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Standard User Sooty_UK
(newbie) Thu 18-Feb-21 12:16:45
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BT-SOGEA Service Issue - VDSL/VDSL2 FTTC


[link to this post]
 
#### Issues with BT SOGEA-FTTC Service ####

Had my TTB-FTTC 80/20 service change over to BT-SOGEA-FTTC 80/20 and I have noted the following issues:-

Post Upgrade of service:-

1. Service will only SYNC with certain CPE’s – Example Cisco C887 and C927
2. SNR levels are as per the stated rates circa 6.2/6.3 dB for Downstream/Upstream
3. Line KDB indicated High Resistance – Openreach attended FNF – NTE replace with 5c variant
4. Openreach reset the DLM – at time of visit. Openreach also stated that my service was Cooper all the way to the exchange.
5. The equipment that does not achieve SYNC I note while trying to train an “Estimated Loop Length” of 900m is seen.
6. I know my local plant route to serving PCP and that distance is 500m – this was also confirmed by Openreach Engineer who attended site via his line diagnostics.
7. The Exchange that is served from the PCP is 900m from my location. Summary, Property to PCP 500m, PCP to Exchange 400m. Total 900m same indication as the “Estimated Loop Length”
8. Taken equipment to another property served via the same PCP, it is enabled with a TTB-FTTC 40/10 Service – Result all equipment achieves SYNC. Distance noted total 475m, Property to PCP 75m, PCP to Exchange 400m.
9. Had the Profile for the BT SOGEA-FTTC change to 40/10 noted that the SNR level increased to 11.2/6.2 dB Downstream/Upstream – no improvement to achieve SYNC. Profile applied is “Super Stable”.
10. Took equipment to a Property with SKY-FTTC 80/20 and noted that all SYNC and achieve PPP sessions (PPPOE).

Now here is the difference –

11. The “Estimated Loop Length” gave an indication of 338m – the property is served via PCP 4, off the same serving exchange. PCP 4 is 338m away from the Property. Noise Margin (dB): 2.5/6.2 Downstream/Upstream.

The distance to the Exchange is 2.3km – this indicates to me that the modem in the unit has achieved SYNC to the DSLAM in PCP-4 (or adjacent to it). Whereas the connection enabled with the SOGEA service is being served via a DSLAM in the Exchange and not adjacent to PCP-1.

Summary:-

I have ruled out Equipment being the issue – used 2 Vendors Cisco and Digi both with ADSL2+/VDSL2 capable modems.

Cisco – SYNC’s on SOGEA-FTTC, TTB-FTTC and SKY-FTTC
Cisco – “Clear Counters” command result - Drops VDSL Connection if connected to SOGEA-FTTC but remains stable if connected to TTB-FTTC and SKY-FTTC
* Note The same condition is noted on both the C887 and C927 units.

Digi – Cannot achieve SYNC on SOGEA-FTTC, SYNC’s on TTB-FTTC and SKY-FTTC

It would appear that services for SOGEA-FTTC are terminated to a DSLAM that is in the Local Exchange, I make this assumption based on the “Estimated Loop Length” indicated for the SOGEA-FTTC and the TTB-FTTC which are both served by PCP-1.

My understanding for any FTTC based service is that the Digital element should be cross tied to the DSLAM at the PCP for onward delivery to the OLT (Optical Line Terminal) located in the exchange. I am unclear if the Analogue service has been discounted from MDF to PSTN service in the Exchange – however the number previously associated with service is “Not in Service”. So I assume this to be the case.

Cisco Units have the current Firmware – Validated for BT Services
Digi Unit is EOL/EOS – all available firmware’s have been tested.

My next course of Action is to raise a “Special Fault Investigation” with my CP as both Access and Digital services are provided by them.

Any suggestions as to why the above conditions are being noted would be appreciated.
Standard User dect
(fountain of knowledge) Thu 18-Feb-21 13:07:48
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Re: BT-SOGEA Service Issue - VDSL/VDSL2 FTTC


[re: Sooty_UK] [link to this post]
 
In reply to a post by Sooty_UK:
Had my TTB-FTTC 80/20 service change over to BT-SOGEA-FTTC 80/20
Some questions,

1) What speed was you getting on TTB-FTTC 80/20 and what speed are you now getting on BT-SOGEA-FTTC 80/20?

2) What line attenuation was you getting on TTB-FTTC 80/20 and what line attenuation are you now getting on BT-SOGEA-FTTC 80/20?

3) Was your line ever EO?

4) What exchange serves you property for copper services?

5) What head end exchange serves your area for fibre services?


Edit: I believe just because you are now on SOGEA doesn't mean they disconnect the main cable pair (E side), the line test equipment is still located in your local PSTN exchange so you still have a main cable pair for that purpose.

