Debugging and troubleshooting VOIP problems.

(SIP, MGCP, H.323, 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

• Wireshark (Ex Ethereal) (Open Source and available for Linux, Windows, Apple, BSD, etc.)
  • Support for decoding many VOIP protocols is included (including IAX)
  • VoIP call analysis and call flow diagram for (SIP, MGCP, H323, etc.)
  • RTP Statistics and graph analysis (jitter, delay, packet lost, etc.)
  • RTP playback (Wireshark only)
• Spirent Communications - Test Solutions for VoIP networks and devices
• tcpdump (standard utility in most Linux distributions)
• WinDump - tcpdump for Windows
• ngrep (Available for Linux, Windows, Apple, BSD, etc.)
  • Dumps only the ASCII portion of packets, excellent for ASCII based protocols
• Packetyzer: User-friendly packet sniffer for Windows, supports SIP
• List of Monitoring and sniffing software
• Rate which provides real time packet-per-second and data transfer rates
• ClarifiedNetworks
  • HowNetWorks - a free VMWare appliance
  • Tia - sophisticated monitoring and flow analysis tool with visualisation, multiple data sources, ...
• TamoSoft CommView - network analyzer for Windows
  • Real-time VoIP call monitoring
  • SIP and H.323 analysis and decoding, call playback
  • Jitter, QoS, Bandwidth charts
• Touchstone
  • WinEyeQ
    • 100% software-based
    • monitors/analyzes/records/replays SIP and H.323 traffic, audio/video media and QOS.
  • TraceBuster (free version available)
    • records/replays SIP and H.323 traffic, audio/video media and QOS.
• SIP Workbench Displays SIP ladder diagram from WireShark/pcap captures
  • Displays STUN/TURN interactions
  • Allow users to filter on particular call flows

Built-in Debug Tools

• xten The x-lite and x-pro SIP soft phones have a buit-in display and decoding of received and sent SIP packets (Hit F9 to activate)
• Asterisk Use the sip debug command
• linphone Outputs useful diagnostics to the console as it uses the oSIP library
• pjsua A command line SIP user agent from pjsip.org, available for various platforms, and very useful to debug SIP functionalities (call, presence, instant messaging, etc.) as well as media quality via RTCP statistics.

Traffic generators

• Codima autoVoIP Traffic Simulator - Simulate and Stress Test all types of VoIP networks
• Spirent Communications - Test Solutions for VoIP networks and devices
• Candela Technologies LANForge FIRE VOIP/RTP/PESQ call generator
• Empirix Signaling and Media load and feature testing
• GL Communications
  • PacketGen - generates SIP calls with or without RTP traffic
  • PacketScan - monitor, collect, and analyze QoS statistics on VOIP traffic
• Integrated Research Prognosis will simulate, record and analyze VOIP traffic in real time.
• Iperf creates network traffic and measures performance
  • Can be used to test a network to see how it might perform with increased VOIP traffic
• Ixia VOIP traffic generators and Network assessment tools
• MyVoIPSpeed simulates VoIP traffic over your Internet connection, measures key diagnostics including Jitter and Packet Loss, and provides an analysis of the voice quality
• PacketIsland 4"x4" in-line micro-appliances used in a distributed multi-site enterprise or SME to generate live VoIP traffic and measure loss, jitter, MOS, route performance, route flaps, etc. Also measures ongoing data traffic in network.
• Sipp SIP Performance Test Tool - Performance tester for SIP
• pjsip-perf Open source call generator from pjsip.org to measure SIP call/transaction performance.
• Touchstone 100% software-based VoIP and video verification tools.
  • WinSIP - SIP signaling and Audio/Video media generator
  • Win323 - H.323 signaling and Audio/Video media generator
• Valid8.com Valid8.com is a leading provider of SIP, H.323, Megaco, SIGTRAN traffic generation solutions.

