Kitz Forum
Broadband Related => Broadband Technology => Topic started by: kezzaman on April 26, 2012, 10:37:31 PM
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Hi,
I was just curious about Output power (dBm), can this alter on different profile snr settings for example if im on a 9snr profile and my dBm is 9, if i was to change to a 12snr profile would my dBm raise, drop, or stay the same because snr doesnt effect it?
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I would expect the output power to remain virtually the same.
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Output power isnt related to any of the DLM profile settings and is independent.
Theres several different PSD masks in use which can affect the output power but this is more to do with line length/quality.
Output power can vary slightly depending upon the line conditions ie it can wap up a bit if the line is struggling, or reduce if the line is syncing at a rate much lower than its capable of. It can do this on the fly without resyncs being needed.
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Cheers for the input guys. I was wondering also is there a tool i could use to monitor the dBm, apart from obviously checking my router stats?
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Cheers for the input guys. I was wondering also is there a tool i could use to monitor the dBm, apart from obviously checking my router stats?
Even better is there a tool i can use to override the dBM and change the value?
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Cheers for the input guys. I was wondering also is there a tool i could use to monitor the dBm, apart from obviously checking my router stats?
Are we talking about wireless?
If so you can see strength using inSSIDer 2.0 (http://www.metageek.net/products/inssider/) and that of your neighbours.
YOU CAN
– Inspect your Wi-Fi and surrounding networks
– Scan and filter hundreds of nearby access points
– Troubleshoot competing access points and clogged Wi-Fi channels
– Highlight access points for areas with high Wi-Fi concentration
– Track the strength of received signals in dBm over time
– Sort results by MAC Address, SSID, Channel, RSSI, Time Last Seen
– Export Wi-Fi and GPS data to a KML file in Google Earth
As for tweeking the strength there are legal limits.
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Even better is there a tool i can use to override the dBM and change the value?
If you mean between the router and MSAN - not that Im aware of.
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Even better is there a tool i can use to override the dBM and change the value?
If you mean between the router and MSAN - not that Im aware of.
Yea thats what i meant.
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Hi guys,
I have some more questions about dBm ;D.
So i read on this site that the average for an ASDL2+ line is about 18-19, so then does it not depend on the length of the line?
I was wondering also is there some kind of formula for which u could use to work out what sort of value of output power dBm you should be getting close to?
:-\
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On adsl2+ the vast majority of lines will be running to their maximum capability... hence the 19dB average.
ie a long line at full power may only get say 4Mbps.. but a shortish line needs that same amount of power to get say 24Mbps.
Its only really when you see a line not syncing at its full capability would you expect to see anything less (although there are some routers that mis-report and a known issue with some Sky lines)
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On adsl2+ the vast majority of lines will be running to their maximum capability... hence the 19dB average.
ie a long line at full power may only get say 4Mbps.. but a shortish line needs that same amount of power to get say 24Mbps.
Its only really when you see a line not syncing at its full capability would you expect to see anything less (although there are some routers that mis-report and a known issue with some Sky lines)
I see... I was worried my dB was to low at 9dBm, but my sync speeds are what they should be, so i guess no problems there.
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The transmitting device only needs to use sufficient power for the receiving device to obtain a clear signal. There is a dialogue between the two ends: "Eh? What? Speak up, I can't hear you!" . . . "Stop shouting, I'm not that deaf, you know" . . . etc, etc.
This is what my modem/router reports --
Current Output Power: 18.6 dBm (Downstream) 12.5 dBm (Upstream)
The DS output power is the level that the DSLAM/MSAN is transmitting to my modem/router (the value is only known by the DSLAM/MSAN and is sent in a data packet so that the modem/router can display it), the US output power is the level that my modem/router is transmitting to the DSLAM/MSAN.
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I see... I was worried my dB was to low at 9dBm,
Is that adsl1?
IIRC my output power when on adsl1 was somewhere in the region 10dBm as this line is/was capable of 24Mbps and therefore didnt need to be at full power to be able to sync at 8128kbps.
Otherwise it may be a router misreport - there are a few that do.
As B*cat say the main thing is that you have enough power to sync at the anticipated speed.
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From what I've seen on the old ADSL1/ADSLmax on 20CN....short lines have reduced power and long lines increased power. I've only seen two power settings quoted in forums from the router stats provided.
My interpretation of this was that BTOR did not want to use full power on short lines as
a) they did not need it to function fully and
b) excess power on the lines means increased cross talk between the cable pairs with other broadband customers.
So to ensure that the ADSL signal actually got to the end of those customers on very long lines it was essential to cut back the power for those on short lines as at full power the cross talk from the short lines would swamp the signal for those on the long ones.
Many routers seem not to report the downstream signal power on ADSL2+, it seems to be a bug in the software somewhere either in the router or the MSAN/DSLAM is not reporting it to the router (mine included) so there does not seem to be the availability of output power figures in router stats as there was on ADSLmax.
