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Author Topic: G.fast - Band Plan changes?  (Read 865 times)

re0

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G.fast - Band Plan changes?
« on: August 22, 2019, 02:09:02 AM »

I had a resync at approx. quarter past midnight. I had investigated it since I have been having some weird spikes recently, some that have knocked out connectivity. In this case, nothing prior to the resync - just 1 as the Retrain Reason.

What I did notice was a sizeable increase in downstream attainable, going from 347 Mbps to 383 Mbps.

Before:
Code: [Select]
Max:    Upstream rate = 67849 Kbps, Downstream rate = 347559 Kbps
Bearer: 0, Upstream rate = 50016 Kbps, Downstream rate = 335116 Kbps

Link Power State:       L0
Mode:                   G.fast Annex A
TPS-TC:                 PTM Mode(0x0)
Trellis:                U:ON /D:ON
Line Status:            No Defect
Training Status:        Showtime
                Down            Up
SNR (dB):        4.7             8.8
Attn(dB):        31.5            0.0
Pwr(dBm):        0.0             4.0
After:
Code: [Select]
Max:    Upstream rate = 67037 Kbps, Downstream rate = 383312 Kbps
Bearer: 0, Upstream rate = 49976 Kbps, Downstream rate = 328995 Kbps

Link Power State:       L0
Mode:                   G.fast Annex A
TPS-TC:                 PTM Mode(0x0)
Trellis:                U:ON /D:ON
Line Status:            No Defect
Training Status:        Showtime
                Down            Up
SNR (dB):        6.9             9.1
Attn(dB):        29.2            0.0
Pwr(dBm):        0.0             4.1

10% would be a lot if no variables had changed, so there must have been a reason - and there was:
Before*:
Code: [Select]
Discovery Phase (Initial) Band Plan
US: (368,1927)
DS: (368,1927)
Medley Phase (Final) Band Plan
US: (368,1808)
DS: (368,1674)
After:
Code: [Select]
Discovery Phase (Initial) Band Plan
US: (348,1802)
DS: (342,1666)
Medley Phase (Final) Band Plan
US: (348,1800)
DS: (342,1666)
It seems they have adjusted the Band Plan for Downstream so it starts 1345.5 kHz lower, and 1035 kHz lower for the Upstream (this is based on 51.75 kHz spacing). The initial plans have changed, too; the Downstream is 13506.75 kHz less at higher frequencies, and Upstream is 6468.75 kHz less.

If we look back to end of May this year, ISPreview had posted some news here about G.fast co-existence. While options have been considered to improve speed and coverage, it seems reducing the start point for G.fast to approx. 17.7 MHz is what has been taken - at least for now.

19.044 ((368 * 51.75)/1000 - previous G.fast start point, in MHz) minus 1.3455 equals 17.6985 MHz, which is only a little above 17.664 MHz (bandwidth for VDSL 17a). While I could be a little bit off, this would still suggest that the start point has been reduced.

In conclusion, it seems Openreach may be now rolling out these changes nationwide to improve coverage (and bring existing users a speed boost). I am not aware of the exact changes made, so I am going on the information I have from my own connection and comparing historical data.

If anyone has access to their G.fast stats, it would be appreciated if you could take a look to see whether your connection has been subject to these changes yet.

*This was not directly before the resync since DSLstats had not been logging pbParams, but these stats are still applicable having checked bitloading from the last snapshot.

Edits:
22/08/2019, 12:48: Clarified some information, fixed a mistake.
« Last Edit: August 22, 2019, 12:48:06 PM by re0 »
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spudgun

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Re: G.fast - Band Plan changes?
« Reply #1 on: August 22, 2019, 04:43:28 AM »

Most interesting, I don't have access to detailed stats via my mt992 (and I'm in Vancouver at the moment) but your post inspired me to check my line data on the Zen portal.
I seem to have had a resync on 22nd August at 0:07 which is my first resync in a couple of months and I've seen a downstream increase from 229mb to 244mb which would be the highest ever for my line. There is no change to my 35mb upload.

