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Standard User Fragsey
(regular) Thu 11-Oct-12 23:28:59
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Engineer install not using JDSU???


[link to this post]
 
Hi finally had my Xilo/Uno FTTC installed today, reading past reviews of what the install entails mine seemed different, just wondering if this is norm. Not saying it was bad, on contrary I am pleased.

1. Engineer phoned at 7:40am saying he would be with me about 8:15-8:20
2. Vivaciti adsl router disconnected at 8:05
3. Promptly at 8:15 engineer knocked at door.
4. Engineer surveyed master socket location, as I was installing in same place he went out to van and grabbed the gear
5. Engineer removed current master socket (old BT Piper logo) tested the pairs with his handset to identify correct pair and wired into a brand new openreach one and fitted the new faceplate.
6. plugged in modem obtained sync.

I thought the engineer used a JDSU to test sync ect. Instead Texted something using his mobile and recived a reply back with the sync speed and error stats. (59Mb) Confirmed all the lights were on, as was not infinity let me plug in my TP-Link router and bam was online. Thanked the engineer and he left at 8:25.

Was a really pleasent chap and good experience.

Have they simplified the line checks so done centrally and texted to the engineer now? I am getting more than was estimated so well pleased smile

sad to leave Vivaciti, though my sync was deteriorating from exchange and Xilo offered a good price for service. Speed test around 56Mb and 13-14Mb up

-------------
http://www.fun4forums.co.uk

Xilo FTTC :: 56Mb d / 14mb u

Previously: Vivaciti LLU :: UKFSN / entanet Max :: <n>ildram Max :: plusnet 512k/1Mbit :: Bulldog 512k :: BTopenworld 512k :: AOL 56k \o/
Standard User RobertoS
(sensei) Thu 11-Oct-12 23:35:36
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Re: Engineer install not using JDSU???


[re: Fragsey] [link to this post]
 
There have been quite a few reports of this type of remote test and feedback. No-one has yet suggested what causes them.

Don't mess with the modem connection to the DSLAM before Saturday.

Enjoy smile.

My broadband basic info/help site - www.robertos.me.uk | Domains,website and mail hosting - Tsohost.
Connection - Plusnet Extra Fibre (FTTC). Sync ~ 57.4/14.6Mbps @ 600m. - BQM

"Where talent is a dwarf, self-esteem is a giant." - Jean-Antoine Petit-Senn.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Allergy information: This post was manufactured in an environment where nuts are present. It may include traces of understatement, litotes and humour.
Standard User WWWombat
(experienced) Fri 12-Oct-12 00:14:50
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Re: Engineer install not using JDSU???


[re: Fragsey] [link to this post]
 
When our current line was upgraded to fibre (in January) the guy did both.

Our old line was converted in the previous June. He certainly texted (cos the numbers he gave me were copied from his phone), but I don't know about the JDSU. I *think* there was one.

However, it really doesn't matter - so long as you think the speed sounds reasonable. The two reasons are:

- It doesn't matter, because DLM monitors and intervenes 48 hours later... so your long term speed is only decided long after the engineer has left. It doesn't matter what the JDSU reports at the time.

- BT largely ignore, at human-level, what the error rates are. It is just left to DLM to handle errors.

After getting lots of errors, and DLM intervention, on the first line, I specifically got the engineer to check (on the JDSU) the CRC count during the second install.

If you see errors at that point, you might get the guy to check the line, but I wouldn't bet on it.

If you see errors later, or increased latency because of interleaving, you are unlikely to get an engineer's attention. If you drop speed a long way, then *that* might trigger a visit, but not the errors/latency alone.

So... an engineer with a JDSU is probably only actually useful if your line fails to sync, or syncs with an abysmal speed. Any speed around or above the prediction will be left anyway - so the JDSU is merely "comfort".


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Standard User asbokid
(member) Fri 12-Oct-12 00:41:23
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Re: Engineer install not using JDSU???


[re: Fragsey] [link to this post]
 
Maybe the CWMP (CPE WAN Management Protocol) element of TR069 is being used?

