Would a fixed SNR help?
- Subscribe to RSS Feed
- Mark Topic as New
- Mark Topic as Read
- Float this Topic for Current User
- Bookmark
- Subscribe
- Printer Friendly Page
- Plusnet Community
- :
- Forum
- :
- Help with my Plusnet services
- :
- Broadband
- :
- Re: Would a fixed SNR help?
Would a fixed SNR help?
11-11-2015 9:51 AM
- Mark as New
- Bookmark
- Subscribe
- Subscribe to RSS Feed
- Highlight
- Report to Moderator
My line suffers from bad overnight REIN and SHINE, with the SNR dropping by up to 4dB, otherwise the line is stable. No phone noise and nothing in the house but we're fed by nearly 4km of overhead cable, which terminates on the same pole as a street light and our electric supply.
With a target SNR of (I guess) 9dB, the ADSL connection is lovely and stable, very few HEC errors or Error Secs. Example stats for 24 hrs below:
Mode: ADSL_G.dmt
Traffic Type: ATM
Status: Up
Link Power State: L0
Downstream Upstream
Line Coding(Trellis): On On
SNR Margin (1 dB): 8.3 10.0
Attenuation (1 dB): 48.5 30.5
Output Power (1 dBm): 19.9 12.3
Attainable Rate (Kbps): 6336 1072
Path 0 Path 1
Downstream Upstream Downstream Upstream
Rate (Kbps): 5472 896 0 0
K (number of bytes in DMT frame): 172 29 0 0
R (number of check bytes in RS code word): 14 16 0 0
S (RS code word size in DMT frame): 1.00 8.00 0.0 0.0
D (interleaver depth): 32 4 0 0
Delay (msec): 8.00 8.00 0.0 0.0
INP (DMT symbol): 1.20 0.09 0.0 0.0
Super Frames: 5249585 5249585 0 0
Super Frame Errors: 177 43 0 0
RS Words: 356971780 44668647 0 0
RS Correctable Errors: 2405139 526 0 0
RS Uncorrectable Errors: 1818 0 0 0
HEC Errors: 1494 37 0 0
OCD Errors: 1 0 0 0
LCD Errors: 1 0 0 0
Total Cells: 1151736928 0 0 0
Data Cells: 508791752 0 0 0
Bit Errors: 0 0 0 0
Total ES: 142 0
Total SES: 0 0
Total UAS: 0 0
BT Speedtest results to match these:
Best Effort Test: -provides background information.
Download Speed
4.73 Mbps
0 Mbps 7.15 Mbps
Max Achievable Speed
Download speed achieved during the test was - 4.73 Mbps
For your connection, the acceptable range of speeds is 2 Mbps-7.15 Mbps.
IP Profile for your line is - 4.83 Mbps
2. Upstream Test: -provides background information.
Upload Speed
0.77 Mbps
0 Mbps 0.83 Mbps
Max Achievable Speed
Upload speed achieved during the test was - 0.77Mbps
Additional Information:
Upstream Rate IP profile on your line is - 0.83 Mbps
However, because this gives a stable line (those stats were from a representative 24 hrs in a 10 day connection period), any re-sync results in a reduction of target SNR (and a much improved speed :)). However, because of the nighttime REIN, errors increase significantly and the line can drop out, resulting in DLM eventually setting the target SNR at 12dB and line speed dropping so I have to go through a period of time with a much lower speed before eventually getting it back to a profile of around 4.8 to 5 Mbps. As an example, the router was accidentally turned off the other night, reconnected with a much lower target SNR producing the following stats in the last 24 hours:
Mode: ADSL_G.dmt
Traffic Type: ATM
Status: Up
Link Power State: L0
Downstream Upstream
Line Coding(Trellis): On On
SNR Margin (1 dB): 4.9 10.0
Attenuation (1 dB): 48.5 31.0
Output Power (1 dBm): 19.9 12.3
Attainable Rate (Kbps): 6840 1068
Path 0 Path 1
Downstream Upstream Downstream Upstream
Rate (Kbps): 6592 896 0 0
K (number of bytes in DMT frame): 207 29 0 0
R (number of check bytes in RS code word): 16 16 0 0
S (RS code word size in DMT frame): 1.00 8.00 0.0 0.0
D (interleaver depth): 32 4 0 0
Delay (msec): 8.00 8.00 0.0 0.0
INP (DMT symbol): 1.15 0.09 0.0 0.0
Super Frames: 5177603 5177603 0 0
Super Frame Errors: 17397 129 0 0
RS Words: 352076970 44055534 0 0
RS Correctable Errors: 19604716 776 0 0
RS Uncorrectable Errors: 180852 0 0 0
HEC Errors: 235643 128 0 0
OCD Errors: 46 0 0 0
LCD Errors: 46 0 0 0
Total Cells: 1368211616 0 0 0
Data Cells: 32583367 0 0 0
Bit Errors: 0 0 0 0
Total ES: 2259 0
Total SES: 270 0
Total UAS: 186 46
Best Effort Test: -provides background information.