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More expert advice as ever from the Tzarina of Kitz :)
If you take a look-see at the ITU-T specs G.992.3 [1]... described within are the parameters used to determine the output power for each subcarrier or tone.
The output power for a tone should never fall outside the bounds of the spectral shaping mask (which is in place to reduce crosstalk amongst the pairs in a cable bundle). That mask which restrains output power is defined as a mathematical function - the transmitter spectral shaping function (tss).
The modem at each end of the transmission line can only control the output power levels used for the subcarriers in its own upstream bands. Neither the DSLAM nor the CPE modem has control over the TX power levels used by the Far End. So that means that our CPE modems can only control the upstream power output levels.
There is a fine tune gain control that is applied by the modem's transmitter for each subcarrier. The gain for an individual tone can be tweaked by +/- 1dBm (as a linear equivalent).
However, the output power can never, or should never, be tweaked to exceed the bounds of the power spectral density (PSD) mask for the bandplan.
In theory it's possible to retrieve the 'gains table' from a Broadcom chipset modem. That table contains those fine tune gain levels that are being applied to each subcarrier.
Here are all the diagnostic data tonemaps used by the Broadcom 6348/6358 chipset modems. The gains table is stored as an array of shorts (16-bit integers). The full source code for the Broadcom kernel driver is here [2]
/* ADSL diag data */
short snr[kAdslMibMaxToneNum];
short showtimeMargin[kAdslMibMaxToneNum];
uchar bitAlloc[kAdslMibMaxToneNum];
short gain[kAdslMibMaxToneNum];
ComplexShort chanCharLin[kAdslMibMaxToneNum];
short chanCharLog[kAdslMibMaxToneNum];
short quietLineNoise[kAdslMibMaxToneNum];
The xdsl diagnostic tool in the firmware of most Broadcom modems (known variously as the xdslcmd, adslctl or adslcfg tool) is not equipped to get the gains table data from the kernel driver. However, it is probably still possible to retrieve that data by hook or by crook.
One quirk of the Broadcom chipsets relates to output power. With the BCM6368 - the latest xDSL Broadcom chipset - the aggregate output power for the downstream bands often drops momentarily to zero for no obvious reason, before returning to a sane value of 19dBm or thereabouts.
Incidentally, you have very tasty looking limbs, kezzaman. Do you strictly need them all?!
cheers, a
[1] http://www.analytic.ru/articles/lib26.pdf
[2] https://forum.openwrt.org/viewtopic.php?pid=120035
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Incidentally, you have very tasty looking limbs, kezzaman. Do you strictly need them all?!
I would like to keep all my limbs but after reading ur post i suppose u could eat my head because i dont think its working anymore. :D
Cheers.
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The transmitting device only needs to use sufficient power for the receiving device to obtain a clear signal. There is a dialogue between the two ends: "Eh? What? Speak up, I can't hear you!" . . . "Stop shouting, I'm not that deaf, you know" . . . etc, etc.
This is what my modem/router reports --
Current Output Power: 18.6 dBm (Downstream) 12.5 dBm (Upstream)
The DS output power is the level that the DSLAM/MSAN is transmitting to my modem/router (the value is only known by the DSLAM/MSAN and is sent in a data packet so that the modem/router can display it), the US output power is the level that my modem/router is transmitting to the DSLAM/MSAN.
Hi,
So by US do you mean upstream?
The only place i can get a reading of output power on my router stats is in the upstream catagory, thats where i got the 9dBm from, so then its that what power my router is transmitting?
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The only place i can get a reading of output power on my router stats is in the upstream catagory, thats where i got the 9dBm from, so then its that what power my router is transmitting?
Your upstream power output is usually way less than the downstream power. (unless you have a problem)... The upstream tones use lower frequencies.
Its not strictly true.... but very roughly and as a guide only, it should be somewhere in the region of about half the downstream adsl2+ output power.
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Incidentally, you have very tasty looking limbs, kezzaman. Do you strictly need them all?!
Excellent and informative post asbokid... however that one line made me laugh :lol:
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The only place i can get a reading of output power on my router stats is in the upstream catagory, thats where i got the 9dBm from, so then its that what power my router is transmitting?
Your upstream power output is usually way less than the downstream power. (unless you have a problem)... The upstream tones use lower frequencies.
Its not strictly true.... but very roughly and as a guide only, it should be somewhere in the region of about half the downstream adsl2+ output power.
I have an issue with my connection which sometimes goes away, most recently was about 2 weeks ago when it went away and liturally the only thing i could see different with my stats was that the upstream output power was 0.5 higher at 9.5, since then its been at 9 and hasnt budged. Do u think an increase of 0.5 could have an affect on someones connection?
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I just noticed that c6em mentioned in his post about some routers not reporting the downstream power on adsl2+
>> the only thing i could see different with my stats was that the upstream output power was 0.5 higher at 9.5
The 2 figures are independent.. A shift in the upstream could indicate problems in those lower frequencies.... or it is also possible that it could indicate some low level noise across the whole adsl2+ frequency range. Without having the downstream power output though, its impossible to say.
