Kitz Forum
Broadband Related => Router Monitoring Software => Topic started by: G.DMT on July 19, 2014, 05:05:01 PM
-
This output from my Billion BiPac 7800N
> adsl info --show
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
-
Using a Huawei HG622 in ADSL2 mode, no "K" value is displayed.
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
-
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):-
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
-
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:
-
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
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 (http://tools.cisco.com/Support/SNMP/do/BrowseMIB.do?local=en&mibName=CISCO-ADSL-DMT-LINE-MIB)
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 (http://www.kitz.co.uk/adsl/interleaving.htm).. and if both the router and the DSLAM are capable of s=1/2 mode
-
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. ;)