A Broadband and ADSL forum. BroadbanterBanter

Welcome to BroadbanterBanter.

You are currently viewing as a guest which gives you limited access to view most discussions and other FREE features. By joining our free community you will have access to post topics, communicate privately with other members (PM), respond to polls, upload your own photos and access many other special features. Registration is fast, simple and absolutely free so please, join our community today.

Go Back   Home » BroadbanterBanter forum » Newsgroup Discussions » uk.telecom.broadband (UK broadband)
Site Map Home Register Authors List Search Today's Posts Mark Forums Read Web Partners

uk.telecom.broadband (UK broadband) (uk.telecom.broadband) Discussion of broadband services, technology and equipment as provided in the UK. Discussions of specific services based on ADSL, cable modems or other broadband technology are also on-topic. Advertising is not allowed.

ADSL speed drop, what to look for?



 
 
Thread Tools Display Modes
  #1  
Old October 30th 14, 09:39 AM posted to uk.telecom.broadband
[email protected]
external usenet poster
 
Posts: 83
Default ADSL speed drop, what to look for?

I know this is the eternal question but still I could do with some
help with what to look for.

I have two POTS lines, one has a Draytek Vigot 2820n and the other a
BT Business Hub 3 (though both are with Plusnet now). The 2820n load
balances the two connections.

For the past several years, in fact ever since ADSL was available
here, both lines have produced a connection speed of just over 4Mb/s,
it has varied a little sometimes with occasional forays to just over
5Mb/s but it's been pretty consistent in general.

However the 2820n is now running at only 3.3Mb/s and seems to be stuck
there, consistent but slower than it always used to be. The BT Hub3
is still giving over 4Mb/s. Both lines are from the same exchange
and, presumably, the route is similar though I can't be absolutely
sure of that of course.

So what should I look at to see what might be wrong? I can't really
unplug everything other than the router for a long time as that POTS
line is our main telephone line. I can disconnect things for a few
minutes, if I do that and there's something causing a problem will I
see an immediate improvement?

The ADSL filters are the 'in the master socket' ones.

The 2820n ADSL Status shows:-

Mode: G/DMT
State: SHOWTIME
Up Speed: 448000
Down Speed: 3360000
SMR Margin: 13
Loop Att: 49


Any/all ideas very welcome.

--
Chris Green

  #2  
Old October 30th 14, 10:39 AM posted to uk.telecom.broadband
Martin Brown
external usenet poster
 
Posts: 343
Default ADSL speed drop, what to look for?

On 30/10/2014 09:39, wrote:
I know this is the eternal question but still I could do with some
help with what to look for.

I have two POTS lines, one has a Draytek Vigot 2820n and the other a
BT Business Hub 3 (though both are with Plusnet now). The 2820n load
balances the two connections.

For the past several years, in fact ever since ADSL was available
here, both lines have produced a connection speed of just over 4Mb/s,
it has varied a little sometimes with occasional forays to just over
5Mb/s but it's been pretty consistent in general.

However the 2820n is now running at only 3.3Mb/s and seems to be stuck
there, consistent but slower than it always used to be. The BT Hub3
is still giving over 4Mb/s. Both lines are from the same exchange
and, presumably, the route is similar though I can't be absolutely
sure of that of course.

So what should I look at to see what might be wrong? I can't really
unplug everything other than the router for a long time as that POTS
line is our main telephone line. I can disconnect things for a few
minutes, if I do that and there's something causing a problem will I
see an immediate improvement?


If there is something major then the sync speed and SNR should change
immediately that you reconnect but the throughput will be limited by
whatever your BRAS is set to at the exchange. There is a table of how
much and how long it takes to adjust after that but upto 3 days.

http://www.kitz.co.uk/adsl/IPprofile.htm

The ADSL filters are the 'in the master socket' ones.

The 2820n ADSL Status shows:-

Mode: G/DMT
State: SHOWTIME
Up Speed: 448000
Down Speed: 3360000
SMR Margin: 13
Loop Att: 49


Any/all ideas very welcome.


First thing to look for is the advanced statistics/diagnostics page
hidden deep in the router's menus somewhere. It should tell you what
sort and how many errors it has seen since rebooting.

SNR that high tends to suggest a noisy line. I'd have expected the
downspeed to be nearer to 4M than it is so I expect you are getting
periodic line drops that are forcing the SNR up.

An ideal line should be at 6dB SNR but long ones like mine and yours
tend to settle at 9dB or 12dB if there are too many line drops.

I like routerstats lite for monitoring lines that misbehave
(dunno if it works with the 2820n)

--
Regards,
Martin Brown
  #3  
Old October 30th 14, 11:17 AM posted to uk.telecom.broadband
[email protected]
external usenet poster
 
Posts: 83
Default ADSL speed drop, what to look for?

Martin Brown wrote:
On 30/10/2014 09:39, wrote:

So what should I look at to see what might be wrong? I can't really
unplug everything other than the router for a long time as that POTS
line is our main telephone line. I can disconnect things for a few
minutes, if I do that and there's something causing a problem will I
see an immediate improvement?