If you are having connection problems though, I wouldnt focus too much on the output power.. The SNRM figures (and fluctuations in them) are more telling.
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My interpretation of this was that BTOR did not want to use full power on short lines as
a) they did not need it to function fully and
b) excess power on the lines means increased cross talk between the cable pairs with other broadband customers.
Thats correct - power cut back is applied on short lines.
You wont see it so much on adsl2+, as even short lines may need near full power to get up to the 24Mbps region.
It can however be clearly seen on adsl1 where the max sync speed is 8128kbps and the shorter lines dont need the additional power and power cut back comes into play to reduce crosstalk by removing any 'surplus power' and thereby reducing the risk of surplus noise from these shorter lines drowning out the longer lines. Why give a line more power than it needs?
I believe sky are currently 'playing' with new power management equipment on their MSANs.. However they dont appear to have got things quite right yet and some lines are finding themselves not being able to sync to their full potential due to the power management module being a bit overzealous with the cutback on shorter lines.... as they appear to be using data obtained during the training period, before the line has fully settled to its full capability :/
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So by US do you mean upstream?
Yes, spot-on. DS and US are relative to the observer which, in this discussion, is either you or me. Some devices won't report the DS power level purely because it hasn't asked the DSLAM / MSAN, at the other end of the link, to report the value.
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If you are having connection problems though, I wouldnt focus too much on the output power.. The SNRM figures (and fluctuations in them) are more telling.
Hi,
Cheers for all the input.
Would you be able to elaborate abit more on the fluctuations in the noise margin, because mine changes everytime i refresh the stats page, usually within a 3db range. Im on 12snr profile at the moment and the DLM isnt active.
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... Is it possible that i could be experiencing gaming online issues because my upstream is suffering from crosstalk at the exchange?
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Its can be normal for SNR (http://www.kitz.co.uk/adsl/linestats.htm#SNR) to fluctuate a bit.. but it depends on how much its fluctuating and and if theres a pattern to it.
routerstats (http://www.vwlowen.co.uk/internet/files.htm) is a good tool for being able to record your SNRm and it will do all the hard work for you, by taking regular snapshots of stats from your router and outputting it as a graph.
Results from a routerstat graph can often be quite telling as whats going on on your line. Its one of the tools we use most to help troubleshoot problematic lines.
>> Is it possible that i could be experiencing gaming online issues because my upstream is suffering from crosstalk at the exchange?
This doesnt sound like crosstalk.. its impossible to say without seeing whats happening to your SNR.. but its probably more likely to be internal wiring, EMI/REIN (http://www.kitz.co.uk/adsl/rein.htm) or a line fault. Crosstalk doesnt cause SNRM's of 12-15dBm
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Theres was another thing that i just thought was a router mistake, for the last 2 days its been reporting my downstream attenuation as 3.7db when its deffinately not, its about 9db. Could this be anything significant?
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Lets just say, if someone did have an issue with crosstalk would an increase in snr fix it?
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Lets just say, if someone did have an issue with crosstalk would an increase in snr fix it?
The crosstalk is the noise. So for noise at a constant level, an increase in the ratio of signal to noise implies that the power of the (wanted) signal has been increased. So in basic terms, yes is the answer to your question.
However the SNR is not the same thing as the SNRM, which is what all modem/routers will report.
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Does the DSLAM tell the modem what output power to use or does the router decide itself?
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In the broadest of terms, at the negotiation of sync phase, the DSLAM tells the modem how well it is "hearing" the modem's signal and the modem tells the DSLAM how well it is "hearing" the DSLAM's signal. One device does not control the other device's power output.
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Lets just say, for some crazy reason i wanted to raise my routers output power a tad, how would one do that? :-\
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I can "see" two options that would allow you to achieve your hypothetical desire:
(1) Modify your modem/router's hardware so that you have a physical "output power control knob" to turn.
(2) Modify your modem/router's firmware so that you can override the negotiated level in the software.
I don't know for sure if either of those suggestions could really be implemented but perhaps Asbokid would comment, please?
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I can "see" two options that would allow you to achieve your hypothetical desire:
(1) Modify your modem/router's hardware so that you have a physical "output power control knob" to turn.
(2) Modify your modem/router's firmware so that you can override the negotiated level in the software.
I don't know for sure if either of those suggestions could really be implemented but perhaps Asbokid would comment, please?
Presumably in theory it's possible to crank up the output power, i.e. the upstream power levels. Except none of the DSL chipset makers release the source code for their DSP hardware drivers, nor even do they document their software interfaces. For those reasons, there's not much chance of succeeding. Success would also only relate to the upstream power. The downstream performance of an xDSL connection is determined by the performance of the analog front end (AFE). The AFE is the circuitry that recovers and digitises the symbols from the QAM-modulated analog signal on the line. However the AFE will be already be running optimally.
cheers, a
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I think theres some confusion going on here (or at least Im confused!).
