Speed lower than expected?

Just got connected at new home yesterday, but sync speed looks lower than expected.

In comparison, at my old house my Billion 7800N would get a sync 4300-4700 on a downstream attenuation of 60dB. This was on G.DMT. Distance from exchange:- Direct: 4.05 km (appx)* By Road: 4.67 km

As I'm now on a new exchange, ADSL2+ is available. First sync was 3,727 on a downstream attenuation of 53.5dB. Distance:- Direct: 2.86 km (appx)* By Road: 4.35 km

For Telephone Number ******** on Exchange HAILSHAM

Your exchange is ADSL enabled, and our initial test on your line indicates that your line should be able to have an ADSL broadband service that provides a fixed line speed up to 2Mbps.

Our test also indicates that your line currently supports an estimated ADSL Max broadband line speed of 7.5Mbps; typically the line speed would range between 6.5Mbps and 8Mbps.

Our test also indicates that your line currently supports an estimated ADSL2+ broadband line speed of 15Mbps; typically the line speed would range between 8.5Mbps and 18.5Mbps.

DSP Firmware Version A2pB025f.d22k
DMT Status No Defect
Operational Mode ADSL2
Upstream 811
Downstream 3727
SNR Margin(Upstream) 10.0
SNR Margin(Downstream) 6.1
Line Attenuation(Upstream) 34.2
Line Attenuation(Downstream) 53.5

I have also been monitoring the downstream SNR Margin, which alternates between 5.9 - 6.1dB. It rose to 6.6dB from 4am to 8am only. Lowest SNR margin recorded during the last 20 hours is 5.2dB.

I'm also getting around ~1,200 CRC errors, and 600 errored seconds per 15 minutes. This was 200 CRC and 100 ES per 15min during 4am to 8am. Hope that is enough statistics, can always post more

Edited by Aaron_01 (Sat 09-Jun-12 12:51:18)

hmm it's gone to 8.6 - 8.9dB now, I was installing a new powerline adapter downstairs and may have moved some aerial/phone wiring out of the way slightly (didn't unplug/reconnect anything). Seems sensitive.

Found out what's making the SNR noise margin better, it was when I connected the Powerline ethernet cable to the router. It increased further to 9.6dB when I connected my netbook to the router as well.

Why is this happening?

edit: hooked up the sony blu-ray player to router with another ethernet cable - 9.9dB. Also CRC and LS errors are non-existent now, 1 or 3 errors in the last 100 samples.

Edited by Aaron_01 (Sat 09-Jun-12 14:36:11)

You are not running on ADSL2+ but on ADSL2 only. But if you were, you are getting about the right sync speed; the BT estimates are way too high.

It may be that your phone # has been moved from someone else and you are being given their estimates, until it catches up.

Thanks for your reply, however I think I can sync higher, as strange as it sounds it is possible with more ethernet devices using up all the ethernet ports on the router.

I resynced a few hours ago manually and got 4,155 with a powerline adapter connected. Will try a resync tomorrow for connecting a Sony Blu-ray player to ethernet port #2 which you can see what this did to the SNRM:

https://dl.dropbox.com/u/12843960/snrm_increase.png

Can't say I happy this inconsistency though... I'd like my router to be doing it's best without relying on some random ethernet devices, plus I can't see how they're both related.

Edited by Aaron_01 (Sat 09-Jun-12 18:45:28)

In reply to a post by Aaron_01:

I think I can sync higher, as strange as it sounds it is possible with more ethernet devices using up all the ethernet ports on the router.

Utter tosh! Yes, you might get about 4.3 Meg on ADSL2, but the router syncs with the exchange exclusively, not with any attached devices.

An increase in Target NM generally results in a lower sync.

You could well have a wiring issue causing the inconsistency. Have you disconnected ring wire? Plugged into test socket?

In reply to a post by XRaySpeX:

Utter tosh! Yes, you might get about 4.3 Meg on ADSL2, but the router syncs with the exchange exclusively, not with any attached devices.

I know, that's why I'm very confused why attaching ethernet devices is improving my SNRM and keeping CRC/ES errors low by a large amount to what I had previously.

An increase in Target NM generally results in a lower sync.

Yes, but my target is still set as 6dB by the DLM. The increase to 8dB as shown in the linked screenshot is from connecting a blu-ray player, not from a resynch.

You could well have a wiring issue causing the inconsistency. Have you disconnected ring wire? Plugged into test socket?

I have an external NTE, so all sockets in the house are normal extension sockets. I plan to install an NTE5 and XTE2005 tomorrow (don't want to touch router again as it's still training) when I find out which socket is closest to the ExtNTE.

In reply to a post by Aaron_01:

I'm very confused why attaching ethernet devices is improving my SNRM and keeping CRC/ES errors low by a large amount to what I had previously.

One thing to look out for is power supply noise, it can vary a lot with moving cables around or plugging in more equipment. Every wire is an aerial. If you've got any ferrite rings try winding the router DC power lead several turns round one. You usually find them in old PC PSUs or TVs.

Well I have installed an NTE5 and XTE2005 to the lounge this afternoon as one of the two cables there was coming directly from the External NTE, there was no difference, synched at 3,680 at 6dB noise margin.

Noise margin as usual went up to 10.5dB once I connected two devices to the router's ethernet ports #1 and #2, which will give me around 4,500 sync rate if I choose to manually re-sync. (I got 4,579 when I tested yesterday so I know it's reachable). FEC errors also stopped accumulating so much with ethernet devices connected (Interleave got enabled on my line in the night)

I could try the ferrite core thing on the Router power lead, though I should mention I already tried the router in another room with no other electrical equipment present, same thing happens. My 2700HGV syncs at 4500 from the get-go without doing any of that connecting ethernet cables nonsense. Another member on the Billion 7800N forum has confirmed the same strange behaviour as me, so it's the router, whatever the heck is going on with it

Edited by Aaron_01 (Sun 10-Jun-12 15:30:34)

Just noticed I'm not getting Caller Display, I think I may have reversed 2 & 5 to A & B on the NTE5 by accident, so would the reversed polarity probably have affected it?

But I can't even remember if Caller Display was working when I moved in, so I'm not 100% if it's the socket work I did, or a problem on my ISP (IDNet) provided line.