What could be causing this?

sWiZzLe

sWiZzLe

sWiZzLe

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Joined
19 Oct 2002
Posts
1,932
Location
Maidenhead
My bandwidth rapidly decreases over say, 2-3 hours from 7.5mb to around 3mb.
I have determined that it is not the fault of my router as to reset the bandwidth all i need to do is unplug the phone line from the wall and immediately replace it.
It is also nothing to do with the adsl filter as i have tried 6 of them and the problem still persists.

There is no problem with the phone line - everything sounds very clear.
The line has been tested several times and everything seems to be fine :confused:

I am going to have to call BT tomorrow....AGAIN :mad: .... and I could really do with possible reason as to why this may be happening before i speak to those idiots ;)

Cheers

===============================
I desperately need to get away from BT!
Last night i was working on a website and was trying to upload stuff and this was my connection:

Took me half an hour to upload 1mb :(
 
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If you run a traceroute when it's slow, and after you've reconnected, does the first hop after your router change?
Might be worth trying something like MTR to see if you're seeing any packet loss, and look at your SNR margin and sync rate both before and after reconnecting.
 
Traceroutes looked pretty identical. Only made 1 hop each time and took 1ms

Unplugged and reconnected line and it went from 3.5 to 5.9

I read somewhere that the Signal to Noise Ratio should be at least 10 dB to get adsl - ideally above 12dB to get traditional fixed adsl.
Anything less than this will see frequent disconnections and other problems.

Is this correct? I have 6.5 :/

Uptime: 0 days, 0:01:14
Bandwidth (Up/Down) [kbps/kbps]: 448 / 5,920
Output Power (Up/Down) [dBm]: 11.5 / 19.5
Line Attenuation (Up/Down) [dB]: 24.0 / 42.0
SN Margin (Up/Down) [dB]: 25.0 / 6.5

Wish id looked at this info before id reset it. I'll have a look later.

Just had a look at my bosses Link information over TeamViewer ....

Uptime: 2 days, 11:46:58
Bandwidth (Up/Down) [kbps/kbps]: 448 / 7,616
Output Power (Up/Down) [dBm]: 11.5 / 19.5
Line Attenuation (Up/Down) [dB]: 11.0 / 20.0
SN Margin (Up/Down) [dB]: 23.0 / 16.5

Line Attenuation & SN Margin are quite a bit different to mine and his bandwidth never drops
 
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I have a similar problem and Im pretty sure its down to a low SNR Margin, check out my stats below taking into account my ADSL re-syncs at will, every few hours mostly...the router doesn't actually reboot because it says its been up for 36 days, the connection just re-syncs.

Downstream Upstream
SNR Margin (dB): 8.0 23.0
Attenuation (dB): 27.5 23.0
Output Power (dBm): 11.9 19.1
Attainable Rate (Kbps): 4480 1052
Rate (Kbps) 4448 448
K 140 15
R 0 0
S 1 1
D 1 1

Also, check for any errors (Super Frames errors, CRC Errors, HEC errors and ES errors.
 
sWiZzLe said:
Traceroutes looked pretty identical. Only made 1 hop each time and took 1ms
Click to expand...

Where were you running it to, because there should definitely have been more hops than your router...

Unplugged and reconnected line and it went from 3.5 to 5.9
Click to expand...

Sounds like the problem's your SNR margin dropping to the point where you get packet loss.

I read somewhere that the Signal to Noise Ratio should be at least 10 dB to get adsl - ideally above 12dB to get traditional fixed adsl.
Anything less than this will see frequent disconnections and other problems.

Is this correct? I have 6.5 :/
Click to expand...

That isn't true - the target SNR margin on Max is 6dB, but that doesn't give you much room for it to drop. Your ISP can get the target SNR margin increased, but you'll see a drop in sync rate.

Line Attenuation & SN Margin are quite a bit different to mine and his bandwidth never drops
Click to expand...

His line's half as long too - unless it's disconnected a lot or his SNR margin's changing a lot, it should be connected at full rate with that SNR margin.
 
Where should the traceroute be running to?

sWiZzLe said:
Uptime: 0 days, 0:01:14
Bandwidth (Up/Down) [kbps/kbps]: 448 / 5,920
Output Power (Up/Down) [dBm]: 11.5 / 19.5
Line Attenuation (Up/Down) [dB]: 24.0 / 42.0
SN Margin (Up/Down) [dB]: 25.0 / 6.5
Click to expand...
Now:
Uptime: 0 days, 6:03:57
Bandwidth (Up/Down) [kbps/kbps]: 448 / 3,520
Output Power (Up/Down) [dBm]: 11.5 / 19.0
Line Attenuation (Up/Down) [dB]: 24.0 / 42.0
SN Margin (Up/Down) [dB]: 25.0 / 11.0
Error Seconds (Local/Remote): 71 / 0
 
Wherever you like - bbc.co.uk, jolt.co.uk, thinkbroadband.org.uk. Anywhere that'll go to the other side of BT's network.

Sync rate's dropped and SNR margin's increased (but only slightly).
 
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