I'm going to recap a few items to see if Ive got this straight for what you are trying to do.
- It would appear that your router doesnt display the downstream output power - some dont.
- The upstream and downstream output power isnt the same. A very rough guide is upstream will be about 1/2 the downstream on adsl2+ but this doesnt always follow.
- Changing your DSLAM line profile doesnt affect the output power.
- Requesting a change in your Target SNRm shouldnt make any difference to output power.
- Line length can affect your output power but it all depends if your line is syncing to its maximum capability.
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Why would you be wanting to change the output power?
The downstream is controlled at the MSAN. Normally its around 18/19dBm but the MSAN can 'tweak it up a bit' > 20dBm if the line needs it.. or the MSAN will reduce the power if it senses that the line doesnt need it. ie a short line syncing at 8Mbps.
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I have an issue with my connection which sometimes goes away, most recently was about 2 weeks ago when it went away and liturally the only thing i could see different with my stats was that the upstream output power was 0.5 higher at 9.5, since then its been at 9 and hasnt budged. Do u think an increase of 0.5 could have an affect on someones connection?
Not really in this case - it could have been a temp blip and output power can vary slightly - also Remember upstream and downstream are independent.
Many routers also only report rounding to 0.5dB.. its not impossible that tiny fluctuations and roundings can make a difference with 0.5dB.
Is it possible that i could be experiencing gaming online issues because my upstream is suffering from crosstalk at the exchange?
doubtful.. I refer you back to this post (http://forum.kitz.co.uk/index.php/topic,11097.msg216472.html#msg216472) which has links to more info about SNR/SNRM and the suggestion of using routerstats to see what is going on for your line.
I think you need to be looking at whats happening with your SNRm before thinking about output power., as any fluctuations in SNRm is an indication of noise on the line, which is what could be causing problems. If the SNRm is too low then this could very well cause problems with gaming etc
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edited to add.. asbokid posted whilst I was posting.
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Ive been through alot with my connection and after all the things ive tried to sort it out with no luck, im starting to think it might be an issue with the upstream, so im not concerntrating to much on my downstream at the moment.
Ive just began running routerstats lite on my laptop, i had to use lite because the full version didnt work with my router dsl-2780.
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Hello,
Heres my routerstats on the downstream, i couldnt get upstream. Can you tell me if they look normal please?
(https://forum.kitz.co.uk/proxy.php?request=http%3A%2F%2Foi47.tinypic.com%2F14c8jkh.jpg&hash=ad18935c318b231e26de08124420da9841546294)
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>> i couldnt get upstream.
Thats a shame if you say its your upstream that is concerning you. :(
>> Can you tell me if they look normal please
That graph is only over a short period of time ( 1 hour) but it seems to be a fair bit of constant fluctuation between 10-12dB.
Whilst indicative that there is some sort of noise going on, most lines should be able to cope with 2dB fluctuations.. that graph over the short period doesnt show anything why your target SNRm would be at 12dB.
It probably needs monitoring over a longer period to see whats really going on.. some lines can be more problematic in the evenings when more people are at home and thats when any effects of EMI are most often seen.
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Thanks Kitz,
My snr doesnt need to be at 12db i was just trying something out, normally im on a 9db profile. I noticed that it never went above 12db only downwards, do u think thats just because it doesnt need to be that high?
I do have a netgear which will work with the full routerstats program, ill get it setup in the week, means going in the loft :no:
and then ill get more results over a longer period of time.
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Regarding 'Output power'. This really shouldn't have any impact on you as EU's, but 'Low Power Mode' (L2) is now being applied at the MSAN's.
This has been pretty quick to come to fruition, and has taken 18 months from concept, through trials, to implementation, and what happens is when there is little (under 128Kbps) no 'traffic flow' seen by the MSAN for 127 seconds. It basically goes to sleep.
A result of this, we are experiencing as engineers, is that our testers are not drawing heavy traffic when plugged into the circuit, and as such we are actually seeing the drop from nominal synch speed, down to figures between 100-200Kbps. The first time this happened to me, my eyes nearly popped out of my head !! We obviously, had not been briefed about this new change. :no: :'( :no: A couple of guys have spent hours chasing a 'perceived' fault condition, when all the time it was just L2 Mode switching in.
The minute the EU accessess the laptop/PC again, the nominal synch is returned instantaneously so you shouldn't in theory notice anything.
This has only been 'in play' for a couple of weeks, and already a main bug bear we have found is with the 2-wire BT Bus Routers. The issue is they tend to lose their PPP Session when it goes into L2 mode, which is damn frustrating for the EU. The only fix at present that I am aware of, is to install the latest BT Business Hub V3.
I believe the guys at Martlesham are still tweaking this ??
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Hi BS,
Is this only relevant to ADSL connections?
I do notice from my graphs that DS Output Power fluctuates a lot more on my connection than any others I have seen.
