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Where's my FASTPATH gone?

DamBuilder
Grafter
Posts: 57
Registered: 12-09-2015

Where's my FASTPATH gone?

First post so please take it easy on me.
I've been on BT Infinity 2 since it first came out in my area over 2 years ago but switched to PN Fibre Extra Tuesday of this week to save a few quid.
On BTI2 I always synced at around 75/18 with a rock solid FASTPATH connection that never dropped off. Data throughput was normally in the region of 65/16.
On Tuesday PN went live so set up my existing Modem/Router (ASUS-DSL68U) with new connection details and all was well. Synced at around 74/17 with FASTPATH, throughput lower than BTI2 at 60/16 but rock solid connection until this morning when I've logged on so see I'm now on INTERLEAVED.
I've got two gamers in my house and the PING on INTERLEAVED will not be acceptable.
I've not constantly been playing with settings. Re-booting the router etc so simple question - Why?
39 REPLIES
Terranova667
Aspiring Pro
Posts: 1,223
Thanks: 51
Fixes: 2
Registered: 19-02-2014

Re: Where's my FASTPATH gone?

Simple answer because DLM feels your line is currently not stable enough to have fast path, it could very well be that when you were switched over to plusnet you ended up with a worse line pair to the cab etc than you did with BT which in turn got rid of the rock solid connection you may have had.
There is nothing you can do i'm afraid except wait and see if DLM removes the interleaving at some point sadly there is no time line for this it could be days, weeks, months maybe not at all as i say it's all down to how DLM views the stability of the line.
Community Veteran
Posts: 38,410
Thanks: 1,000
Fixes: 58
Registered: 15-06-2007

Re: Where's my FASTPATH gone?

I would question whether the line is actually interleaved in the conventional sense
If G.INP has just been enabled there may well be interleaving but at a low level
For example this is my stat report
Quote
Downstream Upstream
Line attenuation (dB):   21.3 0.0
Signal attenuation (dB): Not available on VDSL2
Connection speed (kbps): 48124 9355
SNR margin (dB):         6.4 5.2
Power (dBm):             12.6 4.8
Interleave depth:       8 1
INP:                     49.00 0
G.INP:                   Enabled
As you can see from my BQM ping it really hasn't affected anything much
DamBuilder
Grafter
Posts: 57
Registered: 12-09-2015

Re: Where's my FASTPATH gone?

Quote from: Terranova667
Simple answer because DLM feels your line is currently not stable enough to have fast path, it could very well be that when you were switched over to plusnet you ended up with a worse line pair to the cab etc than you did with BT which in turn got rid of the rock solid connection you may have had.
There is nothing you can do i'm afraid except wait and see if DLM removes the interleaving at some point sadly there is no time line for this it could be days, weeks, months maybe not at all as i say it's all down to how DLM views the stability of the line.

That's the main thing I don't get as nothing that I can see has changed. It's the same modem/router, same copper to the cabinet and same fibre to the exchange. And what's changed at the exchange? A switch? Also the fact that for the first 4 days on PN it was also rock solid on FASTPATH then at 6am this morning it decided to change..!!
DamBuilder
Grafter
Posts: 57
Registered: 12-09-2015

Re: Where's my FASTPATH gone?

Quote from: Oldjim
I would question whether the line is actually interleaved in the conventional sense
If G.INP has just been enabled there may well be interleaving but at a low level
For example this is my stat report
Quote
Downstream Upstream
Line attenuation (dB):   21.3 0.0
Signal attenuation (dB): Not available on VDSL2
Connection speed (kbps): 48124 9355
SNR margin (dB):         6.4 5.2
Power (dBm):             12.6 4.8
Interleave depth:       8 1
INP:                     49.00 0
G.INP:                   Enabled
As you can see from my BQM ping it really hasn't affected anything much


How do I know if G.INP is actually active? According to the router it's enabled but that doesn't necessarily mean that it's active does it?
DamBuilder
Grafter
Posts: 57
Registered: 12-09-2015

Re: Where's my FASTPATH gone?

Also if I'm on an 80/20 line how come the current sync is 85/15.?
elfish
Grafter
Posts: 235
Registered: 22-02-2009

Re: Where's my FASTPATH gone?

