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Author Topic: Broadcom retrain codes  (Read 18810 times)

roseway

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Broadcom retrain codes
« on: May 14, 2013, 07:09:40 PM »

This is a subject which comes up from time to time, and it seems to be time to raise it again. There was a useful discussion about it, starting at http://forum.kitz.co.uk/index.php/topic,11349.msg220024.html#msg220024 . Codes defined in the Broadcom source are:

Code: [Select]
/*  line-drop reason code */
#define kRetrainReasonLosDetector                   0
#define kRetrainReasonRdiDetector                   1
#define kRetrainReasonNegativeMargin                2
#define kRetrainReasonTooManyUsFEC                  3
#define kRetrainReasonCReverb1Misdetection          4
#define kRetrainReasonTeqDsp                        5
#define kRetrainReasonAnsiTonePowerChange           6
#define kRetrainReasonIfftSizeChange                7
#define kRetrainReasonRackChange                    8
#define kRetrainReasonVendorIdSync                  9
#define kRetrainReasonTargetMarginSync             10
#define kRetrainReasonToneOrderingException        11
#define kRetrainReasonCommandHandler               12
#define kRetrainReasonDslStartPhysicalLayerCmd     13
#define kRetrainReasonUnknown                      14
#define kRetrainReasonG992Failure                  15
#define kRetrainReasonSes                          16
#define kRetrainReasonCoMinMargin                  17

An unexplained code which is commonly seen is 8000, and other codes seen are 8800 and (possibly) 2000.

Can anyone add anything to this?

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asbokid

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Re: Broadcom retrain codes
« Reply #1 on: May 14, 2013, 07:50:12 PM »

It's understood that those codes are values for bitwise left shift operations.

e.g. 

1<<15 (or 2^15) is 0x8000 (Retrain Reason: G992 Failure)

1<<13 (or 2^13) is 0x2000 (Retrain Reason: DSL Start Physical Layer Cmd)

cheers, a

EDIT: so combining 0x8000 and 0x800 ((1<<15) & (1<<11)) suggests a G992 Failure because of a Tone Ordering Exception.

Could be wrong though  :blush:
« Last Edit: May 14, 2013, 07:53:24 PM by asbokid »
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ryant704

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Re: Broadcom retrain codes
« Reply #2 on: May 14, 2013, 08:07:42 PM »

:)

I always appear to get 2 when a full DLM is done though the SNRM isn't negative of target (6db).

I've had it in 1 for a week but only once, currently sitting at 0 with a 24 day sync.
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Bald_Eagle1

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Re: Broadcom retrain codes
« Reply #3 on: May 14, 2013, 08:20:31 PM »

I believe the 8xxx & 2xxx codes are from ADSL connections.


On VDSL2 connections, the usual codes are:-

0 = Reboot/power disconnection - possibly actually Loss of Frame or Loss of Signal
2 = DLM initiated resync or from changing a modem setting that needs a resync to accept it.

I have rarely seen reason 1 - don't actually know what it signifies though

Very, very rarely, I have seen reason 3 & reason 4 on a couple of connections - again, I'm not sure what they signify.

I haven't seen ANY of the other codes, even when remotely monitoring a few VERY poor VDSL2 connections.
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asbokid

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Re: Broadcom retrain codes
« Reply #4 on: May 14, 2013, 08:22:06 PM »

2 is equivalent to 1<<1 (Retrain Reason: RDI Detector)

ColinS linked to a couple of good references to RDI or Remote Defect Indication here: [1]

RDI cells are an OAM function of the ATM layer (PTM too?) "used for reporting remote defect indications in the backward direction" according to  [2]

cheers, a

[1] http://forum.kitz.co.uk/index.php/topic,11349.msg220805.html#msg220805
[2] http://www.amazon.com/Implementation-Applications-Technology-Philip-Golden/dp/0849334233
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ColinS

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Re: Broadcom retrain codes
« Reply #5 on: May 14, 2013, 09:10:10 PM »

2 is equivalent to 1<<1 (Retrain Reason: RDI Detector)

