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Vdsl line satistics

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08 May 2021 13:19 #1 by dbigger
Vdsl line satistics was created by dbigger
I have been running my 2862ac for the last 3 months, i love the router , functions and GUI but the modem is awful, Unfourtuantlly i am on a Broadcom cabinet with sky as my ISP. From having a 32Mb connection on the sky ER115 i now have been banded to a 20Mb max profile using the Draytek. Sky say i do not have any fault on the line , but the Attenuation is 28db but i am only 815m from the cabinet. Last night The DLM was trying to bring the line down to 3db it was at 4db when i went to bed and this morning its back at 8db and has accumulated faults.
I have run some modem firmwares for 350hours with out any effect on the cap.
Looking at the line statistics status on drayteks website , the abbreviations are given a description but what is optimum?
Would a kind person explain the line satistics should i be looking for in the modem firmware for a decent line?
ie i get a better Attainable rate with a higher PSD currently 9.8db should i be looking for this figure to be higher or lower?
When the SRN margin reduces , the Attainable rate drops , (i thought it should rise) ?
the NFEC, RFEC & LYSMB appear to be different for each modem firmware.
Stats are only 5 hours old
Running Mode : 17A State : SHOWTIME
DS Actual Rate : 19998000 bps US Actual Rate : 3909000 bps
DS Attainable Rate : 24393724 bps US Attainable Rate : 3909000 bps
DS Path Mode : Fast US Path Mode : Fast
DS Interleave Depth : 1 US Interleave Depth : 1
NE Current Attenuation : 28 dB Cur SNR Margin : 7 dB
DS actual PSD : 9. 8 dB US actual PSD : 7. 4 dB
NE CRC Count : 0 FE CRC Count : 3199
NE ES Count : 0 FE ES Count : 1778
Xdsl Reset Times : 0 Xdsl Link Times : 1
ITU Version[0] : fe004452 ITU Version[1] : 41590000
VDSL Firmware Version : 07-07-0B-05-00-07 [with Vectoring support]
Power Management Mode : DSL_G997_PMS_L0
Test Mode : DISABLE
Far Current Attenuation : 34 dB Far SNR Margin : 6 dB
CO ITU Version[0] : b5004244 CO ITU Version[1] : 434da4a1
Trellis : 1 1
Bitswap : 1 1
ReTxEnable : 0 1
INTLVDelay : 0 13 (1/100 ms)
NFEC : 124 32
RFEC : 12 16
LSYMB : 1094 16
INTLVBLOCK : 124 32
AELEM : 0 ----

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08 May 2021 17:37 #2 by edinburgh
Replied by edinburgh on topic Re: Vdsl line satistics
I actually think it's a myth about the Broadcom cabinet and Draytek, as users don't take into account a number of factors that can affect the quality of the line. When we have no interference, our Draytek can hold onto the line well and I'm connected to a Huawei cabinet.

Frequent disconnections will cap your line and increase the SNR. The banding has nothing to do with the kind of router you use, but rather with the stability of the line.

So, I'd say it's a matter of testing which firmware is best for your line and if you see my queries/posts on the 2762, you'll see that there are a number of firmware types and each has two modem codes for you to try.

So, although Draytek recommend BT firmware, I found that MDM3 firmware on my 2762 and modem code 7C7717 hold my line better, until some arse of a neighbour doesn't start something that will start introducing noise on my line, resulting in a disconnection.

My line is 700m long and our attenuation is 20db, which is considered very good. You can check online calculators to see whether the length of your line and your attenuation are very good or good - see the link below. Also, our actual rate is 53Mbps at 7db (Plusnet), but that really also depends on what kind of product you have bought (fibre vs. fibre extra) and your NGS speed profile (Sky applies Standard as standard, rather than Speed as standard, as many others do), so ensure that you check that, too, by phoning them.

From your stats, you're losing 5mbps somewhere (attainable vs. actual rate), which I'd say is a lot. Have you checked your filter? Do you have a quality one? Your upstream rate is quite low, I'd say, but that really depends on what the company can offer. Ours is 15Mbps, but again, we're on fibre extra.

I'd also check which firmware you're using, as not all firmware supports vectoring. I don't actually know whether Draytek use the same firmware naming for all routers (I presume so), but looking at your modem code, I think you're using 77B507 Modem Code. 77B506 is MDM2 and which on Draytek 2762 is WITHOUT vectoring support, but yours is 77B507, which may be a different modem code from the same firmware? You'll see more details of how different modem codes support various technologies in my post about firmware on 2762.

