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Author Topic: HG612 3B + AC68U with Vodafone  (Read 1077 times)

j0hn

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Re: HG612 3B + AC68U with Vodafone
« Reply #15 on: October 03, 2019, 02:05:25 AM »

The DS is currently 55.4 with interleaving and SNRM of 6.

If the interleaving comes off you will be up to 62 ish.

If the SMRM then goes to 3 then you'll be over 70 again.

The line isn't Interleaved it has G.INP on both upstream/downstream.

3dB would take it to 65-66Mb at best.
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j0hn

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Re: HG612 3B + AC68U with Vodafone
« Reply #16 on: October 03, 2019, 02:13:34 AM »

downstream is 6db SNRM, the sync speed could just be a coincidence.

Sometimes sync speeds do fall on banding boundaries.

https://forum.kitz.co.uk/index.php/topic,16850.msg310430.html#msg310430

Quote
Yesterday, though, I started getting intermittent Internet connection issues and noticed something was up with the dsl connection as it was reconnecting a lot of times,

https://forum.kitz.co.uk/index.php/topic,23740.msg402695.html#msg402695

Quote
Hmm.. This has been locked to 55Mb since it was first plugged in, even with just the vodafone's own router/modem... Is there anything that can be done?

I'm confident the line is banded and with a resync would be 55,399 or less.

xdslcmd info --stats with attainable included would have been nicer
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retx low @ 3dB target SNRM
Zyxel VMG1312-B10A bridged with 1508 MTU + Asus RT-AC68U running Asuswrt-Merlin

temporarychicken

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Re: HG612 3B + AC68U with Vodafone
« Reply #17 on: October 03, 2019, 04:38:42 PM »

Oh I see, I saw a number other than '1' in the interleaving on the O.P. so assumed it was interleaved.

Might I ask why the SNRM is 6 if the line's been banded at 55.4? Wouldn't that be higher since 55.4 is easier to achieve than the claimed attainable of 70 ?
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j0hn

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Re: HG612 3B + AC68U with Vodafone
« Reply #18 on: October 04, 2019, 10:00:35 AM »

The SNRM shown isn't the target SNRM but it's the current SNRM.

Current SNRM changes frequently and may have dropped after syncing.

The line is also a Huawei cabinet and it could technically be on a 5dB SNRM target.
I can't work that out without seeing the --stats command with attainable figures.

edit: claimed attainable of 70 is based on line with previous ISP.
Line might not be capable of that now due to crosstalk or DLM not giving 3dB
« Last Edit: October 04, 2019, 10:04:36 AM by j0hn »
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Sptz

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Re: HG612 3B + AC68U with Vodafone
« Reply #19 on: October 09, 2019, 09:33:10 AM »

It's now changed as can be seen in the attachment. Speeds still don't sustain over 50Mb.
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j0hn

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Re: HG612 3B + AC68U with Vodafone
« Reply #20 on: October 09, 2019, 03:00:22 PM »

Could you post the output of xdslcmd info --stats (The Connection Stats tab on DslStats)

The figures in the HG612 webui are mainly incorrect.
« Last Edit: October 10, 2019, 03:46:18 PM by j0hn »
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Zyxel VMG1312-B10A bridged with 1508 MTU + Asus RT-AC68U running Asuswrt-Merlin

dee.jay

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Re: HG612 3B + AC68U with Vodafone
« Reply #21 on: October 10, 2019, 12:10:07 PM »

The sync rates are about the only ones that are actually correct.
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Weaver

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Re: HG612 3B + AC68U with Vodafone
« Reply #22 on: October 10, 2019, 02:50:06 PM »

Kitz has mentioned this I’m sure, but I forget; why do some people say that sync speed increases if there is no interleave?
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Chrysalis

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Re: HG612 3B + AC68U with Vodafone
« Reply #23 on: October 10, 2019, 03:02:45 PM »

because FEC also gets turned off and FEC uses part of the sync speed for error correction.
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j0hn

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Re: HG612 3B + AC68U with Vodafone
« Reply #24 on: October 10, 2019, 03:41:59 PM »

Kitz has mentioned this I’m sure, but I forget; why do some people say that sync speed increases if there is no interleave?

Very different to ADSL.

Interleaving on FTTC takes roughly 10% off the sync compared to fastpath.
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retx low @ 3dB target SNRM
Zyxel VMG1312-B10A bridged with 1508 MTU + Asus RT-AC68U running Asuswrt-Merlin

Chrysalis

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Re: HG612 3B + AC68U with Vodafone
« Reply #25 on: October 10, 2019, 06:05:59 PM »

Weaver my current stats on the new default interleaving.

Code: [Select]
Max:    Upstream rate = 26704 Kbps, Downstream rate = 82193 Kbps
Bearer: 0, Upstream rate = 20000 Kbps, Downstream rate = 68689 Kbps

note the large gap between max and bearer on downstream rate.
Coding gain does mask some of it tho, the actual sync speed will be below 80 on fast path but still higher than 68.
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Weaver

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Re: HG612 3B + AC68U with Vodafone
« Reply #26 on: October 12, 2019, 09:16:45 AM »

Please forgive my total ignorance - Why is is there this co-occurrence then? Straight interleaving has no overhead, by definition, just a time delay. So there must be a side order of something else that comes along when someone selects ‘interleave’ in this particular case then.

Basically I know nothing about FTTC and its quirks.

Or is there something in the g.993.2 spec itself that I should be looking at ? Not having read it properly.

