Thread: SNR Upstream Downstream problem

I have BSNL UL750C plan and my SNR Upstream is only 6.5db and Downstream 9.5db. Because of this my download speed has dropped down to max 12kbps only. Can anybody tell me how much should be the SNR downstream for my plan. Please .......

SNR value have nothing to do with data plan. It indicates the quality of the signal.

Refer this thread: http://www.indiabroadband.net/broadb...they-mean.html (SNR Margin and Line Attenuation - What do they mean?)

(a)Setup:
http://i40.tinypic.com/xqi4hx.jpg

(b)http://i19.tinypic.com/6kqygzt.jpg
Select only GDMT/T413/Glite bitswap enabled
in your modem.

(c)D/L SNR greater than 10 db and
attenuation less than 15 to 30 db preferred.

(d)Check you connections/connectors
for rusting/oxidisation/blackening
high resistance contacts etc.

(e)How far you are from the Exchange ?

(f) for comparison. mine just now.
........................... Downstream........................Upstream
SNR Margin (dB):.......31.3 ...................... .... 15.0
Attenuation (dB): ......12.0 ......................... 29.3
Output Power (dBm): -21.9 .................................2.0
Attainable Rate (Kbps):.. 24950..................... 1815
Rate (Kbps):................. 2063................................519


(g) 256Kbps speed max D/L 32KB/sec (*conditions apply)
a 2 MB file may be downloaded in approx 1 minute to 2 minutes.

My SNR ratio for the Home 500 plan are as follows:
Downstream Upstream
SNR Margin (dB): 22.4 24.5

Notice that the upstream is always higher than the downstream! I would like to know if this is of concern and needs any correction?
Too add up, i face disconnections of broadband/iptv/telephone occasionally..

Just to add up info.. to someone out there helping me out:

When all is working fine, the DSL light on the modem keeps blinking suddenly... Sometimes., it is up on its own.
But today.., the same thing happened and the DSL was blinking forever.., On checking, i found out that the telephone line was dead!!!

This gets resolved 'automatically':
- When there is an incoming call and the telephone starts ringing all of a sudden!
- After a few minutes or hours.., the line is up all by itself...

[B]PROBLEM[B]

i face disconnections of broadband/iptv/telephone occasionally..

Mention modem/router make model always.

see post No 3 here.

upstream is always higher than the downstream!

NORMAL

thanks a lot for the reply...
bad that i forgot to include the router information...

Its the one supplied by BSNL having 4 ethernet ports, wi-fi - ITI DNA-A211-I

I have attached screenshots of the statistics/DSL settings if they may help...

btw.., the connections are properly laid as said in the post...

change mode to G.dmt from ADSL2+ as shown in your 1st pic.rate should change then to ~2048kbps downstream & 512kbps upstream.in your 2nd pic uncheck all other options except G.dmt enabled under DSL settings.save & reboot the modem.

You mean to change the downstream from 4Mbps to 2Mbps..? well.., im not sure that is advisable cuz i have iptv installed on the same broadband line... the bsnl ppl have recently changed my port for speed upgradation... im afraid that might cause some trouble?

wi-fi - ITI DNA-A211-I

Please see this web site for similar identical modem/router/WIFi.
Chennai Telephones- Changing password in DataOne Pre-configured modem

A software upgrade is recommended by Sem India.
Link if interested.

okay.., i have checked and my router has the latest firmware upgraded version already....
and the configuration in the page is for the bridge mode but my router is already configured in the pppoe mode properly....
anything else...

just do what i have said in my previous post.line rates don't depend on modem settings as much as they depend on settings on the ISP's part.if you are using IPTV then even after doing what i suggested your line rates won't decrease.

Hi folks,

It seems that SNR values are greatly affected once BSNL upgrades the line speeds .. for eg., they have recently upgraded my line speed to 10 mbps / 1 mbps (without my knowledge), and I get SNRs of 14 / 6 -- DS/US consistently, day or night, without any errors or disconnections.

Attenuation is 32/17 -- DS/US consistently

Earlier on a 2 mbps / 256 kbps line, I used to get much higher SNR values.

The officers dont seem to understand these issues...

Any expert views would be greatly appreciated

Thanks !!

I used to face similar problems earlier. I chased the BSNL team constantly and got my line/port changed. Please read: My interactions with BSNL

Hi dude,

Your experiences with BSNL truly set an example for us to follow.

It seems that a consistent SNR is a good thing, but its also preferable to have it in the recommended range.

It could be as simple as corrosion in the junction box outside our homes... and something as complicated as the exchange related issues.

The sad part is that the linemen and the customer care reps are truly ignorant, which makes forums like these the ideal place to learn stuff.

Cheers!!

Yes. The message is - keep bugging them but do not shout or get angry. Explain the problem. Keep repeating your banter till they are forced to look at your argument.

This behaviour is known as assertiveness. Being angry/shouting/abusive does not get you anywhere. They will tell you to go to hell or never even look at your problem out of spite and hurt.

@dnjkane

my line speed to 10 mbps / 1 mbps (without my knowledge)

SNRs of 14 / 6
Attenuation is 32/17 -- DS/US

1.Check your d/l u/l speed at speedtest.net say Mumbai server.

2.What is your tariff plan ? to give speed of 10Mbps?

3.Mention your modem model and make.

