(Two) Zyxel p870h modems cannot establish VDSL line sync, Energy Imports modem works fine

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geostuff

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#143325 10-Apr-2014 14:26

Hi everyone, for years I've looked to the geekzone community for tips and help so thanks to all who contribute here. I'm still a noob at posting on here so forgive me if it's too long or not up to standard ;-)

I recently switched from Slingshot naked ADSL to Slingshot VDSL with homeline, as they still don't offer a Naked option for VDSL. I'm in Dunedin, about 4km from the CBD and located ~550m from the Ravensbourne exchange as the crow flies. A year prior to switching to VDSL, I rewired my home to optimise my connection speeds by running a cat 5e cable from the demarc point in my roof cavity directly to my modem, with no other devices on the line. I have no central filter/splitter as I only have the modem on the line.

I bridged the Energy Imports VB104W modem Slingshot provides and connected that to my Netgear Nighthawk to do all the LAN routing and PPPoE connection, but the Energy Imports modem doesn't sync at high enough speeds; after trawling the web and these forums I decided to get a Zyxel P870H-51a v2 from Acquire to get the best speed and most stable connection. Upon connecting and configuring it, I get no DSL light, and I cannot get the modem to sync with the DSLAM at all. From the other side, Slingshot reports that all they can see is 'CPE silent'. I ran through the settings to check they matched the Energy Imports modem (VLAN ID = 10, Priority = 0) and they all matched up. I contacted Campbell Technologies (the suppliers/tech support for the modem) on advice from Acquire to verify my settings were correct, and even tried setting the modem into routing (PPPoE) mode to see if it could connect at all. No luck. Campbell then shipped out a replacement, thinking the first was faulty. The new one does the exact same thing. Occasionally the DSL light will begin flashing after some time, but it never goes solid green and it is generally off completely. Campbell are beside themselves, can't explain it and are discussing giving me a refund, but I want the better sync speeds - I should be able to get them If I reconnect the Energy Imports modem, it syncs up just fine within a minute.

Upon switching to VDSL (2-3 weeks ago), the Chorus tech advised me not to install the master filter on the day of install, as I didn't need it (he gave me one anyway in case I decide to use it someday); while technically I now have a POTS service, I still have no devices on the line other than the modem. He plugged in his technicolor modem, which synced up easily at 21Mbps down / 10 Mbps up. The Energy Imports VB104W modem Slingshot provided to me syncs up easily as well, but only at 16/10 - and it reports the upstream attenuation as 102.3db (14db downstream). I had a Chorus tech come out and recheck the line - he relocated the line on the pole so that it wasn't running parallel to my incoming AC power cable, but doing so didn't change anything. This time he brought along a Huawei modem and again synced at 21/10. We also tested his Huawei modem right at the pole to see if internal or buried wiring was causing any issues; it decreased my attenuation by 1dB and synced at 22/10 - not much difference really. The Chorus tech also gave me the line stats as reported from the DSLAM, which pretty much matched his Huawei modem's stats:

Line standard   VDSL2
Downstream line rate (kbiUs)   21597
Upstream line rate (kbiUs)   9984
Downstream SNR (dB)   12.2
Upstream SNR (dB)   11.8
Downstream line attenuation (dB) 19.3
Upstream line attenuation (dB)   40.7
Downstream output power (dBmV) 13.5
Upstream output power (dBmV)   7.8
Downstream CRC   1
Upstream CRC    0
Downstream FEC    0
Upstream FEC    0

Here's my Energy Imports VB104W modem stats:

Status: Up Mode: ITU G.993.2(VDSL2) Traffic Type: PTM Line Coding: Enable Up Time: 7018 Downstream Upstream SNR Margin (0.1dB): 12.2 11.9 Attenuation (0.1dB): 13.0 102.3 Output Power (dBm): 8.0 8.2 Attainable Rate (Kbps): -2145785176 0 Rate (Kbps): 16220 10151 D (interleave depth): 1 1 Delay (msec): 0 0
As I said, the Energy Imports modem consistently reports some strange figures.