If there is something major then the sync speed and SNR should change
immediately that you reconnect but the throughput will be limited by
whatever your BRAS is set to at the exchange. There is a table of how
much and how long it takes to adjust after that but upto 3 days.

http://www.kitz.co.uk/adsl/IPprofile.htm


OK, thanks, so if it's something I've done locally (I have been
pushing some wires about recently) then I'll probably see something
fairly quickly but I might not.



The ADSL filters are the 'in the master socket' ones.

The 2820n ADSL Status shows:-

Mode: G/DMT
State: SHOWTIME
Up Speed: 448000
Down Speed: 3360000
SMR Margin: 13
Loop Att: 49


Any/all ideas very welcome.


First thing to look for is the advanced statistics/diagnostics page
hidden deep in the router's menus somewhere. It should tell you what
sort and how many errors it has seen since rebooting.

Command line on the 2820n gives me (among other things):-

--------------------------- ATU-R Info (hw: annex A, f/w: annex A) -----------
Running Mode : G.DMT State : SHOWTIME
DS Actual Rate : 3360000 bps US Actual Rate : 448000 bps
DS Attainable Rate : 3456000 bps US Attainable Rate : 1100000 bps
DS Path Mode : Interleave US Path Mode : Interleave
DS Interleave Depth : 16 US Interleave Depth : 8
NE Current Attenuation : 49 dB Cur SNR Margin : 13 dB
DS actual PSD : 19. 8 dB US actual PSD : 12. 3 dB
ADSL Firmware Version : 232201_A
-------------------------------- ATU-C Info ---------------------------------
Far Current Attenuation : 27 dB Far SNR Margin : 23 dB
CO ITU Version[0] : 00005453 CO ITU Version[1] : 00005443
DSLAM CHIPSET VENDOR : TI

So it look as if something long term has happened given that the
Attainable Rate is only 3456000 bps.

There's loads of stuff available at the command line on the 2820n but
I'm not sure what else might tell me more.


SNR that high tends to suggest a noisy line. I'd have expected the
downspeed to be nearer to 4M than it is so I expect you are getting
periodic line drops that are forcing the SNR up.

An ideal line should be at 6dB SNR but long ones like mine and yours
tend to settle at 9dB or 12dB if there are too many line drops.

There is sometimes noticeable noise on the voice connection, a nasty
buzz (probably 100Hz mains pickup of some sort). The trouble is how
to report it such that something gets done.

I like routerstats lite for monitoring lines that misbehave
(dunno if it works with the 2820n)

Thanks for the reply.

--
Chris Green

  #6  
Old October 30th 14, 12:54 PM posted to uk.telecom.broadband
PlusNet Support Team
external usenet poster
 
Posts: 995
Default ADSL speed drop, what to look for?

On 30/10/2014 11:50, wrote:
Plusnet Support Team wrote:
On 30/10/2014 09:39,
wrote:
--8--snip--8--
The 2820n ADSL Status shows:-

Mode: G/DMT
State: SHOWTIME
Up Speed: 448000
Down Speed: 3360000
SMR Margin: 13
Loop Att: 49


What SNR is reported by the Home Hub. I'm guessing it's going to be lower?

Target SNR and sync rate are inversely proportional. The lower the
target SNR, the higher the attainable rate.

Target SNR will typically be increased by BT's Dynamic Line Management
systems if noise/interference is detected. If no errors are currently
reported on your line and it's performing well, then resetting it is a
fairly trivial thing for us to do.

Thanks Bob. It's actually a Business Hub but that makes no difference
really, it reports "Noise margin (Down/Up): 9.4 dB / 22.0 dB", so
significantly better.

I've just called Plusnet support and they have reset the line for me
so we'll see what happens in the next few hours when I reset the
router.


You may find yourself in the reverse of your original dilemma, if it
settles at 3db or 6db

Bear in mind that the profile at our side is likely to take time to
adjust after the sync rate has been increased so you may need to wait a
day or two for your throughput to catch up.

--
|Bob Pullen Broadband Solutions for
|Support Home & Business @
|Plusnet Plc.
www.plus.net
+--------------- twitter.com/plusnet ----------------
 




Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

vB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
BT speed: sudden drop? Terry Pinnell uk.telecom.broadband (UK broadband) 0 September 5th 13 07:54 PM
Sudden drop in speed Patrick uk.telecom.broadband (UK broadband) 5 February 3rd 08 09:08 AM
Sudden drop in ADSL speed Graham uk.telecom.broadband (UK broadband) 1 February 16th 07 11:25 AM
TalkTalk speed drop [email protected] uk.telecom.broadband (UK broadband) 4 August 30th 05 06:28 PM
Plusnet drop in speed? SRT uk.telecom.broadband (UK broadband) 17 October 18th 04 09:43 PM


All times are GMT +1. The time now is 07:16 AM.


Powered by vBulletin® Version 3.6.4
Copyright ©2000 - 2019, Jelsoft Enterprises Ltd.Content Relevant URLs by vBSEO 2.4.0
Copyright 2004-2019 BroadbanterBanter.
The comments are property of their posters.