If you'd like more information about what the stats mean etc., then have a look at this website, which explains everything in great detail: https://kitz.co.uk/adsl/

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08 May 2021 19:22 #3 by dbigger
Replied by dbigger on topic Re: Vdsl line satistics
Thank you for your reply

I have refer to KITZ website a lot and find lots of useful useful info

The calculators that determine distance from the cabinet say i am 1.8km away but the cabinet is a little over 800m ,the cables do travel underground until the pole 10m from our house there are only 7 properties between the cabinet. I am on a 17a line bu ISP's give me a max of 32Mb The filter plate has been changed i have 5 new ones, i have made a cat5e rj45 to rj11 cable ,with a BT faceplate i managed to reduce the line attenuation by 2db over flying filter . I have also bought a EXFO triple play test set to check the line for faults (should be here next week). the whole house is cat 6 so would be useful for that if not for anything else

I have previously found that the MDM3 firmware worked well and stable, but over 350 hours the DLM didn't want to return to move from a max 20MB banding . With different firmwares i can get the upload up to 5Mb, these are from the FTP site. I have tried over 16 firmwares plus to 2 modem versions in the firmware. some give a poor sync rate so rejected instantly and others start to fault when DLM reduces that line db. I would agree the frequent disconnections would cause banding. at the beginning of March my Attainable Rate was 33Mb and if snr -50 it was 38.

I am having a second line fitted on Wednesday with a different ISP , so i can compare line stats, hence that line stats question

Looking forward to the draytek load balancing to get throughput to a least X2 with a broadcom chip modem on a second WAN vdsl connection.

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08 May 2021 19:30 #4 by edinburgh
Replied by edinburgh on topic Re: Vdsl line satistics

dbigger wrote:
Thank you for your reply

I have refer to KITZ website a lot and find lots of useful useful info

The calculators that determine distance from the cabinet say i am 1.8km away but the cabinet is a little over 800m ,the cables do travel underground until the pole 10m from our house there are only 7 properties between the cabinet. I am on a 17a line bu ISP's give me a max of 32Mb The filter plate has been changed i have 5 new ones, i have made a cat5e rj45 to rj11 cable ,with a BT faceplate i managed to reduce the line attenuation by 2db over flying filter . I have also bought a EXFO triple play test set to check the line for faults. the whole house is cat 6 so would be useful for that if not for anything else

I have previously found that the MDM3 firmware worked well and stable, but over 350 hours the DLM didn't want to return to move from a max 20MB banding . With different firmwares i can get the upload up to 5Mb, these are from the FTP site. I have tried over 16 firmwares plus to 2 modem versions in the firmware. some give a poor sync rate so rejected instantly and others start to fault when DLM reduces that line db. I would agree the frequent disconnections would cause banding. at the beginning of March my Attainable Rate was 33Mb and if snr -50 it was 38.

I am having a second line fitted on Wednesday with a different ISP , so i can compare line stats, hence that line stats question

Looking forward to the draytek load balancing to get throughput to a least X2 with a broadcom chip modem on a second WAN vdsl connection.



Well, with so many disconnections then I'm not surprised that your line is banded. I'd say give your line a bit of a breather, rather than torture it so much. If you start messing too much with it, the DSLAM will think there are issues and apply corrective measures, some of which have already been applied by the sounds of it.

I don;t know how long banding will be on your line - you need to check that with others on here.

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15 May 2021 12:21 #5 by dbigger
Replied by dbigger on topic Re: Vdsl line satistics
That's i thing i don't like about the Draytek , each time a setting is changed it wants to reboot and restart, especially when you are problem sovling, if i batch of setting could be done at one time and then save and reboot? but do agree that so many disconnections will cause a problem.

With the poor installation of the second line on Wednesday by a sub contactor, Openreach have spent the last 3 days sorting out line issues and this should be sorted by Tuesday the 18th including a reset to DLM to all lines.

I have now created another problem of not being able to watch sky demand in a sessions load balancing mode, But i can get twice the download speed.

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16 May 2021 09:08 #6 by edinburgh
Replied by edinburgh on topic Re: Vdsl line satistics

dbigger wrote:
That's i thing i don't like about the Draytek , each time a setting is changed it wants to reboot and restart, especially when you are problem sovling, if i batch of setting could be done at one time and then save and reboot? but do agree that so many disconnections will cause a problem.

With the poor installation of the second line on Wednesday by a sub contactor, Openreach have spent the last 3 days sorting out line issues and this should be sorted by Tuesday the 18th including a reset to DLM to all lines.

I have now created another problem of not being able to watch sky demand in a sessions load balancing mode, But i can get twice the download speed.


But you don't have to reboot each time. Simply click on another item on the menu, make further changes and then reboot on the final one.

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