topic High line attenuation & Low noise margin/packet loss issue in Archive

High line attenuation & Low noise margin/packet loss issue

richardbee13 — Fri, 04 Feb 2022 00:20:58 GMT

My line attenuation is noticeably higher than a neighbour of mine that I assume is connecting to the same cabinet (0.2 miles away for both of us). My stats are:

Line attenuation: D1 - 18.9dB D2 - 50.3dB D3 - 76,7dB

U0 - 7.0dB U1 - 39.5dB U2 - 0.0dB

Noise margin: 4.4dB downstream, 5.9dB upstream

I encounter packet loss, jitter and speed fluctuations frequently.

My questions would be:

Is this fixable with a newer master socket (currently Mk3 openreach mastersocket)?

Should I get openreach to have a look at the line?

Is there any other solution to the above numbers?

Re: High line attenuation & Low noise margin/packet loss issue

TechmanagerMal — Fri, 04 Feb 2022 00:53:00 GMT

Does the broadband check suggest there is an issue and arrange for an engineer visit - Broadband check | Sky.com

Re: High line attenuation & Low noise margin/packet loss issue

Chrisee — Fri, 04 Feb 2022 06:56:47 GMT

@richardbee13 your figures look pretty normal to be honest a noise margin of 4.4dB implies a line with low noise and therefore performing well. The condition of copper lines vary and assuming your connection speed is above the guaranteed minimum Openreach will not take action even if Sky ask..While it is likely that your neighbour's line follows a similar route that cannot be assumed as lines added at different times can use different routes.In the end it is pure luck if yours is a good or bad line all that is guaranteed is the minimum speed anything above that is bunce.

You mention packet loss how are you measuring that and how is the device networked? The most common cause of packet loss on devices connected by wifi is interference. If the line was suffering errors like packet loss you would expect the DLM system in the cabinet to intervene and raise the noise margin dropping the speed but improving stability.

Fortunately these issues will largely disapear when Openreach run fibre to your home.

Re: High line attenuation & Low noise margin/packet loss issue

richardbee13 — Fri, 04 Feb 2022 09:37:38 GMT

I regularly perform network tests on Ookla for my phone (5GHz) and the detailed network statistics on my Xbox console (hard wired) and regularly see flashes of jitter and packet loss. Shouldn't the noise margin hover around Sky's default of 6dB? If not, would it suggest there's something wrong with the line/cabinet?

Re: High line attenuation & Low noise margin/packet loss issue

jamesn123 — Fri, 04 Feb 2022 17:03:28 GMT

@richardbee13

Anything between 3dB & 6dB is normal.

Can you post your full stats as well as Sky's estimates for your line from the line check online

Re: High line attenuation & Low noise margin/packet loss issue

richardbee13 — Fri, 04 Feb 2022 19:25:40 GMT

I try to initate the broadband check and get this. Is there anything I can do about my high line attenuation despite being within half a mile of the cabinet?

Re: High line attenuation & Low noise margin/packet loss issue

TechmanagerMal — Fri, 04 Feb 2022 19:30:48 GMT

@richardbee13 wrote:
I try to initate the broadband check and get this. Is there anything I can do about my high line attenuation despite being within half a mile of the cabinet?

As @Chrisee suggests your line may take a longer route than your neighbour as your numbers suggest.
You need to keep trying the test and if it is not working contact Sky.