Edited by dect (Thu 18-Feb-21 13:16:25)

Standard User Sooty_UK
(newbie) Thu 18-Feb-21 13:27:05
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Re: BT-SOGEA Service Issue - VDSL/VDSL2 FTTC


[re: dect] [link to this post]
 
1) What speed was you getting on TTB-FTTC 80/20 and what speed are you now getting on BT-SOGEA-FTTC 80/20?
Answer:- 68/16

2) What line attenuation was you getting on TTB-FTTC 80/20 and what line attenuation are you now getting on BT-SOGEA-FTTC 80/20?
Answer:-
TTB - No view

SOGEA - See below - Showtime status

Modem Status: TC Sync (Showtime!)
DSL Config Mode: AUTO
Trained Mode: G.993.2 (VDSL2) Profile 17a
TC Mode: PTM
Selftest Result: 0x00
DELT configuration: disabled
DELT state: not running
Trellis: ON ON
SRA: disabled disabled
SRA count: 0 0
Bit swap: enabled enabled
Bit swap count: 0 0
Line Attenuation: 0.0 dB 0.0 dB
Signal Attenuation: 0.0 dB 0.0 dB
Noise Margin: 14.9 dB 22.2 dB
Attainable Rate: 110756 kbits/s 38241 kbits/s
Actual Power: 12.6 dBm - 7.7 dBm
Per Band Status: D1 D2 D3 U0 U1 U2 U3
Line Attenuation(dB): 4.0 9.4 14.9 3.7 8.3 10.8 N/A
Signal Attenuation(dB): 4.0 9.4 14.9 3.7 7.7 10.1 N/A
Noise Margin(dB): 15.1 14.7 14.9 22.6 21.6 22.5 N/A
Total FECC: 65 60
Total ES: 0 8
Total SES: 0 0
Total LOSS: 0 0
Total UAS: 0 0
Total LPRS: 0 0
Total LOFS: 0 0
Total LOLS: 0 0


3) Was your line ever EO?
Answer:- No the line was not an Exchange Only Line

4) What exchange serves you property for copper services?
Answer:- MYELL Exchange - Cabinet 1

4) What head end exchange serves your area for fibre services?
Answer:- MYELL


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Standard User dect
(fountain of knowledge) Thu 18-Feb-21 13:54:25
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Re: BT-SOGEA Service Issue - VDSL/VDSL2 FTTC


[re: Sooty_UK] [link to this post]
 
Personally I don't believe you are being served by a DSLAM at the exchange.
Standard User Sooty_UK
(newbie) Thu 18-Feb-21 14:05:14
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Re: BT-SOGEA Service Issue - VDSL/VDSL2 FTTC


[re: dect] [link to this post]
 
Hello Thanks for the comment - good to understand why you think that.

I am sure that OR will provide clarity - booked for SFI.
Standard User Realalemadrid
(committed) Thu 18-Feb-21 14:48:59
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Re: BT-SOGEA Service Issue - VDSL/VDSL2 FTTC


[re: Sooty_UK] [link to this post]
 
I would say that you are still being served by the same cabinet that you were on for TTB FTTC. Why would it change? There is no possibility of SOGEA coming direct from the exchange so whoever told you it was copper all the way to the exchange is wrong.

Your modem stats are not very helpful, the sync speeds are not shown, the attainable rates are high but are only calculated values so don't mean much. The downstream band attenuation figures are fairly low so you are definitely not 900 m from the cabinet, more like a few hundred. However the noise margin figures are way too high, should be around 6dB or even less on downstream. I guess your throughput speeds are a lot less than you got on the TTB service.

What happens if you do a single resync does anything change, can you find the actual sync speeds in the modem stats because that is what you need to see?
Standard User dect
(fountain of knowledge) Thu 18-Feb-21 15:02:53
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Re: BT-SOGEA Service Issue - VDSL/VDSL2 FTTC


[re: Sooty_UK] [link to this post]
 
In reply to a post by Sooty_UK:
Hello Thanks for the comment - good to understand why you think that.
If you're getting 68Mbps download (on the 80/20 services) and cable line loss is typically 13.8dB per kilometre (assuming copper not aluminium), your distance from the DSLAM would be about 514 metres which matches with the 500 metres quoted by you and the Openreach engineer.
Standard User Sooty_UK
(newbie) Thu 18-Feb-21 19:36:16
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Re: BT-SOGEA Service Issue - VDSL/VDSL2 FTTC


[re: Realalemadrid] [link to this post]
 
Thanks for feedback

So to clarify - when the Service was first deployed the service was 80/20
the Cisco Displayed the following:-

Controller VDSL 0 is UP

Daemon Status: Up

XTU-R (DS) XTU-C (US)
Chip Vendor ID: 'BDCM' 'IFTN'
Chip Vendor Specific: 0x0000 0xD086
Chip Vendor Country: 0xB500 0xB500
Modem Vendor ID: 'CSCO' ' Iet'
Modem Vendor Specific: 0x4602 0x656C
Modem Vendor Country: 0xB500 0x4345
Serial Number Near: FGL2417LVWP C927-4P 15.9(3)M2
Serial Number Far:
Modem Version Near: 15.9(3)M2
Modem Version Far: 0xd086

Modem Status: TC Sync (Showtime!)

