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Understanding my modem stats

MickKi
Grafter
Posts: 543
Registered: 30-09-2007

Understanding my modem stats

Hi All,
Could a kind soul please give me a hand with this lot:
# cat /proc/avalanche/avsar_modem_stats
cat /proc/avalanche/avsar_modem_stats
AR7 DSL Modem Statistics:
--------------------------------
[DSL Modem Stats]
        US Connection Rate:    448    DS Connection Rate:    6976
        DS Line Attenuation:    39      DS Margin:              4
        US Line Attenuation:    25      US Margin:              23
        US Payload :            198607920      DS Payload:            1820368176
        US Superframe Cnt :    5290597 DS Superframe Cnt:      5290597
        US Transmit Power :    0      DS Transmit Power:      0
        LOS errors:            0      SEF errors:            0
        Errored Seconds:        0      Severely Err Secs:      0
        Frame mode:            3      Max Frame mode:        0
        Trained Path:          1      US Peak Cell Rate:      1056
        Trained Mode:          3      Selected Mode:          1
        ATUC Vendor Code:      414C4342        ATUC Revision:  1
        Hybrid Selected:        1      Trellis:                1
        Showtime Count:        1      DS Max Attainable Bit Rate: 6976 kbps
        BitSwap:                1      US Max Attainable Bit Rate:    n/a
        Annex:                  AnxA    psd_mask_qualifier: 0x0000
        Power Management Status: L0    DS HLINSC: 0
        US ACTPSD:              -345    DS ACTPSD: -365
        Total init. errors:    0      Total init. timeouts: 0
        Showtime init. errors:  0      Showtime init. timeouts: 0
        Last showtime init. errors: 0  Last showtime init. timeouts: 0
        ATUC ghsVid:  0f 00 41 4c 43 42 00 00
        T1413Vid: 00 00        T1413Rev: 00            VendorRev: 00
        ATUR ghsVid:  b5 00 54 53 54 43 00 00
        T1413Vid: 00 00 T1413Rev: 00    VendorRev: 00
        [Upstream (TX) Interleave path]
        CRC:    6      FEC:    952    NCD:    0
        LCD:    0      HEC:    68
        [Downstream (RX) Interleave path]
        CRC:    213    FEC:    103765  NCD:    0
        LCD:    0      HEC:    0
        [Upstream (TX) Fast path]
        CRC:    0      FEC:    0      NCD:    1
        LCD:    0      HEC:    0
        [Downstream (RX) Fast path]
        CRC:    0      FEC:    0      NCD:    0
        LCD:    0      HEC:    0

In particular, what are these?
        Frame mode:             3       Max Frame mode:         0
        Trained Path:          1      US Peak Cell Rate:      1056
        Trained Mode:          3      Selected Mode:          1
. . .
        Hybrid Selected:        1      Trellis:                1

Also, the meaning of the different readings under Interleavind Path and Fast Path tables and how I can decipher if interleaving is switched on?
Thanks for any insights.
10 REPLIES
Community Veteran
Posts: 6,735
Thanks: 12
Registered: 02-02-2008

Re: Understanding my modem stats

Attenuation 39dB means you're getting about the best speed you can for the length of the line.
Superuser
Superuser
Posts: 9,773
Thanks: 1,151
Fixes: 63
Registered: 06-04-2007

Re: Understanding my modem stats

There are non-zero entries in the pair of path mode entries that in are use. That would indicate Interleaving is on in your case.
David
MickKi
Grafter
Posts: 543
Registered: 30-09-2007

Re: Understanding my modem stats

Quote from: HPsauce
Attenuation 39dB means you're getting about the best speed you can for the length of the line.

I have seen sync speeds up to 7.6Mbps, but as as soon as the night comes and with a bit of damp weather they drop below 6.8Mbps.  I am really happy that it has been holding onto 6.9Mbps for the last couple of days.
MickKi
Grafter
Posts: 543
Registered: 30-09-2007

Re: Understanding my modem stats

Quote from: spraxyt
There are non-zero entries in the pair of path mode entries that in are use. That would indicate Interleaving is on in your case.

Are you looking at the Frame Mode, Trained Path, Trained Mode, etc?  What do they mean?
Superuser
Superuser
Posts: 9,773
Thanks: 1,151
Fixes: 63
Registered: 06-04-2007

Re: Understanding my modem stats

Quote from: MickKi
Are you looking at the Frame Mode, Trained Path, Trained Mode, etc?  What do they mean?

