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[kitz]

This thread is to clarify some of the confusion regarding BT's implementation of G.INP as I notice that we are being quite heavily linked from quite a lot of other websites and forums.   
There are many informative posts in the relevant threads, but unfortunately some people on external sites are either misquoting or misinterpreting  or misunderstanding information contained in them.   Whilst there's a lot of valuable information which is scattered over several threads, there are also some off topic posts which have just served to confuse matters further and the topics have become so large that its impossible to merge them together.

Im hoping that by starting a new thread we can set some of the key points together in one place.  We are not yet aware of all the information nor what BT are doing but the first posts will be updated when more information is released.

• What is G.INP?
• BT G.INP Rollout
• BT G.INP Updates
• The problems with BT Openreach ECI modems
• ECI modem - Issue 1 - Unable to connect to the Internet
• ECI modem - Issue 2 - Lower Speeds & High Latency
• Rumours
• Huawei HG612 modem
• G.INP compatible Modem/Routers
• Modem/Routers showing increased latency and lower sync speed
• G.INP Observations and benefits

What is G.INP?

G.INP is also known as:-

• PHyR  -  Broadcoms proprietary name and trademark for the invention. Originally only available on Broadcom devices
• G.998.4 -  The ITU standard name for the technology which was standardised & approved in 2010
• Retransmission - or ReTX - How BT refer to it

G.INP offers effective protection against Impulse Noise in order to improve line stability.  It also reduces overheads and latency when compared to traditional methods of interleaving and RS Error Correction.

Any appliance with an electric motor, power switch or power adapter is capable of generating impulse noise. Telephone wiring in subscribers’ homes picks up the noise from such appliances which, in turn, impairs DSL transmission. The severity depends on how close the source of the impairment is to the telephone wiring and the quality of the wiring itself. Service providers tell us, however, that many of their subscribers’ homes have lower quality wiring, so are susceptible to impairment.

Impulse noise comes in two main flavors – intermittent and repetitive. Noise that occurs as sporadic, unpredictable events is called SHINE (single high impulse noise event). SHINE often originates from turning an appliance on or off. Impulse noise that is consistent is known as REIN (repetitive electrical impulse noise). Household dimmers and faulty power adaptors are a common source of REIN.

Impulse noise protection (INP) is generally comprised of techniques used by DSL transceivers to protect against the effects of impulse noise on the transmitted signal. The former best practice for handling impulse noise was to use forward error correction (FEC) based on Reed Solomon codes, together with interleaving (i.e., I-FEC) to detect and then correct errors within a block of data.

I-FEC works well with REIN, but is less efficient with SHINE, because it requires a fixed overhead of between 6% and 12% of bandwidth under normal circumstances, and up to 20% when attempting speeds of 100 Mbps. In effect, this means service providers actually need to squeeze 120 Mbps out of their VDSL2 lines to deliver 100 Mbps service to consumers due to the 20% overhead.

The G.inp standard (G.998.4) was approved by the International Telecommunication Union (ITU) in 2010. It is intended to provide enhanced protection against impulse noise or increase the efficiency of providing INP.

The G.inp standard specifies the use of physical layer retransmission to enhance INP. The approach is similar to the retransmission method used in TCP/IP. Instead of IP packets, however, data transfer units (DTU) are sent between transmitter and receiver. When packets get corrupted during transmission, the transmitting peer is informed and the DTU is resent.

There are several benefits to the G.inp approach. Compared to I-FEC, the method only consumes transmission capacity when retransmission is required, traditionally consuming less than 1% (more on that later). And unlike TCP/IP, all the traffic is protected, including TCP, IP, UDP, SMTP, HTTP and more.

In addition, the round-trip time — i.e., the (minimum) time required for retransmission — is very short in case of G.inp because the DTU error detection and retransmission occurs at the physical layer.. TCP/IP retransmission often takes up to 50 milliseconds, while G.inp only takes a couple of milliseconds (4 milliseconds is typical). The result is also that G.inp achieves enhanced INP with good efficiency at shorter delays compared to I-FEC.

Reducing latency is important even when retransmission is not required. Due to the end-to-end communication between the server and the client, having faster responses reduces the amount of time required to complete an end-user request, such as to start streaming a video or download a webpage. Beyond the speed of the connection, reduced latency improves response times and makes for a better end-user experience.

By providing extra protection and reducing latency on the weakest link – DSL – G.inp improves the entire communication chain.

Source: Alcatel-Lucent

[kitz]

G.INP Rollout

First announced in this thread: BT nationwide rolling out G.INP/PhyR and changes to DLM.

