as it easily explains the feedback loop used over the first 10 days.

Basically, the ADSL connection gets more and more 'ambitious' in the amount of bandwidth it allocates to the line through traffic shaping, until the line falls over (or reaches the maximum sync rate). If the line falls over, the DSLAM at the exchange automatically backs off the rate a smidgen and tests it again.

This is the reason why your DSL connection will be a bit flakey (and maybe slow) over the first week of use, but will settle down.

I have seen issues though where BT's traffic shaping changes fail to occur after a speed regrade, and this results in a reliable connection, just at the same speed you used to get.

The best way to test your connection is on BT's own speed test site, as this will list your traffic shaping stats if it's hitting this limit (although if it doesn't hit it you may still have other issues with your line). BT's tester is at Test Result (http://speedtester.bt.com)

Remember, that it's the connection quality in the ENTIRE loop that is key, so whilst you might be able to get a decent connection at the master socket with all extension sockets disconnected, your home wiring may defeat the object by breaking down with age. Indeed, when I rewired my DSL from the BT junction box on the outside of my house indoors, I went from 768kbit/s to 2350kbit/s (mainly because I bought a house an utter DIY bodger had previously owned - with phone points in the bog and garage!).

Anyway, you can always test the line by unscrewing the front plate off your master socket and connecting to the test jack underneath, which should confirm whether it's the wiring in your house, or the wiring to the street.

One final thing - remember to have a microfilter on each analogue phone/fax/etc connection in the house. Also, if commencing a dialogue with BT, it's advisable to have checked/changed everything that they could slopey-shoulder onto you. e.g. router, RJ11 wiring, etc.

Hope that helps (cos apparently I know nothing about routers ;))

[Keef]

That BT tester would no doubt be useful if it worked. In my case, it asks me for my e-mail address and then tells me I got it wrong, so no test (so there!). Clearly, it knows something I don't.

[Ancient Observer]

BT test worked fine for me. I use BT for phone and broadband - maybe it knew that? I pay for 2 whatevers, and it normally delivers 1.5 to 1.8 whatevers.

[jimtherev]

You can use the test that BT engineers use when they visit, before doing any more diagnostics:

The BT line test facility can be accessed from any BT (or WorldOnline) line by dialling 17070.

Quiet Line Test

Unplug any extention phones, extention cables, answer machines or fax (anything except the phone you will use to do the test!).

Plug a normal touch tone phone directly into the BT master socket; if possible into the test socket behind the faceplate.

Dial 17070, press option 2 (quiet line test)

You should hear 'Quiet Line Test' and then silence, there should be no pops, clicks, whistles, buzzing etc. If there is noise on the line, make sure it's not your phone's connection to the socket (wiggle it about a bit) and that you are using the master socket. If you are sure it's the line making the noise then dial BT (or WorldOnline) and report the fault, they should be able to sort it out. Remember that 'mis-reporting' a fault (e.g. if it turns out to be your phone, extention cord etc.) may be charged a call-out fee by BT (/WOL).

Distance From Exchange

Dial the same line test number as the quiet line test (17070). Then press option 3 (fast test) then press option 1 (to say you are authorised, don't worry about 'not being officially authorised'). The press option 2 (ring back test). Then put the phone down.

You will get called back by the test facility within about 10 seconds, one of the bits of information given will be distance from exchange (in kilometres).

*The distance result may not be accurate, but does serve as a guide.

(and, Keef, I sometimes have the same problem with BT test site; depends on the phase of the moon, I believe.:rolleyes:)

[Rossian]

Thanks for the inputs so far. I spent ages reading your suggested links SB but there was nothing that answered my Qs. Is the s/n ratio of 61dBs down good or bad? ie what exactly are these figures telling me?
"noise margin is the most useful number.." OK - mine is up/down 12.0/13.5dBs is that good or bad? What can I do with this gen?
The problem with most of this stuff is that loads of numbers are bandied about with no accompanying explanation/assessment.
To elaborate. At the moment, for most of the day, I'm struggling to get 0.5mbs. My neighbour about 500yds closer to the exchange is getting 6.2mbs connected to the same piece of wet electric string that I am. WTF! Over?
Any further comments?
The Ancient Mariner

[green granite]

Try reading these links, they might help you understand what the stats mean:

::. Kitz - ADSL Router Line Stats .:: (http://www.kitz.co.uk/adsl/linestats.htm)

Tutorials - ADSL > Understanding Line Loss and Measurements (http://usertools.plus.net/tutorials/id/12)

[Rossian]

Thanks GG those were helpful links. It looks as if it will need a new bit of wire and what are the chances of BT doing that??? The numbers indicate that I'm right on the limit between 512k and 1 Mb which is sort of borne out by the fact that at some times of day I can get better speeds that at other times. However it still comes down to getting BT and my ISP to stop blaming each other and cooperate to improve the service. I think I just caught sight of a pink pig doing a barrel roll past the study window. Unless anyone else wants to add to this I'm content to call a halt to this thread. I've bookmarked the links so thanks again to all.

The Ancient Mariner

[Mike-Bracknell]

"noise margin is the most useful number.." OK - mine is up/down 12.0/13.5dBs is that good or bad? What can I do with this gen?


Something is wrong then, if you only get 0.5mbit/s with a 12dB noise margin. If the line could, it would trade off the higher noise margin for faster speed until it got down to 6-7dB and sit there.

However, since your neighbour gets speeds in the order of magnitude greater than yours, you should be fixable.

Firstly, would you like to PM me with your line's phone number, as i'll then run it through the checker and see whether there's anything that stands out glaringly?

Secondly, who is your ISP?

Thirdly, has BT ever offered to swap line pairs at your house?

I would strongly recommend with the big disparity in numbers here, to do the connection to the router at the master socket's test socket. (see How to test your ADSL in the Master Socket (http://www.skyuser.co.uk/forum/view-master.html) for how to do this).

Cheers,
Mike.

[Keef]

I sometimes have the same problem with BT test site; depends on the phase of the moon, I believe.:rolleyes:)


Thanks! I had a thought - perhaps it doesn't want my e-mail address at all, but rather my ADSL logon which is totally different. Yes, it did!

It didn't tell me anything I didn't know - Down 8128, up 448, Profile 7150, actual 4029.

That's a "bad evening" speed. Speedtest just got 6.97 meg down, 380k up which is about what I expect.

The router tells me the attenuation is 23dB down, 5 dB up, and the noise margin 14dB down, 25dB up.

That's in the Norfolk hideaway. I wish the Essex place were even remotely close to that.
Via the VPN it tells me it's getting 3104k down, 448k up, 6.5dB SNR and 49dB line attenuation.