At a guess...
  • provisioning engineer sends text to an SMS->IP gateway (Asterisk with chan_mobile or similar) (1)
  • SMS contains CLID of premises being provisioned for FTTC
  • SMS<->IP gateway forwards request to network server - maybe bespoke extension to iManager U2000? (2)
  • Server invokes script to search AAA layer with CLID as key
  • found record will hold current IP address for VDSL2 CPE modem
  • script retrieves line stats either from DSLAM (SNMP i/face) (3) or from btagent daemon on CPE modem (161/tcp). (4)
  • live line statistics are sent back via IP<->SMS gateway to the engineer's mobile

clever stuff!

cheers, a

(1) https://wiki.asterisk.org/wiki/display/AST/Introduct...
(2) http://www.huawei.com/en/products/oss/fbb-om-product...
(3) http://insidehuaweima5616msan.wordpress.com/2012/10/...
(4) http://huaweihg612hacking.wordpress.com/2011/08/01/w...

Edited by asbokid (Fri 12-Oct-12 00:53:00)

Standard User WWWombat
(experienced) Fri 12-Oct-12 01:46:13
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Re: Engineer install not using JDSU???


[re: asbokid] [link to this post]
 
It probably also triggers a DLM reset. The cabinet has to know when that 48 hour period is up, right?
Standard User asbokid
(member) Fri 12-Oct-12 04:10:04
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Re: Engineer install not using JDSU???


[re: WWWombat] [link to this post]
 
Reset it as a matter of routine? It would seem very likely, WWWombat, and sensible. Not sure how it's achieved in practice. Just flicking through the config manual for the MA5616 (the littlest Huawei DSLAM). [1]

BT's DLM algorithm still seems a mystery. Is it any different to the algorithm shipped in the standard DSLAM firmware by Huawe/ECI? If so, why? It looks to have all the same functions (three levels) as the default DSLAM 'program', but BT has given it a different name.

Options for general xDSL profile configuration (max/min line rates, PSD masks, SNR margin, interleaving depth, INP duration, etc) are interesting too. There are three different schemes for configuring the xDSL profiles of Central office kit: TIMODE, TR129, and TR165.

The latest standard in xDSL profile configuration protocol is TR165. It is a vector-based protocol. Here once again, we find Beatie setting the standards that the world then follows (BT chairs the TR165 Forum).

cheers, a

[1] http://www.scribd.com/doc/99094075/FTTx-Solution-Con...

Edited by asbokid (Fri 12-Oct-12 04:24:35)

Standard User RobertoS
(sensei) Fri 12-Oct-12 11:02:05
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Re: Engineer install not using JDSU???


[re: WWWombat] [link to this post]
 
In reply to a post by WWWombat:
- It doesn't matter, because DLM monitors and intervenes 48 hours later
That isn't quite correct.

The intervention occurs immediately if necessary, ie "severe instability". BT SIN 498:-
Dynamic Line Management (DLM) is employed in GEA-FTTC. DLM constantly manages lines to maintain a target link quality (speed and stability). It does this for as long as the product exists.
At provision, the line is put on “wide open” VDSL2 line profiles allowing the upstream and downstream line speeds to run at the upper limit of the product option selected.
On the first day of operation, DLM will intervene if severe instability is detected. Otherwise, DLM will wait until the day after provision before deciding if it must intervene, provided that the line has been trained up for at least 15 minutes during the preceding day.
As I understand it, the word "day" there refers to a period ending at starting at one midnight and ending at the next. This is why I advise people to avoid trying to achieve better speeds by playing with the OR modem before midnight of the day after installation.

My broadband basic info/help site - www.robertos.me.uk | Domains,website and mail hosting - Tsohost.
Connection - Plusnet Extra Fibre (FTTC). Sync ~ 57.4/14.6Mbps @ 600m. - BQM

"Where talent is a dwarf, self-esteem is a giant." - Jean-Antoine Petit-Senn.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Allergy information: This post was manufactured in an environment where nuts are present. It may include traces of understatement, litotes and humour.
Standard User RobertoS
(sensei) Fri 12-Oct-12 11:03:43
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Re: Engineer install not using JDSU???


