3Bb Modem Unreliable But Fast Vs Dlink Reliable But Slow

[caramba77]

Hi,

I've recently subscribed to the 3BB 13Mb/1Mb offer. I'm using the 3BB modem linked to a D-Link 2640BT that acts as wireless router. With this setup I got 7Mb/0.8Mb which I was happy about. However, after one day the connection got really unstable. The DSL light on the modem would still be on, but Internet froze, sometimes coming back after 30 secs or so, sometimes needing to disconnect the Wifi at the two laptops and reconnecting again. At times the DSL light would go off as well, searching for a connection.

I then setup my D-Link to act as modem and router, got the default settings from the 3BB modem transferred to the D-Link (VPI:0, VCI:33, ADSL2+, Annex M). The connection works fine and seems more reliable. However, the speed is slightly lower down to 5Mb/0.5Mb. Of course I could live with that if there's no choice, but I was wondering if there are some settings in the DLINK that could justify this speed decrease? Would a new modem/router work better?

Or any thoughts why the 3BB modem keeps dropping out while the DLINK doesn't?

Thanks!

[Dork]

There is no reason that the DLink should slow down your internet speed like that.

I think you should firstly check the ADSL statistics to see if there is a line problem. On a DLink I think they are located under something like Staus/Statistics.

The ADSL upstream/downstream sync speeds should be about 20% higher than your package speed. If they aren't, then look at the SNR margin and attenuation to see if they are out of range.

If that isn't the problem, next I would look at whether it's a wifi issue. Try again using a cable connection between your notebook and the DLink.

[caramba77]

Thanks for your reply.

I've pasted the statistics below. The upstream/downstream rates are well below my 13Mbs/1Mbs package and reflect the speedtests I did. I did already connect with LAN cable to bypass any potential wireless problems.

I'm not sure how to interpret the SNR or attenuation data...Any thoughts?

Mode: ADSL2+AnnexM

Type: Fast

Line Coding: Trellis On

Status: No Defect

Downstream / Upstream

SNR Margin (dB): 6.1 / 5.8

Attenuation (dB): 12.0 / 7.9

Output Power (dBm): 11.6 / 12.9

Attainable Rate (Kbps): 5024 / 790

Rate (Kbps): 5851 / 737

D (interleaver depth): 32 / 2

Delay (msec): 128 / 8

HEC Errors: 0 / 17954

OCD Errors: 0 / 0

LCD Errors: 0 / 0

Total ES: 0 / 3099

[Dork]

That's definitely the problem. The SNR margin is too low. It should be at least double that.

For attenuation (signal drop) the lower the better. For SNR, the higher the better. The SNR margin range depends on the line speed and distance between your modem and the ISP's DSLAM.

You should try the same thing with your 3BB modem to determine whether the problem is with the modem or the phone line. If the 3BB modem gives a similar result you need to call 3BB to send a technician to repair the phone line.

If the 3BB modem shows much better results but you still want to use the DLink then try upgrading it's firmware. Actually, you should do that anyway.

[caramba77]

Firmware on the D-Link is already updated. I checked the 3BB modem which gives me below values.

Downstream Upstream

SNR Margin : 6.1 / 5.9 db

Line Attenuation : 12.5 / 11.6 db

Data Rate : 8419 / 1080 kbps

Max Rate : 9784 / 1317 kbps

POWER : 12.9 / 10.3 dbm

Pretty much the same as with the D-Link, so I assume the line is bad. It still doesn't really explain then why the D-Link is slower but more reliable than the 3BB.

As for the phone line, I'm in an appartment building and 3BB is only responsible for the line up to the building. I assume there is no way of finding out whether the building internal phone line is bad or whether it's the 3BB line outside?

[Dork]

Firmware on the D-Link is already updated. I checked the 3BB modem which gives me below values.

Downstream Upstream

SNR Margin : 6.1 / 5.9 db

Line Attenuation : 12.5 / 11.6 db

Data Rate : 8419 / 1080 kbps

Max Rate : 9784 / 1317 kbps

POWER : 12.9 / 10.3 dbm

Pretty much the same as with the D-Link, so I assume the line is bad. It still doesn't really explain then why the D-Link is slower but more reliable than the 3BB.

As for the phone line, I'm in an appartment building and 3BB is only responsible for the line up to the building. I assume there is no way of finding out whether the building internal phone line is bad or whether it's the 3BB line outside?

I think because the line conditions are unstable, the DLink is taking that into account and syncing at a lower speed which makes it less likely to drop the sync. That's why it's more reliable.

As for getting the phone line repaired, the ISP's in Thailand don't charge for a callout even if it turns out to be a fault at the customers premises so you could start with them. They'll be very used to that and just come to wherever their termination point is, test the line at that point and either fix it or tell you it's fine. If the problem is in your building, that could be a bit of a pain in the ass to track down. The problem might even be inside your apartment. Sometimes even another extension jack that isn't being used can be the culprit. Check or isolate those yourself and test again.