Here is my line info from the DSLAM, from a screencap of the Chorus tech's PC when we were testing the line at the pole:

Data Operational Information
Provider 53269742
DSLAM Make / Model ALCATEL 7302
DSLAM Port RSB-DSLAM-05:1-1-3-45
PSTN Operational Information
Provider 53269742
E><change Code RSB
E><change Type 61E
Switch Name RAVENSBOURNE 2
Switch Type NEAX 61E-G9-RLU

LSD Results for Line: RSB-DSLAM-05:1- 1- 3 -45
Inspection ID:           5251738

Line Configuration
CPE Type:   Unknown
DSL Type:   non.shdsl.opermode vdsl2.g9932.profile.8b, line.type.pots, latency.fast
Line ID:      RSB-DSLAM-05:1-1-3-45
User Label: 104364541-RSB-DSLAM-05 -1-005-45
Spectrum Profile Name:    EUBAV-VDSL2-1
Service Profile Name:       EUBAV-FF-FSFS
Service Template Name:   VDSL2_8b_HSI

CPE Info
Nodem Vendor ID:    B5004244434DOOOO
System Vendor ID:    B5004244434DOOOO
System Vendor Model: 4132707636463033376700000000000000
Serial Number:

Line Operational Info
Service Stability: STABLE
line Status:          Down

Diagnosis Result
Problem:
location:                              xDSL
Description:                         CONNECTION_ STATUS -CPE_SILENT-parameter.line.failure-LOS
Impact:                               no.connectivity.impact
Confidence:                         100

Parameter
lqd.parameter.actual.bitrate                   9984           21600
lqd.parameter.attainable.bitrate
qd. parameter.rel.capacity .occupation
lqd.parameter.attenuation
lqd.parameter.loop.attenuation
lqd.parameter.noise.margin
lqd.parameter.actual.psd
lqd.parameter.power
lqd.atm.traffic.rate.title                          NaN            NaN

TL;DR

VDSL is up and running at my place, it works fine with three different brands of modem, but two different brand-new Zyxels won't even give me a solid DSL light.

Can anyone give me an idea as to what to do next? How could three different VDSL modems sync up perfectly fine, but the Zyxel can't even be seen by the DSLAM? Is there some basic setting I didn't configure correctly?

I will happily provide more information, just let me know what will help.

Thanks for all your contributions.

Rob

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#1022889 10-Apr-2014 14:26

Hello... Our robot found some keywords in your post, so here is an automated reply with some important things to note regarding broadband speeds.

If you are posting regarding DSL speeds please check that

- you have reset your modem and router

- your PC (or other PCs in your LAN) is not downloading large files when you are testing

- you are not being throttled by your ISP due to going over the monthly cap

- your tests are always done on an ethernet connection to the router - do not use wireless for testing

- you read this topic and follow the instructions there.

Make sure you provide information for other users to help you. If you have not already done it, please EDIT your post and add this now:

- Your ISP and plan

- Type of connection (ADSL, ADSL2, VDSL)

- Your modem DSL stats (do not worry about posting Speedtest, we need sync rate, attenuation and noise margin)

- Your general location (or street)

- If you are rural or urban

- If you know your connection is to an exchange, cabinet or conklin

- If your connection is to a ULL or wholesale service

- If you have done an isolation test as per the link above

Most of the problems with speed are likely to be related to internal wiring issues. Read this discussion to find out more about this. Your ISP is not intentionally slowing you down today (unless you are on a managed plan). Also if this is the school holidays it's likely you will notice slower than usual speed due to more users online.

A master splitter is required for VDSL2 and in most cases will improve speeds on DSL connections. Regular disconnections can be a monitored alarm or a set top box trying to connect. If there's an alarm connected to your line even if you don't have an alarm contract it may still try to connect so it's worth checking.

I recommend you read these two blog posts:

- Is your premises phone wiring impacting your broadband performance? (very technical)

- Are you receiving a substandard ULL ADSL2+ connection from your ISP?

I am the Geekzone Robot and I am here to help. I am from the Internet. I do not interact. Do not expect other replies from me.

geostuff

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#1023451 11-Apr-2014 14:30

Bump.

Can anyone offer any advice on this problem?

I am at a total loss to explain how three different brand modems work perfectly on my VDSL line yet two brand-new Zyxels can't even establish a link to the exchange. Did I misconfigure it somehow?

networkn

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#1023468 11-Apr-2014 14:41

I've never seen that and I have been selling Zyxel for years. I called the supplier and they have seen it a couple of times and think it's a DSLAM compatibility issue. They have said they will credit you for those modems through your original supplier against the purchase of their newer modem the VMG-8324 which I think there is a $50 difference in price.

sbiddle

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#1023470 11-Apr-2014 14:43

My explanation is very simple - the connection is so poor the modem is attempting to train but then failing.

geostuff

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#1023492 11-Apr-2014 15:53

Thanks for your replies!

