Fibre 80/20 speed expectations

[#1]

@RealAleMadrid @ncd 

Both thanks for your input so far, I have EXACTLY the issue you have both been describing.

My cabinet went offline back in November overnight and when it came back up, my neighbors and I all seemingly had a DLM reset and we noticed looking at our status that for the first time ever we had G.INP applied to the Upstream and my line also received a greater than 50 G.INP setting, in my case 55, it was 47-49 on average mostly impacted by my cross-talking neighbor.  When she turns her modem off and I leave things a good 24 hrs I would normally get a full 79999 sync and 47 G.INP for DL.  

Ever since the cabinet came back with the new capabilities I've been stuck at a throughput of 67Mbps, however I'm synced at 79999/20000.  @Gandalf  did mess with my profile and got me up to 72Mbps but that lasted only until the DLM decided to take action when my neighbor came home and fired up her modem and voila 24hrs later I went from 49 back to 55, still sync though at 79999.  I'm guessing I'm on a retry "high" and affected by this anomoly...it's frankly making me crazy as we tend to do 4k streaming and one stream alone will avg 30-40mbps, we do max our line out in the evenings with 2 streams and whatever elso going on so my view is I'd like the line to not be hobbled.

Reading through your posts it sure sounds like my issue is similar, it's very frustrating as the line is stable and will go for months on end without a resync.

Strangely my PN Dashboard says my sync is 72.1Mbps, but PN staff tell me to ignore this, I'm wondering if this is the multiplier that is being taken from IP Profile and Retry High params, would make sense as I'm sure there's some overhead in the calculation as when I had no issues I would get around 76Mbps throughput consistently, but the dashboard would show my true sync speed and the average would be closer to 76Mbps.

My stats:

DSLAM type / SW version:	BDCM:0xa48c (164.140) / v0xa48c
Modem/router firmware:  	AnnexA version - A2pv6F039v.d26a
DSL mode:               	VDSL2 Profile 17a
Status:                 	Showtime
Uptime:                 	16 days 4 hours 29 min 52 sec
Resyncs:                	1 (since 12 Dec 2019 01:13:33)
			
				Downstream	Upstream
Line attenuation (dB):  	11.9		0.0
Signal attenuation (dB):	Not available on VDSL2		
Connection speed (kbps):	79999		20000
SNR margin (dB):        	4.8		7.8
Power (dBm):            	13.9		-1.9
Interleave depth:       	8		8
INP:                    	55.00		47.00
G.INP:                  	Enabled		Enabled
Vectoring status:       	5 (VECT_UNCONFIGURED)		

RSCorr/RS (%):          	1.8551		156.1647
RSUnCorr/RS (%):        	0.0000		0.0000
ES/hour:                	0.18		5.73

Connection stats

xdslctl info --stats
xdslctl: ADSL driver and PHY status
Status: Showtime
Last Retrain Reason:    0
Last initialization procedure status:   0
Max:    Upstream rate = 23738 Kbps, Downstream rate = 85031 Kbps
Bearer: 0, Upstream rate = 20000 Kbps, Downstream rate = 79999 Kbps
Bearer: 1, Upstream rate = 0 Kbps, Downstream rate = 0 Kbps
Link Power State:       L0
Mode:                   VDSL2 Annex B
VDSL2 Profile:          Profile 17a
TPS-TC:                 PTM Mode(0x0)
Trellis:                U:ON /D:ON
Line Status:            No Defect
Training Status:        Showtime
                Down            Up
SNR (dB):        4.8             7.8
Attn(dB):        11.9            0.0
Pwr(dBm):        13.9           -1.9

[#2]

Hi @Kevin, All,

---

@Kevin wrote:

@ncd I keep wondering if I really need a static IP. Think I've had it since I joined the original fttc trial.

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I do use the static IP, mainly when developing things at home before hosting somewhere more permanent. I could use dyndns or similar but the static IP with a DNS alias is much easier.

I'm about 300 odd metres from my cabinet, so although I sync at the max 80Mb, I doubt I will reach the theoretical max.

One day I'll have it taken off, just to see how much speed I actually gain. Probably only another couple of Mb's!

I'm about half of that distance but do have the lovely view of the cabinet from the house 😉 

I'd like to think we can get closer to the theoretical max than we are today or if not understand why it's not possible.

The only streaming problems I have is SkyGo, and that is more down to their rubbish player. Netflix, Iplayer (and the other channels players) and Amazon Prime all work fine.

---

It's less about streaming not working for me, I use an offsite backup provider and happened to move provider so ended up resyncing a lot of data which got me looking into my maximum rates a little further. A few Mb increase can really make a difference in this scenario but for the most part it's fine.

