VOS3000 Debug Trace: Complete Call Signaling Analysis & Troubleshooting Guide
VOS3000 debug trace is an essential tool for diagnosing and resolving VoIP signaling issues. When calls fail, registrations don’t complete, or audio problems occur, the debug trace function provides detailed visibility into SIP and H.323 message flows, enabling administrators to pinpoint root causes quickly. This comprehensive guide covers all debug trace features based on official VOS3000 2.1.9.07 documentation.
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Table of ContentsVOS3000 Debug Trace: Complete Call Signaling Analysis & Troubleshooting Guide Understanding VOS3000 Debug Trace What Debug Trace Captures (VOS3000 Debug Trace) Enabling Debug Trace Access Location Debug Trace Configuration Options Trace File Management (VOS3000 Debug Trace) Trace File Parameters Two-File Rotation System Using Trace for Troubleshooting Accessing Trace Results (VOS3000 Debug Trace) Interpreting Trace Output (VOS3000 Debug Trace) SIP Message Format H.323 Message Format (VOS3000 Debug Trace) Common Debugging Scenarios (VOS3000 Debug Trace) One-Way Audio Diagnosis Registration Failure Analysis (VOS3000 Debug Trace) Call Drop Investigation (VOS3000 Debug Trace) Advanced Trace Configuration Trace Mask Settings Performance Impact (VOS3000 Debug Trace) CDR End Reason Reference (VOS3000 Debug Trace) Server-Side End Reasons (VOS3000 Debug Trace) Related Resources (VOS3000 Debug Trace) Frequently Asked QuestionsWhere are trace files stored?How long should I keep debug trace enabled?Can I export trace data for analysis?Why can’t I see trace for old calls?Does trace capture RTP media content? Get Expert Help with VOS3000 Debugging Need Professional VOS3000 Setup Support?
Understanding VOS3000 Debug Trace
Reference: VOS3000 2.1.9.07 Manual, Section 2.17.1 (Page 205)
The debug trace function in VOS3000 captures all signaling messages processed by the softswitch, including SIP INVITE, REGISTER, BYE messages and H.323 signaling. This provides a complete record of call flows for troubleshooting and analysis.
What Debug Trace Captures (VOS3000 Debug Trace)
ProtocolMessages CapturedUse CasesSIPINVITE, REGISTER, BYE, CANCEL, OPTIONS, 1xx/2xx/3xx/4xx/5xx/6xx responsesCall setup failures, registration issues, NAT problemsH.323Setup, CallProceeding, Alerting, Connect, ReleaseComplete, H.245 messagesGateway interconnection, codec negotiationRTPMedia stream information (limited)Audio path verification, codec confirmation
Enabling Debug Trace
Reference: VOS3000 2.1.9.07 Manual, Section 2.17.1 (Page 205)
Access Location
Navigate to: System > Debug trace in the VOS3000 client menu.
Debug Trace Configuration Options
SettingDescriptionRecommendationOn/OffEnable or disable trace captureEnable only when troubleshootingTrace LengthDuration to capture (in minutes)Set specific duration or uncheck for continuous
Step-by-Step Debug Trace Activation:
====================================
1. Open VOS3000 Client
2. Navigate to:
Menu bar > System > Debug trace
3. Configure Settings:
Check “On” to enable trace
☐ Uncheck “Trace length” for continuous capture
OR set specific duration (e.g., 30 minutes)
4. Click OK to start capture
5. Reproduce the problem:
– Make test call
– Attempt registration
– Generate the issue you’re investigating
6. View Trace Results:
– Current Call: Right-click > Trace
– CDR: Right-click > Call analysis
Important Notes:
================
– Trace impacts performance slightly when enabled
– Disable trace when not actively troubleshooting
– Trace files rotate automatically when size limit reached
Trace File Management (VOS3000 Debug Trace)
Reference: VOS3000 2.1.9.07 Manual, Section 2.17.1 (Page 205) and Section 4.3.5.2 (Page 237-238)
Trace File Parameters
ParameterDefaultRangeDescriptionSS_TRACE_FILE_LENGTH40960KBSize of softswitch debug file (KB)SS_TRACE_CALL_FILE_SIZE1616-2048 MBCall signaling trace file size limit (MB)SS_TRACE_REGISTER_FILE_SIZE1616-2048 MBRegistration signaling trace file size limit (MB)SS_TRACE_MASKERRORERROR/DEBUGLevel of debug information to displaySS_TRACETOFILEOnOn/OffOutput debug information into file
Two-File Rotation System
Reference: VOS3000 2.1.9.07 Manual, Section 2.17.1 (Page 205)
VOS3000 Trace File Rotation:
=============================
VOS3000 uses 2 files to record trace signaling:
File 1: trace1.log (or similar)
File 2: trace2.log (or similar)
How It Works:
=============
1. System writes to File 1
2. When File 1 reaches size limit (SS_TRACE_FILE_LENGTH)
3. System switches to File 2
4. When File 2 reaches size limit
5. System overwrites File 1 (oldest data lost)
6. Cycle continues…
Advantages:
===========
– Actual storage is double the file size limit
– Continuous capture without manual intervention
– Recent history always available
– Automatic cleanup of old data
Important:
==========
All trace signaling is saved unless file has been covered.
