Inconsistent speed- low SNR high attenuation
- 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
- :
- Inconsistent speed- low SNR high attenuation
Inconsistent speed- low SNR high attenuation
13-08-2014 6:31 PM
- Mark as New
- Bookmark
- Subscribe
- Subscribe to RSS Feed
- Highlight
- Report to Moderator
Mode: ADSL_2plus
Traffic Type: ATM
Status: Up
Link Power State: L0
Downstream Upstream
Line Coding(Trellis): On On
SNR Margin (0.1 dB): 26 245
Attenuation (0.1 dB): 575 342
Output Power (0.1 dBm): 0 128
Attainable Rate (Kbps): 6672 1004
Path 0 Path 1
Downstream Upstream Downstream Upstream
Rate (Kbps): 5746 444 0 0
MSGc (# of bytes in overhead channel message): 60 46 0 0
B (# of bytes in Mux Data Frame): 176 19 0 0
M (# of Mux Data Frames in FEC Data Frame): 1 1 0 0
T (Mux Data Frames over sync bytes): 1 1 0 0
R (# of check bytes in FEC Data Frame): 14 0 0 0
S (ratio of FEC over PMD Data Frame length): 0.9801 1.3675 0.0 0.0
L (# of bits in PMD Data Frame): 1559 117 0 0
D (interleaver depth): 32 1 0 0
Delay (msec): 7.84 0.34 0.0 0.0
INP (DMT symbol): 1.14 0.0 0.0 0.0
Super Frames: 50718407 837508 0 0
Super Frame Errors: 0 0 0 0
RS Words: 3347414898 0 0 0
RS Correctable Errors: 60000939 0 0 0
RS Uncorrectable Errors: 704678 0 0 0
HEC Errors: 0 53318 0 0
OCD Errors: 457 0 0 0
LCD Errors: 0 0 0 0
Total Cells: 2525505724 610396 0 0
Data Cells: 531179073 2082 0 0
Bit Errors: 0 0 0 0
Total ES: 7997 0
Total SES: 969 0
Total UAS: 14 4294967274
I've also posted my current speed and another speed test few days ago and current line speed.
Re: Inconsistent speed- low SNR high attenuation
13-08-2014 7:01 PM
- Mark as New
- Bookmark
- Subscribe
- Subscribe to RSS Feed
- Highlight
- Report to Moderator
Do those stats cover about 10 days? (From the superframe count, 17ms for each superframe.) Were there any thunderstorms over that period, which would have caused a lot of extra errors?
Re: Inconsistent speed- low SNR high attenuation
13-08-2014 8:19 PM
- Mark as New
- Bookmark
- Subscribe
- Subscribe to RSS Feed
- Highlight
- Report to Moderator
Re: Inconsistent speed- low SNR high attenuation
13-08-2014 8:22 PM
- Mark as New
- Bookmark
- Subscribe
- Subscribe to RSS Feed
- Highlight
- Report to Moderator
Re: Inconsistent speed- low SNR high attenuation
13-08-2014 8:28 PM
- Mark as New
- Bookmark
- Subscribe
- Subscribe to RSS Feed
- Highlight
- Report to Moderator
Whats happening is your getting packet loss as the connection struggles, but not quite enough to case a disconnect
Martin
Re: Inconsistent speed- low SNR high attenuation
13-08-2014 8:44 PM
- Mark as New
- Bookmark
- Subscribe
- Subscribe to RSS Feed
- Highlight
- Report to Moderator
Quote from: Simonleeuk As I said networking is not my area but I was under the impression that SNR below 6 is bad and can result in frequent disconnections and problems with line synchronisation?
Simon,
Martin is near the mark. A SNRM below 6dB is not necessarily bad, it all depends upon the line, in much the same way that a SNRM above 6dB may or may not be "bad".