So it's only bragging rights really! 

---

I've already lost that one unfortunately with several friends and colleagues on G.fast!

Cheers,

N

[#3]

Hi @fwdlink 

This does indeed sound very similar. I'd be happy with 76Mbps as that's ~10% increase on what I have today and would make a difference to my use case.

I'm keen to get to the bottom of this problem too, if not to improve but to understand what is going on.

For completeness I'll also post my stats:

====================================================================================
    VDSL Training Status:   Showtime
                    Mode:   VDSL2 Annex B
            VDSL Profile:   Profile 17a
                G.Vector:   Disable
            Traffic Type:   PTM Mode
             Link Uptime:   3 days: 22 hours: 57 minutes
====================================================================================
       VDSL Port Details       Upstream         Downstream
               Line Rate:     20.033 Mbps       79.998 Mbps
    Actual Net Data Rate:     20.000 Mbps       79.999 Mbps
          Trellis Coding:         ON                ON
              SNR Margin:       11.0 dB           11.4 dB
            Actual Delay:          0 ms              0 ms
          Transmit Power:      -12.5 dBm          13.0 dBm
           Receive Power:      -18.7 dBm           6.2 dBm
              Actual INP:        0.0 symbols      48.0 symbols
       Total Attenuation:        0.0 dB           7.5 dB
Attainable Net Data Rate:     26.579 Mbps      102.155 Mbps
====================================================================================
  VDSL Band Status        U0      U1      U2      U3      U4      D1      D2      D3
  Line Attenuation(dB):	 1.8	 4.6	 7.4	  N/A	  N/A	 4.2	 8.1	 12.6	
Signal Attenuation(dB):	 1.8	 15.5	 6.6	  N/A	  N/A	 5.0	 8.0	 12.6	
        SNR Margin(dB):	 10.9	 11.0	 11.0	  N/A	  N/A	 11.4	 11.3	 11.4	
         TX Power(dBm):	-25.9	-41.1	-12.7	  N/A	  N/A	 9.7	 7.8	 7.0	
====================================================================================

The last reset was due to my messing, it's normally rock solid.

You mentioned that you had been working with @Gandalf on this issue and you were able to have an improvement until DLM happened? Do you have a link to the thread and what was actually changed?

Thanks!

N

[#4]

My current Smart Hub 6 (Business) stats....

DSL uptime:

8 Days, 14 Hours 16 Minutes 56 Seconds

Data rate:

20.00 Mbps / 80.00 Mbps

Maximum data rate:

30882 / 84981

Noise margin:

12.7 dB / 3.9 dB

Line attenuation:

0 dB / 14.2 dB

Signal attenuation:

0 dB / 14.2 dB

VLAN id:

101

Modulation:

G_993_2_ANNEX_B

Latency type:

Fast Path

From member centre.....

Current Line Speed (Download): 73.8Mbps

I can't do a speed test at the moment as Netflix is being watched!

[#5]

Hi @ncd I've looked into this and it's an odd one but there isn't anything we can do remotely I'm afraid. Everything on our testing checks out OK with your sync speed at 80mbps, the profile on your account at 78mbps the highest it goes. 

The banding on your line is: "Downstream: 0.128M-80M with Retransmission (Low). Upstream: 0.128M-20M with no error protection" which shows you're on an open unrestricted banding.

We could arrange an engineer visit to investigate this, although the chances they'd be able to fix this are likely to be minimal.

Hi @fwdlink One of my colleagues has responded to your other thread, with regards to the connection profile on your account this isn't actually affecting your speeds because you don't have a static IP.

This profile is just something that should always match the IP profile of the line and if it's set underneath this and if you have a static IP it'll then restrict your throughput.

Unfortunately the problem appears to be the IP profile which we've got absolutely no control over I'm afraid. I'm happy to arrange an engineer to investigate this if you'd want but I'm not confident this is something they'd be able to look into.

[#6]

Hi @Gandalf ,

Thank you for replying.

Hi @ncd I've looked into this and it's an odd one but there isn't anything we can do remotely I'm afraid.

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Oh it's definitely odd 😉 but do we know where the issue lies? As per the comments in my original ticket (195816868) I think I've done everything possible on my side to try to eliminate any issues. 

---

Everything on our testing checks out OK with your sync speed at 80mbps, the profile on your account at 78mbps the highest it goes. 

What about the static IP? What does this change? In a previous comment someone mentioned this was related to a "Plusnet profile".

---

The banding on your line is: "Downstream: 0.128M-80M with Retransmission (Low). Upstream: 0.128M-20M with no error protection" which shows you're on an open unrestricted banding.

