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chris6273
Recognised Expert
613 Views
Message 1 of 25

Weird throughput 'problems'

Hi guys,

 

I've recently been having a few weird problems with my connection:

 

For some odd reason over the past few weeks, I've noticed a much lower throughput on my connection, both in the morning (Early) and at night.

 

When downloading a file from ThinkBroadband or Nvidia (Which used to max out my connection), The download fluctuates quite a lot from ~1MB/s to 1.8MB/s, and doesn't go any higher. I have just tested my speed on the 1GB file from ThinkBroadband and it is hovering around 1212KB/s 😞 .

 

I'm synced at:

 

DownStream Connection Speed22965 kbps
UpStream Connection Speed1211 kbps

 

 

Now the weird part - When I perform a ping and tracert when downloading these files, It is around what it should be (~23ms) and doesn't indicate that my connection is being maxed out (I used to get 2.4-2.5MB/s before these problems).

 

However if I download multiple copies of backups from Rapidshare at the same time, my connection maxes out and my ping goes sky high as it should indicating I can't get any more throughput. It also maxes out sometimes when downloading single files from Rapidshare, but it only seems to do it on files from Rapidshare.

 

Here is a tracert from when I have been downloading the 1GB file from Thinkbroadband which is stable around ~1200KB/s for some reason:

 

"

C:\Users\Chris>tracert bbc.co.uk

Tracing route to bbc.co.uk [212.58.241.131]
over a maximum of 30 hops:

1 <1 ms <1 ms <1 ms edge1-r-0-0-1.evansnet.co.uk [10.5.14.254]
2 8 ms 9 ms 8 ms 217.32.141.2
3 12 ms 10 ms 10 ms 217.32.140.222
4 18 ms 14 ms 23 ms 213.120.161.98
5 16 ms 12 ms 15 ms 217.41.222.22
6 14 ms 14 ms 19 ms 217.41.222.178
7 13 ms 13 ms 13 ms acc1-10gige-0-3-0-1.bm.21cn-ipp.bt.net [109.159.
248.112]
8 30 ms 21 ms 24 ms core2-te0-3-0-15.ilford.ukcore.bt.net [109.159.2
48.26]
9 29 ms 52 ms 24 ms peer2-xe1-1-0.telehouse.ukcore.bt.net [109.159.2
54.140]
10 25 ms 25 ms 25 ms 194.74.65.42
11 * * * Request timed out.
12 24 ms 71 ms 26 ms ae1.er01.rbsov.bbc.co.uk [132.185.254.46]
13 28 ms 25 ms 24 ms 132.185.255.134
14 23 ms 28 ms 27 ms 212.58.241.131

Trace complete."

 

1gb.png

 

and here is a tracert from when downloading a Test File from Rapidshare:

 

"

C:\Users\Chris>tracert bbc.co.uk

Tracing route to bbc.co.uk [212.58.241.131]
over a maximum of 30 hops:

1 1 ms <1 ms 2 ms edge1-r-0-0-1.evansnet.co.uk [10.5.14.254]
2 13 ms 13 ms 15 ms 217.32.141.2
3 68 ms 55 ms 39 ms 217.32.140.222
4 85 ms 82 ms 86 ms 213.120.161.98
5 91 ms 92 ms 90 ms 217.41.222.22
6 88 ms 91 ms 94 ms 217.41.222.178
7 85 ms 101 ms 85 ms acc1-10gige-0-3-0-1.bm.21cn-ipp.bt.net [109.159.
248.112]
8 93 ms 95 ms 101 ms core2-te0-3-0-15.ilford.ukcore.bt.net [109.159.2
48.26]
9 99 ms 105 ms 103 ms peer2-xe1-1-0.telehouse.ukcore.bt.net [109.159.2
54.140]
10 113 ms 116 ms 150 ms 194.74.65.42
11 * * * Request timed out.
12 88 ms 88 ms 93 ms ae1.er01.rbsov.bbc.co.uk [132.185.254.46]
13 102 ms 89 ms 99 ms 132.185.255.134
14 92 ms 93 ms 93 ms 212.58.241.131

Trace complete."