Timescale

07 Jan 2015: BT Openreach is rolling out G.INP technology nationwide on VDSL lines. G.INP -alternatively known as PhyR, gives effective protection against noise bursts.
12 Jan 2015: Roll out to Huawei cabs commences and should be complete by end of March 2015.
22 Mar 2015: Roll out to ECI cabs anticipated to commence April 2015†

----

Stage One - Update DSLAMs in the cabinet.

Involves 5-10 minutes downtime during the wee small hours whilst configuration changes are made to the DSLAMs in the fttc cabinets.
14th Jan Some users start to report small over-night outages. 

Stage Two -  G.INP & DLM profile applied to line.

Rollout at a rate of 45,000 lines per day†
Feb - Users on Huawei cabs start to see G.INP appear in their line stats.
Mar - ECI cab in Martlesham Heath G.INP live†


How to tell if G.INP has been applied to your line.

Obvious signs to look for are G.INP Framing and use of Bearer 1 †
Profiles available to the ISP show similar to:
0.128M-80M Downstream, Retransmission Low - 0.128M-20M Upstream, Retransmission Low


Updates

• 22/04/2015 - ECI Rollout Suspended until further notice.
  We already suspected that the rollout to ECI cabs may have been suspended.
  This was confirmed by Joe Garner (BT Openreach CEO) on 21st April in an email with adslmax.
  
  In addition we suspect it may have been suspended for all new lines:
   - We have seen brand new Huawei cabs enabled this month without G.INP
   - Observed a line that previously had G.INP enabled unexpectedly have it removed after a DLM reset due to an unrelated line fault.  3 weeks later it is still g.inpless despite using g.inp compatible routers.
  
  
• 24/04/2015 - Update from BT Openreach to ISPs
  
  

  We have not yet started the rollout for the ECI infrastructure

  More information can be found at ISPreview
  
  Unfortunately it still leaves a lot of unanswered questions and no acknowledgement if a firmware update will be rolled out for the ECI and Homehub5A users. Some of the information regarding interleaving doesnt seem to tie up with what users have been experiencing and it also opens up the question about those users on ECI cabinets would have experienced upstream interleaving due to the Infineon chipset's inability to support upstream ReTX.
  
  

  ECI equipment (either modems or DSLAMS) doesn’t currently support upstream retransmission.

  
  which is rather concerning due to the fact that DSLAM upstream is EU downstream :/
  
  
• 23/05/2015 - Openreach to roll out 'fix'.
  Please read important G.INP update for more information.
  
  
• 03/06/2015 - Roll out of new profiles complete.
  It would appear that new profiles should have now been rolled out to all Huawei cabs - - link AAISP.
  

  BT have confirmed that all trial lines have been loaded with the new profiles, further to this BT have confirmed that all other affected lines have now had the new profiles loaded. That is all lines across all providers.

  
  However we note there are still quite a lot of lines which still have g.inp applied on the upstream, so despite the above it may still not be complete.
  
  
• 18/06/2015 - Progress report
  Mk1 to Mk2 updates about half way done. 
  Any Huawei lines which missed Mk1 because their line went live after March or have had a DLM reset will go straight to Mk2 profile when the  Mk1 -> Mk2 upgrades are complete.
  ECI situation to be reviewed after completion of the Huawei cabs.
  
  
• 12/07/2015 - Progress report
  All Huawei Mk1 -> Mk2 upgrades should be complete.
  Currently rolling out G.INP to the 'catchup' lines.  Anticipated full completion of the Huawei lines within the next couple of weeks.

[kitz]

The problems with BT Openreach ECI modems.


ECI modem - Issue 1
8th Jan 2015: ECI modems with old firmware connected to a G.INP enabled DSLAM, will appear to have sync but are not able to complete the initialisation process or get a PPP session.

Problem

ECI modems cannot to connect to the Internet.  Sync light is on.

Solution

EU's will need to contact their ISP to arrange an Openreach Engineer to perform a DLM reset on the line.  This should remove the ReTX profile and allow the ECI modem to sync up and be able to download the latest firmware. 

Openreach engineers are only allowed to perform a DLM reset if a hard fault has been found.  A faulty ECI modem is considered a hard fault.   

Note:  If you have internet access using the modem, then it will have been updated with the latest firmware. Issue 1 is separate to issue 2 and where a lot of people are mixing up facts
 

ECI modem - Issue 2
Large increase in latency and reduction in connection speed.

