- statistics utility for aprx
is a statistics utility for aprx
has following runtime options:
- -f /var/run/aprx.state
- Turn on verbose debugging, outputs data to STDOUT.
- SNMP data mode, current counter and gauge values.
- Use UNIX time_t for timestamps, instead of human
readable text format.
- 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.
- 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
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 gives formatted historical periodic accumulates of
interface traffic counters, and Erlang value estimates based on that.
SNMP /dev/ttyUSB1 816675 11332 0 0 15
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
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
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
- Counter of received frames.
- Counter of dropped bytes.
- Counter of dropped frames.
- Reception Erlang value estimate.
- Dropped bytes Erlang value estimate.
There is no configuration file.
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.
value that the estimators present are likely somewhat
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
The HDLC bit stuffing ratio is guessed to be 8.2 bits for each 8 bits of
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.
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
Principal contributors and test users include: Pentti Gronlund, OH3BK
Reijo Hakala, OH1GWK
. Debian packaging by Kimmo Jukarinen,