 

RSTest.png

 

The Speedtest I took earlier showed:

 

Download speedachieved during the test was - 15.42 Mbps
For your connection, the acceptable range of speeds is 4 Mbps-21 Mbps.
IP Profile for your line is - 20.26 Mbps

 

 

Does anyone know what could be going on? It seems I can only max out my connection when downloading from Rapidshare, and sometimes when doing speedtests at Speedtest.net). It definately has me stumped, because all hosts I've tried apart from Rapidshare are slow (around the 1-1.8MB/s mark). The tracert also shows no signs of congestion when downloading ThinkBroadband and Nvidia files.

 

I am not using a proxy, and have tried this on other computers in my household, including my servers. The same problem occurs on every computer in my household and the 1Gbps Network isn't a problem. Here is a test file from my file server ruling out a LAN Problem:

 

1GB2.png

 

 

Any ideas guys? I've seen some people on the new 80Mbps FTTC package have similar problems (Slow downloads and normal pings), but I don't know the results from one when downloading from Rapidshare.

 

 

Cheers

___________________________________

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24 REPLIES 24
Distinguished Sage
Distinguished Sage
597 Views
Message 2 of 25

Re: Weird throughput 'problems'

If you are on a standard ADSL2+ connection, your synch speed is too high. I suspect that your downstream noise margin is much too low. A figure of between 3 and 6db would be normal, anything less will result in line instability.

 

I expect that your downstream CRC errors are very high, which would cause erratic throughput.

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Distinguished Sage
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Message 3 of 25

Re: Weird throughput 'problems'

Depends Keith. If he lives literally right next to the exchange there's nothing wrong. The max connection rate on ADSL2+ is in excess of 23meg.

Can you post your hub statistics please Chris?
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Distinguished Sage
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Message 4 of 25

Re: Weird throughput 'problems'

On a previous posting he was not using a BT Home hub, and was manually adjusting the SNR to a low value using a program.

I was wondering if it had been set too low.

 

BT only state "up to 20Mb" for their service.

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Distinguished Sage
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Message 5 of 25

Re: Weird throughput 'problems'

Actually only up to 16 now 😉

But fair comment if he's been messing around with the SNR
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Distinguished Sage
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Message 6 of 25

Re: Weird throughput 'problems'


@Webby wrote:
Actually only up to 16 now 😉

But fair comment if he's been messing around with the SNR

Not so optimistic about speed now, probably helps to make Infinity look better Smiley Wink

See http://community.bt.com/t5/BB-Speed-Connection-Issues/Massive-error-spike-on-my-24Meg-connection-Hel...

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Distinguished Sage
Distinguished Sage
562 Views
Message 7 of 25

Re: Weird throughput 'problems'

it is still up to 20mb but the advert has changed to download speed and not connection speed as before as it was thought misleading - same thing happened to infinity as well



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Distinguished Sage
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Message 8 of 25

Re: Weird throughput 'problems'

I know 🙂

ADSL2+ allows a connection rate of up to 24meg if you're close enough to the exchange though was my point.
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Distinguished Sage
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Message 9 of 25

Re: Weird throughput 'problems'

Webby

 

I think BT are a bit funny about people living in the exchange to get 24mb - unless your an engineer ofcourseSmiley Very Happy



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chris6273
Recognised Expert
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Message 10 of 25

Re: Weird throughput 'problems'

I have adjusted my SNR to go lower than it is supposed to, however I have overcome the problems of my other thread by reducing my sync speed to ~23 Meg. CRC Errors are not a problem anymore, as shown in the stats:

 

Here are my line stats:

 

            Down Up
SNR (dB): 2.7 6.2
Attn(dB): 16.5 6.4
Pwr(dBm): 0.0 12.5
Max(Kbps): 26544 1208
Rate (Kbps): 22965 1211

 

Counters
SF: 3100230 2960548
SFErr(CRCErr): 20185 0
RS: 0 0
RSCorr: 0 0
RSUnCorr: 0 0

HEC: 3655 0
OCD: 9 0
LCD: 0 0
Total Cells: 2726107711 1941447
Data Cells: 78994946 9412
Drop Cells: 0
Bit Errors: 0 0

 

 

Even if CRC errors are a problem, it doesn't explain why I can max out my connection when downloading a file from Rapidshare, but can't when downloading one from Thinkbroadband/Nvidia and some other sites when I have been able to in the past. They both go over the same Point to Point connection to the exchange.

 

Does anyone know what could be the problem?

___________________________________

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