ColinS linked to a couple of good references to RDI or Remote Defect Indication here: [1]
Gosh!  :blush:

Errm, actually I think the (use of the) values do seem to be different between ADSL and VDSL, just as Paul (BE1) has said.  Even more :-[ I think I am the one who got the weird 3's & 4's he mentions at the time of my voice fault shortly after I went FTTC.  I have also seen 2000s, 8000s & 8800s back last year on ADSL when the Gas Board were digging up the road alongside my E-side for a couple of months, and it was causing me grief. :(

I had the impression wrt to the RDI description that it was on ADSL where - on BE as I was at the time - it's IPoEoA.  Since VDSL uses an 'Ethernet-like' PTM transport instead, I doubt it does apply here.

So, we're all right here - a bit each!  ;D
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kitz

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Re: Broadcom retrain codes
« Reply #6 on: August 05, 2013, 08:02:04 PM »

Just to add to this for posterity  - VDSL connection, HG612 modem.

Retrain Reason: 2

Does also seem to cover "Negative SNRM" here.
ie when phone rings, if SNRM plummets and dsl connection is lost.
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kitz

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Re: Broadcom retrain codes
« Reply #7 on: August 13, 2013, 11:12:59 PM »

Quote
On VDSL2 connections, the usual codes are:-

../..
Very, very rarely, I have seen reason 3 & reason 4 on a couple of connections


Oops before I forget

Quote
Retrain Reason:   3

Engineer testing from the cab caused my line to d/c
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ColinS

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Re: Broadcom retrain codes
« Reply #8 on: August 13, 2013, 11:41:33 PM »

On VDSL2 connections, the usual codes are:-
Retrain Reason:   3
Engineer testing
Just a bit of fun ;D
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kitz

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Re: Broadcom retrain codes
« Reply #9 on: August 30, 2013, 08:40:52 PM »

 :lol:  ^

...  and to further update..  I seem to get 0 if I do a manual reboot.

So far confirmed (by me) seems to be

0 = manual resync/reboot by the EU
2= loss of sync due to low SNRm
3= remote disconnection.

which is unfortunately & stangely not the same as BE's observations :(
« Last Edit: August 30, 2013, 08:45:00 PM by kitz »
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ryant704

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Re: Broadcom retrain codes
« Reply #10 on: September 03, 2013, 12:21:35 PM »

2 isn't negative just applied when you have a negative SNRM. I have 15SNRM down and 8SNRM up, 2 is used when the DLM intervenes and a re-sync is needed. Currently banded due to powercuts :(
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boe323

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Re: Broadcom retrain codes
« Reply #11 on: October 14, 2013, 09:35:09 AM »

2 as always been tied down to the dlm initiating a resync, if you look at your stats after the dlm as ordered the resync, you will see loads of errors, my guess is that the dlm onpurpose causes the errors to force the resync.(just a guess)
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burakkucat

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Re: Broadcom retrain codes
« Reply #12 on: October 14, 2013, 09:06:45 PM »

Please see replies No.1 & 4, above, from Asbokid.

Quote
It's understood that those codes are values for bitwise left shift operations.

Quote
2 is equivalent to 1<<1 (Retrain Reason: RDI Detector)

In other words, 'Retrain Reason: 2' is stating that 'RDI Detector' was the cause of the retrain.  :)
« Last Edit: October 14, 2013, 09:09:34 PM by burakkucat »
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ryant704

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Re: Broadcom retrain codes
« Reply #13 on: October 21, 2013, 11:14:40 AM »

What does this actually mean?

#define kRetrainReasonAnsiTonePowerChange           6

I currently have a Retrain Reason: 6
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burakkucat

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Re: Broadcom retrain codes
« Reply #14 on: October 21, 2013, 06:38:52 PM »

Retrain reason: 6

6 == 4 + 2 == (2^2) + (2^1) == (1<<2) + (1<<1)

So a combination of RdiDetector and NegativeMargin, perhaps?  :-\

I'm confused.  ???  Has anyone seen ColinS recently? He may be able to explain things . . .
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