Another broadband slow down!

ryanjkeen · ‎24-02-2012

Hi Everyone,

Another broadband slow down!,

Att - MOD - Mark or John - this is just like the last problem you both got involved with.. and the fix was to migrate to fibre... this time although fibre is in the area its not available to business yet!

2 weeks ago the customer started to notice a lag when browsing, I went in and had a look and couldn’t believe how bad the browsing speed was, most sites where timing out, ping tests were 25% losses; we took unplugged the router (BT 2701)gave it 30mins, and plugged in my laptop in only, we tested and tested and got the same results.

I didnt have a spare router to hand so I reset the router to defaults, swapped the filter, plugged it in to the test socket and left it.

Thursday ran a speed test on the Bt web site (when it finally loaded) and got silly 300kbs results on 8185 kbs line

So I made the call to Broadband Support he found the results of the speed test an said mmm let me run a line check, I pointed out that the noise margin drops from 4ish to 2.7 ish after a while and sits there - this was ignored and I was told to hang on while he ran a line check..

a line check came back with no faults and was told a call would be made to me on monday to confirm the problem was still present... since when does the router need 72 hours plugged in to the test socket to give a new result??

I suggested an SNR reset and was told the computer had advised that an SNR reset was not needed and to leave it till monday when I would get a call..

Modem Type:	Built in modem - ADSL
DSL Line (Wire Pair):	Line 1 (inner pair)
Current DSL Connection:

Rate:	8361 kbs	984 kbs
Max Rate:	8185 kbs	1229 kbs
Noise Margin:	2.6 dB	5.0 dB
Attenuation:	47.5 dB	25.0 dB
Output Power:	20.5 dBm	12.2 dBm

Protocol:	G.DMT2+ Annex A
Channel:	Fast
DSLAM Vendor Information	Country: {46336} Vendor: {TSTC} Specific: {4101
ATM PVC:	0/38

Rate Cap:	8185 kbs
Attenuation @ 300kHz:	47.5 dB
Uncanceled Echo:	-19.6 dB	Ok
VCXO Frequency Offset:	15.4 ppm	Ok
Final Receive Gain:	23.1 dB	Ok
Impulse Noise Comp. Tones:	0	Ok
Excessive Impulse Noise:	0	Ok

nayan007 · ‎24-02-2012

Did you raise any support ticket for this,if yes then please post it here,so that it will be easy for the admins to check your work progress with the ticket number and will revert you back

spank · ‎27-02-2012

2.6db on the dowstream? way too low.

Should be 6db for stability unless you are about 500m from the exchange then fair enough, but considering your speed it's more.

SNR reset might set it to 6db but there may be a fault on the line and doing an SNR without a boost engineer is, in my opinion, pointless.

I have seen many 3db issues recently but wholesale seem to think this is acceptable....6db seems more stable in my experience.

I would be pushing for a boost engineer.

MHC · ‎27-02-2012

@spank wrote:
2.6db on the dowstream? way too low.

Should be 6db for stability unless you are about 500m from the exchange then fair enough, but considering your speed it's more.

SNR reset might set it to 6db but there may be a fault on the line and doing an SNR without a boost engineer is, in my opinion, pointless.

I have seen many 3db issues recently but wholesale seem to think this is acceptable....6db seems more stable in my experience.

I would be pushing for a boost engineer.

I have to disagree with you there.

I had a 45dB+ line and it would sync at 3dB and remain there for weeks. During that time it would fluctuate and overnight drop down significantly often staying at 0.5dB for hours before climbing back up. I also saw my line working at 0dB and even negative for a short while.

If for some reason I had a resync back to 6dB, initiating a resync a few days later wpould immediately drop it to 3dB.

I will agree that 6dB offers greater stability but in my experience 3dB works fine with the 2700's modem.

spank · ‎27-02-2012

It only really affects longer lines MHC. It doesn't affect everyone with 3db, there's more to it than just the db levels obviously but anyone with intermittent sporadic throughput that has not been able to get to the bottom of it with 3db, it's usually that.

MHC · ‎27-02-2012

I have a 2700 installed for a friend and his line is very long with attenuation (from memory) of over 68dB. The line runs quite happly at 3dB.

Mine, which was similar to the OPs was of the same order of attenuation.

spank · ‎27-02-2012

Maybe the OP could run some ping tests and check the times to make sure it's not something internal, not seeing anything there about eliminating the network.

Call BT and get a line test done to check for errors as well.

If there are no errors then ask for an SNR reset, see if the margin changes to 6db and report back as I would be interested to know the outcome.

I know where your coming from mhc, it doesn't affect everyone with 3db but I know of many users with exactly the same types of issue and it's turned out to be something to do with the 3db. Whether it's the margin itself or something else entirely, and just affecting people with 3db, I don't know but I wouldn't dismiss it just yet.