Slow downstream sync rate for the attenuation

Forums › 2degrees (including Slingshot, Orcon, Flip, Stuff Fibre, MyRepublic, 2talk and Vocus) › Slow downstream sync rate for the attenuation

influx

26 posts

Geek

#151059 12-Aug-2014 19:04

The situation: Good ping, good upstream, bad downstream

After moving house the first line stats showed
attenuation: 31db
downstream: 3863kbps
upstream: 1095kbps
ping: surprisingly very good at 10ms akl/35ms aus/135ms usa west coast

There was a phone jack downstairs that wasn't working so initially that was my suspicion as causing some of the problem along with bad wiring somewhere, so after waiting 2 frustrating months dealing with overseas staff who after putting me on a bunch of "faster" profiles made it even slower (2.7mbps), and contradict each other whether interleaving was on or off even though I could see the status of it in the router stats (this was a major facepalm), Orcon finally sent a Chorus tech who fixed the faulty phone jack and that immediately bumped up the downstream to 8000kbps. He also installed a master splitter but unfortunately that didn't change anything. I was also advised that outside the house and at the exchange my line was getting a max of 9000kbps and cant be improved any further.

Since then the router stats have been
attenuation: 31db
downstream: 7500-8200kbps
upstream: 1031kbps
ping: the same

SNR Margin has also stayed at around 9db as I'm on Orcon ULL gear I think. Upstream has slightly decreased though..

A few things that I don't understand are
Before the phone jack was fixed, why was the upstream nearly maxed but downstream was that bad? Shouldn't the upstream have been affected too?
Why does Chorus see my lines max at 9Mbps at the exchange if the attenuation is 31db? Shouldn't it be around 14/15mbps?
How is the ping so good relative to the rather poor line quality?

Would a port reset help? Or to switch from Orcon ULL gear to Telecom?
As a gamer I'm happy with the ping and don't want to make any changes that might affect it for the worse. But I want to get to the bottom of why the line stats are this weird.
I've exhausted my options talking to the tech support on the phone, and would appreciate if an actual NZ based person with a bit more knowledge on the subject could explain certain things.

RunningMan

8953 posts

Uber Geek

#1107241 12-Aug-2014 19:22

8000kb/s downstream is about right for 31dB attenuation. On perfect lines with no-one else using xDSL (i.e. no crosstalk) you could get faster, but real world, what you have is fine.

The upstream uses a different part of the frequency spectrum, so is less affected by physical wiring issues.

Latency (ping) is dependant on the interleaving setting, not sync rate. Higher sync rate means more data per second, not that the data gets there any quicker. The interleaving is what affects the time it takes for that data to get to the other end.

EDIT: You don't have a poor quality line, it is just long.

hio77

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Lizard Networks

#1107256 12-Aug-2014 19:22

ping has nothing todo with your connection rates, the main thing that will contribute to it is interlevings.

depending on distance, its very possible to get in the 5ms range to your local city with interlevings off.

upstream, your talking 60kbit, thats within the realm of noise causing a slightly slower sync, and anthing over 1mbit for adsl is pretty nice on its own.
if you really care about upstream, ild speak to orcon to see if they offer annex M on their gear.

likely your better off on ULL than chorus gear, its uncommon to be put on the wrong network nowdays.

While it is possible, the line could be faster given your attenuation and snr.. you need to consider crosstalk, and cable quality. As you have a master filter already installed, your internal wiring is near perfect already.
If the chorus tech didnt run a new Cat5 run when he installed the filter, it is possible replacing the cable from the ETP to your DSL jackpoint MAY net you a slight boost.

#include <std_disclaimer>

Any comments made are personal opinion and do not reflect directly on the position my current or past employers may have.

Behodar

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#1107267 12-Aug-2014 20:12

RunningMan: 8000kb/s downstream is about right for 31dB attenuation.

I'm at 27 and get 14500, so in my opinion 8000 does look a bit low for 31.

Try to find out whether you're on a cabinet or connected directly to the exchange. If it's a cabinet then you should ask to be moved to Chorus gear.

WrEK

86 posts

Master Geek

#1107547 13-Aug-2014 12:07

influx:

Since then the router stats have been
attenuation: 31db
downstream: 7500-8200kbps
upstream: 1031kbps
ping: the same

Possibly modulating on ADSL1, have a look and if so try setting to ADSL2+ G.992.5

influx

26 posts

Geek

#1107578 13-Aug-2014 12:43

Behodar:
RunningMan: 8000kb/s downstream is about right for 31dB attenuation.

I'm at 27 and get 14500, so in my opinion 8000 does look a bit low for 31.

Try to find out whether you're on a cabinet or connected directly to the exchange. If it's a cabinet then you should ask to be moved to Chorus gear.

According to Chorus maps, and Orcon I'm connected to the exchange. In the >10 Mbps zone.
The Chorus guy said I was connected to a small older cabinet, not the bigger mainstream ones using fibre.

influx

26 posts

Geek

#1117952 29-Aug-2014 13:36

influx: Why does Chorus see my lines max at 9Mbps at the exchange if the attenuation is 31db? Shouldn't it be around 14/15mbps?

So this still doesn't make any sense....

RunningMan

8953 posts

Uber Geek

#1117986 29-Aug-2014 14:28

It is impacted by the quality and type if cable installed in your area as well as crosstalk from other xDSL services in the same feeder so you can't make an exact comparison between a given attenuation and a sync rate.

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Coil

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#1117987 29-Aug-2014 14:32

You cant just say 31dB will get you 12Mb/s or what ever. Its all dependant on the guage and quality of the copper and how many joins plus crosstalk to name a few. I have seen lines at 30Db get 16Mb/s and other get 5Mb/s at best.

sbiddle

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#1117988 29-Aug-2014 14:33

influx:
influx: Why does Chorus see my lines max at 9Mbps at the exchange if the attenuation is 31db? Shouldn't it be around 14/15mbps?

So this still doesn't make any sense....

It makes lots of sense. Attenuation is simply one variable of many that determine what sync rates will be.

dcole13

534 posts

Ultimate Geek

#1118030 29-Aug-2014 16:25

WrEK:
influx:

Since then the router stats have been
attenuation: 31db
downstream: 7500-8200kbps
upstream: 1031kbps
ping: the same

Possibly modulating on ADSL1, have a look and if so try setting to ADSL2+ G.992.5

Try this. I have been with Orcon for a while, and then recently when I was only getting 8Mbps down they found out that I was on ADSL1 instead of ADSL2+. Also, if you don't have a master splitter get one now.

Home ADSL: School:

influx

26 posts

Geek

#1118219 29-Aug-2014 20:39

My router is definitely set to ADSL2+ and hasn't been changed since the last house where I was seeing speeds of 16Mbps.

Looks like I'm outta luck then. Thanks for the informative replies.

RunningMan

8953 posts

Uber Geek

#1118255 29-Aug-2014 21:34

influx: My router is definitely set to ADSL2+ and hasn't been changed since the last house where I was seeing speeds of 16Mbps.

Different house + different line + different feeder + different cable gauge = different crosstalk & different sync rate.