[re: WWWombat] [link to this post]
 
In reply to a post by WWWombat:
It probably also triggers a DLM reset. The cabinet has to know when that 48 hour period is up, right?
See my reply to your previous post.

My broadband basic info/help site - www.robertos.me.uk | Domains,website and mail hosting - Tsohost.
Connection - Plusnet Extra Fibre (FTTC). Sync ~ 57.4/14.6Mbps @ 600m. - BQM

"Where talent is a dwarf, self-esteem is a giant." - Jean-Antoine Petit-Senn.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Allergy information: This post was manufactured in an environment where nuts are present. It may include traces of understatement, litotes and humour.
Standard User WWWombat
(experienced) Fri 12-Oct-12 12:29:30
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Re: Engineer install not using JDSU???


[re: asbokid] [link to this post]
 
I think it is sensible. With that interaction, the engineer is effectively telling the DSLAM that the line is ready, modem in place, and that DLM should both start properly *now*, and ignore anything else up to this point (which might include some installation SNAFU's).

As for BT's DLM (and them chairing the various workgroups on it): BT has got a good research group, and do a lot of work at making the technology work when deployed in a widespread world (ie not just blue sky work, or kept in the lab). Their DLM is probably an output of this work.

For example, I've come across this before: Muse report on "Enhanced DSL Algorithms" (2005)
However, I just found this: Muse report on "Static and Dynamic Spectral Management Analysis" (2006)

BT seem to call it DSM rather than DLM, and I've seen it referred that way elsewhere (and referenced as DSM level 1 - where vectoring is considered to be DSM level 3).

Using that as a search, I've found the following references too:
[32] Report on Dynamic Spectrum Management (DSM) Methods in the UK
Access Network, UK NICC ND 1513 (2010-01).
[33] Dynamic Spectrum Management (DSM), NICC Work Item 308 – under
study, 2012.
[34] Vectored VDSL performance in the UK, NICC Work Item 309 – under
study, 2012.
[35] Specification of the Access Network Frequency Plan applicable to
transmission systems connected to the BT Access Network, UK NICC ND
1602 (2011-09).

Thanks for the other links & references. More for me to read...
Standard User WWWombat
(experienced) Fri 12-Oct-12 14:30:32
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Re: Engineer install not using JDSU???


[re: RobertoS] [link to this post]
 
In reply to a post by RobertoS:
In reply to a post by WWWombat:
- It doesn't matter, because DLM monitors and intervenes 48 hours later
That isn't quite correct.

The intervention occurs immediately if necessary, ie "severe instability". BT SIN 498:-
Dynamic Line Management (DLM) is employed in GEA-FTTC. DLM constantly manages lines to maintain a target link quality (speed and stability). It does this for as long as the product exists.
At provision, the line is put on “wide open” VDSL2 line profiles allowing the upstream and downstream line speeds to run at the upper limit of the product option selected.
On the first day of operation, DLM will intervene if severe instability is detected. Otherwise, DLM will wait until the day after provision before deciding if it must intervene, provided that the line has been trained up for at least 15 minutes during the preceding day.
As I understand it, the word "day" there refers to a period ending at starting at one midnight and ending at the next. This is why I advise people to avoid trying to achieve better speeds by playing with the OR modem before midnight of the day after installation.

I understand that, and understand what is written too.

For one part, I tend to ignore the "severe instability" exception. It is indeed exceptional - to the extent that I don't think we've seen any cases of it happening on the install day (although Bald Eagle might have seen it after some of the resets while his line was being "fixed"). For most people posting on here, we'd recognise a severe instability long before we got to talking about the quirks of DLM.

As for the other part, on the timing, I agree. DLM actually works that way *normally* - it sees a problem one day, and takes action the next day (experience shows this change is between 4AM and 8AM).

But experience of the *initial* period - the first few days after a reset/install - is slightly different. Those experiences are that the first change (not for a sever instability) comes after 48 hours. I've gone through this experience more than once.

Granted my experience of the 48 hour period is not *that* recent, so things could have changed. But the SIN has had that wording since I first saw it - more than 18 months ago.
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