I have taken that to be that power is increased whenever my connection is "struggling" to maintain SNR levels.
These fluctuations can be seen minute by minute, sometimes by almost 1 dBmV.
The 2nd graph is from a much longer FTTC connection (1600m or so), only able to achieve 18Mb sync speed, yet Output Power hardly fluctuates at all, even over a 4 day period
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Interesting:
I wonder what the line monitoring programs such as Routerstats/Routerstatslite and the DMT tool will make of the gyrations in sync speed.
The SNR margin may start to show interesting behaviour as well.
If you are using the web while all around you are not the reduced power should manifest itself as a greater SNR margin.
On the other hand the action in raising/lowering power on other lines will cause increased cable cross talk on yours - hence reducing SNR margins while its happening.
Whether you will see this in practice is another matter....
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BE (apologies first re: the other thing I was attempting to do for you ....... have been extremley busy of late)
Regarding the 'Cool Broadband' issue. I know for fact in relation to ADSL, it can only be applied to 21CN circuits ..... NOT 20CN. I don't know about VDSL though pal ??
As I say, this thing was thrust upon us with no communique whatsoever !! When I know more, I'll let you know.
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Here is a forum link I've found to a BT overview of the 'swap to low power' concept, plus a pdf link to a more technical document describing how it works and the issues surrounding it.
http://www.thinkbroadband.com/news/5150-bt-wholesale-adsl2-to-go-all-cool.html (http://www.thinkbroadband.com/news/5150-bt-wholesale-adsl2-to-go-all-cool.html)
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>> This really shouldn't have any impact on you as EU's, but 'Low Power Mode' (L2) is now being applied at the MSAN's.
Thanks BS for that info. I'd previously seen that BT were meant to be bringing in 'Cool Broadband' (http://www.btplc.com/Innovation/Innovation/Coolbroadband/index.htm). They do indeed seem to have rolled it out PDQ
>> I have taken that to be that power is increased whenever my connection is "struggling" to maintain SNR levels.
Lots of bit swapping will also cause changes in output power.
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c6em
"The SNR margin may start to show interesting behaviour as well".
All I can tell you is that when I witnessed the decrease in speed on my JDSU, as you would expect, the SNR increased dramatically !! From memory It was around the 47/48dB mark.
Now then, interestinglt enough, when I rang our BB SMC Helpdesk, they could still 'see' me in synch at the nominal 11.8Meg the EU would usually enjoy. Also, he could 'see' the SNR was at 5dB. When I explained the readings I could see on my JDSU, that's when the info about 'Cool broadband' came to light.
I really don't know how routerstats would behave in this situation ??
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It was around the 47/48dB mark. .../snip/....
Also, he could 'see' the SNR was at 5dB. When I explained the readings I could see on my JDSU, that's when the info about 'Cool broadband' came to light.
I really don't know how routerstats would behave in this situation ??
This could all prove interesting.. no doubt if we start to see some weird routerstats we will know the cause :(
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Latest update.
This is by word of mouth, I have nothing to substantiate it, but after speaking with colleagues it would seem the L2 (Power save mode) is to be switched off with regard to Business Broadband. Again, it's just heresay, but apparently there have been over 48,000 complaints nationwide around this latest technology.
More to come as I get it ..... :)
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Thanks, BS. The information you are able to provide is always welcomed. :)
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FWIW, I just found this:-
ADSL Power Management (http://www.zhone.com/support/manuals/docs/26/2600-A3-ZB20-70/adsl_power_management.htm)
Also this which mentions bit-swapping & VDSL2:-
Low-Power Modes for ADSL2 and ADSL2+ (http://focus.ti.com.cn/pdfs/bcg/adsl2_low_power_wp.pdf)
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is this cool broadband only on BT MSAN's too... have LLU ISPs been rolling it out?
my output power is always at 19.1db so I dont think theres anything changin on my end
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Ive just been informed that my neighbour who is on BT is having problems with speed..could it be related to L2 mode?
I went along 3 weeks back or so and tested his connection with my Netgear router for comparison to mine and other neighbours connected to same JB, he has now told my next door neighbour that he thinks I have broke his broadband connection because it is now slow (3 weeks later) , I can not confront him to help him deal with it as I will be dropping next door neighbour in the poo... so I have to smile and say hello and speak to him knowing he thinks ive broke his line,
I could drop this into conversation about L2 or just pop over and say "are you having any problems? because loads of people on BT ...blah blah..."
his SNR was fine and he was only getting 8Mb sync from a possible 16Mb connection, he has long extension cables running everywhere of which he attaches the home hub... but still, he has had it for years...
he has a V2 Home Hub which I know has a Broadcom 6358 chip , is it possible to enable telnet on this device and perhaps run DMT Tool on it? I can check power mode via that (im unfamilair with telnet commands in CMD)
I would just wait 130 seconds with all programs closed and the ping the router with aldslctl info --stats and check the L0/L2 state yes?
if not, could I do it with Netgear with just the connection to exchange and no IP address (not connected to BT Broadband) as I dont have and cant get his login details (and wouldnt want to as he was paranoid the last time I wanted to)
:(
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if not, could I do it with Netgear with just the connection to exchange and no IP address (not connected to BT Broadband) as I dont have and cant get his login details (and wouldnt want to as he was paranoid the last time I wanted to)
I think so.