@chrys About the max and bearer lines - my VMG 1312-B10A shows utter bonkersness in the max values - I can’t make any sense of it. For me it doesn’t seem to correspond to any x I can think of in “the max of x” as far as I can see

@j0hn - wait, I’m suddenly realising that I might not be reading this as intended - maybe. Are we saying that the value of the quoted sync rate drops by 10% if someone chooses interleave or that one has to take the sync rate and multiply it by 0.9 to get the effective throughput ? I just am being more than a bit slow here
« Last Edit: October 12, 2019, 09:31:09 AM by Weaver »
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j0hn

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Re: HG612 3B + AC68U with Vodafone
« Reply #27 on: October 12, 2019, 11:54:24 AM »

Interleaving comes with FEC overheads.

N - N Value (NFEC)

RS codeword size.  Reports the actual number of Reed-Solomon redundancy per codeword used in the latency path.  Used with the R value to express the rate of FEC applied.

R Value - RS check Bytes (RFEC)

Number of (redundant/parity) bytes occupied by the Error Correction process (overhead).
Often used to describe the level of error correction and can range from 0 to 20. The more check bytes that are used then the more errors can be corrected. The value 0 indicates no Reed Solomon coding.   Use this value with N to express the rate of FEC applied as a percentage. eg R/N

If Chryralis posts his full stats you can see how much overhead is used by FEC on his line with Interleaving is enabled.

Post your own --stats and compare.

A line on FTTC that is fastpath or has G.INP will sync at the full rate and show a similar attainable.

Something like
sync: 41,111
attainable: 41,216

when interleaving is enabled there's an effect on both sync and attainable.
overheads reduce sync.
attainable is inaccurate * more info below.

for the same line interleaving would do something similar to
sync: 36,132
attainable: 43,324

sync reduced, attainable increased.

*
an older inaccurate "basic" method of working out the attainable used by most modems (and Broadcom chipsets) exaggerates the attainable with INP/Interleaving. newer Lantiq chipsets/firmware use a newer "improved" method of calculating the attainable and don't do this.

There's an example on the forum of a user with a Lantiq chipset who's interleaved posting their stats before and after a firmware upgrade.
Post 1 shows an Attainable way above sync and post 2 showed an accurate attainable.
1st time I've seen an accurate attainable with interleaving which ejs suggests shows Lantiq using a better method of calculating attainable on newer firmware which makes sense.
Can't find the post.

WWWombat detailed the different ways modems can calculate the attainable in this post
« Last Edit: October 12, 2019, 06:50:19 PM by j0hn »
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Zyxel VMG1312-B10A bridged with 1508 MTU + Asus RT-AC68U running Asuswrt-Merlin

Chrysalis

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Re: HG612 3B + AC68U with Vodafone
« Reply #28 on: October 12, 2019, 05:30:27 PM »

Please forgive my total ignorance - Why is is there this co-occurrence then? Straight interleaving has no overhead, by definition, just a time delay. So there must be a side order of something else that comes along when someone selects ‘interleave’ in this particular case then.

Basically I know nothing about FTTC and its quirks.

Or is there something in the g.993.2 spec itself that I should be looking at ? Not having read it properly.

@chrys About the max and bearer lines - my VMG 1312-B10A shows utter bonkersness in the max values - I can’t make any sense of it. For me it doesn’t seem to correspond to any x I can think of in “the max of x” as far as I can see

@j0hn - wait, I’m suddenly realising that I might not be reading this as intended - maybe. Are we saying that the value of the quoted sync rate drops by 10% if someone chooses interleave or that one has to take the sync rate and multiply it by 0.9 to get the effective throughput ? I just am being more than a bit slow here

the max prediction is quite possibly not accurate when interleaving is applied, there is coding gain which will push it up tho.  The sync speed reduction comes from FEC which is enabled alongside interleaving. kitz mentions it here https://kitz.co.uk/adsl/error_correction.htm

John here is my (interleaved) stats from the midnight yesterday, you can fetch historical stats from link in my sig if you want also.

Code: [Select]
xdslctl info --stats
xdslctl: ADSL driver and PHY status
Status: Showtime
Last Retrain Reason:    1
Last initialization procedure status:   0
Max:    Upstream rate = 26774 Kbps, Downstream rate = 82359 Kbps
Bearer: 0, Upstream rate = 20000 Kbps, Downstream rate = 68689 Kbps

Link Power State:       L0
Mode:                   VDSL2 Annex B
VDSL2 Profile:          Profile 17a
TPS-TC:                 PTM Mode(0x0)
Trellis:                U:ON /D:ON
Line Status:            No Defect
Training Status:        Showtime
                Down            Up
SNR (dB):        6.1             9.4
Attn(dB):        15.2            0.0
Pwr(dBm):        4.5             4.6

                        VDSL2 framing
                        Bearer 0
MSGc:           18              150
B:              51              236
M:              1               1
T:              64              5
R:              12              16
S:              0.0241          0.3771
L:              21256           5410
D:              1345            1
I:              64              255
N:              64              255

                        Counters
                        Bearer 0
OHF:            74052238                18714292
OHFErr:         9               39
RS:             1777339917              1215827841
RSCorr:         104456          307
RSUnCorr:       13              0

                        Bearer 0
HEC:            0               0
OCD:            0               0
LCD:            0               0
Total Cells:    2253654117              0
Data Cells:     215409838               0
Drop Cells:     0
Bit Errors:     0               0

ES:             62346           7301
SES:            70              1
UAS:            145             114
AS:             114626

                        Bearer 0
INP:            3.00            0.00
INPRein:        0.00            0.00
delay:          8               0
PER:            1.54            6.15
OR:             124.06          202.87
AgR:            68813.19        20203.27

Bitswap:        41496/41497             9/9
« Last Edit: October 12, 2019, 05:40:52 PM by Chrysalis »
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