It will be interesting to see if other people have seen something similar.
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kitz

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Re: G.fast - Band Plan changes?
« Reply #2 on: August 22, 2019, 09:33:23 AM »

Interesting.   Thank you for reporting your findings.   Nice little speed boosts there  :thumbs:
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j0hn

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Re: G.fast - Band Plan changes?
« Reply #3 on: August 22, 2019, 12:00:32 PM »

https://www.ispreview.co.uk/index.php/2019/08/band-plan-change-boosts-speed-on-some-uk-g-fast-broadband-lines.html

Info taken from and linked to this thread.
Positive change from OpenReach. Pointless having such a large gap in spectrum if it's not needed.
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re0

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Re: G.fast - Band Plan changes?
« Reply #4 on: August 22, 2019, 01:11:10 PM »

I was contemplating not posting about this, but I am glad I did now.

A free speed boost is a good speed boost. Even though us closer-to-the-cab people can't benefit from speed, it gives a nice margin. :)

From the article:
Quote
We have asked the operator and are awaiting their feedback, so at the moment this is not confirmed.
Would be interesting to know whether there have been other changes I haven't picked up on, and whether this is nationwide yet.
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adslmax

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Re: G.fast - Band Plan changes?
« Reply #5 on: August 22, 2019, 01:31:30 PM »

Maybe Openreach has finally listened to my complaints few months ago over poor estimated speed on G.fast 114/9 but still not good enough. Hoping for FTTP to come along from this ISP Exascale
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Browni

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Re: G.fast - Band Plan changes?
« Reply #6 on: August 22, 2019, 02:35:59 PM »

Same here @re0.

I'm not at home so don't have full access to my line stats but a live view can be seen at http://stats.browni.co.uk/
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dee.jay

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Re: G.fast - Band Plan changes?
« Reply #7 on: August 22, 2019, 04:46:57 PM »

Would this imply that the distance reach for G.Fast has extended slightly?
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re0

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Re: G.fast - Band Plan changes?
« Reply #8 on: August 22, 2019, 07:20:46 PM »

I'm not at home so don't have full access to my line stats but a live view can be seen at http://stats.browni.co.uk/
I see a change in your downstream pattern that may suggest the change is in effect for you. You could probably tell from an Attenuation drop (which appears to be applicable from a previous post of yours), but most reliable way of looking at pbParams since it would outline the Band Plan. Note: At least on my Zyxel and DSLstats v6.5, pbParams doesn't update automatically so it may be necessary to run with --pbParams parameter in telnet or SSH.

Would this imply that the distance reach for G.Fast has extended slightly?
Very slightly. Though I would guess the biggest sync speed (note: NOT attainable) gains for those with approx. 240m line length since it should bring them close to 330 Mbps downstream. For upstream, I have not seen anything convincing yet to suggest any improvement to speed so far.
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adslmax

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Re: G.fast - Band Plan changes?
« Reply #9 on: August 22, 2019, 09:10:54 PM »

re0 will these see slight change in dsl checker estimated speed range?
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re0

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Re: G.fast - Band Plan changes?
« Reply #10 on: August 22, 2019, 09:36:27 PM »

re0 will these see slight change in dsl checker estimated speed range?
Not seen any yet, but still early days. I presume that the estimates will be updated after few days following these changes.
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re0

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Re: G.fast - Band Plan changes?
« Reply #11 on: September 11, 2019, 02:19:01 PM »

It's been a few weeks, and I thought I should drop an update stating that I have seen no changes to the DSL checker estimates for G.fast following this Band Plan change. I thought there would be a slight increase, but perhaps they are going to be conservative with the estimates or it isn't prime time yet.
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kitz

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Re: G.fast - Band Plan changes?
« Reply #12 on: September 12, 2019, 08:04:07 AM »

Thanks for checking and letting us know.  Please do tell if they do update.
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S.Stephenson

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Re: G.fast - Band Plan changes?
« Reply #13 on: September 16, 2019, 11:10:02 PM »

it isn't prime time yet.

It doesn’t look like G.fast will ever see prime time.
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re0

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Re: G.fast - Band Plan changes?
« Reply #14 on: September 17, 2019, 01:12:00 AM »

It doesn’t look like G.fast will ever see prime time.
Sure, talking about it in general. :D But I was referring to it being prime time for changes to the estimates. :)
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