Sync speed dropped after switching to PS

[#1]

Hello.

I switched from Now TV Broadband (uses Sky backhaul) to Plusnet in September and I initially saw a decrease in sync speed from 40000 kbps to about 37000 kbps with an actual download speed slightly less. As far as I know, both Sky and PN use the same physical line to the cabinet which I believe should reflect the same sync speed (actual speed may vary due to backhaul congestion etc) but correct me if I am wrong. Therefore the reduction in sync speed is unexpected. I contacted Plusnet CS and an engineer checked the line and although he thought it was syncing too low he couldn't find any specific fault. As no fault was found and I was still above the minimum estimate, Plusnet refused to go any further.

The speed has been slowly decreasing and today I am only getting 28mbps with a sync of 32397kbps. This follows me recently replacing the master socket with a brand new one and replacing the PN Hub One router with a Draytek 2762. (I have no internal phone wiring btw)

I am convinced the line is faulty or at least degraded but it is not sufficient for Plusnet or Openreach to look into.

First of all can anyone explain why the line immediately synced slower when switched from Sky to Plusnet?

Secondly can anyone suggest anything that might help recover the speeds to something closer to what Sky provided?

I have seen a few similar cases like mine when searching for help/answers which leads me to believe perhaps Plusnet are having system wide issues or simply provide an inferior service to the Sky/Now TV.

Hopefully someone, ideally Plusnet, can help resolve this. If not, come the end of my contract I don't see any point staying with Plusnet and will likely switch back to Sky. The speed is generally Ok but I can get better for the same price so why would I stay?!

Thanks.
James.

[#2]

Hi @jmackay I'm sorry to see your speeds have dropped following switching your services to us. Upon further investigation your speeds are artificially restricted by the dynamic line management(DLM) software at the cabinet to max 32.4mbps.

Unfortunately it'd be difficult to advise the reason for this as line tests aren't showing any issues and your connection seems stable, so I've arranged for a DLM reset to be carried out.

Due to the time of night the request won't be passed on to Openreach until tomorrow and we're generally advised to allow 3 working days for these to be fulfilled so I'd recommend checking back on Friday.

Let us know if you've not seen an increase by then so we can investigate further.

[#3]

Hi Gandalf and thanks. Let's see if that helps.
Do you think there is a possibility the line suffered a fault ages ago and the DLM cap remained since? Does the cap normally get removed in time if the line returns to a stable state or are there instances where it could get 'stuck'?
I seem to remember having issues with a BT supplied line in the past and it always improved when switching to a Sky supplied line but if my point above about BT and Sky sharing the same physical line is correct then this shouldn't be true, unless I am wrong. If the DLM reset doesn't help maybe we can try a lift and shift?
I appreciate the help. Thanks.

[#4]

Thanks for getting back to us @jmackay 

It’s possible your speeds have been capped as a result of a fault and DLM will always monitor your connection and take action where it sees fit. If your line remains stable and error free, it would automatically remove the banding with time.

When you move between providers, you’re normally mapped on to a different port at the cabinet and possibly another pair, depending on what work an engineer does to fulfil the switchover.

Once DLM is reset and your speeds are uncapped if you aren’t happy with speed you get there wouldn’t be much we’d be able to do as you’re within the expectations of your line so any fault we raise with our suppliers would likely get rejected by an engineer and a call out charge applied, unless there are other issues like errors or your connection is dropping.

A lift and shift can only be requested by an engineer if both they and DCoE(Diagnostics Centre of Excellence) at Openreach deem it appropriate. As an ISP apart from being able to request a remote DLM reset which is a relatively recent process, we can do nothing more remotely to affect a fibre sync speed. 

[#5]

Hi @Gandalf 

I believe the DLM reset has now occurred. There doesn't appear to be much difference. I am currently syncing at 33647kbps and have a measured speed of 30.9mbps on speedtest.btwholesale.com.

In the fault ticket, I can see there was Cross Talk detected - is this likely to affect my sync rate and speed?

[#6]

Hi @jmackay It's disappointing to see your speeds hadn't improved much folowing the line reset, but it looks like that's as much as your line can handle as you're currently within our suppliers expectations of between 30mbps to 44.5mbps.

Cross-talk is interference at the cabinet from other people's connections, which is probably a contributing factor to this. With regards to why you've had higher with SKY before moving to us, it's possible that you were on a 3dB SNRM target and upon completion of a migration order the software at the cabinet is reset and moved to the default 6dB.

With time and stablity you may get a 3dB SNRM back if that was case, although there wouldn't be anything we'd be able to do to influence this I'm afraid. 

Let us know if there's anything else you'd need help with.

[#7]

@Gandalf I think you're right about Sky using a 3dB SNR margin. I have forced my router to resync with an SNR margin of 3dB by using the SNR tweak function (adsl snr -30) and this now shows a sync rate and speed of 39998kbps / 37.42mbps - almost exactly what I was getting when with Sky. Time will tell whether this remains stable though! Hopefully! If this does remain OK I think this might answer why I have been seeing reduced speeds since switching to Plusnet.

It seems strange that Sky and Plusnet use a different margin if it is controlled by Openreach. Puts an unfair advantage on Sky. If Plusnet do have control over this then I suggest you make this available on request or by default.

Thanks for your help.

[#8]

Thanks for getting back to me @jmackay 

As far as I'm aware the DLM software belongs to Openreach regardless which service provider supplies you with fibre. If you had 3dB with SKY when you moved to another provider (us in this case) DLM would be automatically reset.

It's good to see you've managed to set the SNRM target at 3dB yourself, fingers crossed your line can now handle it.