Two lines, but different broadband speeds (was Jos390)

Hi,

I'm a new member here, so I hope I'm asking in the right forum.

We run a business from home and recently took a second line so that we can provide internet to our customers. The new line was taken from the first from where it joins the house, so both lines share the same outer cable from the cabinet (but presumably have different lines?). The old line was installed 10 years ago. Both lines are with TalkTalk Business and often have similar IP addresses (both start with 92.15.43. today, for instance).

However, the new line is usually about 1Mb faster than the old and the speed is far more consistent. The new line runs consistently at about 3Mbps whilst the old line varies between 0.5-2.9Mbps. The old line has always had periods of slower speeds followed by periods of good speeds, so sometimes we can stream TV and sometimes not. It has been too slow for streaming for about 2 weeks so far this time.

Things I have tried: I have plugged the router into the BT test socket and have tried connecting to the router with a cable instead of WiFi but the speed is always about the same. I have tried 3 different routers.

Can the wiring of the BT socket or the cable from the cabinet make this type of difference? Or is the difference caused by some setting in the exchange or elsewhere? Can equipment near the BT socket cause problems?

Any help with this much appreciated - teenagers are revolting!

Edited by deleted (Tue 18-Nov-14 16:51:26)

Once the cable gets to the pole, the lines could then be in separate cables to the cabinet and then from the cabinet again, separate cables are possible and even different routes. Even if the lines are in the same cable one could be close to another noisy line ... so yes, different speeds are quite possible.

However, as one is stable and the other varying does suggest either an intermittent fault or an intermittent source of noise. And yes, local equipment can cause the problem.


First stage is to get line stats - Attenuation and SNR (margin) for both lines at times when they are both running well and also when one has a problem. That will be a start.

Have two lines and one was nice and stable and one would be less stable in the winter months, different drop wires to the property but go to the same pole.

When things were good speeds with ADSL2+ were similar.

Since getting FTTC there is very little between the two lines in terms of performance.

So original posters situation is far from unique, but as suggested line stats for both lines and then doing the usual ring wire, better quality RJ11 modem lead and avoiding putting modem in an electrically noise area are all good things to do.

Hi, thanks for your reply. I have copied the current connection details below. If/when the old line improves again I'll check the details and post the results.

NEW LINE

DSL Type: ITU-T G.992.3
Bandwidth (Up/Down) [kbps/kbps]: 945 / 3.581
Data Transferred (Sent/Received) [GB/GB]: 1,07 / 1,23
Output Power (Up/Down) [dBm]: 12,6 / 0,0
Line Attenuation (Up/Down) [dB]: 31,1 / 53,0
SN Margin (Up/Down) [dB]: 6,7 / 4,7
System Vendor ID (Local/Remote): TMMB / ----
Chipset Vendor ID (Local/Remote): BDCM / IFTN
Loss of Framing (Local/Remote): 0 / 0
Loss of Signal (Local/Remote): 0 / 0
Loss of Power (Local/Remote): 0 / 0
Loss of Link (Remote): -
Error Seconds (Local/Remote): 31.072 / 0
FEC Errors (Up/Down): 171.482 / 1.463.354
CRC Errors (Up/Down): 9.358 / 101.367
HEC Errors (Up/Down): 8.240 / 828.733


OLD LINE

DSL Type: ITU-T G.992.1
Bandwidth (Up/Down) [kbps/kbps]: 800 / 2.400
Data Transferred (Sent/Received) [MB/GB]: 68,71 / 1,99
Output Power (Up/Down) [dBm]: 12,6 / 17,8
Line Attenuation (Up/Down) [dB]: 31,5 / 56,5
SN Margin (Up/Down) [dB]: 10,0 / 8,6
System Vendor ID (Local/Remote): TMMB / ----
Chipset Vendor ID (Local/Remote): BDCM / IFTN
Loss of Framing (Local/Remote): 0 / -
Loss of Signal (Local/Remote): 0 / -
Loss of Power (Local/Remote): 0 / -
Loss of Link (Remote): -
Error Seconds (Local/Remote): 39 / -
FEC Errors (Up/Down): 277 / 32.198
CRC Errors (Up/Down): 183 / 346
HEC Errors (Up/Down): -83 / 346 / 3.443

Best wishes,
Jos

Edited by deleted (Tue 18-Nov-14 17:01:04)

Some of the speed difference is likely to be from the fact the old line is running at an 8.6 SN margin and the new is at 4.7.

