topic Re: Internet dropouts - what is a good snr for a G.fast line? in Archived Posts

Internet dropouts - what is a good snr for a G.fast line?

sg19 — Thu, 08 Apr 2021 11:46:59 GMT

Hi,

Apologies for the post, but we're having near-daily internet dropouts, and I wasn't able to find much info on what constitutes a good snr for a g.fast connection.

The error is the logs is

"03:10:32, 08 Apr. WAN connection WAN2_INTERNET_PTM disconnected.[ERROR_NO_CARRIER]"

- seemingly indicating the line has dropped, but it reconnects within a minute or two, at full speed -

"03:12:19, 08 Apr. DSL Link Up: Down Rate=329289kbps, Up Rate=49399kbps; SNR Margin Down=13.7dB, Up=15.4dB"

We're approx 60m from the cab. We have no dial tone but are on a plan without a phoneline, so I assume that's normal (and hard to test the line quality!)

I was hoping to understand if we are in a reasonable noise range, and if we are, any ideas on what could be causing this?

Thanks

Re: Internet dropouts - what is a good snr for a G.fast line?

XRaySpeX — Thu, 08 Apr 2021 12:05:43 GMT

Your NM isn't high because the line is noisy but because your sync is almost max for G.Fast, 330 Meg.

Re: Internet dropouts - what is a good snr for a G.fast line?

sg19 — Thu, 08 Apr 2021 12:41:31 GMT

Thanks xrayspex,

I assume that the nm is reasonable for the line then?

Any ideas on what else could be causing the dropouts?

It's gotten worse over time, when first installed the DSL uptime would be in weeks, now it's down to hours!

Thanks

Re: Internet dropouts - what is a good snr for a G.fast line?

pip11 — Thu, 08 Apr 2021 13:15:28 GMT

I'd still do a quiet line test. 17070 option 2, best with corded phone. You may get a dull background hub with a cordless.

Re: Internet dropouts - what is a good snr for a G.fast line?

XRaySpeX — Thu, 08 Apr 2021 15:11:58 GMT

No dice, @pip11 ! OP has bought SOGEA BB, no landline.

Re: Internet dropouts - what is a good snr for a G.fast line?

sg19 — Thu, 08 Apr 2021 15:50:22 GMT

Yep, what Xrayspex says - no landline in our package. I've tried a hardwired handset and there is no power/dialtone, so a line test will be tricky 😞

Any other ideas we should try ?

If the noise looked reasonable, maybe I'll have to speak with support and look at the router?

Appreciate the forum may not be the place for this, and g.fast is a bit niche, but thanks for the replies thus far

Re: Internet dropouts - what is a good snr for a G.fast line?

pip11 — Thu, 08 Apr 2021 16:20:50 GMT

Speaking to CS is your only route.

Re: Internet dropouts - what is a good snr for a G.fast line?

sg19 — Sat, 08 May 2021 15:56:10 GMT

Hi,

Just so that if anyone else stumbles across this thread, this is what I've done since the last message. I purchased a Modem/Router combo, the Zyxel XMG3927-B50A, that supports G.Fast out of the box. I had to set the Vlan ID to 101, and enter the usual password/username combo, but it was able to connect to the line and establish the link.

It currently sits at a sync ranging from 305-309mbps, so less than the 330 of the EE provided box - but my DSL link uptime is now sitting at 14 days, where I installed it 14 days ago... So no line drops!

I suspect my line is still somewhat at fault, and probably quite noisy, given that the BT broadband availability checker states that my line, even on the "impacted" "low" value should be 330mbps, so I may contact CS/BT to look into it more in the future

I would still be keen to know what a "good" SNR value is for a 330mbps G.Fast line, as I should be less than 100m from the box, as the cable goes - if anyone knows ?

Thanks

Re: Internet dropouts - what is a good snr for a G.fast line?

XRaySpeX — Sat, 08 May 2021 16:04:53 GMT

What are your full router stats now?

Re: Internet dropouts - what is a good snr for a G.fast line?

sg19 — Sat, 08 May 2021 19:12:34 GMT

Hi XRaySpeX, they are a SNR Margin of 17.8/12.9 and currently synced at 50.2/305 Mbps

Re: Internet dropouts - what is a good snr for a G.fast line?

XRaySpeX — Sat, 08 May 2021 19:18:32 GMT

@sg19 wrote:

so I may contact CS/BT to look into it more in the future

Not BT with whom you have no contract.

Re: Internet dropouts - what is a good snr for a G.fast line?

sg19 — Sat, 08 May 2021 19:28:00 GMT

Just CS then. What would a good SNR be for a G.Fast line @330mbps ?

Thanks

Re: Internet dropouts - what is a good snr for a G.fast line?

pip11 — Sat, 08 May 2021 21:36:16 GMT

Depends what the maximum data rate is.

Re: Internet dropouts - what is a good snr for a G.fast line?

XRaySpeX — Sat, 08 May 2021 22:07:23 GMT

NM is 6dB or 3dB on a v. stable line (but I'm not sure if that's applied to G.Fast) unless the sync speed is hitting the max speed that that BB mode is physically capable of (330 Meg on G.Fast) in which case the NM is increased accordingly.