Monitoring and Test Tools

• ACQUA: VoIP Speech Quality Analysis System
• Agilent Technologies DNA MX and TNA software
• Brix Networks real-time VoIP performance management and service assurance solutions
• ClarifiedNetworks Monitoring and high level flow analysis and visualization
• ClearSight Networks ClearSite Analyzer
• Codima Toolbox VoIP Management from pre deployment to post deployment and network visualization in Visio
• Consultronics
• Empirix monitoring and analysis
• Fluke Networks OptiView VoIP, ProtocolExpert Plus and Link Analyzer
• Hammer Call Analyzer
• Inet GeoProbe IP
• Intelica VoIP Intelligence Call Monitoring, Analysis and Reporting
• Malden
• Minacom QOS monitoring and testing
• NetTest monitoring of QOS and network performance
• NetIQ monitoring of QOS and network performance
• PacketIsland micro-appliances and asterisk agent for QoS monitoring of SIP and Cisco SCCP VoIP calls
• PathSolutions SwitchMonitor VoIP
• Packet Data Systems Clarinet Protocol Test System
  • Simulation and analysis of SIP, SIP-T & H.323. QOS measurement, recording, replay etc.
• Psytechnics monitoring of QOS
• Qovia monitoring of QOS
• Rochelle Analog QOS products - can be used with an ATA
• Sage Instruments VOIP test equipment and systems
• Spirent Communications - Test Solutions for VoIP networks and devices
• Sunrise Telecom VOIP and Telecom test equipment
• TamoSoft CommView and CommView for WiFi network analyzers for wired and wireless (802.11 a/b/g/n) networks
  • Real-time VoIP call monitoring
  • SIP and H.323 analysis and decoding, call playback
  • Jitter, QoS, Bandwidth charts
• Telchemy monitoring of QOS
  • Their technology appears in numerous other products list
• Touchstone
  • WinEyeQ
    • 100% software-based
    • monitors/analyzes/records/replays SIP and H.323 traffic, audio/video media and QOS.
  • TraceBuster
    • records/replays SIP and H.323 traffic, audio/video media and QOS.
• Unsniff Network Analyzer RTP/SIP/IAX2 visual analysis, one-click playback, whitepapers
• Valid8.com Valid8.com is the leading provider of SIP, H.323, Megaco, SIGTRAN conformance test solutions.
• Viola Networks NetAlly RealTime and VoIP Assessment
• VQManager web-based, 24 X 7 real-time QoS monitoring tool for VoIP networks.
• WildPackets EtherPeek VX - monitor QOS, packet loss, voice quality, etc.
• See Also:
  • Call Quality Metrics
  • Network World Review of 7 VOIP Analysis Tools

Asterisk Tools

• Nocom A simple script for viewing Asterisk config files with comments and empty lines removed.

Network Impairment Simulators

• Apposite Technologies Linktropy 4500 hardware appliance to emulate WAN bandwidth, delay, and loss up to 155 Mbps.
• Candela Technologies LANForge ICE Network Emulator
• IPWave simulates many types of network impairments
• NIST Net allows a single Linux PC set up as a router to emulate a wide variety of network conditions
• Shunra Network Simulator Shunra Virtual Enterprise (Shunra VE) network simulator creates a model of any production environment, including the network, remote locations, and the number and distribution of local and remote end-users. With Shunra VE, users can test the functionality, performance, scalability and robustness of the VoIP infrastructure under current and future production conditions — before deployment over the network.
• Simena Network Emulator hardware appliance can simulate just about any possible network condition including latency, bandwidth, congestion, packet loss, etc. Test where your VoIP will break!
• Spirent Communications - Test Solutions for VoIP networks and devices
• UDP Packet Reflector and Forwarder open source tool that can drop packets, duplicate packets, and add jitter on a per port basis.

Decoding VOIP audio streams

There are several approaches to converting an RTP stream of packets into a playable audio.
See: Converting RTP to audio

SIP Debug

• Callflow - creates a diagram of SIP flows
• PacketIsland 4"x4" in-line micro-appliances can capture SIP traffic and display ladder graphs of SIP call flow. SIP data from thousands of calls can be stored for weeks or months.
• Sipsak Command line utility for testing SIP devices and Programs
• SIP Scenario - creates a diagram of SIP flow
• siptest a command line test tool for sending and receiving SIP messages
• sipviewer a visual SIP message trace tool
• SIPFlow Standard - Java tool for displaying SIP traffic captured in real-time, or imported from Ethereal or tcpdump
• Distributed SIPFlow - Distributed application for capturing and displaying SIP callflows.
• Wireshark (Ex Ethereal) using the VoIP call analysis feature.
• Free VoIP TraceBuster Decode and analyze Ehtereal/WireShark capture files!

Protocol Debug

• Protocol Verification and Testing

Other Sites

• VoIP Spear — Web site that monitors your Internet connection 24×7x365 and shows you what your VoIP QoS is.
• Spirent Communications - Test Solutions for VoIP networks and devices
• http://www.voiptroubleshooter.com/ Entire site focused on VOIP troubleshooting
• http://www.broadbandreports.com/tools Diagnostic, testing, and monitoring tools
• http://www.testyourvoip.com/ Test your connection performance to one of serveral locations.
• TechTraces.com Sample VOIP call flows, traces and network captures.

• CallManager Express Resource - design, tips and tricks and troubleshooting help for Cisco's SMB voice platform.

See also

• Asterisk debugging
• One-way Audio
• Important thing to look at if you get one way audio problem with Asterisk 1.4.10 and FreePBX 2.3.0

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