@ DamBuilder, have you tested the latency times?
As oldjim has stated, if G.INP has been enabled, your modem may report interleaving applied, but the advantage of G.INP is that you don't get hit by the 8ms+ of additional delay.
As for why its been applied, it could be down to a few different factors, but DLM monitors the connection from your modem to the DSLAM (cabinet). If the error count has risen above the specified level, DLM will intervene. It also looks at disconnections, so if you are turning your modem off/resync'ing, it will flag that.
elfish
Grafter
Posts: 235
Registered: 22-02-2009

Re: Where's my FASTPATH gone?

Quote from: DamBuilder
Also if I'm on an 80/20 line how come the current sync is 85/15.?

That's stating the max attainable rate of your line. These figures are meant to show how fast your line could achieve, but when interleaving, G.INP etc. are enabled they can get skewed due to overhead.
DamBuilder
Grafter
Posts: 57
Registered: 12-09-2015

Re: Where's my FASTPATH gone?

Quote from: elfish
@ DamBuilder, have you tested the latency times?
As oldjim has stated, if G.INP has been enabled, your modem may report interleaving applied, but the advantage of G.INP is that you don't get hit by the 8ms+ of additional delay.
As for why its been applied, it could be down to a few different factors, but DLM monitors the connection from your modem to the DSLAM (cabinet). If the error count has risen above the specified level, DLM will intervene. It also looks at disconnections, so if you are turning your modem off/resync'ing, it will flag that.

Yes prior to this morning average ping was always 16-17 but it's now double that.
And since PN going active Tuesday I'm pretty sure the modem has only been restarted a couple of times at the beginning and once last night.
elfish
Grafter
Posts: 235
Registered: 22-02-2009

Re: Where's my FASTPATH gone?

Ok, it does sound like traditional interleaving has been applied to both down and up stream's which will be the reason for the increase in latency.
As already stated by Terranova667, there is nothing you or PN can do, as they have no control over DLM/interleaving settings on FTTC. You will just have to wait until DLM deems your line worthy of disabling interleaving. This change does happen a lot quicker than it did on ADSL, so hopefully it should go back to Fastpath pretty quickly. I would recommend to leave you Asus on and not be tempted to re-sync it.
FYI, there are two main variations of DSLAM's (cabinets), ECI and Huawei, currently the ECI DSLAM's are not enabled for G.INP, whereas the Huawei are enabled for G.INP, so depending on your connected DSLAM, G.INP may not be possible even if your Asus supports it.
You can find out what type of DSLAM you are connected to by following the instructions over on the kitz website:
http://www.kitz.co.uk/adsl/cabinet-lookup.htm
DamBuilder
Grafter
Posts: 57
Registered: 12-09-2015

Re: Where's my FASTPATH gone?

Thanks 'elfish' I'll check that out and sit here watching the stats lol.
Oh how I long for those days 30 months ago when I was the first fibre customer from our cabinet and was synced at 76/19 and almost achieving that in throughput as well. I had those speeds for about 12 months but since then I have watched them slowly drop...!!
DamBuilder
Grafter
Posts: 57
Registered: 12-09-2015

Re: Where's my FASTPATH gone?

I'm on an ECI cabinet.
elfish
Grafter
Posts: 235
Registered: 22-02-2009

Re: Where's my FASTPATH gone?

No problem.
Yep, when others start going on to the FTTC service, performance decreases, and its annoying seeing one's speed drop over time.
Vectoring is the answer to this, and hopefully will be rolled out in the future.
"I'm on an ECI cabinet." And that will explain why you are not getting G.INP. Openreach are hoping to roll out G.INP on ECI DSLAM's in the near future.
DamBuilder
Grafter
Posts: 57
Registered: 12-09-2015

Re: Where's my FASTPATH gone?

I might still pester PN in a couple of days if it hasn't come back as I had FASTPATH for 30 months on BT Infinity 2 and only 3.5 days on PN Extra.
Best prepare for my 16 year old boy coming back from football with his "I told you so" comments about changing to PN from BT 'cos all his mates say it's rubbish for PS4 gaming..!!
elfish
Grafter
Posts: 235
Registered: 22-02-2009

Re: Where's my FASTPATH gone?

Smiley
Certainly, as a paying customer you are entitled to complain and there is no reason not too.
My line has been through pretty much all the variations, from Fastpath to interleaving on down and up stream separately and both, and G.INP down and up plus both, so its always changing, but it does seem coincidental that the change has happened so soon after changing to PN.
As you said, contact them and see what they have to say.