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Are BT limiting Uplink speeds to 10Mbps?

danludlow
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Registered: ‎03-12-2014

Are BT limiting Uplink speeds to 10Mbps?

For many months (years perhaps?) my uplink speed never fell below 10Mbps, in the early days it hit 17Mbps if memory serves, and for most of the past year it was around 12Mbps, sometimes 11.5Mbps, sometimes 13.2Mbps or so. About 3 months ago it dropped suddenly to 9.5Mbps or just below, I have never seen it higher since.

Broadband was being discussed in the pub and a guy seemingly in the know (BT Engineer?) suggested that BT have throttled back the uplink to get more capacity down.

Is this the case, does anybody know?

Also suggested that speeds will be increased by removing the cap that keeps 100Mbps connection restricted to 80 (79) Mbps in the near future.

Again, does anybody know this as fact?

10 REPLIES
ffox
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Re: Are BT limiting Uplink speeds to 10Mbps?

Community Veteran
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Registered: ‎15-06-2007

Re: Are BT limiting Uplink speeds to 10Mbps?

They don't

The usual reason why it drops is crosstalk and  the system doesn't usually enable G.INP on the upstream

Mine started well above 10Mb/s but has dropped below it for a while now
These are my stats after a power cut - the Billion Router always resyncs faster than all the others round me and the default upstream margin is - or was last time I checked - 6dB so you can see the effect of crosstalk on the noise margin
Note that the default downstream noise margin is 3dB

Connection speed (kbps):	53466		10294
SNR margin (dB):       	          1.7		  1.8

 

Browni
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Re: Are BT limiting Uplink speeds to 10Mbps?

No.

I must have been really bad in a previous life as this was my 3rd ISP in a row that used lithium.
Now you're stuck with me because my new ISP doesn't run a forum Cheesy
danludlow
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Registered: ‎03-12-2014

Re: Are BT limiting Uplink speeds to 10Mbps?

Thanks for your reply and also the other replies. So the guy in the pub was assuming then, it appears. Not the most helpful advice. My speed seems to mirror yours so crosstalk likely cause. Have now got a neighbour sharing the same pole for the first time in a couple of years, he says he's asked for FTTC and BT tell him they can't supply anything better than ADSL2+, maybe there's a clue there?

Browni
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Re: Are BT limiting Uplink speeds to 10Mbps?

That's possible as the FTTC cabinet could be full.
A check on http://dslchecker.bt.com/ would confirm.

I must have been really bad in a previous life as this was my 3rd ISP in a row that used lithium.
Now you're stuck with me because my new ISP doesn't run a forum Cheesy
Community Veteran
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Registered: ‎15-06-2007

Re: Are BT limiting Uplink speeds to 10Mbps?

To add - my upstream gave up the ghost and resynched at a lower speed but with G.INP enabled

Connection speed (kbps):	49775		8778
SNR margin (dB):        	3.1		5.5
Power (dBm):            	12.9		5.1
Interleave depth:       	4		4
INP:                    	55.00		46.00
G.INP:                  	Enabled		Enabled
danludlow
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Re: Are BT limiting Uplink speeds to 10Mbps?

That's odd isn't it, Oldjim, I didn't think there was G.INP enabled on upstream. A few months ago I saw an Openreach guy working in our cabinet and asked him if G.INP was operating on it (up or down). "What's that?" he asked.

Community Veteran
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Registered: ‎15-06-2007

Re: Are BT limiting Uplink speeds to 10Mbps?

Depends on the cab and the router

It is enabled on a Huawei cabinet but not an ECI cabinet

You need a router which supports it and the Plusnet supplied one doesn't

RealAleMadrid
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Re: Are BT limiting Uplink speeds to 10Mbps?

Upstream G.Inp seems to be quite rare, the only time I saw it on my line was when there was a fault and the sync speeds had dropped significantly. After the line was repaired and DLM reset G.Inp was removed as expected and was re-enabled on downstream only after a couple of days. As my upstream sync is 20Mbps it probably isn't needed on upstream anyway but would be nice to have fewer errors.

Community Veteran
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Registered: ‎15-06-2007

Re: Are BT limiting Uplink speeds to 10Mbps?

I had and have some very bad bursts of upstream errors - these are now the FEC errors - these are using a log scale so it is a lot worse than would appear at first sight

2017-08-31_130440.png

Actually looking at the graph it appears to be at regular intervals so worth a bit of investigation