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Author Topic: Can someone please explain the (0) in K: 163(0) 15 ?  (Read 1953 times)

G.DMT

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Can someone please explain the (0) in K: 163(0) 15 ?
« on: July 19, 2014, 05:05:01 PM »

This output from my Billion BiPac 7800N
> adsl info --show

Code: [Select]
                Down            Up
SNR (dB):        3.1             17.0
Attn(dB):        61.0            31.5
Pwr(dBm):        19.4            12.5
                        G.dmt framing
K:              163(0)          15
R:              16              16
S:              1               8
D:              32              4

The 'K' values have an unexpected (0) after the number value in the first column.  :hmm:

I have seen the explanation page

"K Value - Bytes in the DMT Frame" from:
http://www.kitz.co.uk/adsl/linestats_errors.htm

But I am left wondering why this (0) is there?
Presumably this number enclosed in the brackets could/can/does vary?

Perhaps more importantly,
1) do other people see similar 'extra' values like this in their logs?
2) can I expect to see anomalies like this in logs from other Broadcom 63xx chipsets?
3) is that 'extra' number useful enough that it should be recorded with others stats?

Thanks.  ;D
 
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burakkucat

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Re: Can someone please explain the (0) in K: 163(0) 15 ?
« Reply #1 on: July 19, 2014, 05:37:34 PM »

Using a Huawei HG622 in ADSL2 mode, no "K" value is displayed.

Code: [Select]
Down Up
SNR (dB): 6.3 6.3
Attn(dB): 47.5 28.4
Pwr(dBm): 0.0 12.8

ADSL2 framing
Bearer 0
MSGc: 40 10
B: 246 145
M: 1 1
T: 1 1
R: 8 0
S: 1.4098 4.5625
L: 1447 256
D: 32 1
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Bald_Eagle1

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Re: Can someone please explain the (0) in K: 163(0) 15 ?
« Reply #2 on: July 19, 2014, 05:58:00 PM »

Using a Huawei HG622 in ADSL2 mode, no "K" value is displayed.


Having just checked some of your previous ADSL testing data, the HG612 doesn't report a 'K' value for ADSL2 & ADSL2+, but it does report it for a G.DMT connection (also with a zero in brackets):-

Code: [Select]
xdslcmd: ADSL driver and PHY status
Status: Showtime
Retrain Reason: 0
Max: Upstream rate = 1064 Kbps, Downstream rate = 5904 Kbps
Channel: Fast, Upstream rate = 928 Kbps, Downstream rate = 5248 Kbps

Link Power State: L0
Mode: G.DMT
TPS-TC: ATM Mode
Trellis: ON
Line Status: No Defect
Training Status: Showtime
Down Up
SNR (dB): 6.3 7.0
Attn(dB): 46.0 23.5
Pwr(dBm): 20.0 12.6
G.dmt framing
K: 165(0) 30
R: 0 0
S: 1 1
D: 1 1
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burakkucat

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Re: Can someone please explain the (0) in K: 163(0) 15 ?
« Reply #3 on: July 19, 2014, 06:11:40 PM »

Thank you. (I'm glad someone keeps all the data. I tend to just harvest it for the current "question in hand" and then treat it as ephemera.) That said, I am unable to deduce the meaning of the parenthesised zero.  :no:
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kitz

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Re: Can someone please explain the (0) in K: 163(0) 15 ?
« Reply #4 on: July 22, 2014, 12:49:35 PM »

The K value will only appear for adsl1. adsl2/2+ uses different (and more efficient) framing overheads with different values.

The value in brackets is possibly the g.DMT framing mode which some routers will show

Quote

DmtOverheadFraming ::= TEXTUAL-CONVENTION
    STATUS current
    DESCRIPTION
        "There exist two types of ADSL framing: full overhead and
        reduced overhead.  Furthermore, there exist two versions of
        full overhead and two versions of reduced overhead.  The
        table below defines the four resulting framing structures:

        'structure0'    Full overhead framing with asynchronous
                        bit-to-modem timing (enabled synchronization
                        control mechanism).

        'structure1'    Full overhead framing with synchronous
                        bit-to-modem timing (disabled synchronization
                        control mechanism).

        'structure2'    Reduced overhead framing with separate fast
                        and sync bytes in fast and interleaved latency
                        buffers respectively (64 kbps framing overhead).

        'structure3'    Reduced overhead framing with merged fast and
                        sync byte, using either the fast or interleaved
                        latency buffer (32 kbps framing overhead).


link Cisco

afaik it will be either 0 or 3 which are the only values that Ive seen used in the UK.

I think (but Im not certain) which value is used may have something to do with the configurement /capabilities of  MSAN/DSLAM you are connected to and it makes a difference to the max sync speed when interleaved ie the 8128/7616 mentioned on this page..  and if both the router and the DSLAM are capable of s=1/2 mode


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G.DMT

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Re: Can someone please explain the (0) in K: 163(0) 15 ?
« Reply #5 on: July 23, 2014, 12:28:24 AM »

Thankyou Kitz.
 That sounds plausible. ;-)

And leads me to the assumption that the value is very unlikely to change.
Short of Interleave being turned off or BT upgrading the network equipment in the local/regional area (Yeah right, I wish !!!)
 As that is little more than a wild guess on my part, I should probably log it- to see it not changing for months.  ;)
 
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