Print

Please login or register.
1 Hour 1 Day 1 Week 1 Month Forever
Login with username, password and session length

[licquorice]

Any equipment attached to the network has always had to be compliant and approved. However, it has never been enforced.

[Chrysalis]

I didn't think UPBO was anything to do with the DLM, I thought it was mostly based on the length of your own line.

DLM also controls power masking I believe.

[WWWombat]

DLM also controls power masking I believe.

The ANFP allows for a dynamic UPBO, as well as a static option. As far as I can make out, the static one is in use, and is dependent on the electrical line length estimations made by the modems as they sync.

Downstream appears to have no dynamic option. Just a static option, based on electrical distance from the exchange.

[Chrysalis]

Well I see my own UPBO vary from sync to sync, so on my own line its shifting between different profiles, even changing the modem can make it act different, as proven when I switched to zyxel.

I also have seen lines matching my electrical distance using different UPBO profiles to my own line.

[ejs]

How do you know the UPBO values are changing? Is it just that you've seen the transmit power figure change, and have concluded it must be that it's the DLM fiddling with the power setting? It could be that conditions change, which result in the amount of power being used varying.

[Chrysalis]

The SNRM changes significantly (not a small variance) and the ES count jumps up when it reduces which is what one would expect with a lower SNRM, there is several posts made by me (and others) on here about it.

If you check my MDWS history, you will see on some resync events I have changes in my US characteristics.

skyeci had the same also when he switched to a zyxel modem.

I believe what it is, its the newer broadcom chipset drivers that negotiates a higher UPBO.  Because the newest chipset driver also does it on the 8800nl and its why I am not using the latest driver on my 8800nl, my new zyxel devices which have newer drivers than the older 8800nl also do it, but my older zyxel 8324 didnt used to do it but that had an older chipset driver.  However even on the older driver, occasionally UPBO intensity changes on a new sync event.

You can tell the power masking in use simply by looking at the SNR and bitloading patterns across the US tone ranges.  Those people like kev who have low US speeds for their attenuation are stuck on the wrong UPBO profile, they have the back off applied on the U2 range instead of U1.

[ejs]

And what does different modem/firmware combinations giving different results have to do with the DLM causing the difference?

[kitz]

The DLM system then cannot interpret the data for all lines on that DSLAM.

Woah, thats pretty bad. Not being able to interpret data for the bad device is kinda fair enough, but to mess up everyone else's figures on the DSLAM is not good

I'd take a stab at Asus too, but there also have been problems with a few of the older Drayteks which do not appear to play nice on Openreach's cabs.

Even so...  how can it be allowed to screw up the data for everyone else on the cab.  Surely there must be some code they could put in to properly escape individuals set of data.   Thus they can use ILQ Grey for the offending line.

I'm not quite sure what they can do about the existing rogue modems..  no doubt they should be able to track back and identify which line it belongs to.   They should be able (in time) to be able identify the modem type and contact the manufacturer... who will hopefully be able to provide new firmware.   The problem then is.. would all users update the firmware?

------

I didn't think UPBO was anything to do with the DLM, I thought it was mostly based on the length of your own line.

You are correct.  Spectral Power Management is completely separate to DLM management.
I have also seen mine vary between resyncs - even using the same modem, but its not DLM related. 

Spectral Management (UPBO & PSD masks) are used to lessen the effects of crosstalk. eg:
On ADSL/ADSL2+ to stop shorter lines drowning out longer ones.
On VDSL to stop VDSL lines drowning out ADSL/ADSL2+

Sometimes your modem can give you a little bit of a power boost (AGC) if there has been a lot of bitswap in an attempt to keep the line in sync...  but there is still supposed to be a max figure. Not sure what it is on VDSL because of all the different profiles, but it was 20dBm for ADSL2+

Thats one of the reasons why there is the huge possibility for some of the ASUS modems to cause havoc on some DSLAMs as they are about the only modem I know of whereby it allows you to completelely turn off UPBO and adjust the AGC GAIN... thus affecting every other connected line.
There was quite a long thread on here a few years ago about it. These ASUS modems totally over-ride DSLAM spectral management which is a DSL standard and not really supposed to be tweaked by the EU at all. 

[kitz]

Is this the sort of thing you mean?

Same modem... same sync speed but look how atm my line is having one of its oscillating fits.    Note how the power is now ramped up - probably AGC GAIN.

I need to do a full power down really and see if I can clear it.


---
ETA...  also note that despite my SNRm oscillating and its now below 6dB, my err/secs are far lower than what they usually are.   
Its exceedingly rare that I have all green traffic lights at this time of day, yet my line conditions are actually worse, so you'd expect the reverse to happen.   But when you look at power and see that Ive been given a power boost, which is attempting to keep the line stable.   

AGC GAIN doesnt always kick in, sometimes the line will go down first.   Next time I resync it may well take it away again.

[ejs]

I thought that with ECI cabinets, reporting identical power figures for both downstream and upstream - one of the power figures is incorrect?

--

Apparently Origin Broadband have been supplying Asus DSL modem/routers to their customers, with the DSL-N16 as their basic model. Of course we don't actually know that the offending modem/firmware combination is an Asus.

[kitz]

Yes.   Downstream is also reporting the upstream figure, thats why they mirror each other :/
But it does show that Ive had a power boost.   It will at some point take it back off me when I reboot


---
ETA

Attaching full years power so you can see it being applied and then when things are nice and stable (like it was before a few days ago) I get it taken back off me.
I think this is the effect what Chrys means about power being reduced.    Mine will possibly now stay high...  until I power down for a while. 

[jelv]

I'm not quite sure what they can do about the existing rogue modems..  no doubt they should be able to track back and identify which line it belongs to.   They should be able (in time) to be able identify the modem type and contact the manufacturer... who will hopefully be able to provide new firmware.   The problem then is.. would all users update the firmware?

Cap the speed at some artificially low figure? That would push users towards contacting their ISP and providing the ISP could tell that the user had plugged in a rogue modem from information provided by OpenReach they should be able to sort it.

[skyeci]

When openreach identified the line/modem (including model/brand & what firmware it was on) that was causing huge issues to my and possibly neighbouring lines I was told even though they knew it needed to be either replaced or removed they said they had no authority to intefer with that service even though it was their network. After several weeks of not getting anywhere Openreach then informed me they had asked the ISP of the offending modem to request it's replacement but that was as far as it would go and would not be followed up further. Due to them telling me the details of the modem and being on good terms with my neighbours I found it myself in the end .
 I am interested to see if they will  now be changing their approach.

[burakkucat]

Due to them telling me the details of the modem and being on good terms with my neighbours I found it myself in the end.

It would not be appropriate for you to mention the device's make & model in the public view but would you send a pm to kitz, roseway and myself with the details, please?

[Chrysalis]

seems the view has changed,  a couple of years back it was either kitz or wombat who said DSM was part of DLM.

anyway there is dynamic power masks they not static, and no it doesnt oscillate "during" a sync, what i am talking about is the DSM been adjusted on the dslam on a new sync event to adapt to other lines, a system somewhere will be setting these parameters aka some form of line management and DLM stands for dynamic line management.

I also perhaps should clarify openreach themselves have told me this. You welcome to pm me kitz about it but I wont post more about the openreach source in the thread.