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Line speed conundrum

Old 22nd Jan 2015, 11:22
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Line speed conundrum

For about the last 3 weeks, one's line has been getting slower and slower and I'm posting this at a download of 0.32Mbps and upload of 0.52Mbps The broadband is with SKY, the line with BT. SKY have tested everything, agreed it is so slow and suggested BT tested the line. After being told that the line was 'absolutely fine' by a lovely call centre operator on the Indian sub-continent, the problem persists. BT offered to send an engineer round, but if found to be internal there'd be a £120 fee just like that….So I've tested the speed up until the entry point to one's castle and it is always the same, 0.32 down and 0.52 up. It would seem that either a) there's a restriction on the line (though there's no reason why there might) or b) there's some type of local external fault, but it's strange that one's upload speed is as before, somewhat slow, yet the download is now a constant 10% of what it once was. Any ideas ?



SHJ
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Old 22nd Jan 2015, 14:15
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DSL is pretty complex, here are some things I would do. It is not a troubleshooting guide as such but may give you some ideas.

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Test without WiFi, use an ethernet cable.

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Check that you have correct wiring of filter(s).

Why you need ADSL filters (microfilters)| Help | BT.com Help

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With everything unplugged from the phone line do an online BT line test. Anyone can do this for you. Just put the phone number into the web page. You of course cannot use your own DSL since it is unplugged:-) MAKE SURE YOU CAN PUT IT ALL BACK CORRECTLY.

https://www.bt.com/consumerFaultTrac...g.do?pageId=21

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Open the Master socket (has a horizontally split facia and the bottom half has two screws). There should (must I think) only be one on the line. Plug your router into the normal BT phone socket that you will find inside. I think it's usually on the right hand side. Do not use any extension cables or other rubbish on the line to the router:-)

This removes all premises wiring and devices from the system. Try it out. Try a different cable and filter. Ideally if you have an old modem--phone_socket cable with an RJ-11 on one and and a BT plug on the other use that, this allows you to leave out the filter. If it is an internal device causing the problem unplug progressively until you find the culprit.

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The diagnostics here may be helpful. I don't have a BT line so I can't go very far. It may just end up with a line test and a speed test but there was mention of extraction of BRAS setings.

BTW Performance Test

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Check the sync speeds etc., on the router. Post all of the line details here.
Screenshot is good.

The information looks something like this. This is from a Cisco which I happen to have a note of handy but all routers that I have seen have a similar page(s).

DSL Mode: ITU G.992.1 (G.DMT) Annex A
ITU STD NUM: 0x03 0x3
Vendor ID: 'STMI' 'TSTC'
Vendor Specific: 0x0000 0x0500
Vendor Country: 0x0F 0xB5
Chip ID: C196 (0)
DFE BOM: DFE3.0 Annex A (1)
Capacity Used: 83% 51%
Noise Margin: 11.0 dB 27.0 dB
Output Power: 18.5 dBm 12.5 dBm
Attenuation: 23.5 dB 10.5 dB


Interleave Fast Interleave Fast
Speed (kbps): 8192 0 448 0
Cells: 66780345 0 188102394 0
Reed-Solomon EC: 1797 0 0 0
CRC Errors: 28 0 0 0
Header Errors: 19 0 0 0
Total BER: 2992E-12 0E-0
Leakage Average BER: 1704E-12 0E-0
We want as much as possible but up and down, speed, noise margin, attenuation, and error rate are critical, if available.

Above by the way was a pretty good line with a very low error rate.

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Make sure no one else or no other process on your computer is using the line.
You could compare the Windows Task Manager/Networking rates with the speedtest rates.
You are using WPA2 on your wifi?
Your family is not downloading movies?
Most routers keep a list of all the computers that have been ussued DHCP addresses. Might be worth a check to see if there is unauthorised use.

###

Modern DSL (I am a wee bit out of date) monitors the line for errors over the long term and slowly adjusts the connection speed over time. It is all done at the provider end. You need to get Sky to tell you what is going on with your settings. Switching off the router at night for example can fool the system into thinking that you have a bad line and to it cranking down the speed. To fix this you need to get the provider to reset it. BRAS?

Read the plusnet guide linked below.

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Try a different router. Sadly many of the free routers now are locked to one provider. You will have to put your login and password into the the router. The login usually looks like an email address and indeed confusingly may be or may not be an actual email address, [email protected] was one form I saw recently. Something like 00192D3DB123@skydsl came in one I got from a charity shop. I think I had to do a bit of fiddling (software only) to un-Sky it.

Where do all the old routers go? The charity shops used to have loads of them but they have none at all now.

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Run the speed test and during the download test run in a command window

tracert -d 8.8.8.8

post the results. Repead for upload test.

What you want to see is much of the delay being generated in the second hop. If significant delay is being added later then there may be a problem in the providers network. This is very difficult to read if not used to network troubleshooting so don't get too excited about apparent anomalies. I have added some interpretation at the ends of the lines. < means less than.


C: \Users\fred>tracert -d 8.8.8.8

Tracing route to 8.8.8.8 over a maximum of 30 hop

1 5 ms 6 ms 2 ms 10.xxx <2ms - WiFi hop
2 20 ms 11 ms 17 ms 192.xxx <11 - DSL hop
3 15 ms 14 ms 16 ms 192.168.240.2 <14
4 14 ms 12 ms 13 ms 192.168.134.2 <12
5 13 ms 14 ms 12 ms 192.168.71.209 <12
6 14 ms 16 ms 13 ms 192.168.69.252 <13
7 18 ms 28 ms 44 ms 192.168.195.252 <18
8 19 ms 40 ms 17 ms 217.39.0.2 <17
9 * 23 ms * 192.168.2.1 <23
10 34 ms 27 ms 28 ms 217.41.219.192 <27
11 85 ms 163 ms 31 ms 109.159.249.103 <31
12 48 ms 21 ms 32 ms 109.159.255.197 <21
13 30 ms 28 ms 101 ms 194.72.31.81 <28
14 52 ms 28 ms 30 ms 109.159.253.67 <28
15 32 ms 18 ms 29 ms 216.239.47.179 <18
16 * 22 ms 23 ms 216.239.47.29 <22
17 27 ms 31 ms 26 ms 8.8.8.8 <27
###
Some links:

Broadband Terminology Guide
This is pretty good.

