10mbps - before I kill my ISP

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blahsum

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Hi all

Looking at comments here and below the general article, many people have experienced a drop from 10mbps back to 4mbps. I've experienced this recently and I am not happy at all.

The problem is that I keep getting different answers. At first my ISP claimed I cannot reach 10mbps because my line does not support it. Not so, I'd point out, since I had a stable 10mbps line for several months.

Then I was told I'm too far from the exchange. Again I point out that I had the line speed before and, on top of that, I am less than a kilometer away (as the crow flies) from my exchange.

Now they say the DSLAM is too congested, yet when I originally got 10mbps, it was because a Telkom techie told me the local system had been upgraded. So either Telkom somehow forgot to put in any real capacity when it made the upgrades or I am yet again being fed a story.

One term I do not understand is line stabilization. Apparently my line only stabilises at 4mbps. So why did it stabilise at 5mbps a week ago and at 10mbps hardly two months ago? Is there something wrong with the physical cable? Is this just jargon for an exchange that is over-capacity? And why can I not stabilise at 6mbps? Did Telkom suddenly more than double its ADSL customers on my local exchange? Maybe I should buy Telkom stock, because that is one hell of a customer base increase! :)

Has anyone got some advice on how to approach this? Like I mentioned, I had 10mbps and it was spectacularly stable. Yet ever since my ISP moved to a different network, I have been hovering around 4-5mbps and experiencing all kinds of latency and disconnect problems.

thanks,
 
Hi and welcome to myBB.

Could you log in on your ADSL modem's web interface and go to its ADSL stats page and then post it here.
We're particularly interested in the SNR/noise margins, line attenuations and line speeds.

The line attenuation values should give us an estimation of what maximum line speed you should be able to get - unless of course the DSLAM/exchange is only configured to support up to say 4Mbps.
 
blahsum said:
Hi all

Snip


Has anyone got some advice on how to approach this? Like I mentioned, I had 10mbps and it was spectacularly stable. Yet ever since my ISP moved to a different network, I have been hovering around 4-5mbps and experiencing all kinds of latency and disconnect problems.

thanks,
Click to expand...

Hi and welcome
Like Pada says post the stats for us to look at .
Also who is your ISP and what area are you in ??
 
One thing most people don't know, the more often you have your line/port reset on telkom's side, the bigger the chances are their automated systems will start to enforce lower max sync speeds on your line.

So if you have a stable 10Mpbs line, you should do everything in your power to never have line resets done on your modem by the ISP, because everytime it does, the system records it, and once it reaches a threshold, they enforce lower max sync speeds to try and keep the line stable.

The other possibility is, something on your line changed, with weather or something degraded the line, and now you have lower sync speeds regardless of what you used to have. In this instance, your best bet is to get Telkom to replace the entire copper line from your house to the dslam.
 
Sure - here are the stats:

Type Interleave Path

Status SHOWTIME

Data rate(Kbps)
4089Kb 507Kb

Noise Margin
8 6

Output power(dBm)
125 186

Attenuation(dB)
49 43

I'm located in Newlands, Jhb and my ISP is Afrihost. That said, I also have a small account with WebAfrica and they reported line instability/syncing problems as well. But that was when I experienced serious problems with the line. This has been resolved and the line seems to be stable. So I am not getting any performance problems anymore. Right now I'm trying to find out why I have dropped so low.

Tinuva has a point: I have requested several port resets - this might be the root of the problem. It's a pity Afrihost never mentioned this when they recommended all the resets! Is there a way to clear that record?

And thanks for all the help!
 
Looking at the above, the problem may not be the port resets alone, your attenuation is quite high, I doubt you will get anything more than 5mbit/sec on those, 49/43 is really high. Interleave path also means you latency will be higher than usual, but sync speed will be more stable.

As it stands, you need to find the cause of the higher attenuation, can be a blown lightning protection unit, faulty alarm system on the line, a bad POTS filters, or even degradation on the line outside of the house.

My suggestion, first try unplugging everything on the tellephone line (alarm, pots filters, phones) and run only the adsl modem straight on the line and see if the attenuation is still that high, if it is, then you may need to get the copper line from the house back to the dslam replaced, although to get telkom to do this is harder than you can imagine. Back at my parents place, I manually cut the line in half, and blamed it on the trees hanging over it, and they replaced it, fixing all the issues they had.
 
Your upstream line attenuation is way too high. Typically it is about half of the downstream line attenuation.
I'm not sure if the path interleaving has anything to do with it being that high though.

i'd recommend t hat you do as Tinuva said by unplugging everything except for the ADSL modem and then checking your stats again.
 
Thanks guys - this is with the modem straight into the line - no filters and such.

What is the chance that the router/modem is the cause? It's not the best...
 
Hi blahsum,

Here is my line speed and i live on the 18th floor in a block of flats.
noise margin upstream: 17 db
output power downstream: 0 db
attenuation upstream: 11 db

noise margin downstream: 22 db
output power upstream: 5 db
attenuation downstream: 16 db

That what you want for your line to sync at 10Mbps.

Blahsum has your router moved position since it was installed or any appliences put next to it tv aerial any order cables?

Let us know :)

blahsum said:
Thanks guys - this is with the modem straight into the line - no filters and such.

What is the chance that the router/modem is the cause? It's not the best...
Click to expand...
 
My stats:

Upstream 911700
Downstream 10014100
SNR Margin(Upstream) 5.5 dB
SNR Margin(Downstream) 10.95 dB
Line Attenuation(Upstream) 16.5 dB
Line Attenuation(Downstream) 40.5 dB

This is probably around the maximum allowed db before you need to start syncing downwards. Your downstream could probably handle 7mb, but upstream is horrendous. It looks more like a general fault or issue rather than a natural occurrence. Like Amphibious said, check for other devices that may be interfering.
 
blahsum said:
Hi all

Looking at comments here and below the general article, many people have experienced a drop from 10mbps back to 4mbps. I've experienced this recently and I am not happy at all.

The problem is that I keep getting different answers. At first my ISP claimed I cannot reach 10mbps because my line does not support it. Not so, I'd point out, since I had a stable 10mbps line for several months.

Then I was told I'm too far from the exchange. Again I point out that I had the line speed before and, on top of that, I am less than a kilometer away (as the crow flies) from my exchange.

Now they say the DSLAM is too congested, yet when I originally got 10mbps, it was because a Telkom techie told me the local system had been upgraded. So either Telkom somehow forgot to put in any real capacity when it made the upgrades or I am yet again being fed a story.

One term I do not understand is line stabilization. Apparently my line only stabilises at 4mbps. So why did it stabilise at 5mbps a week ago and at 10mbps hardly two months ago? Is there something wrong with the physical cable? Is this just jargon for an exchange that is over-capacity? And why can I not stabilise at 6mbps? Did Telkom suddenly more than double its ADSL customers on my local exchange? Maybe I should buy Telkom stock, because that is one hell of a customer base increase! :)

Has anyone got some advice on how to approach this? Like I mentioned, I had 10mbps and it was spectacularly stable. Yet ever since my ISP moved to a different network, I have been hovering around 4-5mbps and experiencing all kinds of latency and disconnect problems.

thanks,
Click to expand...

Don't let your ISP manage your line. Get it transferred back to Telkom immediately. It's coz of stuff like this that I always say NEVER give your ISP your line.
 
I had a similar issue and after many phone calls to Telkom, a techy came and replaced the distribution box outside my house. They also replaced the cable that leads from the inside to the box; ever since then I haven't had any issues.
 
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