DSL Config Mode: AUTO
Trained Mode: G.993.2 (VDSL2) Profile 17a

TC Mode: PTM
Selftest Result: 0x00
DELT configuration: disabled
DELT state: not running
Link Status: UP

Full inits: 2
Failed full inits: 0
Short inits: 0
Failed short inits: 0

Firmware Source File Name
-------- ------ ----------
VDSL user config flash:c900_VA_A_39x3_B_39x3_26u.bin-v2

Modem FW Version: 4.14L.04
Modem PHY Version: A2pv6F039x3.d26u

Line:

XTU-R (DS) XTU-C (US)
Trellis: ON ON
SRA: disabled disabled
SRA count: 0 0
Bit swap: enabled enabled
Bit swap count: 61 1
Line Attenuation: 16.7 dB 0.0 dB
Signal Attenuation: 0.0 dB 0.0 dB
Noise Margin: 6.1 dB 6.0 dB
Attainable Rate: 76941 kbits/s 16339 kbits/s
Actual Power: 13.7 dBm 6.8 dBm
Per Band Status: D1 D2 D3 U0 U1 U2 U3
Line Attenuation(dB): 11.4 28.3 44.7 5.4 23.0 36.5 N/A
Signal Attenuation(dB): 10.7 28.0 44.7 5.2 22.8 36.3 N/A
Noise Margin(dB): 6.2 6.0 6.0 7.1 6.0 6.0 N/A
Total FECC: 6494 11
Total ES: 10 6484
Total SES: 10 0
Total LOSS: 1 0
Total UAS: 39 19010
Total LPRS: 0 0
Total LOFS: 8 0
Total LOLS: 0 0


DS Channel1 DS Channel0 US Channel1 US Channel0
Speed (kbps): 0 64501 0 16315
SRA Previous Speed: 0 0 0 0
Previous Speed: 0 64579 0 16345
Reed-Solomon EC: 0 6494 0 11
CRC Errors: 0 0 0 3
Header Errors: 0 2 0 0
Interleave (ms): 0.00 8.00 0.00 0.00
Actual INP: 0.00 3.00 0.00 0.00

Training Log : Stopped
Training Log Filename : flash:vdsllog.bin

Post Change to 40/10 service the following is relevant

Controller VDSL 0 is UP

Daemon Status: Up

XTU-R (DS) XTU-C (US)
Chip Vendor ID: 'BDCM' 'IFTN'
Chip Vendor Specific: 0x0000 0xD086
Chip Vendor Country: 0xB500 0xB500
Modem Vendor ID: 'CSCO' ' '
Modem Vendor Specific: 0x4602 0x0000
Modem Vendor Country: 0xB500 0x0000
Serial Number Near: FCZ202191VK C887VA-K 15.5(3)M
Serial Number Far:
Modem Version Near: 15.5(3)M
Modem Version Far: 0xd086

Modem Status: TC Sync (Showtime!)

DSL Config Mode: VDSL2
Trained Mode: G.993.2 (VDSL2) Profile 17a
TC Mode: PTM
Selftest Result: 0x00
DELT configuration: disabled
DELT state: not running

Full inits: 7
Failed full inits: 0
Short inits: 0
Failed short inits: 0

Firmware Source File Name
-------- ------ ----------
VDSL user config flash:vdsl.bin-A2pv6C035j1

Modem FW Version: 120330_1738-4.02L.03.A2pv6C035j0.d23j
Modem PHY Version: A2pv6C035j0.d23j
Trellis: ON ON
SRA: disabled disabled
SRA count: 0 0
Bit swap: enabled enabled
Bit swap count: 0 0
Line Attenuation: 0.0 dB 0.0 dB
Signal Attenuation: 0.0 dB 0.0 dB
Noise Margin: 11.2 dB 6.1 dB
Attainable Rate: 73800 kbits/s 13386 kbits/s
Actual Power: 13.8 dBm 6.6 dBm
Per Band Status: D1 D2 D3 U0 U1 U2 U3
Line Attenuation(dB): 11.1 28.3 46.0 5.2 23.1 36.4 N/A
Signal Attenuation(dB): 11.1 28.3 46.0 4.9 22.9 36.2 N/A
Noise Margin(dB): 11.1 11.3 11.2 8.6 6.3 6.0 N/A
Total FECC: 10801 98679
Total ES: 5 6652
Total SES: 5 0
Total LOSS: 5 0
Total UAS: 23 238195
Total LPRS: 0 0
Total LOFS: 5 0
Total LOLS: 0 0


