NAME

       aprx-stat - statistics utility for aprx(8)

SYNOPSIS

       aprx-stat [-t] [-f/var/run/aprx.state] {-S|-x|-X}

DESCRIPTION

       aprx-stat is a statistics utility for aprx(8) program.

OPTIONS

       The aprx-stat has following runtime options:

       -f /var/run/aprx.state
              Turn on verbose debugging, outputs data to STDOUT.

       -S     SNMP data mode, current counter and gauge values.

       -t     Use UNIX time_t for timestamps, instead of human readable text format.

       -x     Lattest of extended historical gauge values.  This gives for each input interface

              • SNMP data

              • last 90 of 1 minute values,

              • 10 of 10 minute values,

              • 3 of 60 minute values.

       -X     Full  extended  historical gauge values.  This gives all the contents of historical
              value data ring-buffers.

              • SNMP data

              • 1 minute resolution: 24 hours

              • 10 minute resolution: 7 days

              • 60 minute resolution: 3 months

SNMP DATA OUTPUT

       For each interface feeding AX.25 packets and/or KISS frames to  this  program,  there  are
       following kind of
       SNMP  /dev/ttyUSB1   798282 11088   0  0     3
       SNMP  ax0   798282 11088   0  0     7
       SNMP  ax1   798282 11088   0  0     94

       where columns are:

       • "SNMP" - keyword

       • Interface (AX.25 IF name, or serial port device name)

       • Received byte counter

       • Received frame (packet) counter

       • Dropped byte counter

       • Dropped frame counter

       • Age in seconds of last update of this statistics.

EXTENDED DATA OUTPUT

       Extended  data output gives formatted historical periodic accumulates of interface traffic
       counters, and Erlang value estimates based on that.

       SNMP  /dev/ttyUSB1   816675 11332   0  0     15

       1min data
       2007-12-24 14:10  /dev/ttyUSB1  1m    374    6      0    0   0.047  0.000
       2007-12-24 14:09  /dev/ttyUSB1  1m    377    5      0    0   0.047  0.000
       2007-12-24 14:08  /dev/ttyUSB1  1m    347    5      0    0   0.043  0.000
       2007-12-24 14:07  /dev/ttyUSB1  1m    140    2      0    0   0.018  0.000
       •••

       10min data
       2007-12-24 14:10  /dev/ttyUSB1 10m   3829   55      0    0   0.048  0.000
       2007-12-24 14:00  /dev/ttyUSB1 10m   2182   28      0    0   0.027  0.000
       2007-12-24 13:50  /dev/ttyUSB1 10m   3205   44      0    0   0.040  0.000
       2007-12-24 13:40  /dev/ttyUSB1 10m   3811   50      0    0   0.048  0.000
       •••

       60min data
       2007-12-24 14:00  /dev/ttyUSB1 60m  22510  295      0    0   0.047  0.000
       2007-12-24 13:00  /dev/ttyUSB1 60m  24886  347      0    0   0.052  0.000
       •••

       The output repeats for all interfaces.

       The SNMP dataset is given in the beginning,  and  described  above.   Then  each  extended
       output line has following fields:

       • Timestamp is two fields, date and time (in minute resolution) is in UTC.

       • Alternate  timestamp  format  is UNIX time_t as an integer, counting seconds from epoch,
         and as single field.

       • Interface name is same as in SNMP case.

       • Data qualifier tells what integration period the data is valid for: 1m, 10m, 60m.

       • Counter of received bytes on interface (including KISS flags etc.)

       • Counter of received frames.

       • Counter of dropped bytes.

       • Counter of dropped frames.

       • Reception Erlang value estimate.

       • Dropped bytes Erlang value estimate.

TODO

BUGS

SEE ALSO

       aprx(8)

CONFIGURATION FILE

       There is no configuration file.

NOTES: ERLANG

       The Erlang is telecom measurement of channel occupancy, and in this application  sense  it
       does tell how much traffic there is on the radio channel.

       Most  radio  transmitters are not aware of all transmitters on channel, and thus there can
       happen a collision causing loss of both messages.  The higher the  channel  activity,  the
       more  likely  that  collision  is.   For further details, refer to statistical mathematics
       books, or perhaps on Wikipedia.

       In order to measure channel activity, the aprx program suite has these built-in statistics
       counter and summary estimators.

       The  Erlag  value that the estimators present are likely somewhat underestimating the true
       channel occupancy simply because it calculates estimate of channel bit transmit rate,  and
       thus  a  per-minute  character  capacity.  It does not know true frequency of bit-stuffing
       events of the HDLC framing, nor each transmitter  pre-  and  port  frame  PTT  times.  The
       transmitters need to stabilize their transmit oscillators in many cases, which may take up
       to around 500 ms!  The counters are not aware of this preamble-, nor postamble-times.

       The HDLC bit stuffing ratio is guessed to be 8.2 bits for each 8 bits of payload.

NOTES: SUID ROOT

       This program needs probably to be run as suid-root !  It is considered safe to do  so,  as
       this  checks  that  the -f parameter file is of correct "magic value", and will not try to
       create it if it does not exist, nor modify that file under any circumstances,  nor  reveal
       content of "wrong magic kind" of file.

AUTHOR

       This  little  piece  was  written by Matti Aarnio, OH2MQK during a dark and rainy fall and
       winter of 2007-2008 after a  number  of  discussions  grumbling  about  current  breed  of
       available  software  for  APRS  iGate  use  in Linux (or of any UNIX) platforms.  Fall and
       winter 2009-2010 saw appearance of digipeater functionality.

       Principal contributors and test users  include:  Pentti  Gronlund,  OH3BK,  Reijo  Hakala,
       OH1GWK.  Debian packaging by Kimmo Jukarinen, OH3GNU.

                                             2.9.1 -                                 aprx-stat(8)