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High upstream attenuation on new 80/20 FTTC connection

pseudonoise
Newbie
Posts: 3
Registered: 19-07-2016

High upstream attenuation on new 80/20 FTTC connection

Hello, I've very recently upgraded from ADSL to the 80/20 FTTC product.

I'm most likely one of the first connections as the cabinet has just gone live after a very long wait !

The following connection speed ranges were forecast for my line (and given by Plusnet in my upgrade offer)

 

VDSL Range A (Clean) Downstream 52.8 to 68.2 Mbps and Upstream 12.3 to 18.2 Mbps

 

My reported BRAS (from Openreach tests) profile is 40.5 Mbps Downstream and 20 Mbps Upstream.

 

However I'm getting the following from my TPlink TD-W9970 router

 

Upstream  Current Rate     9466 Kbps  Max Rate  9471 kbps   SNR Margin  5.1 dB

Downstream Current Rate  46870 kbps Max Rate 55414 kbps SNR Margin  5.8 dB

Upstream Line Attenuation  38.8 dB   Packet Errors 0

DownstreamLine Attenuation 17.2 dB  Packet Errors 0

  

Which is less than forecast. The key factor appears to be the very high upstream attenuation.

I've changed routers, connected directly to the "real" master socket behind the NTE ADSL faceplate with an external filter (to eliminate any impact of extension wiring and/or filter problems in the ADSL faceplate) and all the results are almost identical.

I've spoken to Plusnet support and provided the same background data but I've had a range of differing comments the last comment that I'm on the wrong "profile" and that will be changed to 80/20.

I think the reason for the lower than expected upstream speed is due the 38dB attenuation figure compared to the 17.2 dB downstream figure.

I'd be most grateful for any advice on how to get my connection performing closer to predicted figures (especially the upstream) and the best way to work with Plusnet to this aim !

Many thanks

5 REPLIES
pseudonoise
Newbie
Posts: 3
Registered: 19-07-2016

Re: High upstream attenuation on new 80/20 FTTC connection

UPDATE

I've just been told by Plusnet Customer Service 

Question #129543671

Response

"I have tested your connection today and have found no further issues since raising fault, the connection is up and running and speeds are running within estimates."

This is not true as both the upstream and downstream connection speeds are below the lowest estimates provided in their response.

I'm not impressed.

Mantaray
Grafter
Posts: 46
Thanks: 2
Registered: 20-09-2013

Re: High upstream attenuation on new 80/20 FTTC connection

I find support answer the question they want to answer and not the one you have asked. Being ignored and not actually having my question answered since my line was messed up by the migration.
Community Veteran
Posts: 4,969
Thanks: 362
Fixes: 16
Registered: 10-06-2010

Re: High upstream attenuation on new 80/20 FTTC connection

Upstream attenuation often is higher than downstream attenuation for FTTC. Higher frequencies have higher attenuation, and the first large upstream band of frequencies is higher than the first large downstream band.

I'm not sure why Plusnet apparently quoted you the A range of speeds, self-install ought to quote the B range of speeds really. BT Consumer's "minimum guaranteed speed" is the middle of the B range.

Would a lower estimate have made a difference in your decision to upgrade (or a different ISP might have had a more suitable offering)?

pseudonoise
Newbie
Posts: 3
Registered: 19-07-2016

Re: High upstream attenuation on new 80/20 FTTC connection

Update
After talking to Plusnet last night they have updated me to tell me the SVLAN I'm on is experiencing high utilisation - and that ihas been passed to the Complex team for action. I've also signed up with Think broadband quality monitor which is also showing about 5% lost packets Sad. Which would explain problems with VoIP.

Any thoughts from the community ?
gofaster
Rising Star
Posts: 364
Thanks: 11
Registered: 01-08-2007

Re: High upstream attenuation on new 80/20 FTTC connection

A hot SVLAN can give packet loss and thus low speeds during peak periods.

But it shouldn't have any effect on your synch speed.