DS Channel1 DS Channel0 US Channel1 US Channel0
Speed (kbps): 0 39998 0 8496
SRA Previous Speed: 0 0 0 0
Previous Speed: 0 39998 0 8496
Reed-Solomon EC: 0 10416 0 98679
CRC Errors: 0 2197 0 0
Header Errors: 0 0 0 0
Interleave (ms): 0.00 12.00 0.00 4.00
Actual INP: 0.00 8.00 0.00 4.00

Training Log : Stopped
Training Log Filename : flash:vdsllog.bin

The unit that won't SYNC on SOGEA displays the following:- Note the Loop Length

ss541313>adslst
Modem Status: Inactive
Link Uptime: 0 Hrs 0 Mins 0 Secs
Firmware Version: SW 1.11
Operational Mode: -
Remote Vendor ID:
Est'd Loop Length (ft): 2626

Downstream Upstream
-------------- --------------
Speed (kbps): 0 0
Attainable Rate (kbps): 0 0
Relative Capacity (%): 0 0
Attenuation (dB): 0.0 0.0
Noise Margin (dB): 0.0 0.0
Output Power (dBm): 0.0 0.0
FEC: 0 0
CRC: 0 0
HEC: 0 0

Same Unit connected on the TTB-FTTC Service which is served via the same PCP.

ss541313>adslst
Modem Status: Showtime
Link Uptime: 0 Hrs 6 Mins 32 Secs
Firmware Version: SW 1.11
Operational Mode: VDSL2 Profile 17A
Remote Vendor ID: IFTN
Est'd Loop Length (ft): 1560

Downstream Upstream
-------------- --------------
Speed (kbps): 39992 4888
Attainable Rate (kbps): 63084 5274
Relative Capacity (%): 63 92
Attenuation (dB): 24.8 0.1
36.1
46.6
0.0
0.0
Noise Margin (dB): 11.5 6.3
6.3
6.2
0.0
0.0
Output Power (dBm): 13.7 6.4
FEC: 211 27495
CRC: 0 3978
HEC: 0 0

To be clear - Openreach informed me I was connected to exchange on Cooper all the way - I questioned this stating this is an FTTC service and I should be terminated at PCP to the DSLAM .

If the Est'd Loop Length is accurate then the terminating DSLAM is not within Range and the Distance noted is accurate to the actual distance based on the Route between Property and Exchange via PCP.
Standard User mysticeddy
(regular) Thu 18-Feb-21 23:03:27
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Re: BT-SOGEA Service Issue - VDSL/VDSL2 FTTC


[re: Sooty_UK] [link to this post]
 
In reply to a post by Sooty_UK:
If the Est'd Loop Length is accurate then the terminating DSLAM is not within Range and the Distance noted is accurate to the actual distance based on the Route between Property and Exchange via PCP.


There’s no “if” here; the estimate is not accurate. As dect says, you would not get the sync speed you are currently attaining if you were indeed served from a DSLAM in the exchange.
Standard User dect
(fountain of knowledge) Fri 19-Feb-21 09:27:38
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Re: BT-SOGEA Service Issue - VDSL/VDSL2 FTTC


[re: Sooty_UK] [link to this post]
 
In reply to a post by Sooty_UK:
Est'd Loop Length (ft): 2626
There are a few issues with your assumption

1) 2626 ft = 800m not 900m you claim is the distance to your local exchange (MYELL)

2) I have explained that 68Mbps means you're more likely to be served by a DSLAM connected to PCP 1 (500m) than a DSLAM at MYELL Exchange (900m)

3) The only DSLAM (VDSL2) in Coronation Street is outside the exchange connected to PCP 28 and it serves the local area.

4) I have explained that your line will pass through a DSLAM (connect to PCP 1) where the VDSL tones will be added but will still continue on to MYELL exchange as it still needs to be connected to line testing equipment. I suspect this is what the engineer meant although may not have explained it clearly to you.

I really don't know why your own kit (Cisco/Digi) will not SYNC, I suspect the SFI engineer will test and possibly change the DSLAM port and D side pairs if required but I don't think they are going to support your own kit, If you have a ISP router and it works you will probably be left to investigate it further yourself.

Edit: added some clarity for point 2

Edited by dect (Fri 19-Feb-21 15:57:50)

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