If you meet the 3BB technicians that come you can offer them a tip to check your internal lines (perhaps THB500-1000). Often they'll be pretty happy with that.

[caramba77]

Thanks for all your advice! Very helpful and definitely what I needed to narrow down the problem.

I'll get in touch with 3BB and have them check their side of the line. If it's in my building I'll likely just cope with it. 5-6Mbs is well acceptable, despite the little nagging pain of knowing that I pay for 13Mbs.

Cheers

[Dork]

Thanks for all your advice! Very helpful and definitely what I needed to narrow down the problem.

I'll get in touch with 3BB and have them check their side of the line. If it's in my building I'll likely just cope with it. 5-6Mbs is well acceptable, despite the little nagging pain of knowing that I pay for 13Mbs.

Cheers

You're welcome. Hope you get it sorted out.

I understand that fixing the line in the apartment might seem to much of a hassle. The good news is that it is almost certainly simply a bad connection somewhere that can be fixed in 2 mins with a screwdriver. The bad news is that a dodgy connection invariably gets worse so sooner or later you're not going to have any connection.

Good luck! Cheers

[wpcoe]

At two locations -- Jomtien and Hua Hin -- I found the 3BB technicians to be competent and friendly. When they show up, point out the SNR numbers you have and it will indicate to them that (a) you have a clue to what you are talking about and ( where to focus their attention.

[luwahn]

Hi,

I've recently subscribed to the 3BB 13Mb/1Mb offer. I'm using the 3BB modem linked to a D-Link 2640BT that acts as wireless router. With this setup I got 7Mb/0.8Mb which I was happy about. However, after one day the connection got really unstable. The DSL light on the modem would still be on, but Internet froze, sometimes coming back after 30 secs or so, sometimes needing to disconnect the Wifi at the two laptops and reconnecting again. At times the DSL light would go off as well, searching for a connection.

I then setup my D-Link to act as modem and router, got the default settings from the 3BB modem transferred to the D-Link (VPI:0, VCI:33, ADSL2+, Annex M). The connection works fine and seems more reliable. However, the speed is slightly lower down to 5Mb/0.5Mb. Of course I could live with that if there's no choice, but I was wondering if there are some settings in the DLINK that could justify this speed decrease? Would a new modem/router work better?

Or any thoughts why the 3BB modem keeps dropping out while the DLINK doesn't?

Thanks!

Thanks for your reply.

I've pasted the statistics below. The upstream/downstream rates are well below my 13Mbs/1Mbs package and reflect the speed tests I did. I did already connect with LAN cable to bypass any potential wireless problems.

I'm not sure how to interpret the SNR or attenuation data...Any thoughts?

Mode: ADSL2+AnnexM

Type: Fast

Line Coding: Trellis On

Status: No Defect

Downstream / Upstream

SNR Margin (dB): 6.1 / 5.8

Attenuation (dB): 12.0 / 7.9

Output Power (dBm): 11.6 / 12.9

Attainable Rate (Kbps): 5024 / 790

Rate (Kbps): 5851 / 737

D (interleaver depth): 32 / 2

Delay (msec): 128 / 8

HEC Errors: 0 / 17954

OCD Errors: 0 / 0

LCD Errors: 0 / 0

Total ES: 0 / 3099

What speed test program(s) do you use?

[lomatopo]

FWIW, we had some D-Link 2640BT devices in several installs and these units had problems with TOT and True DSL lines. I spent weeks trouble-shooting the problems - D-Link released several flawed firmware releses - ultimately we replaced the units with TP-Link (TD-W8901G), and more recently ASUS (DSL-N12U), which worked fine on the same "bad" lines. The ASUS unit is particularly impressive: ease of use, set-up, UI, performance, but then it is quite new.

My favorite picture, albeit from a gruesome article where a 3BB technician was electrocuted in Pattaya, which illustrates the challenges of DSL here.

[bangkokstick]

Hello,

Can I know if you still have problems with you Dlink ADSL router and 3bb connection ? Mine seems to disconnect often because of this modem:

Dlink dsl-2750u

Can I know your MTU size in the router admin ? Mine is set to 1400 and BRU 1492.

Do you know which other options I could change/select to improve the connection ?

Cheers.

[Dork]

Hello,

Can I know if you still have problems with you Dlink ADSL router and 3bb connection ? Mine seems to disconnect often because of this modem:

Dlink dsl-2750u

Can I know your MTU size in the router admin ? Mine is set to 1400 and BRU 1492.

Do you know which other options I could change/select to improve the connection ?

Cheers.

Changing the MTU won't help with modem disconnects. Have you looked at the line statistics (SNR margin and line attenuation) to see whether they are in range? That is the most common cause of ADSL modems dropping sync.

If they are out of range you need to call 3BB to check the line. If there is a line problem it could be either between the local DSLAM and your premises, in which case they will fix it or the problem could be within your premises, in which case you have to isolate the problem yourself.

If there is no problem with the line, try another ADSL modem/router.