The
utility is part of the isdn4bsd package and is used to provide the user with a
detailed mnemonic display of the layers 1, 2 and 3 protocol activities on
the D channel and hex dump of the B channel(s) activities.
Together with two passive supported cards and an easy to build cable it can
also be used to monitor the complete traffic on a S0 bus providing S0 bus
analyzer features.
The
utility is only available for passive supported cards.
The following options can be used:
-a
Run
in analyzer mode by using two passive cards and a custom cable which can
be build as described in the file
cable.txt
in the isdn4bsd source distribution.
One card acts as a receiver for the
transmitting direction on the S0 bus while the other card acts as a receiver
for the receiving direction on the S0 bus.
Complete traffic monitoring is
possible using this setup.
-b
switch B channel tracing on (default off).
-d
switch D channel tracing off (default on).
-f
Use
filename
as the name of a file into which to write tracing output (default filename is
isdndecode<n> where n is the number of the unit to decode).
-h
switch display of header off (default on).
-i
print layer 1 (I.430) INFO signals to monitor layer 1 activity (default off).
-l
switch displaying of Layer 2 (Q.921) frames off (default on).
-o
switch off writing decode output to a file (default on).
-p
Use
filename
as the name of a file used for the -B and -P options (default filename
is isdntracebin<n> where n is the number of the unit to decode).
-u
Use
number
as the unit number of the controller card to decode (default 0).
-x
Decode Layer 3 packets with an unknown protocol discriminator.
-B
Write undecoded binary decode data to a file for later or remote
analyzing (default off).
-P
Read undecoded binary decode data from file instead from device (default off).
-R
Use
unit
as the receiving interface unit number in analyze mode.
-T
Use
unit
as the transmitting interface unit number in analyze mode.
When the USR1 signal is sent to a
process, the currently used logfiles are reopened, so that logfile
rotation becomes possible.
The decode output should be obvious.
It is very handy to have the following
standard texts available when tracing ISDN protocols:
I.430
ISDN BRI layer 1 protocol description.
Q.921
ISDN D-channel layer 2 protocol description.
Q.931
ISDN D-channel layer 3 protocol description.
FILES
/dev/i4btrc<n>
The devicefile(s) used to get the decode messages for ISDN card unit <n>
out of the kernel.
EXAMPLES
The command:
isdndecode -f /var/tmp/isdn.decode
will start D channel tracing on passive controller 0 with all except B
channel tracing enabled and logs everything into the output file
/var/tmp/isdn.decode.
