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Standard User No_One
(committed) Tue 01-Jan-13 17:34:16
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Reduced SNR = No speed increase


[link to this post]
 
I've just tried reducing my SNR from 6 to 3 but I'm seeing no change in sync. Has anyone got any idea why this might be? Am I just hoping for too much? My router is a Billion Bipac 7800N and my ISP is Zen

Here's the stats from telnet before

adsl: ADSL driver and PHY status
Status: Showtime
Retrain Reason: 8000
Max: Upstream rate = 1164 Kbps, Downstream rate = 18408 Kbps
Path: 0, Upstream rate = 1167 Kbps, Downstream rate = 14335 Kbps

Link Power State: L0
Mode: ADSL2+
TPS-TC: ATM Mode
Trellis: U:ON /D:ON
Line Status: No Defect
Training Status: Showtime
Down Up
SNR (dB): 6.1 5.4
Attn(dB): 26.0 14.0
Pwr(dBm): 0.0 12.9

And stats after

adsl: ADSL driver and PHY status
Status: Showtime
Retrain Reason: 8000
Max: Upstream rate = 1172 Kbps, Downstream rate = 17336 Kbps
Path: 0, Upstream rate = 1171 Kbps, Downstream rate = 14328 Kbps

Link Power State: L0
Mode: ADSL2+
TPS-TC: ATM Mode
Trellis: U:ON /D:ON
Line Status: No Defect
Training Status: Showtime
Down Up
SNR (dB): 3.4 6.0
Attn(dB): 26.0 14.0
Pwr(dBm): 0.0 12.6
Standard User ukhardy07
(fountain of knowledge) Tue 01-Jan-13 18:52:54
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Re: Reduced SNR = No speed increase


[re: No_One] [link to this post]
 
EDIT RE-READ WHAT YOU WROTE.

Your SNR has reduced so what I wrote was irrelevant and as such I've removed it.

Edited by ukhardy07 (Tue 01-Jan-13 18:53:43)

Standard User ukhardy07
(fountain of knowledge) Tue 01-Jan-13 18:54:51
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Re: Reduced SNR = No speed increase


[re: No_One] [link to this post]
 
It's probably because the initial sync was at around 10am.

When you lowered the SNR it was probably later in the evening say 5pm.

Try resyncing with the 3db SNR at around 10 / 11am that will probably speed things up smile


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Standard User StephenTodd
(committed) Tue 01-Jan-13 22:18:24
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Re: Reduced SNR = No speed increase


[re: ukhardy07] [link to this post]
 
ukhardy07 is likely correct. Warning: If he is, when you resync at 10/11am you will get a faster speed. However, around 5pm as noise increases, your SNR will probably drop to somewhere around 0 or below and you'll lose connection again.

Could well be worth it for you if you benefit more from faster speed during the day than you lose from occasional disconnections. Many people on FTTC would love the chance to make that tradeoff for themselves rather than having it imposed on them.

--
Moved (with trepidation) to BT Infinity 2 for upload speed. Happy BE user for several years.
Standard User XRaySpeX
(eat-sleep-adslguide) Wed 02-Jan-13 00:55:16
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Re: Reduced SNR = No speed increase


[re: StephenTodd] [link to this post]
 
In reply to a post by StephenTodd:
However, around 5pm as noise increases, your SNR will probably drop to somewhere around 0 or below and you'll lose connection again.
Or more likely, if you have a good line, only drop a few tenths dB and not discon.

1999: Freeserve 48K Dial-Up => 2005: Wanadoo 1 Meg BB => 2007: Orange 2 Meg BB => 2008: Orange 8 Meg LLU => 2010: Orange 16 Meg LLU => 2011: Orange 19 Meg WBC
Standard User tommy45
(knowledge is power) Wed 02-Jan-13 01:44:00
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Re: Reduced SNR = No speed increase


[re: ukhardy07] [link to this post]
 
In reply to a post by ukhardy07:
It's probably because the initial sync was at around 10am.

When you lowered the SNR it was probably later in the evening say 5pm.

Try resyncing with the 3db SNR at around 10 / 11am that will probably speed things up smile
But as this is a BTW 21cn connection there are things like DLM and bras profiles at play too, Remove those factors and set the line config to fastpath , I'm failrly sure the OP would see a higher sync speed

Standard User Banger
(eat-sleep-adslguide) Wed 02-Jan-13 01:52:50
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Re: Reduced SNR = No speed increase


[re: No_One] [link to this post]
 
I have heard of some ISPs locking the SNR at the line card and it cant be overidden by a router tweak, think it was reported by an Openreach guy on here or was it sync being locked for cheap 12 meg connections. Someone may confirm later.

Tim
www.vivaciti.net & freenetname
Billion 7800 on 24 Meg Variety LLU
My Broadband Speed Test

Edited by Banger (Wed 02-Jan-13 01:54:35)

Standard User ukhardy07
(fountain of knowledge) Wed 02-Jan-13 07:09:47
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Re: Reduced SNR = No speed increase


[re: tommy45] [link to this post]
 
I had wrote this kind of thing initially but then deleted it.

If you look at the stats after the forcing a lower SNR the SNR actually drops from 6 to 3. If DLM had capped the sync it would have came back in at 6db.

The issue is not that throughput didn't increase, they're moaning that the actual router sync didn't go up.

The lower SNR indicates that the "tweak" went through as such.
Standard User No_One
(committed) Sun 26-May-13 12:32:58
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Re: Reduced SNR = No speed increase


[re: No_One] [link to this post]
 
Well since I posted this I've tried reconnecting with the reduced SNR at various times of day. But still the sync speed never increases. Could there be something stuck at the exchange end that a line profile reset might sort?
Standard User yarwell
(sensei) Sun 26-May-13 13:29:31
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Re: Reduced SNR = No speed increase


[re: No_One] [link to this post]
 
can you post a set of data at the before and after state ie normal and reduced SNR ? Done within a few minutes of each.

--

Phil

MaxDSL - goes as fast as it can and doesn't read the line checker first.

MaxDSL diagnostics
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