No, the path Mode pairs I was referring to are these:

        [Upstream (TX) Interleave path]
        CRC:    6       FEC:    952     NCD:    0
        LCD:    0       HEC:    68
        [Downstream (RX) Interleave path]
        CRC:    213     FEC:    103765  NCD:    0
        LCD:    0       HEC:    0
        [Upstream (TX) Fast path]
        CRC:    0       FEC:    0       NCD:    1
        LCD:    0       HEC:    0
        [Downstream (RX) Fast path]
        CRC:    0       FEC:    0       NCD:    0
        LCD:    0       HEC:    0

Since there are non-zero entries in the Interleave path pair that would indicate Interleaving is on in your case.
Sorry I've no idea what Frame mode, etc mean. I assume they are to do with the inner workings of the transmission protocols that DSL modems use.
David
MickKi
Grafter
Posts: 543
Registered: 30-09-2007

Re: Understanding my modem stats

Thanks.  Smiley
Here are in no particular order some tidbits that I managed to decipher or guess from Google-ing aroung:
ATUC Vendor Code:  414C4342  This means that the DSLAM chipset is a STMicro Alcatel.  Let's hope that I don't run into trouble when it is upgraded to ADSL2+, because my modem does not have an Alcatel chipset.  Tongue
Showtime Count:  1  This I believe means that the modem has successfully sync'ed with the exchange, otherwise it would be zero.
BitSwap:  1   This is for G.DMT stability and helps to minimize minor, long-term changes in noise by adjusting the number of bits applied to specific tones while keeping the total number of bits allocated constant.  When ADSL2+ comes along I understand that we may get seamless rate adaptation - SRA (the speed automatically adjusts up/down for the current SNR so as to maintain a connection, instead of dropping the connection, resync'ing and arriving at a lower speed).
Trellis:  1  This refers to Trellis Coded Modulation (TCM) which uses clever algorithms to squeeze more data down a voice line with fewer errors.
Annex:  AnxA  This threw me out a bit.  For a moment I thought that the BT exchange is ADSL2+ enabled, but I think that it refers to "DSL over POTS" type of connection (as opposed to DSL over ISDN, etc.).
Power Management Status: L0  This indicates that the line power is on, as opposed to off (L3) or powered on but reduced (L1).
Total init. errors:  0  and other references to init. errors and init. timeouts are probably related to sync'ing with the BT exchange (I am guessing here guys, so correct me please if I'm wrong).
Trained Path:  1  This means that the line has been through its training period and the Trained Mode:  3 probably means the ATM overhead framing mode 3 has been set (Asynchronous Transfer Mode).  If it was set to mode 1 then my line would offer STM (Synchronous Transfer Mode) which I know it does not.  No idea what Trained Modes 0 and 2 are (it may be related to the line latency, or size (bits) of the overhead).
LOS errors:  0  Refers to Loss Of Signal.
SEF:  0  Probably refers to severely errored frames(?)
The Cyclic Redundancy Check and the Forward Error Correction are usually enabled at the same time the Interleaving is switched on, so your suggestion is good.
I think this covers the basics, the rest are either self explanatory, or totally indecipherable by me at least.  Crazy
Superuser
Superuser
Posts: 9,773
Thanks: 1,151
Fixes: 63
Registered: 06-04-2007

Re: Understanding my modem stats

There are Annex A ADSLx over POTS sections in each of the ADSLx types. The original ADSL is described in ITU G.992.1 also known as G.DMT (Distributed Tone Modulation).
This Wikipedia reference describes G.DMT and makes reference to some of the parameters you referred to.
David
Neo
Grafter
Posts: 55
Registered: 06-07-2007

Re: Understanding my modem stats

@ MickKi
Might I suggest the use of my Router Stats Logger? Judging by your data, it would appear you have a suitable router Wink
MickKi
Grafter
Posts: 543
Registered: 30-09-2007

Re: Understanding my modem stats

Thanks Neo,
The AR7 chip may be suitable for the Router Stats Logger, however, I am running it in bridged mode just as a modem and for the life of me I cannot switch on SNMP (the intention being to capture stats using MRTG).  I believe that SNMP will only work when it is configured as a NAT router.
In addition, I do not run MSWindows so the binary for the Router Stats Logger is of no use to me.  It looks like a pretty slick application all the same.  Smiley
Neo
Grafter
Posts: 55
Registered: 06-07-2007

Re: Understanding my modem stats

Quote from: MickKi
Thanks Neo,
You're welcome MickKi Wink
Quote from: MickKi
The AR7 chip may be suitable for the Router Stats Logger, however, I am running it in bridged mode just as a modem and for the life of me I cannot switch on SNMP (the intention being to capture stats using MRTG).  I believe that SNMP will only work when it is configured as a NAT router.
Yes, it's possible that the SNMP function is only available when the higher level stuff is active. However, SNMP can easily swamp a router (esp. if it's only got 8MB RAM) - see http://www.routertech.org/pages.php?page=47
Quote from: MickKi
In addition, I do not run MSWindows so the binary for the Router Stats Logger is of no use to me.
Shame, although Wine for Linux might work (assuming you have Linux).
Quote from: MickKi
It looks like a pretty slick application all the same.  Smiley
Thanks Smiley