The 4dB difference between the 2 could be making a reasonable difference on connection speeds. What you may find though is that the new line may have more errors and be a little more unstable and may well slow down over time in order to improve the stability.

Looking at the errors (bearing in mind we don't know how long these have been up) the new line does seem to have more errors than the old - do you have the uptime for the 2 connections so we know if we are comparing like for like?

In reply to a post by ian72:

Looking at the errors (bearing in mind we don't know how long these have been up) the new line does seem to have more errors than the old - do you have the uptime for the 2 connections so we know if we are comparing like for like?

The new line was installed a year ago and the current connection has been up for 15 days. I have restarted the old line's modem a couple of times today (sometimes it re-connects at a higher speed) so it has only been up for a couple of hours.

Best wishes,
Jos

It could just be the DLM system is treating the 2 lines differently. The SNR on the new line is definitely lower than would normally expect. You may find if you rebooted the router for it that it would reduce the speed as the SNR target is probably 6dB.

Rebooting both at the same time and getting stats could show the real differences between the 2 and would give us a level playing field to compare error rates.

In reply to a post by MrSaffron:

So original posters situation is far from unique, but as suggested line stats for both lines and then doing the usual ring wire, better quality RJ11 modem lead and avoiding putting modem in an electrically noise area are all good things to do.

Thanks for your reply. I've just switched the RJ11 modem leads and the old line is still slower than the new. But if you think it might speed up both connections I'll certainly try a different RJ11 lead - how do I tell a good from a bad lead if I look for one?

I disconnected the ring wire about a year ago.

The modem is located on my desk next to a laptop, a laser printer, a desktop system and a 4 socket extension for the laptop printer and router. Is this the sort of equipment that will cause electrical noise problems? For comparison, the new line's modem is next to a wireless access point, a couple of switches, a network drive and 2 x 4 socket extensions (for all these items plus a couple of wireless access point located on the roof). The router/modems are the same model, Technicolor TG 852n. We had the same problems with the old line with an old Netgear router.

Best wishes,
Jos

In reply to a post by ian72:

Rebooting both at the same time and getting stats could show the real differences between the 2 and would give us a level playing field to compare error rates.

Do a couple of minute matter? These are the stats after switching the RJ11 leads:


NEW LINE

Uptime: 0 days, 0:25:25
DSL Type: ITU-T G.992.3
Bandwidth (Up/Down) [kbps/kbps]: 904 / 3.339
Data Transferred (Sent/Received) [GB/GB]: 1,08 / 1,24
Output Power (Up/Down) [dBm]: 12,7 / 0,0
Line Attenuation (Up/Down) [dB]: 30,8 / 53,5
SN Margin (Up/Down) [dB]: 6,0 / 5,9
System Vendor ID (Local/Remote): TMMB / ----
Chipset Vendor ID (Local/Remote): BDCM / IFTN
Loss of Framing (Local/Remote): 9 / 0
Loss of Signal (Local/Remote): 1 / 0
Loss of Power (Local/Remote): 0 / 0
Loss of Link (Remote): -
Error Seconds (Local/Remote): 31.099 / 0
FEC Errors (Up/Down): 61 / 230
CRC Errors (Up/Down): 6 / 16
HEC Errors (Up/Down): 3 / 47

OLD LINE

Uptime: 0 days, 0:27:33
DSL Type: ITU-T G.992.1
Bandwidth (Up/Down) [kbps/kbps]: 832 / 2.304
Data Transferred (Sent/Received) [MB/GB]: 87,13 / 1,99
Output Power (Up/Down) [dBm]: 12,6 / 17,6
Line Attenuation (Up/Down) [dB]: 31,5 / 56,5
SN Margin (Up/Down) [dB]: 10,0 / 8,9
System Vendor ID (Local/Remote): TMMB / ----
Chipset Vendor ID (Local/Remote): BDCM / IFTN
Loss of Framing (Local/Remote): 9 / -
Loss of Signal (Local/Remote): 1 / -
Loss of Power (Local/Remote): 0 / -
Loss of Link (Remote): -
Error Seconds (Local/Remote): 50 / -
FEC Errors (Up/Down): 87 / 3.872
CRC Errors (Up/Down): 22 / 0
HEC Errors (Up/Down): -2 / 0 / 2

Thanks,
Jos

Interestingly the new line is now on ADSL2 (G.992.3). Both were previously on ADSL (G.992.1).