Problem
Users with ECI modems are reporting doubling of latency and large decrease in sync speed.

We are seeing ever increasing numbers of users complaining of massive increases in ping times such as 9ms > 30ms > 50ms and loss of sync speed anything up to 15Mbps.  Users who are literally next to the cab and previously syncing at a full 80Mbps with no interleaving have seen speeds plummet to 67Mbps.

ISP's may see blank results when performing a GEA test on the line.

Solution

As yet there is no fix.  BT have not responded to any enquiries about this.
Calling out an Openreach engineer for a request for DLM reset is of no use.  DLM resets either will not take or will not stick.
 
Due to lack of an official response, we can only conclude that it would appear that the ECI modems are not compatible with g.inp and the above firmware 'fix' that was rolled out, was simply to enable the modem to connect to the BT network. 

Any lines which are connected using an non-compatible g.inp modem/router appear to default to a DLM profile that applies fairly heavy interleaving and error correction overheads.
Whether this is by design or not is unknown.  It is known that BT first commenced G.INP trials on a limited number of lines in 2013, which is before the DLM changes in Nov 2014 due to the ASSIA court case†.
It's looking increasingly likely that the ECI firmware update mentioned in issue 1 simply sets the  ECI modem to  RETX_ENA=1, yet the modem seems to be incapable of performing ReTransmission correctly hence why we see Issue 2.  See this post for more details.

The only solution we can offer is:
1). Wait and see if BT give an official statement and announce if they are able to release yet another f/w update for the ECI modems and/or if they can make changes to the DLM system which is less harsh for non-compliant modems.
2). Purchase a compatible modem/router.

Use of a compatible G.INP modem/router returns the DLM to normal within 24hrs or so.
AAISP are still waiting for a reply - link.


Rumours

• 1) "The f/w not been updated because the modem is connected to a line that is attached to a DSLAM that does not use the same chipset as the modem".
  False:  G.INP is standardised technology regulated by the ITU. G.998.4 should work regardless or not of the manufacturers chipset.  If its not working then it doesnt have G.998.4 technology enabled.  Also if the modem hadn't received the update then it wouldn't be able to connect to the internet.
• 2) "The modem's firmware is not updated until the DSLAM has had it's firmware updated."
  False: BT have been rolling out ECI modem firmware for a good while.  Software is updated automatically using the BTAgent and/or VLAN 301 regardless or not if the DSLAM has been upgraded
• 3) "The modem's firmware is updated when the DSLAM pushes the firmware onto the modem".
  False: BT have been rolling out ECI modem firmware for over a year.  Software is updated automatically using the BTAgent and/or VLAN 301 regardless or not if the DSLAM has been upgraded.  The upgrade for the DSLAM is an entirely separate process.

Huawei HG612 modems.

These should be fine and work well as long as they have been upgraded to the latest firmware.

Anyone using an unlocked HG612 should ensure they are using HowlingWolfs latest firmware B030SP08
This will show in your stats as

Code: [Select]

Software version    V100R001C01B030SP08
Firmware version    A2pv6C038m.d24j

Compatible Modem/Routers known to work with G.INP:

ASUS DSL-AC68U
Billion 8800NL
Billion 8800AXL
BT HomeHub 5 Type B  (BCM chipset & Software version V0.07.01.0235-BT)
Draytek Vigor 2860 series - 28/04/15 Appears to only work with g.inp beta f/w available here.  May also work with the vectoring f/w on the same page
Fritzbox vdsl routers - 7390 & 7490 are ok. unsure if it applies to all models.
Netgear DGND3700v1 (Custom firmware: 2015-02-08)
Netgear D6400 - Now seems to be working.
Sky Hub SR102
Talk Talk Super router (Huawei HG635)
Thomson TG589vn v3
TP-Link TD-W9980 - compatible if using f/w TD-W9980_V1_150507 .
Zyxel VMG8324
Zyxel VMG8924


Discussion on G.INP compatible modem/routers


Modem Routers showing increased latency and lower sync

The first three on the list all contain the same Lantiq VRX-268 modem chipset & SoC. All 3 appear to be showing similar symptoms.

BT Openreach ECI modem
BT Homehub 5 Type A (Software version 4.7.5.1.83.8.204)
TP Link TD-W9980. -    TP-Link are working on a fix - see below
Draytek Vigor 2850 series. -  12/05/2015.  Draytek currently dont have any plans to release g.inp f/w for the 2850
Netgear D6400 - Users of this router appear to be having a problem getting Netgear to acknowledge that there is an issue - see here  Now seems to be working.


