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Fix Bsnl broadband frequent disconnection problem

By Silver Moon On May 31, 2012 20 Comments

Bsnl has plenty of high speed (4 MPBS) plans as mentioned here :


http://bsnl.co.in/opencms/bsnl/BSNL/services/broadband/new_BB_postpaid.html .

These are on the NIB - II Network. Ip addresses begin with 117.

One known problem with the high speed internet is that it gets disconnected frequently. So like Yahoo Messenger or Pidgin or Skype could go offline every 5 minutes and then connect back.

How to Fix

Here are a couple of tweaks that might fix the problem.

1. Disable all modulations except G.Dmt Enabled. This will limit the download speed to around 4.8 Mbps (4984 Kbps) and the upload speed to 207 Kbps.

But can make the connection a lot more stable.

Change the settings in the admin panel (192.168.1.1) and then restart modem.

2. Choose a LAN Ip with larger number in 4th octet like 192.168.1.100 , 192.168.1.101 , instead of 192.168.1.2 , 192.168.1.3

Not sure why it would effect the stability , but it may have some effect if multiple computers are using the same connection in a LAN.

3. Check the hardware

Make sure that the adsl line is stable - Link light stays stable. SNR Margin should be high and line attenuation should be low.

SNR Margin (Signal to Noise Ratio Margin) – You have to watch out for SNR Margin (usually in 20?s) and if it is too low you may get disconnected often.
Line Attenuation – It measures loss of signal over distance and its value in 20?s means excellent.

Meaning of various values are as follows :

SNR Margin
A higher signal to noise ratio will result in less errors.
6bB. or below = Bad – experience intermittent synchronisation problems.
7dB-10dB. = Fair
11dB-20dB. = Good
20dB-28dB. = Excellent
29dB. or above = Outstanding

Attenuation Rates

Attenuation is the loss of signal over distance. Unfortunately, dB loss is not just dependent on distance. It also depends on cable type and length of the cable, including location other connection points on the cable.



20bB. and below = Outstanding
20dB-30dB. = Excellent
30dB-40dB. = Very Good
40dB-50dB. = Good
50dB-60dB. = Poor and may experience connectivity issues
60dB. and above = Bad and will experience connectivity issues

Also check the following :

Phone line has not too much noise.
Wirings are not too old and torn
Splitter should be OK

Last Updated On : 7th November 2012

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About the Author: Silver Moon

Php developer, blogger and Linux enthusiast. He can be reached at m00n.silv3r[at]gmail[dot]com
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  • bp

    disconnecting every 10 min.

    DownstreamUpstream SNR Margin:6.06.6dbLine Attenuation:1.06.2dbData Rate:242021159kbpsAttainable Rate:256201160kbpsOut Power:0.010.3dbm

  • saurabh

    i have modem TP-link TD-W8901G
    Please throw some light on how to configure these setting here

  • pratyush97

    still getting slow speeds

    • http://www.binarytides.com/ Silver Moon

      check the Datarate (downstream) towards the bottom of the page. it shows 2048 kbps which is 2mbps.

      if your broadband plan is 4mbps then your speed is capped/limited to 2mbps only. contact the sde of local bsnl telephone exchange to lift the cap and increase speed to 4mbps. once the cap is removed, the downstream data rate would show 4096 kbps or above.

      • pratyush97

        Okay thanks :)

  • Sajid

    i did chng d modulation to gmt still d same prob

  • Sajid

    same issue i am using a dna a211 i modem it keeps disconnecting after 2 to 3 minutes
    dese are my stats what shud i do
    my snr margin is 13.2 in downstream and 7 in upstream
    attentuation is 27 and 16 respectively
    plz help coz it is getting really irritating for me
    i m frm kanpur

    • http://www.binarytides.com/ Silver Moon

      the snr is lower than average. it should be around 18 for downstream or higher.
      attenuation is higher than average. should be around 22 or lesser.

      could be a cable issue between your house and the telephone exchange.