It is only the modem part that is being interrogated.
That should sync regardless of IP Address or not.
It would effectively make it just the same as the HG612 VDSL2 modem without a separate router connected.
You could easily test that on your own connection by disconnecting the router, removing your own ISP login details & reconnecting the router.
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>> apparently there have been over 48,000 complaints nationwide around this latest technology.
Thanks BS... it will be interesting to see how this spans out.
I could be being pessimistic but some of the so called 'green' approaches arent necessarily for the better. It seems to be trendy to be green, but some of the power savings (not just in IT/ADSL) Im sure could be better concentrated in other areas, rather than governments and corporates throwing away huge sums of money in areas which make little difference.
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Interesting link there BE.. the previous gumph I had seen was more marketing gumph for power saving modules and the benefits. That last link quite clearly states there are quite a few disadvantages and hence why BT is one of the ISPs listed as abandoning it for VDSL2.
The items listed in 4.3.x of that document dont make good reading :(
>> is this cool broadband only on BT MSAN's too... have LLU ISPs been rolling it out?
Sky have their own version they are playing with.. reportedly by ASSIA (http://www.assia-inc.com/DSL-solutions/pdf/Brief-Power-Management.pdf)
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@ BA - yeah well i already done that on his connection last time. got a sync etc and could pull stats...just no IP Address or Internet, which was fine.
Im a bit annoyed he wont confront me about it, for all I know he could have just meant it as a joke, something to talk about, it was when they were at pub on Saturday (him and my neighbour are best buddies of 40 years and go out drinking every friday and saturday) , now he see's him all the time and he only mentioned it other night...3 weeks or more since I was at his house doing it.. if it was my fault it would have happened straight away, another grievence brought on because of sky's doing, now im starting to fall out with neighbours lol.... I knew I should of walked away when he was concerned about his personal stuff and bank details...!!
@ KITZ - that link, isnt that just explaining about the Power Management Module they have always had in DLM...? Im sure it is, although it will be PMM that manages ASSIA's version of L2/Cool Broadband if and when they roll one out.
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>> that link, isnt that just explaining about the Power Management Module they have always had in DLM.
Not that Im aware of - AFAIK its a separate module.
ASSIA DSL Expresse is the industry’s first DSL management platform to incorporate Dynamic Spectrum Management (DSM) Level 2, a next-generation technology for DSL network optimization.
The ASSIA DSL Expresse Power Management
module enhances this functionality by controlling
power-related parameters that are defined
in DSL standards. The Power Management
module reduces DSLAM power consumption....//snip
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I may be wrong, but I think that module has always been part of the DLM/DSM and has been long before the cool broadband thingy came around - the PMM dynamically shapes power to get as much speed as possible on as little power as possible, where as before it was just full power the whole time while the connection is up (I think)...i may be wrong like.. but what they talk about in the paper isnt L2 low power modes like BT's cool broadband, but it WILL be that module that handles it when its integrated...perhaps...again im probably wrong, ive not known sky to be using lower power modes yet (ones like cool broadband anyway) - the £500,00 per yer per 1 million DSL users is typical savings just from DLM/DSM's power/spectrum management , in other words that what ASSIA say you will save just from using their software, I would imagine L2 modes will save MUCH much more... I just hope ASSIA's version doesnt have same problems as BT's lol...
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I could be wrong too... but I was led to believe that the PMM (Power Management Module) is a 'bolt on' to the 'normal' DLM .. and is practically the same as BT's propitiatory 'Cool broadband'.
According to this page:- DSL Expresse (http://www.assia-inc.com/DSL-solutions/DSL-products/DSL-expresse/) is the suite, but Power Management is an optional feature. Its the PMM that is doing the 'green stuff' that coolbroadband does. In fact from the diagram on that page, you can see the PMM isnt part of the standard DLM and sits on top of the existing DLM architecture.
Apparently its since the very beginning of this year when Sky have been playing with the ASSIA PMM that some lines have been getting much lower syncs than the line should :(
>> I just hope ASSIA's version doesnt have same problems as BT's lol.
Funny enough some were saying that they hope BT's doesnt run into the same problems that Sky did with the ASSIA PMM :-[
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I could be wrong too... but I was led to believe that the PMM (Power Management Module) is a 'bolt on' to the 'normal' DLM .. and is practically the same as BT's propitiatory 'Cool broadband'.
According to this page:- DSL Expresse (http://www.assia-inc.com/DSL-solutions/DSL-products/DSL-expresse/) is the suite, but Power Management is an optional feature. Its the PMM that is doing the 'green stuff' that coolbroadband does. In fact from the diagram on that page, you can see the PMM isnt part of the standard DLM and sits on top of the existing DLM architecture.
