Debugging and troubleshooting VOIP problems.

(SIP, MGCP, H.323, RTP, Skinny etc.)

One of the primary techniques is to view what is actually getting sent and received by VOIP devices. There are several ways to do this:

• Monitor Ethernet Traffic
• Debugging displays from a VOIP program

It helps to understand whats supposed to be happening. Studying the relevant RFCs and other protocol documents and tutorials is helpful.

Ethernet Monitoring Tools

• ClarifiedNetworks
  • HowNetWorks - a free VMWare appliance
  • Tia - sophisticated monitoring and flow analysis tool with visualisation, multiple data sources, ...
• List of Monitoring and sniffing software
• ngrep (Available for Linux, Windows, Apple, BSD, etc.)
  • Dumps only the ASCII portion of packets, excellent for ASCII based protocols
• sngrep (Available for Linux, Apple, BSD.) by Irontec
  • Curses based SIP dialogs monitoring tool.
  • Support UDP, TCP and TLS.
  • Graphical(curses) dialog summary and dialog flow detail.
  • Very useful for debugging and learning purposes.
  • GPL License
• Packetyzer: User-friendly packet sniffer for Windows, supports SIP
• Rate which provides real time packet-per-second and data transfer rates
• SIP Workbench Displays SIP ladder diagram from WireShark/pcap captures
  • Displays STUN/TURN interactions
  • Allow users to filter on particular call flows
• Spirent Communications - Test Solutions for VoIP networks and devices
• STINGA SS7 Protocol Analyzer and Monitoring System
  • Call trace, mature SS7 protocol decodes
  • SIP, SS7, SIP-T, SIGTRAN, ISDN, MGCP and Megaco/H.248
  • Performance analysis
  • Open MySQL database
• TamoSoft CommView - network analyzer for Windows
  • Real-time VoIP call monitoring
  • SIP and H.323 analysis and decoding, call playback
  • Jitter, QoS, Bandwidth charts
• tcpdump (standard utility in most Linux distributions)
• Touchstone
  • WinEyeQ
    • 100% software-based
    • monitors/analyzes/records/replays SIP and