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This is why I'm so confused! It looks like the "link" from my vdsl modem to the cabinet is solid and I'm not affected in anyway by DLM (I've not seen a forced resync as per https://community.plus.net/t5/Library/FTTC-DLM-What-it-is-How-it-works/ba-p/1322799 ).

---

We could arrange an engineer visit to investigate this, although the chances they'd be able to fix this are likely to be minimal.

---

I'd tend to agree, unless we think there is a physical problem at play here between the cabinet and my kit I'm not sure what they do to improve this?

Since there are a number of us (@Kevin, @ejs, @RealAleMadrid) affected by this or a similar problem do we understand where the restriction on throughput could be?

Thanks again for your help!

N

[#7]

Hi @ncd I'm afraid it'd be difficult to find out where the issue lies because we've exhausted all our diagnostic processes. Regarding why a static IP affects your speed in the way it does, it's down to how we route sessions across our network.

When you have a static IP you go through a L2TP tunnel having additional equipment in the route where your session terminates. This will also affect you if you're on a 20CN ADSL1 service (I've not seen one of these in 2 years as the majority of ADSL connections nowadays are provisioned on BT's 21CN service). There's a bit more information Here.

It's not a bad thing at all, it's just how we allocate static IPs out, and it also makes it easier to keep the IP if you move house.

Going back to the problem as I think I've gone at a tangent, I'm afraid there's not much more we'd be able to do.

[#8]

Hi @Gandalf ,

Thanks for your reply and happy new year!

It's frustrating that whilst you are able to acknowledge that there is an issue that affects throughput there is nothing we can easily do about it 😞

If we know there is additional equipment in the way then this sounds like there may be capacity issues or something else is restricting throughput....

The only time I've heard of L2TP mentioned in this context is when connecting via a RAS/B-RAS but I was under the impression with VDSL this is no longer in the pipeline as this is the "new" network as opposed to the old (as per https://community.plus.net/t5/Plusnet-Feedback/How-do-Plusnet-now-speed-limit-connections-IP-Profile...). Are you able to confirm this?

I'm sorry but I don't like not understanding where the problems are - if we at least understand that there is a limit imposed by a piece of network infra that I'm traversing and where that is I feel we have a fighting chance of resolving. 

Thanks again for your help!

Cheers,

N

[#9]

Happy new year @ncd While I understand the desire to get to the bottom of a problem, could I ask are you experiencing any actual performance problems with your connection bar seeing a slightly lower than expected throughput on a test?

[#10]

Hi @Gandalf ,

As per the original ticket I am moving backup provider so have ended up downloading and uploading a lot of my historical data. I'm going to have to do this again as the new provider is sub-optimal so the lost 10% makes a difference in total time to retrieve my old datasets.

Thanks,

N

[#11]

Thanks for the clarification @ncd 

At this stage as the next step I'd drop us a reply on your support ticket 195816868 with your availability for an engineer to visit so we can arrange this for further investigation, because I'm afraid there really isn't anything we can do further remotely as there are no restrictions to your speeds either by DLM or your account's profile.

Once you've responded to the ticket if you can drop us a reply over here we'll get this picked back up as soon as we can.

[#12]

@Gandalf 

I am surprised that you are even considering an engineer visit for what is obviously a Openreach or BT Wholesale profile issue. It is extremely unlikely that an Openreach engineer will have a clue about the IP profile and the strange effect that retransmission high has on the throughput and even more unlikely that he could do anything about it. As I have mentioned previously there has never been any explanation of why a GEA test reports a downstream rate lower than the modem sync speed so that the IP profile is reduced to around 88% of the sync speed. Unfortunately I don't believe PlusNet are able to do anything about this. My IP profile is currently 87.6% of the sync speed when it should around 91-92% on ReTx high.☹️

[#13]

Understand what you've said.

I wish there was more we could do but unfortunately we've sort of reached the end of the road with this where an engineer is ultimately the final next step if anyone affected are wanting to progress this as a fault with us.

[#14]

Openreach engineers can generally diagnose line faults but that is not the situation in this case so what can they do?

[#15]

Hi @Gandalf  and @RealAleMadrid ,

Thanks for both replying.

Whilst I'm happy for an engineer to visit, looking at my line stats I'm not sure there is any fault between my equipment and the cabinet. The sync speed looks good and the other stats (SNR, Attenuation and power) look solid too which points to an issue outside of my control.

As per @RealAleMadrid I'm also unsure what value they can add to the discussion?

As we've established that I'm not unique in facing this issue is there another group (either internal to plusnet or external in the form of BTW)  that we could escalate to with a view to obtaining a resolution or at least more clarity where the fault lies?