Apparently its since the very beginning of this year when Sky have been playing with the ASSIA PMM that some lines have been getting much lower syncs than the line should :(
>> I just hope ASSIA's version doesnt have same problems as BT's lol.
Funny enough some were saying that they hope BT's doesnt run into the same problems that Sky did with the ASSIA PMM :-[
hmmm... I wonder if we could get some sky users to kill all background programs and wait for 127 seconds and ping the router and see if its in L2 mode? ive never noticed it? my ongoing graphs show the output power as 19dBm..even through the night?
I had heard that PMM is optional too... doesnt mean sky dont/do use it, according to our shared 'info source' they do use it, but I was under the impression the PMM tries to get best speeds on as little power as possible, if DLM database knows of many active neighbouring lines then it may automatically kick back on power a bit (reducing speed slightly) on those lines to prevent crosstalk into each other, I was under impression PMM was a way of making lines more 'neighbour friendly' and as a result also save money - and because of 'bugs' it has it can result in the lower sync rates we discussed some weeks back, I wasnt aware of and didnt think it shuts down into a 'sleep mode' when its not in use or being used very little... I would like to know if it does... I dont think it does, but im usually wrong haha
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Im afraid I dont know enough first hand about the ASSIA PMM, but reading the technical gumph it would appear to be similar to coolbroadband.
What I cant confirm is when/if Sky started using it.
>>> but I was under the impression the PMM tries to get best speeds on as little power as possible,
Sort of... because the DSLAMs/MSANs have always had power cutback facilities.. and bitswap requires the ability to increase/decrease the power output. My own line has had power cut back applied way back to 2003 and its an integral part of dsl which is primarily there to reduce xtalk, but also and importantly.. without it for bitswapping, the line would continually lose sync at small changes in SNR. Traditional power management needs to be there for adsl to work.
The new stuff is all about being green and reducing carbon footprints and taking power management to a new level blah blah blah. :-\
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I see... ah well, Im sure it will all come too light soon when we (sky users) all start getting 'stuck' in low power mode and they get 48,000 complaints in haha , but I dont see it active on my line, I would have thought my graphs (which log every 1 minute) would show reduced output power when idle and it does not, all through night it stays on 19dBm , I dont know if DLM is turned off on my line, our "source" told me that for sky to over=ride DLM and put you onto a manual profile it actually turns off DLM on the line???? I have seen the Interleaving Depth increase without it then..
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hmmm... I wonder if we could get some sky users to kill all background programs and wait for 127 seconds and ping the router and see if its in L2 mode? ive never noticed it? my ongoing graphs show the output power as 19dBm..even through the night?
Could you explain that in more detail as I am on Sky LLU and here are my router stats:
DSP Firmware Version A2pB025f.d22k
DMT Status No Defect
Operational Mode ADSL2+
Upstream 1051
Downstream 8629
SNR Margin(Upstream) 7.7
SNR Margin(Downstream) 8.3
Line Attenuation(Upstream) 19.5
Line Attenuation(Downstream) 33.0
Just noticed from those stats that my download speed it lower than normal.
EDIT:
Just turned off a few protocols and router reconnected with a higher speed:
DSP Firmware Version A2pB025f.d22k
DMT Status No Defect
Operational Mode ADSL2+
Upstream 1065
Downstream 10027
SNR Margin(Upstream) 7.9
SNR Margin(Downstream) 7.1
Line Attenuation(Upstream) 19.6
Line Attenuation(Downstream) 33.0
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See this thread on the Plusnet forums for an example of what happens when a customer has their line activated for L2 mode by accident.
In this case rather than the entire exchange being activated - it was just one line, so we are just seeing the effect on their line of the syncs/SNR margin varying wildly. We are not seeing any cross talk effects (if there are any) from other adjacent lines to theirs also hopping in/out of L2 mode.
http://community.plus.net/forum/index.php/topic,105008.0.html (http://community.plus.net/forum/index.php/topic,105008.0.html)
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hmmm... I wonder if we could get some sky users to kill all background programs and wait for 127 seconds and ping the router and see if its in L2 mode? ive never noticed it? my ongoing graphs show the output power as 19dBm..even through the night?
Could you explain that in more detail as I am on Sky LLU and here are my router stats:
naah thats just normal power state, dunno what protocols you turned off to get higher sync rate though? possibly noise is reduced allowing you too sync a bit higher because your SNRM was 8.3db before- kill all background and foreground tasks so nothing is using the web, wait a few minutes with DMT Open and fire off this command in one of DMT's user queries box's
adslctl info --stats
5th line down there is:
Link Power State: L0
if its L0 then your in normal mode, if its L2 then its in power saving mode, this power saving mode (well, BT's version) reduces sync speed to 128k or something like that, and output power right down after 127 seconds of none-to-low use (128Kbps or less traffic), then when you use it again its supposed to kick back up to full sync speed...although the link that c6em supplys show it shifting someones connection between 6Mb / 3db SNRM (full) and 3Mb / 15db SNRM (Low Power) , Im sure I read it was 128k it lowers it too, obviously not, maybe it reduces power until you have 15db SNRM..??? I dunno...black sheep may be able to shed some light here?