If you need to preserve trace data, copy files before rotation.
Using Trace for Troubleshooting
Accessing Trace Results (VOS3000 Debug Trace)
Reference: VOS3000 2.1.9.07 Manual, Section 2.17.1 (Page 205)
Access MethodLocationInformation ShownCurrent Call TraceCurrent Call > Right-click > TraceReal-time call signaling for active callsCDR Call AnalysisCDR > Right-click > Call analysisComplete signaling flow for completed callRegistration AnalysisRegistration Management > Right-clickRegistration message flow and status
Interpreting Trace Output (VOS3000 Debug Trace)
SIP Message Format
Sample SIP INVITE Trace Output:
===============================
———- 2026-04-03 10:25:32.123 ———-
INVITE sip:[email protected] SIP/2.0
Via: SIP/2.0/UDP 192.168.1.50:5060;branch=z9hG4bK123456
From: ;tag=12345
To:
Call-ID: [email protected]
CSeq: 1 INVITE
Contact:
Content-Type: application/sdp
Content-Length: 200
v=0
o=user 123 456 IN IP4 192.168.1.50
s=Session
c=IN IP4 192.168.1.50
t=0 0
m=audio 10000 RTP/AVP 0 8 18
a=rtpmap:0 PCMU/8000
a=rtpmap:8 PCMA/8000
a=rtpmap:18 G729/8000
Key Headers to Analyze:
=======================
– Via: Message path and NAT information
– From/To: Caller and callee identities
– Call-ID: Unique call identifier
– Contact: Where to send responses
– SDP (body): Media negotiation details
H.323 Message Format (VOS3000 Debug Trace)
Sample H.323 Setup Trace Output:
================================
———- 2026-04-03 10:26:15.456 ———-
H.225 Setup Message:
Protocol Identifier: 0.0.8.2250.0.4
Source Address:
IP: 192.168.1.50
Port: 1720
Destination Address:
IP: 192.168.1.100
Port: 1720
Source Info:
E164: 0987654321
Destination Info:
E164: 1234567890
Active MC: FALSE
Conference ID: 0x12345678…
Key Elements to Analyze:
========================
– Protocol Identifier: H.323 version
– Source/Destination: Endpoint addresses
– E164 numbers: Calling/called numbers
– Conference ID: Call identifier
Common Debugging Scenarios (VOS3000 Debug Trace)
One-Way Audio Diagnosis
Trace FindingMeaningSolutionSDP shows private IP in c= lineNAT issue – endpoint behind NATEnable media proxy, check NAT settingsRTP port mismatch between INVITE and 200 OKSDP negotiation problemCheck codec compatibility, port rangesContact header has wrong IPSIP ALG interferenceDisable SIP ALG on router
Registration Failure Analysis (VOS3000 Debug Trace)
Trace FindingMeaningSolution401 Unauthorized responseAuthentication credentials requiredConfigure correct username/password403 Forbidden responseAccount locked or IP not allowedCheck account status, IP whitelistNo response to REGISTERNetwork or firewall issueCheck SIP port 5060, firewall rulesAuthentication retry exceededWrong credentials repeatedlyVerify credentials, check for typos
Call Drop Investigation (VOS3000 Debug Trace)
Trace FindingMeaningSolutionBYE at 30-second intervalNAT binding timeoutIncrease NAT keepalive, disable SIP ALGSession timer expirySession timer not refreshedCheck SS_SIP_SESSION_TTL settingRTP timeout in traceNo media received for configured timeCheck media path, SS_MEDIA_CHECK_TIMEOUT503 Service UnavailableGateway overloaded or downCheck gateway status, line limits
Advanced Trace Configuration
Trace Mask Settings
Reference: VOS3000 2.1.9.07 Manual, Section 4.3.5.2 (Page 238)
SettingInformation LevelWhen to UseERRORErrors and warnings onlyNormal troubleshooting, production systemsDEBUGDetailed debug informationComplex issues, development testing