4.Your SNR is still not satisfactory and attn is also high.

5.Post MoD selected attn d/l u/l Snr d/l u/l line speed data.

6. Mine . just now .

Statistics -- ADSL

Mode: ADSL2
Line Coding: Trellis On
Status: No Defect
Link Power State: L0

Downstream Upstream
SNR Margin (dB): 30.3 17.7
Attenuation (dB): 8.5 19.6
Output Power (dBm): -14.4 1.4
Attainable Rate (Kbps): 13172 1371

Hi,

Thanks a lot for your interest!

Please find the details as under:


1.Check your d/l u/l speed at speedtest.net say Mumbai server.
It is 0.5 mbps and 0.33 mbps respectively


2.What is your tariff plan ? to give speed of 10Mbps?
Tariff plan is 512 kbps unlimited, however for some reason they have set my link speed as 10 mbps (for no apparent reason)


3.Mention your modem model and make.
HuaWei WA1003A -- old type II modem


4.Your SNR is still not satisfactory and attn is also high.
I agree !! --- but they are always consistent (24 hours)
I am about 2.5 km from the exchange

5.Post MoD selected attn d/l u/l Snr d/l u/l line speed data.

Modem Status

Connection Status Connected
Us Rate (Kbps) 884
Ds Rate (Kbps) 9943
US Margin 6
DS Margin 13
Modulation ADSL2Plus
LOS Errors 0
DS Line Attenuation 32
US Line Attenuation 17
Path Mode Interleaved


I hope this info. is sufficient!

BTW, I plan to visit the exchange office ASAP.

Thnx a lot!

Wish, every one responds to my post ,
like you have done.
quoting my text point by point
use [ quote ] blah blah [ /quote] without space !
Thanks.
Your set up is fine. for the selected traffic plan
Usually I get replies " it does not work " !
" tried no use " etc. ( may be true !!!!!)

6. Problem SNR values
Now to increase your SNR values, you can try this.
Uncheck Mod mode adsl2+ and keep rest. save reboot.
If only GDMT/Glite/T413 can be selected try.
Keep Bitswap enabled.
recheck SNR Attn.
feedback.

REF:Quidway WA-1003A ADSL MODEM MENU
Egret Net Web Design Louisville Kentucky Testimonials

Hi essbebe -- thanks!
I also appreciate well written stuff..

My modem doesn't have a multi-select option for "Modulation", so I can select just one.

The results are as follows:


FOR GDMT
Us Rate (Kbps) 928
Ds Rate (Kbps) 10208
US Margin 8
DS Margin 12
Modulation GDMT
LOS Errors 0
DS Line Attenuation 35
US Line Attenuation 14
Path Mode Interleaved


FOR GLITE
Us Rate (Kbps) 928
Ds Rate (Kbps) 4864
US Margin 6
DS Margin 7
Modulation GLITE
LOS Errors 0
DS Line Attenuation 32
US Line Attenuation 14
Path Mode Interleaved


FOR T1413
Us Rate (Kbps) 1024
Ds Rate (Kbps) 10208
US Margin 9
DS Margin 12
Modulation T1413
LOS Errors 0
DS Line Attenuation 34
US Line Attenuation 14
Path Mode Interleaved


FOR ADSL2
Us Rate (Kbps) 867
Ds Rate (Kbps) 9943
US Margin 6
DS Margin 13
Modulation ADSL2
LOS Errors 0
DS Line Attenuation 35
US Line Attenuation 17
Path Mode Interleaved


The speed results are consistent at 0.5 mbps and 0.33 mbps

The total SNR (US+DS) is always consistently between 19 and 20 (except for GLITE).

I had earlier called the Dataone testing guy, for his ZTE modem, the SNR (composite) was 19.5 DB. He had no logical explanation to offer.

Sorry for the long email.

Very good post.
Added Reputation point/s to you.

The SNR and SNR margin are different.
Since you say you get a stable connection,
you can choose the best.
7.
Still attempt to reduce ATTN figure pending.
Please give feedback
after line check by bsnl staff.
( check for corroded contacts/oxidisztion/ intermittent joints
RG11 connectors may be worn out )

8. confirm the telephone is not noisy.
and you get the ringer sound normally.

Have already tried isolation tests, checking for corrosion etc., loose joints, changing RJ11 connectors etc.
The line is stable with very rare asynch. occassions, but SNR is still the same.

To answer the other questions, phone line is not noisy and ringer is normal.

I will get junction box and phone line checked by the BSNL lineman.
Will post here as soon as possible.

i have a feeling its a line problem.. as your sync rates are also a bit weird compared to the standard ones.. i had this issue once and the lineman had to replace an underground cable

see this for detailed explanations.
Tutorials - ADSL > Understanding Line Loss and Measurements

@super -- yep I agree .... tomorrow I'll finally get a chance to visit the exchange and demand a line change etc.

@essbebe -- thnx for the very helpful guide.

BSNL lineman aaya aur gaya, and I wasn't there to welcome him

BTW I still get a consistent DS/US margin of 14/6 ...

Do you guys get DSL errors ? -- This is new for me, never had it before.


DSL Network Statistics

Transmit

Tx PDUs 67879
Tx Total Bytes 25426051
Tx Total Error Counts 0

Receive

Rx PDUs 63347
Rx Total Bytes 42320192
Rx Total Error Counts 22