6dB is the normal target SNRM used for synching up a line, thereafter SNRM will vary depending on the ambient electrical noise. If noise increases, SNRM goes down. The target SNRM needs to be high enough to mitigate ambient noise pushing the current SNRM so low that there is no useful margin left. Therefore on bad lines, the target SNRM might be set higher than 6dB. Conversely on very good lines, the target SNRM can be set at 3dB to gain more synch speed, at the risk of encountering more errors and thereby significantly reducing the effective data transfer speed.
What one needs to know in respect of your line is why is the SNRM presently so low? Is a tweak in the router forcing it low to get the best possible synch speed but then unwittingly causing transmission errors which hammers the throughput speed? As ejs noted above, your synch speed is exceedingly high for the line's attenuation. This makes me thing that this router is doing naughty things to the DLM by forcing the SNRM below 3dB.
Or is the SNRM being depressed by electrical interference (REIN)?
The latter is a night mare and needs to be discerned by running something like routerstats to monitor the SNRM over time. What is the router? It might do this for you.
Can you please check through all of the router settings and see if there is anything there which is tweaking the SNRM. Thereafter, I think there needs to be a discussion with PlusNet about checking / setting / resetting the target SNRM value. This will shave a bit off the synch speed, but it ought to deliver better data throughput speeds.
Kevin
In another browser tab, login into the Plusnet user portal BEFORE clicking the fault & ticket links
Superusers are not staff, but they do have a direct line of communication into the business in order to raise issues, concerns and feedback from the community.
If this post helped, please click the Thumbs Up and if it fixed your issue, please click the This fixed my problem green button below.
Re: Inconsistent speed- low SNR high attenuation
13-08-2014 9:03 PM
- Mark as New
- Bookmark
- Subscribe
- Subscribe to RSS Feed
- Highlight
- Report to Moderator
Statistics -- xDSL
Mode: ADSL_2plus
Traffic Type: ATM
Status: Up
Link Power State: L0
Downstream Upstream
Line Coding(Trellis): On On
SNR Margin (0.1 dB): 29 230
Attenuation (0.1 dB): 575 341
Output Power (0.1 dBm): 0 128
Attainable Rate (Kbps): 6476 1024
Path 0 Path 1
Downstream Upstream Downstream Upstream
Rate (Kbps): 5778 444 0 0
MSGc (# of bytes in overhead channel message): 59 46 0 0
B (# of bytes in Mux Data Frame): 180 19 0 0
M (# of Mux Data Frames in FEC Data Frame): 1 1 0 0
T (Mux Data Frames over sync bytes): 1 1 0 0
R (# of check bytes in FEC Data Frame): 14 0 0 0
S (ratio of FEC over PMD Data Frame length): 0.9968 1.3675 0.0 0.0
L (# of bits in PMD Data Frame): 1565 117 0 0
D (interleaver depth): 32 1 0 0
Delay (msec): 7.97 0.34 0.0 0.0
INP (DMT symbol): 1.14 0.0 0.0 0.0
Super Frames: 3281 2990 0 0
Super Frame Errors: 0 0 0 0
RS Words: 213284 0 0 0
RS Correctable Errors: 112 0 0 0
RS Uncorrectable Errors: 0 0 0 0
HEC Errors: 0 0 0 0
OCD Errors: 0 0 0 0
LCD Errors: 0 0 0 0
Total Cells: 725618 498608 0 0
Data Cells: 203 3950 0 0
Bit Errors: 0 0 0 0
Total ES: 0 0
Total SES: 0 0
Total UAS: 15 15
Re: Inconsistent speed- low SNR high attenuation
13-08-2014 9:04 PM
- Mark as New
- Bookmark
- Subscribe
- Subscribe to RSS Feed
- Highlight
- Report to Moderator
What happens is that you end up constantly trying to counter BT's DLM and you can end up with 15dB margins set on BTs system. As the offsets used in these tweak are often percentages each time you have to up it trying to counter DLM the less stable your line becomes
The only tweak which sometimes be useful is tweaking to increase the margin, which gets you more stability but a slower speed, but these das the ISP can ask BT for a stable or super stable setting which does the same thing, but without the trickery
Martin
Re: Inconsistent speed- low SNR high attenuation
13-08-2014 9:10 PM
- Mark as New
- Bookmark
- Subscribe
- Subscribe to RSS Feed
- Highlight
- Report to Moderator
Is this a recent problem or an ongoing one ?