Iam sure that sky's PMM is just a module that assia have that claims to save money on energy costs overall, like "assia's version" of something thats always been around and in use for DSL, I havent seen this L2 mode implemented on sky yet, it doesnt seem to have any L2 sleep state on it like this cool broadband, well, sky dont use it (yet) if it does...
here are my power graphs & sync rate for last 9 hours duriing the night:
as you can see 19dBm and 11Mb all night, surely if sky had this sleep mode it would show on that, my sync rate is the same
(https://forum.kitz.co.uk/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FngaRk.png&hash=6fc1a17a0024c961b69a16c8f7b54384b796aa7e)
(https://forum.kitz.co.uk/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FbE035.png&hash=240921eb09b787349b3e942901cfcfae02d19ab2)
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>> surely if sky had this sleep mode it would show on that, my sync rate is the same
>> Link Power State: L0
>> if its L0 then your in normal mode, if its L2 then its in power saving mode
You are quite correct - Id expect it to show a reduction, therefore you arent.
As mentioned above, Im not in a position to confirm if Sky are or not... but yes querying the router should give you the router power state.
Yet our mutual source said they were playing with it earlier in the year and that he had seen it on his Sky line ??
So I dunno whats going on.
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Yet our mutual source said they were playing with it earlier in the year and that he had seen it on his Sky line ??
So I dunno whats going on.
Was he not on about when he got connected and was monitoring the power levels during his 10 day training? he mentioned to me that it he'd seen power levels adjusting and acting rather oddly during his line training? - he said that the PMM should be turned off during line training because its affecting the training... dunno, perhaps he could clarify, maybe you could ask him? - I think PMM is just assia's own power management feature, Iam not aware of any L2 mode it invokes that reduces users sync rates by quite a bit when traffic is low, there doesnt appear to be anything on sky's forums about it, I would expect to see users on there with it "complaining"... I will ask on sky forum and see if they can shed any light on it, if I speak to Stanley or Liam at sky I will ask them if they can clarify this :)
check it here:
http://helpforum.sky.com/t5/Sky-Broadband-Speed/is-L2-Sleep-Mode-Green-Broadband-active-on-sky/m-p/439239/message-uid/439239#U439239
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..it seems my pst has been removed from the forum , but can still be accessed by those that have the link... >:D - something they want to hide?
it may be cos i mention ASSIA and PMM - so I have reposted without
http://helpforum.sky.com/t5/Sky-Broadband-Speed/is-Green-Broadband-sleep-mode-active-on-sky-EDITED/m-p/439305/message-uid/439305#U439305
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ok..had a reply and my original post mysteriously re-appeared??? as if it was removed temporarily for some reason?
anyway, they say
Thanks for posting about this, we're not aware of any plans at present to introduce anything like this onto our network and our equipment at exchanges.
so..who knows? but it doesnt look like sky's PMM is being used in similar routine as BT's Cool Broadband
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Thanks snadge.. I cant access the first but I can the 2nd. :)
When I get more time, I shall try do some serious digging sometime to see what the ASSIA PPM actually is, because from the gumph I dont think its the 'normal' power module and there is something different about it.. I just dont know what it is yer..
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yep, I think its just assia's version of typical DSL power management and it may or may not be suprerior to others...
I deleted the first topic when it reappeared because the 2nd one had an answer - the first one mentioned ASSIA and PMM, I know they can be a bit touchy aobut revealing the "innards" of their systems, because they would not reveal them to me via email once haha., when I asked about PMM, saying its against rules to reveal the inner workings of skys systems...which is fair enough 8)
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Well, as of today ALL L2 Power Saving Mode, should have been switched off. Shame, as I've had some easy faults. ;) ;D ;D
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Well, as of today ALL L2 Power Saving Mode, should have been switched off. Shame, as I've had some easy faults. ;) ;D ;D
Thanks for that info BS. I take it that it wasnt much of a success then.. I wonder if they will try and develop it further in the future?
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Well, as of today ALL L2 Power Saving Mode, should have been switched off. Shame, as I've had some easy faults. ;) ;D ;D
was this active up and down the country? (I wonder if my neighbour was affected as he has been moaning about slow/problematic BT connection recently)
have they abandoned the idea altogether?
cheers
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Ha ha, Kitz .... I wouldn't say it was one of our better success stories. I've no other info to hand as yet, but I would imagine the 'boffs' will be working away until they get a fix on this?? There's a lot of money to be saved to just let it be.
Snadge, yes, it was implemented nationwide but it has nothing to do with slow speeds. The issue was loss of PPP Sessions on business routers. Not synch, nor speed ........ just the IP Address.