@networkn - Cheers for checking with the supplier. I'm having a look into the VMG-8324 now, though it has a whole mess of features I don't want since the modem is only being used as a bridge. Still, if it is as good or better than its predecessor I'll be happy. Do you know how long this model has been out? Do you know anyone that purchased one, and are they happy with it? Unfortunately I can't get the detailed hardware specs for either model to compare them.

@sbiddle - I have always suspected that, but if the connection is that poor, why is/were a) my attenuation reasonably low; b) my previous ADSL connection speeds are not all that bad - synced about 11/0.9; and c) three other modems work fine on the same line?

networkn

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#1023494 11-Apr-2014 15:56

geostuff: Thanks for your replies!

@networkn - Cheers for checking with the supplier. I'm having a look into the VMG-8324 now, though it has a whole mess of features I don't want since the modem is only being used as a bridge. Still, if it is as good or better than its predecessor I'll be happy. Do you know how long this model has been out? Do you know anyone that purchased one, and are they happy with it? Unfortunately I can't get the detailed hardware specs for either model to compare them.

@sbiddle - I have always suspected that, but if the connection is that poor, why is/were a) my attenuation reasonably low; b) my previous ADSL connection speeds are not all that bad - synced about 11/0.9; and c) three other modems work fine on the same line?

I run the 8324 and have about 20+ of them in the market now (Have been selling them about 6 months). Obviously overkill for a bridge, but you will need to make a call. I am with Sbiddle, your line stats are awful, it certainly will be a factor. 11Mbps on ADSL isn't a particularly good connection considering it's theoreticalyl possible to get 24mbps.

sbiddle

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#1023518 11-Apr-2014 16:19

geostuff:
@sbiddle - I have always suspected that, but if the connection is that poor, why is/were a) my attenuation reasonably low; b) my previous ADSL connection speeds are not all that bad - synced about 11/0.9; and c) three other modems work fine on the same line?

Your attenuation isn't low - it's very high, hence your poor ADSL2+ speeds as well. You either have a wiring fault or are a lot further from the exchange than you think.

As for the reason other modems work? Every modem will perform slightly differently, which is something you should realise since you're seemingly wanting to get a higher sync rate which IMHO you're not going to get.

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RunningMan

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#1023525 11-Apr-2014 16:30

As others have mentioned, your downstream attenuation is pretty high, probably right at the very limit of a reliable VDSL connection. The different modems you have tried are reporting different figures, probably due to measuring it slightly differently, but both are pretty high.

Being right on the edge may mean some modems just can't sync properly.

The underlying reason could be as simple as distance from the exchange (cabinet), or another wiring fault somewhere.

geostuff

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#1023553 11-Apr-2014 17:40

Your attenuation isn't low - it's very high, hence your poor ADSL2+ speeds as well. You either have a wiring fault or are a lot further from the exchange than you think.

As for the reason other modems work? Every modem will perform slightly differently, which is something you should realise since you're seemingly wanting to get a higher sync rate which IMHO you're not going to get.

You say you don't think I will get a higher sync rate, but the fact is that two Chorus modems (Huawei and Technicolor) sync at 21/10. My Slingshot EI modem only syncs at 16/10. I just want to achieve what the Chorus modems can get. I know that there are likely all sorts of wiring issues between me and the exchange, which I confirmed with Chorus is down the bottom of the hill. The exchange is ~550m as the crow flies, but I realise the loop length could be twice that.

Still, using SamF's very helpful guide (Topic# 105744) and his link to speedtest.net's dsl speed calc I assumed my attainable speed is ~24Mbit on VDSL2 with my downstream attenuation of 19dB. Like I mentioned, two different Chorus modems sync fine at 21/10 despite my high attenuation, so I know it is possible.

I appreciate all the information guys. I suppose from my point of view here in Dunedin 11Mbps on ADSL2+ is considered well above average, and I have mates on the outskirts of town still on ADSL at 1.5-3Mbps so I felt I had it pretty good. I know my house wiring is well above board, with cat 5e run straight from the trurip cable to my modem but the Chorus tech did mention that Dunedin has the oldest copper in the country (most not even twisted pairs apparently) so internal wiring might be a moot point.

