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10 Day Fluctuation - Is there a fault ?

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Csutty987
Hooked
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Registered: ‎30-06-2017

10 Day Fluctuation - Is there a fault ?

I got my Fibre Unlimited 38Mbp/s package activated yesterday, with a given estimate of 22-30. 

I heard that the 10 day fluctuation is due to Plusnet testing different speeds and connections to find one that best suits your line. 

If that is true, I would imagine a fluctuation around 15-25 roughly.

However the best I have gotten so far is 3Mbp/s.

Speedtests tell me I should be getting 23-26Mb but whenever I actually download something the best I get is 3Mb which I honestly find terrible. I have used multiple programs and checked just about all settings on my computer/programs to no avail. Is this normal to get a massive 15Mb lower than the minimum guarantee for the first ten days or is there actually a fault here?

 

I have tested everything via ethernet cable on the same computer. 

From Plusnet themselves :

Estimated line speed:30Mb (This may vary between 22.4Mb and 30.8Mb) - Checked on 2017-06-14 21:00:51

Current line speed:37 Mb

 

 

 

 

 

11 REPLIES 11
rongtw
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Re: 10 Day Fluctuation - Is there a fault ?

Hi , there is No 10 day fluctuation  , and PN does not test your line .

what happens is  the DLM    "dynamic line Management"  a automatic system checks your line and will find what it thinks is best for your line in the first 48 Hours Thumbs_Up

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Csutty987
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Re: 10 Day Fluctuation - Is there a fault ?

Thanks for the insight. I was given the ten day thing by Plusnet - to give the new internet 10 days to 'settle in' was roughly the quote I think. I can handle waiting another 24 hours to see if it improves before asking further. I am still concerned though, I feel like 3Mb out of 22-30 is more than just this DLM testing what is best for my line. This is the first time I've actually had decent internet so I'm a little inexperienced with what to expect though.

Browni
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Re: 10 Day Fluctuation - Is there a fault ?

As Ron says, there is no 10 day period.

I've been meaning to find BT's definition of DLM for a while so here it is from the horses mouth so to speak

2.2.1 Dynamic Line Management

Dynamic Line Management (DLM) is employed in GEA-FTTC. DLM constantly manages lines to maintain a target link quality (speed and stability). It does this for as long as the product exists.

At provision, the line is put on “wide open” VDSL2 line profiles allowing the upstream and downstream line speeds to run at the upper limit of the product option selected.  

On the first day of operation, DLM will intervene if severe instability is detected. Otherwise, DLM will wait until the day after provision before deciding if it must intervene, provided that the line has been trained up for at least 15 minutes during the preceding day.

If DLM intervenes it will set a profile with a maximum rate and a minimum rate, where the minimum rate is set at approximately half of the maximum rate. The purpose of the minimum rate is to ensure that the line does not train at a rate which is significantly below the level the line should be able to achieve. If this happened, then the line is likely to remain at a very low rate until a re-train is forced by the user by powering off the modem.  

Note : It is the DLM system that sets the line profile, and this should not be interfered with by CPs/users setting rates, SNR margins etc. at the modem.  

Note : The upstream throughput is also constrained on the DSLAM to the upstream rate requested in the order, i.e. 2 Mbit/s, 10 Mbit/s or 20 Mbit/s, so even if the VDSL2 upstream line speed is higher, the upstream throughput is constrained to the level ordered for the product.

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dvigelis
Grafter
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Registered: ‎26-06-2017

Re: 10 Day Fluctuation - Is there a fault ?

Dont you mix Megabites with megabits? Your estimate 25MBits is 3 Megabites. Dont you expets to get 25Megabites a secont download speed?
Browni
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Re: 10 Day Fluctuation - Is there a fault ?

Fix

Good point @dvigelis.

@Csutty987 how are you measuring your download speeds? Steam and other download sites tend display MB/s whereas speeds are normally Mb/s.

Csutty987
Hooked
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Registered: ‎30-06-2017

Re: 10 Day Fluctuation - Is there a fault ?

Ah. It appears I am at fault Crazy The difference between MB and Mb in my question was mere coincidence, yet that is what is confusing me. Before this I had not even noticed the capitalised B on programs (particularly Steam, Battle.net and Origin), as opposed to the speed internet packages give. Thanks for the help guys, but it appears I am just stupidHuh

Gandalf
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Re: 10 Day Fluctuation - Is there a fault ?

It's easily done Smiley

 

Welcome to the community forums by the way.

From 31st October 2022, I no longer have a regular presence here as I’ve moved on to a new role.
Anoush Mortazavi
Plusnet
Browni
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Re: 10 Day Fluctuation - Is there a fault ?

Wee update now that G.fast is in the wild/..

2.2.1 Dynamic Line Management Dynamic Line Management (DLM) will be used on G.fast pilot lines. DLM monitors and manages lines to maintain a target link quality (speed and stability). DLM runs once a day based on line performance data collected during the previous day and makes changes in the G.fast line configuration if needed. Two parameters can be varied by DLM within the line configuration; the level of retransmission or the target noise margin. DLM operates independently on the downstream and upstream channels, although the same process is applied in each direction. For poor lines (i.e. those not meeting the target link quality) increasing the level of retransmission is chosen in preference to increasing the target margin by DLM. Once the highest level of retransmission is reached then target margin is increased until the target link quality is achieved. For good lines (i.e. lines running in excess of the target link quality) a reduction in the target margin is chosen in preference to reducing the level of retransmission. If a line meets the target link quality then DLM will take no action. Retransmission is applied by default in both the downstream and upstream channels at a low level to all new lines and is then increased by DLM if needed. In addition, maximum line rate caps are applied by default and within the DLM process which align to the selected product (i.e. the 330Mbit/s product will be capped at a maximum Ethernet throughput rate of 330Mbit/s). Note: It is the DLM system that sets the line profile, and this should not be interfered with by CPs/users setting rates, SNR margins etc. at the modem.

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tiffy
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Re: 10 Day Fluctuation - Is there a fault ?

@Browni

While trying to get to grips with G.Fast technology came across your post, most helpful, many thanks.
Was not even sure that DLM technology was still applicable to G.Fast, found information very limited even on the usually well informed sites such as kitz & TBB, perhaps not looking in the correct places !

Perhaps you could help further with a few of my queries:

As DLM is still used with G.Fast and in most cases the new G.Fast extension pods are being attached to the PCP cabinets, does this contain it's own DSLAM ?

I believe G.Fast "pods"can be situated in alternative locations such as manholes, telegraph poles, buildings communial areas etc., under these circumstances does that become the location of the DSLAM ?

G.Fast has not yet been rolled out in my area, even it was my location is much too far away from the PCP to be viable, just interested in the technology and keen to update my knowledge on the system.

Browni
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Re: 10 Day Fluctuation - Is there a fault ?

As far as I am aware the only ones seen in the wild are those that are attached to the PCP and I would guess that is where the DSLAM IS.
tiffy
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Re: 10 Day Fluctuation - Is there a fault ?

@Browni

Thanks for the response, much appreciated.

I have read that an enhanced revision of VDSL2 vectoring is applied to G.Fast DLM by default and G.Inp technology is also applied as per VDSL2 (currently on Huawei FTTC cabinets only), I would think that with the much higher frequencies / bandwith involved with G.Fast, vectoring would become essential to achieve even the min. predicted distances from the PCP..

PCP deployment is likely a much easier, faster and cost effective option for BT as power for the DSLAM is already available from it's local FTTC cabinet (mains and battery backup) as is a fibre link back to the exchange.