Summary of useful tools for debugging VoIP/SIP

Blueworx Voice Response VOIP_MONITOR
Provided as part of Blueworx Voice Response. Allows all SIP sequences to be monitored. Become dtuser and type VOIP_MONITOR. (Use the Ctrl-C key combination to stop it). Pipe to tee filename to record to a file for subsequent analysis offline. See Using VOIP_MONITOR for more information.
Blueworx Voice Response debugmon
debugmon is a Blueworx Voice Response tool for recording voice input and output on specific telephony channels. Use with -n option for DTNA Option 8 allows a record to be started and stopped on a specific channel (about 30 seconds wrap-around buffer). Also records channel commands and status showing internal operation. Use Option 9 to extract trace data into AIX file. Use option v to record voice input and output continuously (no 30 second limit).
Blueworx Voice Response dnd
dnd is a tool which was used during DTNA development and might be useful in diagnosing some problems. The stats/monitor option shows time spent in the DTNA interrupt handler and within DSP code sections. The report option gives a snapshot of the RTP streaming taking place on DTNA channels, and shows endpoint addresses/ports and packet counts.
AIX Trace
VoIP SIP and Media activity traced to AIX trace channel 1. Use trace -1 to start, trcstop -1 to stop, print_trace or trcrpt to print. The content is fairly ‘esoteric’ but is essential for IBM support to debug problems. The trace level for VoIP SIP/Media is controlled with -Tx option on SIP_VOIP Custom Server main args() properties. (Use -T3 for the maximum level). You can use dt_alarmd to stop tracing when Blueworx Voice Response error occurs. (Refer to the Blueworx Voice Response for AIX: Problem Determination information for further details.)
AIX iptrace
Traces all activity on system unit IP connection. Refer to AIX man command or publications for usage information. As root, start with iptrace /tmp/ip.rpt, for example. To stop tracing, locate and kill the iptrace process. At this point you have a file (/tmp/ip.rpt) that contains the binary trace information. You then have two options:
  • To format the file into text output using ipreport /tmp/ip.rpt >ip.fmt, for example.
  • To import the binary trace file into a trace analysis tool such as etherreal.
Alternatively, search for INVITE to see first SIP message of sequence. After that you should be able to see RTP messages (usually 214 bytes including IP/UDP/RTP headers). Look for messages such as DEST UNREACH, which indicates that AIX is throwing away incoming packets due to incorrect socket setup.
AIX netstat
To see allocated sockets, use netstat -f inet -a. To see the number of packets being sent received, use netstat -D. To see information about a specific interface use netstat -v en0, for example. Other netstat options may also be useful.
AIX vmstat
To see CPU utilization, use vmstat 1, for example.

Other CPU monitoring tools may be useful such as smon.