Performance Impact (VOS3000 Debug Trace)
Performance Considerations:
==========================
SS_TRACE_MASK = ERROR (Default):
– Minimal performance impact
– Captures only error conditions
– Suitable for production systems
– Adequate for most troubleshooting
SS_TRACE_MASK = DEBUG:
– Higher performance impact
– Captures all message details
– More disk space usage
– Use for complex debugging only
Recommendations:
================
1. Use ERROR level for normal operations
2. Switch to DEBUG only when needed
3. Disable trace when not troubleshooting
4. Monitor disk space on busy systems
5. Set appropriate file size limits
Production Guidelines:
======================
– Keep SS_TRACETOFILE = On (writes to file, not memory)
– Set SS_TRACE_FILE_LENGTH appropriately (40MB default)
– Use SS_TRACE_MASK = ERROR
– Disable during high-traffic periods if possible
CDR End Reason Reference (VOS3000 Debug Trace)
Reference: VOS3000 2.1.9.07 Manual, Section 4.5 (Page 243-248)
When analyzing call failures, the end reason in CDR combined with trace provides complete information:
Server-Side End Reasons (VOS3000 Debug Trace)
End ReasonDescriptionTrace AnalysisResponse timeoutNo answer before timeoutCheck INVITE sent, no 180/183/200 receivedConnection timeoutNo SIP response after retriesCheck INVITE sent, check network pathAccount lockedAccount disabled403 Forbidden in traceSession timeoutSession timer expiredCheck UPDATE/re-INVITE messagesNo matching rateNo rate for destinationCall rejected before INVITE sentInsufficient balanceAccount out of funds403 Forbidden after billing checkThe called not onlineNo route availableNo matching routing gateway
Related Resources (VOS3000 Debug Trace)
Faster Support for VOS3000 Troubleshooting
VOS3000 Softswitch FAQ
NoAvailableRouter Error Troubleshooting
SIP ALG Problems Troubleshooting Guide
VOS3000 Downloads
Frequently Asked Questions
Where are trace files stored?
Trace files are stored in the VOS3000 installation directory, typically under a “trace” or “log” subdirectory. The exact location depends on your installation path. The files are managed automatically by VOS3000’s two-file rotation system.
How long should I keep debug trace enabled?
Enable debug trace only when actively troubleshooting issues. For production systems, keep trace disabled or set to ERROR level to minimize performance impact. Enable DEBUG level only when investigating complex issues, then disable after resolution.
Can I export trace data for analysis?
Yes, you can use the call analysis feature in CDR to view detailed trace for specific calls. For bulk analysis, trace files can be copied from the server and analyzed with text editors or tools like Wireshark (for SIP traces saved in pcap format).
Why can’t I see trace for old calls?
Trace files have size limits and use rotation. When files exceed SS_TRACE_FILE_LENGTH or SS_TRACE_CALL_FILE_SIZE, older data is overwritten. If you need to preserve trace data for compliance or analysis, copy trace files before rotation occurs.
Does trace capture RTP media content?
No, VOS3000 debug trace captures signaling only (SIP and H.323). It does not capture the actual RTP media content (voice/audio). For media analysis, you would need separate packet capture tools like tcpdump or Wireshark on the server.
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