I know that there are likely all sorts of wiring issues between me and the exchange, which I confirmed with Chorus is down the bottom of the hill. The exchange is ~550m as the crow flies, but I realise the loop length could be twice that. Still, using SamF's very helpful guide (Topic# 105744) and his link to speedtest.net's dsl speed calc I assumed my attainable speed is ~24Mbit on VDSL2 with a downstream attenuation of 19dB. Like I mentioned, two different Chorus modems sync fine at 21/10 despite my high attenuation, so I know it is possible.

The big problem is that if I say 'modem Z doesn't work on my line', Chorus will simply inform me that their modems work fine so it is a problem with my modem, not their lines.

Any idea why the upstream attenuation is so high compared to the downstream? I don't remember that being the case with ADSL.

I think I am going to try the VMG model to see if it works, seems to be the only option really.

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#1023558 11-Apr-2014 17:52

With a downstream line attenuation of 19.3dB, you are lucky to have VDSL at all.

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RunningMan

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#1023560 11-Apr-2014 18:13

geostuff: [snip] with cat 5e run straight from the trurip cable to my modem

Well that's a problem in itself.

Basically, you're at the limit of a workable VDSL connection - it's marginal if it should have been installed at all. Different brand modems are going to perform differently at the end of a very long cable.

If you know the Huawei or one of the others gives better sync rate, and that is what you are aiming for, then go and get one of those... you already know it will work.

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#1023746 12-Apr-2014 00:53

If it really is one of those 70's trurip lead ins that's the first thing Chorus should be replacing.

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#1023996 12-Apr-2014 14:39

Ragnor: If it really is one of those 70's trurip lead ins that's the first thing Chorus should be replacing.

get this done.

it might improve things slightly, but looking at your line, you should not even been allowed to get VDSL.

count your lucky blessings and buy a modem that goes nicely on it.

different modems will sync differently, different modems are good for different lengths, different modems are good and bad for if its exchange or cabinet vdsl.

your not going to magically fix your current modem.

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Any comments made are personal opinion and do not reflect directly on the position my current or past employers may have.

geostuff

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#1024008 12-Apr-2014 15:04

Ragnor: If it really is one of those 70's trurip lead ins that's the first thing Chorus should be replacing.

@Ragnor my home was built in 1990 so if you're referring to the cable that runs from the street to my home it is not that old; it appears to be a four-wire black cable, probably 24 gauge wire I'd say. It is buried from the pole at the street, inaccessible from that point until it pops out in my roof cavity where I've made the connection to a cat 5e cable. Now that I've tested the Chorus modem down at the street as I mentioned in my original post I don't believe the wiring from the street to my modem is affecting the connection to a large degree; the Chorus/Telecom Huawei modem synced at 22/10 at the pole, and attenuation changed from 19/40 to 18.6/38.8 [DS/US] so not that much of a difference. Prior to that test I seriously considered burying a new cat 6A cable from the pole all the way to the modem, but it doesn't seem as though that would make a great deal of difference for the time, labour and expense of it all.

If you are referring to the local loop cable/s (from the exchange 550m away to the pole on the street by my house) I don't know what I could possibly do to get Chorus to consider replacing those, considering their modems work well on the line as it is. I wonder if they'd consider letting me run my own cabling from the exchange directly to my house? In my dreams I suppose :-\

Someone mentioned to me that I might have what he called a 'split line', where someone else is sharing my cable? Whatever the case, I imagine in reality all I can do is make due with what I've got and wait for fibre to make it to my house sometime this decade.

geostuff

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#1024015 12-Apr-2014 15:25

hio77: get this done.

it might improve things slightly, but looking at your line, you should not even been allowed to get VDSL.

count your lucky blessings and buy a modem that goes nicely on it.

different modems will sync differently, different modems are good for different lengths, different modems are good and bad for if its exchange or cabinet vdsl.

your not going to magically fix your current modem.

As I just mentioned, replacing the cable that runs to my house from the street will barely do anything for my line stats. It would involve digging a 300mm deep trench 25m long through established gardens, retaining walls and under a bit of concrete - not much fun and quite expensive for very little reward (if any), considering the line stats at the street are damn close to what I achieve at the house already.

I've been told that Chorus will allow a VDSL connection right down to a 15Mbps DS sync rate before they will recommend you move back to ADSL2+. If this is the case, my attenuation could be much worse and still get VDSL - as I sync at 21Mbps with the Huawei or Technicolor modems.

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