Updates from TP-Link.
07/04/2015 -
TP-Link are aware of the problem on the TD-W990. We will keep you updated.
09/04/2015 -   
TP-Link are aware of a compatibility issue with the chipset which should be capable of G.INP.    TP-Link R&D are jointly working with Lantiq on finding a solution for the TD-W9980.
11/04/2015 -
PN User JHewess is testing beta f/w for TP-link which appears to be successfully working with G.INP on his line.
13/04/2015 -
TP-Link releases beta f/w for g.inp.   More information & download http://forum.kitz.co.uk/index.php/topic,15322.0.html
15/04/2015
TP-Link hope to have news about an official f/w release soon.   Problem identified with the underlying Lantiq f/w.
19/05/2015 -
TP-Link releases official g.inp firmware TD-W9980_V1_150507 . -  Now marking the TD-W9980 as compatible.

[kitz]

G.INP Observations when it goes wrong.




G.INP Benefits.

The vast majority of people on a Huawei cabinet and those using a HG612 or other G.INP compatible modem have seen no issues.
Most have seen significant improvements to their line which include increased speed, removal of interleaving, less errors.

There is a dedicated thread - G.INP enabled Stats Comparison where members of the kitz community have been posting comparison stats and observations about their line.

[boost]

Nice one

[jelv]

With not expecting FTTC until the back end of this year I was aware that there was some issue but hadn't been following it. Suddenly activity started at the beginning of February and my install is 14th April so I was starting to look at this. I'd resigned my self to wading through the many convoluted topics around this subject so the publishing of this brilliant summary could not have come at a better time for me. Thank you Kitz!

Would I be correct to assume new Huawei cabinets will be installed with this already enabled?

When the engineer comes I guess I should be making a fuss if he provides me with a ECI modem!

[Dray]

Are you sure you're getting a Huawei cabinet?

[jelv]

Are you sure you're getting a Huawei cabinet?

I think so - just taken a quick snap from outside our house - see attached.

[kitz]

Aye - looks like the type of cab that houses the Huawei MA5603T. 
Watch for that lock type to be changed

Would I be correct to assume new Huawei cabinets will be installed with this already enabled?

Yes

When the engineer comes I guess I should be making a fuss if he provides me with a ECI modem!

Yes.   But you may not get anywhere.   Unfortunately for a good while some area's have only been supplying ECI modems.   I know going back to when mine was installed that the contractor only had ECI modems on their vans.   Its been like that for a while and one of the OR guys has confirmed that their supplies dept only has ECI's in stock - this is the NW so not sure if it will be different down south, but just making you aware that he genuinely may not have a HG612 available.

[Dray]

Talking of 'shades of grey'  I believe there are 2 types of G.Vector. Maybe ASUS are saying it supports one but not the other?

[Dray]

I was referring to "system" and "board" but maybe not.

[kitz]

I emailed one of the software developers @ TP-Link today and ask if there's any chance that g.inp could be upgraded purely as software update.   It does seem to be that the Lantiq's are predominantly the modems affected by this.   However its not gone unnoticed that the Fritzbox also has the same chipset, so perhaps something could be done.   If I get any info I'll pass it on.

[Chrysalis]

this post was a good idea, as I suspect many only check the forums and not your main site.

[NewtronStar]

The only solution we can offer is:
1). Wait and see if BT give an official statement and announce if they are able to release yet another f/w update for the ECI modems.
2). Purchase a compatible modem/router.


Modem Routers showing increased latency and lower sync

The first three on the list all contain a similar Lantiq VRX-268 modem chipsets and all seem to be in a similar situation.

BT Openreach ECI modem
BT Homehub 5 Type A (Software version 4.7.5.1.83.8.204)
TP Link TD W-9980


*Unconfirmed if all models

going back to your solutions is it a case of a firmware upgrade to enable g.inp on the incompatible modems listed as the firmware can only control the hardware and if the hardware lacks the capability then no firmware would be able get g.inp running 

[AArdvark]

I was referring to "system" and "board" but maybe not.

Sorry, now I understand. Completely missed what you meant.

Do you mean:
As per the links below at the higher scale ?
Whether 'Vectoring' is implemented at the Card or Full DSLAM level for the lower scale ?

This :
http://www2.alcatel-lucent.com/techzine/boosting-vdsl2-bit-rates-with-vectoring/
then this:
http://www2.alcatel-lucent.com/techzine/vdsl2-vectoring-in-a-multi-operator-environment-separating-fact-from-fiction/