I found that it would be beneficial to automate the process of serial traffic data monitoring. A bash script: "monitor_serial" was created to do this for NST. It essentially just automates the process just described above. The big advantage with monitor_serial beside automation is that traffic serial data will continue to be displayed on the screen and only blocked for a user specified collection time. The Serial Tap Cable described above is best used with the monitor_serial utility program. The reset_serial utility is called by monitor_serial for the base initialization.
The usage information for monitor_serial is presented:
[root@probe tmp]# /usr/local/bin/monitor_serial -h
Usage: monitor_serial -d1 <1st serial dev> [-s <usec>] [-b <baud>] [-u <"stty options">]
[-f1 <1st serial dev capture file>] [-n1 <1st serial dev nickname>]
[-d2 <2nd serial dev>] [-f2 <2nd serial dev capture file>]
[-n2 <2nd serial dev nickname>]
This utility program will monitor serial traffic for up to 2 serial devices. Data will
be collected for a user specific collection time (See: -s option). The "hexdump" utility
is then used to display the serial traffic in both the Hex and ASCII format. To exit
type the "Ctrl-c" key sequence.
-s <microseconds> | --sleep <microseconds>
Sleep value in microseconds to collect data before
sending it to the hexdump utility. Default: 500000 usecs (1/2 sec)
-b <baud rate> | --baud <baud rate>
Baud rate for the serial device. Default: 9600 baud
-u <"stty options"> | --stty-opts <"stty options">
User specified stty options must be put within double quotes:
Example (even parity): -u "parenb -parodd"
-d1 <serial dev name> | --device-1 <serial dev name>
Name of the first serial device to
to monitor: Ex: "/dev/ttyS1"
-f1 <1st capture file name> | --file-1 <1st capture file name>
Capture file full path name for the 1st serial device.
Default: /tmp/serial_capture_dev1
-n1 <1st nickname> | --nickname-1 <1st nickname>
Used to describe a more meaningful name to the first serial
device.
-d2 <serial dev name> | --device-2 <serial dev name>
Optional name of a second serial device
to monitor. Ex: "/dev/ttyUSB0"
-f2 <2nd capture file name> | --file-2 <2nd capture file name>
Optional capture full path file name for the
2nd serial device.
Default: /tmp/serial_capture_dev2
-n2 <2nd nickname> | --nickname-2 <2nd nickname>
Used to describe a more meaningful name to the second serial
device.
-h | --help
Displays this help information
Now lets demonstrate by example the features of the monitor_serial utility program. We will analyze the NTP clock status command issued on a Cisco Router 3620. The Minicom program will be used to issue the command: "show ntp status\r". The serial port communication parameters are: (115200 baud, no parity, 8 data bits, and 1 stop bit - 115200N81).
** Note 1: The monitor_serial utility program will put the capture serial device in: "raw" mode.
** Note 2: Remember that the raw
capture files are available after stopping
monitor_serial. The default files are
names are: /tmp/serial_capture_dev1 and
/tmp/serial_capture_dev2.
In this example the DTE Serial Tap (NST Probe) is
connected to serial device: /dev/ttyUSB0 and
the DCE Serial Tap (Cisco 3620 Router) is connected to serial
device: /dev/ttyS1.
[root@probe tmp]# /usr/local/bin/monitor_serial -d1 /dev/ttyUSB0 -s 2000000 -b 115200 -n1 "NST Probe" \
> -d2 /dev/ttyS1 -n2 "Cisco 3620"
*** Serial Data Capture From Device: /dev/ttyUSB0 -- NST Probe -- and Device: /dev/ttyS1 -- Cisco 3620 -- ***
*** Waiting for data, collection interval: 2000000 (usecs) ***
%%%%%% Capture From Serial Device 2: /dev/ttyS1 -- Cisco 3620 -- %%%%%%
00000000 0d 0a 73 68 6f 70 72 6f 75 74 65 3e 20 |..shoproute> |
0000000d
###### Capture From Serial Device 1: /dev/ttyUSB0 -- NST Probe -- ######
00000000 73 68 6f 77 20 6e 74 70 20 73 74 61 74 75 73 0d |show ntp status.|
00000010
%%%%%% Capture From Serial Device 2: /dev/ttyS1 -- Cisco 3620 -- %%%%%%
00000000 73 68 6f 77 20 6e 74 70 20 73 74 61 74 75 73 0d |show ntp status.|
00000010 0a 43 6c 6f 63 6b 20 69 73 20 73 79 6e 63 68 72 |.Clock is synchr|
00000020 6f 6e 69 7a 65 64 2c 20 73 74 72 61 74 75 6d 20 |onized, stratum |
00000030 32 2c 20 72 65 66 65 72 65 6e 63 65 20 69 73 20 |2, reference is |
00000040 32 30 34 2e 33 34 2e 31 39 38 2e 34 30 0d 0a 6e |204.34.198.40..n|
00000050 6f 6d 69 6e 61 6c 20 66 72 65 71 20 69 73 20 32 |ominal freq is 2|
00000060 35 30 2e 30 30 30 30 20 48 7a 2c 20 61 63 74 75 |50.0000 Hz, actu|
00000070 61 6c 20 66 72 65 71 20 69 73 20 32 35 30 2e 30 |al freq is 250.0|
00000080 30 31 30 20 48 7a 2c 20 70 72 65 63 69 73 69 6f |010 Hz, precisio|
00000090 6e 20 69 73 20 32 2a 2a 31 38 0d 0a 72 65 66 65 |n is 2**18..refe|
000000a0 72 65 6e 63 65 20 74 69 6d 65 20 69 73 20 43 33 |rence time is C3|
000000b0 32 38 33 30 37 43 2e 45 31 42 45 31 42 41 36 20 |28307C.E1BE1BA6 |
000000c0 28 31 33 3a 32 39 3a 33 32 2e 38 38 31 20 45 44 |(13:29:32.881 ED|
000000d0 54 20 46 72 69 20 4f 63 74 20 33 20 32 30 30 33 |T Fri Oct 3 2003|
000000e0 29 0d 0a 63 6c 6f 63 6b 20 6f 66 66 73 65 74 20 |)..clock offset |
000000f0 69 73 20 30 2e 34 36 31 37 20 6d 73 65 63 2c 20 |is 0.4617 msec, |
00000100 72 6f 6f 74 20 64 65 6c 61 79 20 69 73 20 31 31 |root delay is 11|
00000110 30 2e 32 36 20 6d 73 65 63 0d 0a 72 6f 6f 74 20 |0.26 msec..root |
00000120 64 69 73 70 65 72 73 69 6f 6e 20 69 73 20 34 2e |dispersion is 4.|
00000130 30 39 20 6d 73 65 63 2c 20 70 65 65 72 20 64 69 |09 msec, peer di|
00000140 73 70 65 72 73 69 6f 6e 20 69 73 20 33 2e 35 31 |spersion is 3.51|
00000150 20 6d 73 65 63 0d 0a 73 68 6f 70 72 6f 75 74 65 | msec..shoproute|
00000160 3e 20 |> |
00000162
The Minicom screen appearance for the above command:
shoproute> show ntp status
Clock is synchronized, stratum 2, reference is 204.34.198.40
nominal freq is 250.0000 Hz, actual freq is 250.0010 Hz, precision is 2**18
reference time is C328307C.E1BE1BA6 (13:29:32.881 EDT Fri Oct 3 2003)
clock offset is 0.4617 msec, root delay is 110.26 msec
root dispersion is 4.09 msec, peer dispersion is 3.51 msec
shoproute>