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Standard User MrGimper
(newbie) Thu 27-Jul-17 11:59:41
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Max Sync question

[link to this post]
Hi All

I'm about 300m from my cabinet (Huawei), cabinet is 285m straight down a hill, following a row of telephone poles and manhole covers. Pole to my house, so about 300m all in. Internal wiring from outside wall to master socket down length of lounge of about 11m. Cabling done by BT at install. I'm on the infinity 2 80/20 package and get those speeds no probs. Recently replaced the BH5 with a Billion 8800nl V1 and am now seeing max downstream of ~87-88.

Question is, being close to the cabinet (I believe 300m is close), why is my max downstream not higher. I see people much further away getting max of 100-120.

I don't have any issues, just curiosity really. Stats below. Shout if you need anything else. Thanks

DSLAM/MSAN type: BDCM:0xa48c / v0xa48c
Modem/router firmware: AnnexA version - A2pv6F039g1.d24m
DSL mode: VDSL2 Profile 17a
Status: Showtime
Uptime: 22 hours 17 min 43 sec
Resyncs: 0 (since 27 Jul 2017 09:22:31)

Downstream Upstream
Line attenuation (dB): 14.2 0.0
Signal attenuation (dB): Not monitored
Connection speed (kbps): 79999 19999
SNR margin (dB): 7.4 15.1
Power (dBm): 13.9 6.4
Interleave depth: 16 1
INP: 48.00 0
G.INP: Enabled Not enabled
Vectoring status: 5 (VECT_UNCONFIGURED)

RSCorr/RS (%): 0.0000 0.1259
RSUnCorr/RS (%): 0.0000 0.0000
ES/hour: 0 8.57

adsl info --vectoring
adsl: ADSL driver and PHY status
Status: Showtime
Last Retrain Reason: 0
Last initialization procedure status: 0
Max: Upstream rate = 26698 Kbps, Downstream rate = 87631 Kbps
Bearer: 0, Upstream rate = 19999 Kbps, Downstream rate = 79999 Kbps
Bearer: 1, Upstream rate = 0 Kbps, Downstream rate = 0 Kbps
Vectoring state: 5
VCE MAC Address: 0:0:0:0:0:0
Total error samples Ethernet pkts sent: 0
Total error samples Ethernet pkts discarded: 0
Total error samples statuses sent: 0
Total error samples statuses discarded: 0
Standard User lee111s
(fountain of knowledge) Thu 27-Jul-17 12:31:02
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Re: Max Sync question

[re: MrGimper] [link to this post]
Could be different quality/guage wiring. Internal setup can hinder the max rate (extensions etc)

Crosstalk is the big player though. It's a total lottery. You can have a relatively low use cabinet but if your copper cable is in the "wrong" place in the bundle, you can suffer a lot of crosstalk from only a few other subscribers.
Standard User MHC
(sensei) Thu 27-Jul-17 12:49:42
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Re: Max Sync question

[re: MrGimper] [link to this post]
I would say your estimate of length may be a little low. Don't forget to add the rise of teh cable up teh pole, the small extra amounts from pole to pole as it is not taut and horizontal, The underground cables from last pole to the first manhole which could be 1 to 2m down, then possibly a 1m loop in each manhole and then to the original PCP, then the PCP to VDSL cabinet, possibly with some slack too.

Your attenuation suggests maybe mid to high 300s - although it could be due to lighter, finer gauge conductors. For a 14.2 dB attenuation, 88Mbps Max attainable is about right - obviously noise levels can push that up or down.

I am on a line with 16.3 dB attenuation and have a Max attainable of about 79Mbps and it is suggested that at 60Mbps and above 3dB can be worth around 11Mbps, so comparing the two there is around 2dB difference which would suggest somewhere from 6 to 10 Mbps extra so yours ties in fairly well.



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Standard User MrGimper
(learned) Thu 27-Jul-17 13:04:26
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Re: Max Sync question

[re: MHC] [link to this post]

It doesn't seem to go from pole-to-pole... looks like it comes out of the ground, up the pole and then spans from the pole across the road opposite to my house. However, totally understand your point. Wishing I'd got BT to put the master socket in where the cables entered the house, and the put the modem/router there and ran Cat 5e/6 to where the router is now. Never mind
Standard User MrGimper
(learned) Thu 27-Jul-17 13:05:39
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Re: Max Sync question

[re: lee111s] [link to this post]
Thanks. No internal extensions, not even a phone attached to the socket. Only used for BB. Just another lottery to add to the many other lotteries in life then!
Standard User Realalemadrid
(regular) Thu 27-Jul-17 13:57:39
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Re: Max Sync question

[re: MrGimper] [link to this post]
The max attainable speed is not your sync speed, it is a calculated value that has no real relevance to your actual sync speeds which are at the maximum possible for 80/20 FTTC so you are getting the best speeds that you can.
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