Download Speed
5.7 Mbps
0 Mbps 7.15 Mbps
Max Achievable Speed
Download speed achieved during the test was - 5.7 Mbps
For your connection, the acceptable range of speeds is 2 Mbps-7.15 Mbps.
IP Profile for your line is - 5.82 Mbps
2. Upstream Test: -provides background information.
Upload Speed
0.72 Mbps
0 Mbps 0.83 Mbps
Max Achievable Speed
Upload speed achieved during the test was - 0.72Mbps
Additional Information:
Upstream Rate IP profile on your line is - 0.83 Mbps
Now don't get me wrong, I love this download speed and would like to keep it, but experience tells me that eventually that error level will affect my profile and the speed will drop. I know that the line can be stable when the stats show a daytime SNR margin of 7-8 dB and this can give me an IP Profile of around 5Mbps. Is there anyway that the SNR margin can be fixed so that an accidental re-sync doesn't result in a lovely improved speed that eventually will end up below the optimal - if you see what I mean? Or can the IP Profile be fixed in anyway - any suggestions gratefully received!
Re: Would a fixed SNR help?
11-11-2015 3:32 PM
- Mark as New
- Bookmark
- Subscribe
- Subscribe to RSS Feed
- Highlight
- Report to Moderator
Are you on an ADSL2 exchange or on ADSL MAX Premium?
Are you using a Plusnet supplied modem/router and is it in the master socket with a micro filter face plate ?
Ian
Re: Would a fixed SNR help?
11-11-2015 4:17 PM
- Mark as New
- Bookmark
- Subscribe
- Subscribe to RSS Feed
- Highlight
- Report to Moderator
Router is the horrid 2704n, so I can't run RSL but it does seem to be quite good at hanging on to the line. Connected to the master socket with a filtered facelate and bell wire disconnected.
Very happy with Plusnet up to now - a reliable 4.5Mb + download speed is brilliant compared to the 0.3 to 1.5Mb I was getting from my previous ISP.
Re: Would a fixed SNR help?
11-11-2015 4:31 PM
- Mark as New
- Bookmark
- Subscribe
- Subscribe to RSS Feed
- Highlight
- Report to Moderator
You can tell: run the BT diagnostic speed test. If it reports on download only you are on ADSL Max, if it reports on up and down you are on 21CN.
jelv (a.k.a Spoon Whittler) Why I have left Plusnet (warning: long post!) Broadband: Andrews & Arnold Home::1 (FTTC 80/20) Line rental: Pulse 8 Home Line Rental (£14.40/month) Mobile: iD mobile (£4/month) |
Re: Would a fixed SNR help?
11-11-2015 4:45 PM
- Mark as New
- Bookmark
- Subscribe
- Subscribe to RSS Feed
- Highlight
- Report to Moderator
Best Effort Test: -provides background information.
Download Speed
5.7 Mbps
0 Mbps 7.15 Mbps
Max Achievable Speed
Download speed achieved during the test was - 5.7 Mbps
For your connection, the acceptable range of speeds is 2 Mbps-7.15 Mbps.
IP Profile for your line is - 5.82 Mbps
2. Upstream Test: -provides background information.
Upload Speed
0.72 Mbps
0 Mbps 0.83 Mbps
Max Achievable Speed
Upload speed achieved during the test was - 0.72Mbps
Additional Information:
Upstream Rate IP profile on your line is - 0.83 Mbps
So I assume it's 21CN WBBC?
Re: Would a fixed SNR help?
11-11-2015 6:22 PM
- Mark as New
- Bookmark
- Subscribe
- Subscribe to RSS Feed
- Highlight
- Report to Moderator
Re: Would a fixed SNR help?
11-11-2015 6:46 PM
- Mark as New
- Bookmark
- Subscribe
- Subscribe to RSS Feed
- Highlight
- Report to Moderator
Plusnet could change it to ADSL2+, ADSL2 can be very stable on long lines, but of course you won't know if ADSL2 is more stable or less stable and if it's faster or slower on your line without trying it. Unfortunately a possible drawback of ADSL2+ is that the DLM is slightly different and has banded profiles, which it doesn't have on 21CN WBC ADSL1. I'd be inclined to try ADSL2, and if you can set the 2704N to ADSL1, then you can mostly switch it back to how it was before yourself (although the DLM would still be different). But it's your line so it's your decision, and Plusnet should be able to just do the fixed 9 dB target SNRM instead.