  • Manoj

    Repeated siconnections on BSNL BB in Pune. It’s going on for 7 months now, and happens every 2-3 weeks. BSNL after calls and screams fixes after 2 weeks then off it goes again. Values as below :
    Mode: ADSL_2plus
    Traffic Type: ATM
    Status: Up
    Link Power State: L0

    Downstream Upstream
    SNR Margin (0.1 dB): 378 270
    Attenuation (0.1 dB): 70 39
    Output Power (0.1 dBm): 208 70
    Attainable Rate (Kbps): 21,476 588

    Path 0 Path 1
    Downstream Upstream Downstream Upstream
    Rate (Kbps): 2,048 509 0 0

    MSGc (# of bytes in overhead channel message): 59 81 0 0
    B (# of bytes in Mux Data Frame): 64 13 0 0
    M (# of Mux Data Frames in FEC Data Frame): 1 16 0 0
    T (Mux Data Frames over sync bytes): 1 1 0 0
    R (# of check bytes in FEC Data Frame): 16 16 0 0
    S (ratio of FEC over PMD Data Frame length): 1.0 13.612 0.0 0.0
    L (# of bits in PMD Data Frame): 648 147 0 0
    D (interleaver depth): 64 4 0 0
    Delay (msec): 16.0 13.6 0.0 0.0
    INP (DMT symbol): 6.32 1.74 0.0 0.0

    Super Frames: 268,785 246,116 0 0
    Super Frame Errors: 31 902 0 0
    RS Words: 998,792 76,031 0 0
    RS Correctable Errors: 0 0 0 0
    RS Uncorrectable Errors: 0 0 0 0

    Any ideas. The link lgiht as well as DSL light go off together every 3 minutes, and return after 3 minutes. Fed up with this provider.

  • Parag

    “Disable all modulations except “G.Dmt Enabled:”.

    I am not getting this option in my Teracom modem pls

  • Pavan

    Attenuation (0.1 dB): Downstream 80 and upstream 65
    SNR Margin (0.1 dB): Downstream 131 and upstream 230
    i have frequent disconnections every 2-5 mins they last for about 10 mins unless i restart my modem (D-Link DSL-2730U). My net plan is bsnl BB Home Combo UL 750. any ways make it stable please help

    • Silver Moon

      try disabling all modulations except g.dmt

  • Pavan

    if i disable everything leaving G.Dmt does it have any negative effect and can you please explain ‘modulation’.

    • Silver Moon

      it is just a setting and specifies the modulation type.
      for more information check
      http://en.wikipedia.org/wiki/G.992.1

      g.dmt is previous version of adsl2. it has lesser speed hence is more stable.

  • D L S

    Have got a,
    Attenuation (0.1 dB): Downstream 430 and upstream 280
    SNR Margin (0.1 dB): Downstream 81 upstream 280

    The lineman in my area is really a stupid man, all he does is comes down at my home, sees if telephone is working fine and internet link is up at that particular time or not and then leaves.

    But very often as he leaves, internet disconnects. And this has been happening for over 2 months.

    I am based in Ahmedabad, Gujarat. Does anyone have any particular details about technical support of BSNL Office or something? I have tried 1500 and 1504. No proper response. They register the complaint which I can anyways do myself using “Automated Complaint Booking Service” and then the same stupid lineman comes and goes.

    Thanks, I look forward to your response.

    • Silver Moon

      check up with the broadband department of your local telephone exchange.

      • D L S

        Nothing worked, finally found out the email address for Ahmedabad SDO and emailed him, his assistant called me up and arranged an immediate visit from an engineer, he saw the Attenuation was over 430 something, he said its just because my home is around 6 kms from the exchange, he asked the local lineman to once again change the cable.

        Now lets see if it really gets sorted.

        Internet speed has greatly reduced in past 3 hours, whereas I have actually submitted application about 15 days ago to upgrade to a higher package from 1 Nov 2012.

        • CoolGuy

          Hi bro, I’m having the same problem with BSNL. How is your connection now? Any suggestion?

          • Silver Moon

            my connection became much more stable and better after changing the adsl modulation setting as shown in the post.

  • Mirza

    Thank you for this post, It really solved my disconnection problem. I was really fed up with this frequent disconnects and about to leave Bsnl and subscribe any other ISP. Now everything works fine.. Thanks again.