Download speed reduction

[sammy7]

I have a 2048 Kbps ADSL line and the maximum download speed on that line has ALWAYS been 220 KB/s.

However, on 15 November 2014 my Telkom line was completely dead for a few hours, and since then my maximum download speed has dropped from 220 KB/s to around 190 KB/s.

I contacted Telkom support via 10210 and email, but that was a complete waste of time. They said something about a switch-over to another system.

I have no way of knowing what the cause is, and I have very limited knowledge in this regard, but if I had to guess, I would say the problem stems from one of two possible causes:

(1) My line SNR Margin used to be between 25 and 30 dB (very good) but now it fluctuates between 10 and 15 dB, which is not good. As I understand it, for a stable ADSL2+ connection a router will always target and maintain minimum 12 dB, and it will drop the line speed until it can sustain a 12 dB SNR-M.

(2) The area line upgrade or switch-over to higher possible ADSL/VDSL speeds decreased the SNR Margin and thus decreases the router download speed for lower tier ADSL accounts (like 2 Mbit accounts).

My router still syncs at 2048 Kbps downstream.

I've done all the usual stuff like leave the router off for an hour, but to no avail.

I am clueless. Anyone else experience this problem or have some ideas perhaps?

Thanks a lot.

 

[Chevron]

I have a 2048 Kbps ADSL line and the maximum download speed on that line has ALWAYS been 220 KB/s.

However, on 15 November 2014 my Telkom line was completely dead for a few hours, and since then my maximum download speed has dropped from 220 KB/s to around 190 KB/s.

I contacted Telkom support via 10210 and email, but that was a complete waste of time. They said something about a switch-over to another system.

I have no way of knowing what the cause is, and I have very limited knowledge in this regard, but if I had to guess, I would say the problem stems from one of two possible causes:

(1) My line SNR Margin used to be between 25 and 30 dB (very good) but now it fluctuates between 10 and 15 dB, which is not good. As I understand it, for a stable ADSL2+ connection a router will always target and maintain minimum 12 dB, and it will drop the line speed until it can sustain a 12 dB SNR-M.

(2) The area line upgrade or switch-over to higher possible ADSL/VDSL speeds decreased the SNR Margin and thus decreases the router download speed for lower tier ADSL accounts (like 2 Mbit accounts).

My router still syncs at 2048 Kbps downstream.

I've done all the usual stuff like leave the router off for an hour, but to no avail.

I am clueless. Anyone else experience this problem or have some ideas perhaps?

Thanks a lot.

Have you tried using another ISP?

Could just be shaping or slow server you're downloading from.

 

[Sinbad]

Pretty sure most modems target SNR of 6, not 12.
Sounds like an ISP issue to me as well.

 

[sammy7]

Have you tried using another ISP?
Could just be shaping or slow server you're downloading from.

Yes tried 3 different ISPs over number of days. One is unshaped and always gives full speed.
Using international (paid) and local NNTP servers which always gives full speed.

Pretty sure most modems target SNR of 6, not 12.
Sounds like an ISP issue to me as well.

Router targets SNR-M of 6 for ADSL and SNR-M of 12 for ADSL2+

 

[Sinbad]

Yes tried 3 different ISPs over number of days. One is unshaped and always gives full speed.
Using international (paid) and local NNTP servers which always gives full speed.




Router targets SNR-M of 6 for ADSL and SNR-M of 12 for ADSL2+

Mine targets 6 on ADSL2+... just saying.

If multiple ISPs are giving slow performance then the issue could well be with your exchange.

 

[GODZILLA99]

Try and switch your adsl profile to adsl g.dmt in your router settings if it is available.

 

[sammy7]

...then the issue could well be with your exchange.

I also think it's a Telkom exchange problem. What specifically should I ask Telkom to do? The assistants at 10210 are not always well informed on these matters.

Try and switch your adsl profile to adsl g.dmt in your router settings if it is available.

G.Dmt is already "Enabled" in router settings. Though I have no idea what it does...

 

[James Erlingson]

We really are splitting hairs here hey? i mean 190kbps vs 220kbps really isn't that much difference. We talking a few seconds longer on a song downloading. I don't think there is anything wrong with your line, most likely its the site you are downloading from or possibly the range from your router \ Modem.

I don't want to be rude or anything but if you were on a 4mbps line and only getting 190kbps then thats a problem because it should be around 410kbps which is significantly faster.

 

[moeminty]

Wow you uses to get 220 KB/s and now you're getting 190KB/s :/
That's not bad at all the highest I got on my 2MB Line was 200 but it stays around 180 and 190 nowadays.
190 is still fast enough.

 

[sammy7]

So true that empty cans always rattle the most.

Never ceases to amaze me...

 

[luketang56]

I have a 2048 Kbps ADSL line and the maximum download speed on that line has ALWAYS been 220 KB/s.

However, on 15 November 2014 my Telkom line was completely dead for a few hours, and since then my maximum download speed has dropped from 220 KB/s to around 190 KB/s.

I contacted Telkom support via 10210 and email, but that was a complete waste of time. They said something about a switch-over to another system.

I have no way of knowing what the cause is, and I have very limited knowledge in this regard, but if I had to guess, I would say the problem stems from one of two possible causes:

(1) My line SNR Margin used to be between 25 and 30 dB (very good) but now it fluctuates between 10 and 15 dB, which is not good. As I understand it, for a stable ADSL2+ connection a router will always target and maintain minimum 12 dB, and it will drop the line speed until it can sustain a 12 dB SNR-M.

(2) The area line upgrade or switch-over to higher possible ADSL/VDSL speeds decreased the SNR Margin and thus decreases the router download speed for lower tier ADSL accounts (like 2 Mbit accounts).

My router still syncs at 2048 Kbps downstream.

I've done all the usual stuff like leave the router off for an hour, but to no avail.

I am clueless. Anyone else experience this problem or have some ideas perhaps?

Thanks a lot.

Yes I also experienced this. On my 4Mb/s line I used to get 420KB/s max then Telkom installed FTTC, my attenuation came down from 43dB to 15dB, but the max I could get was 390KB/s. I am not sure why this happens as my line in both cases was syncing at 4096. Anyways, doesn't bother me, but that was my experience, so maybe this has happened at you as well.

 

[Lupus]

I had an iburst 2 meg modem and the most I could ever get out of it was 160kb/s I am now on ADSL 2meg and get 190kb/s so no complaints my side