Just wondering if a new modem is the cause, or whether something else has changed
One suspicion would be a faulty modem, I wonder if recent lightning has caused damage.
Martin
Re: Inconsistent speed- low SNR high attenuation
13-08-2014 9:19 PM
- Mark as New
- Bookmark
- Subscribe
- Subscribe to RSS Feed
- Highlight
- Report to Moderator
The "expectation" for a line having an attenuation (effectively length) of 57dB (4.1km) is 3.5Mbps - you are getting 5.7Mbps. Note that you cannot do anything about attenuation, short of moving to a house nearer the exchange!
It looks like your TARGET SNRM is 3dB - I suggest that it would be worth while having a conversation with PluseNet (via this thread) to look at error counts and consider moving the TARGET SNRM to 6dB. At worse this is going to move the synch rate to 4.5Mbps, which is still well within expectations. Though the synch rate will be reduced, the effective data rate should be markedly improved due to there being fewer errors on the line.
If you feel up to it, setting up a TBB BQM plot as described here - http://community.plus.net/forum/index.php/topic,106312.0.html - would be useful, though if you do not have affixed IP address, it will need re-doing after each disconnect.
Kevin
In another browser tab, login into the Plusnet user portal BEFORE clicking the fault & ticket links
Superusers are not staff, but they do have a direct line of communication into the business in order to raise issues, concerns and feedback from the community.
If this post helped, please click the Thumbs Up and if it fixed your issue, please click the This fixed my problem green button below.
Re: Inconsistent speed- low SNR high attenuation
13-08-2014 9:21 PM
- Mark as New
- Bookmark
- Subscribe
- Subscribe to RSS Feed
- Highlight
- Report to Moderator
Re: Inconsistent speed- low SNR high attenuation
13-08-2014 9:30 PM
- Mark as New
- Bookmark
- Subscribe
- Subscribe to RSS Feed
- Highlight
- Report to Moderator
Re: Inconsistent speed- low SNR high attenuation
13-08-2014 9:34 PM
- Mark as New
- Bookmark
- Subscribe
- Subscribe to RSS Feed
- Highlight
- Report to Moderator
It may also be worth trying directly into the master socket (the test socket behind the faceplate) just to eliminate wiring
Martin
Re: Inconsistent speed- low SNR high attenuation
13-08-2014 9:39 PM
- Mark as New
- Bookmark
- Subscribe
- Subscribe to RSS Feed
- Highlight
- Report to Moderator
Quote from: 11110_110 Why are you testing with wifi ?
As always, this is a good question, one I failed to ask and yes the results could be indicative of speed testing over wifi - however what did I miss for you to believe they were conducted over wifi?
In another browser tab, login into the Plusnet user portal BEFORE clicking the fault & ticket links
Superusers are not staff, but they do have a direct line of communication into the business in order to raise issues, concerns and feedback from the community.
If this post helped, please click the Thumbs Up and if it fixed your issue, please click the This fixed my problem green button below.
Re: Inconsistent speed- low SNR high attenuation
13-08-2014 9:40 PM
- Mark as New
- Bookmark
- Subscribe
- Subscribe to RSS Feed
- Highlight
- Report to Moderator
Thanks Townman for your suggestions. Yeh looking at other threads Plusnet moderators on this forum seem to be really helpful so hopefully they can have a look into this for me. Anyway way of prompting them to join the thread?
- 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
- :
- Inconsistent speed- low SNR high attenuation