Internode :: Support :: FAQ :: ADSL :: ADSL Troubleshooting

samknowsbroadband has good stuff.

BTW Performance Test

###
Deary me I must be bored this afternoon.
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Old 22nd Jan 2015, 16:37
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Sky provide your broadband so Sky are responsible for sorting it out. After all, you pay them for it don't you?
They should liaise with BT Wholesale or Openreach to get it sorted. They will often tell customers to call BT and get the line tested because it saves them paying Openreach the (minimal) cost for a line test.

BT provide you with a telephone service only. If a BT line test comes back as OK that just means it can't find a fault which will affect your telephony service. There may well be something on the line causing a broadband problem however.

If you call a BT engineer out to look at the problem and he/she finds a fault on the BT line then the fault is fixed free-of-charge of course. However, if the engineer finds that the problem has been caused by your own equipment connected to the line such as extension wiring, modems, 'phones etc - or you have damaged the BT line or main socket - then the engineer will fix the problem and you would be charged £129.99 for the repair.

Go to www.youtube.com/user/btcare for some videos on how to do some basic checks at home first. Providing your line speed is fast enough of course!
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Old 22nd Jan 2015, 18:04
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a) there's a restriction on the line (though there's no reason why there might)
Could be....

(a) the usual old story of rate limiting, packet shaping, contention etc.
(b) rate-adaptive magic in the exchange gone a little haywire
(c) your router is going dodgy


b) there's some type of local external fault, but it's strange that one's upload speed is as before, somewhat slow, yet the download is now a constant 10% of what it once was. Any ideas ?
Water in ducts ?
BT monkey tugged on your wires whilst trying to fix someone elses ?


My suggestion :
- Try a different router
- Try a new filter
- Get Sky to re-test when you've done both
- Find an excuse to moan to BT Retail's Escalation Team (who give themselves the posh name of "chairman's office") ... convince them to send out a BT "engineer" under their own initiative and thus minimise the risk of you being exposed to £120.
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Old 22nd Jan 2015, 18:07
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Sky provide your broadband so Sky are responsible for sorting it out. After all, you pay them for it don't you? They should liaise with BT Wholesale or Openreach to get it sorted.
Only if he's renting the BT line via Sky.

But the very fact that he's spoken to BT Retail in India suggests he's got a BT line with a Sky service independently activated on it. In which case Sky would only liaise with BT insofar as it covers the DSL side of things. When it comes to the copper, that would be between the subscriber and BT Retail.

The unwashed masses cannot talk to BT Retail about a line if its being rented by the SP from Wholesale or Openscreech.
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Old 22nd Jan 2015, 21:47
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I have a spare (old) modem that I keep just for testing where speeds are decaying or the line is not working. Thus far, from about six tests over three years for various friends, the problem has always been with the wires between the BT exchange and the master socket.

It's a bit of a faff to set up the modem for the different accounts, and to be honest modems usually either work, or don't work. It seems to convince the BT India Helpdesk though, when I say "I've tried a different modem in the master socket".

What I have had to change a few times is the ADSL filter - and I've had new ones fresh from the placcy wrapper turn out to be dud.
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Old 22nd Jan 2015, 21:47
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The OP says that his broadband is with Sky and his line is with BT (presumably BT Consumer and not BT Business. BT Retail no longer exists).

I therefore refer the honourable gentleman to my reply.
If Sky provide the broadband then Sky are responsible for getting it fixed when it goes wrong (even if they have to ask BT Wholesale or Openreach to do so on their behalf).
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Old 23rd Jan 2015, 07:43
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BT (presumably BT Consumer and not BT Business. BT Retail no longer exists).
Well forgive me if I missed that most riveting news of bad getting even worse !

I therefore refer the honourable gentleman to my reply.
If Sky provide the broadband then Sky are responsible for getting it fixed when it goes wrong (even if they have to ask BT Wholesale or Openreach to do so on their behalf).
You of course still maintain your assumption that the fault is an ADSL fault not a copper fault ! What I said still applies 101% .... Sky cannot talk to BT Retailer/Consumer/whatever they decide to call themselves next week.
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Old 23rd Jan 2015, 18:12
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Thanks for the replies chaps! Due to non digital issues I've not had the chance to chase BT or SKY the last 2 days sadly. When I joined SKY they didn't have line rental and therefore it had to be BT, and like a good many people I've been lazily passive and not changed the line rental to SKY which became available approx 3 years ago. As has been mooted one doesn't seem to speak with the other, which is a pain in the wotsit I'm pretty sure that the fault is outside, the property is fed by a copper overhead wire which only allows for a max 2Mbps download no matter what. A neighbour is fed by fibre optic and gets 150Mbps

I'll get onto BT in the morning and take my chances that their engineer agrees with my prognosis and not a far flung desk jockey-ess.



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Old 26th Jan 2015, 14:16
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Just an update, SKY, after doing a 24hr diagnostic test decided to reset one's connection and it is now up to it's previously dizzily fast speed of 1.65Mbps down and 0.52Mbps up again. It would appear that their diagnostic system had detected instability on the line over a period (cause unknown) and it had limited the line, somehow without informing them. Hopefully that's that for the next while.


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