Re: Would a fixed SNR help?
11-11-2015 7:04 PM
- Mark as New
- Bookmark
- Subscribe
- Subscribe to RSS Feed
- Highlight
- Report to Moderator
Re: Would a fixed SNR help?
11-11-2015 10:41 PM
- Mark as New
- Bookmark
- Subscribe
- Subscribe to RSS Feed
- Highlight
- Report to Moderator
Re: Would a fixed SNR help?
12-11-2015 8:32 AM
- Mark as New
- Bookmark
- Subscribe
- Subscribe to RSS Feed
- Highlight
- Report to Moderator
Quote from: jg321 It'll be WBC on an ADSL1
Correct. This is what you get on 21CN exchanges.
Quote from: jg321 (aka ADSL Max) profile.
Wrong! ADSL Max is a 20CN exchange feature.
jelv (a.k.a Spoon Whittler) Why I have left Plusnet (warning: long post!) Broadband: Andrews & Arnold Home::1 (FTTC 80/20) Line rental: Pulse 8 Home Line Rental (£14.40/month) Mobile: iD mobile (£4/month) |
Re: Would a fixed SNR help?
12-11-2015 8:38 AM
- Mark as New
- Bookmark
- Subscribe
- Subscribe to RSS Feed
- Highlight
- Report to Moderator
Downstream Upstream
Line Coding(Trellis): On On
SNR Margin (1 dB): 8.3 10.0
Attenuation (1 dB): 48.5 30.5
Output Power (1 dBm): 19.9 12.3
Attainable Rate (Kbps): 6460 1060
Path 0 Path 1
Downstream Upstream Downstream Upstream
Rate (Kbps): 5504 896 0 0
These are after a graceful disconnect this morning, following two overnight re-syncs.
Re: Would a fixed SNR help?
12-11-2015 6:34 PM
- Mark as New
- Bookmark
- Subscribe
- Subscribe to RSS Feed
- Highlight
- Report to Moderator
I'm not convinced the target SNRM is being changed by the DLM. The DLM wouldn't normally change it so often, and the DLM does not need to wait for you to do a re-sync to apply the new target SNRM.
Instead, the target SNRM might usually be 6. If the ADSL connects at a time when there's a lot of interference present, you'll get a lower speed. If the interference then goes away, the current SNRM would then rise above 6.
The target SNRM can only be set to 3, 6, 9, 12 or 15. If you want it more stable, Plusnet would have to fix it at 9. If you want more speed, Plusnet would have to fix it at 6, although there could potentially then be times when the CRC / uncorrected error rate gets so high it will result in slow and unreliable download speeds.
Re: Would a fixed SNR help?
13-11-2015 9:40 AM
- Mark as New
- Bookmark
- Subscribe
- Subscribe to RSS Feed
- Highlight
- Report to Moderator
Anyway, even with a daytime SNRM of around 8dB, router stats are showing an attainable rate of 6424, whilst the downstream rate, which I know the IP Profile is based on, is only 5504, so I was wondering if there was anyway to get the downstream rate higher. I've done a graceful disconnect and reconnect but it didn't have any effect - would a full reboot of the router make any difference?
Re: Would a fixed SNR help?
13-11-2015 9:51 AM
- Mark as New
- Bookmark
- Subscribe
- Subscribe to RSS Feed
- Highlight
- Report to Moderator
The problem will be if you keep rebooting the risk is that the target SNRM will be set higher by the DLM and you'll get slower speeds. Your best bet is to accept whatever speed it settles at after a night time resync and then continually monitor the SNRM to see if there's a drop at a particular time that you can associate with something being turned on.
jelv (a.k.a Spoon Whittler) Why I have left Plusnet (warning: long post!) Broadband: Andrews & Arnold Home::1 (FTTC 80/20) Line rental: Pulse 8 Home Line Rental (£14.40/month) Mobile: iD mobile (£4/month) |
Re: Would a fixed SNR help?
13-11-2015 9:57 AM
- Mark as New
- Bookmark
- Subscribe
- Subscribe to RSS Feed
- Highlight
- Report to Moderator
- Subscribe to RSS Feed
- Mark Topic as New
- Mark Topic as Read
- Float this Topic for Current User
- Bookmark
- Subscribe
- Printer Friendly Page