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 Contents
🔍 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)
| Protocol | Messages Captured | Use Cases |
|---|---|---|
| SIP | INVITE, REGISTER, BYE, CANCEL, OPTIONS, 1xx/2xx/3xx/4xx/5xx/6xx responses | Call setup failures, registration issues, NAT problems |
| H.323 | Setup, CallProceeding, Alerting, Connect, ReleaseComplete, H.245 messages | Gateway interconnection, codec negotiation |
| RTP | Media 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
| Setting | Description | Recommendation |
|---|---|---|
| On/Off | Enable or disable trace capture | Enable only when troubleshooting |
| Trace Length | Duration 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
| Parameter | Default | Range | Description |
|---|---|---|---|
| SS_TRACE_FILE_LENGTH | 40960 | KB | Size of softswitch debug file (KB) |
| SS_TRACE_CALL_FILE_SIZE | 16 | 16-2048 MB | Call signaling trace file size limit (MB) |
| SS_TRACE_REGISTER_FILE_SIZE | 16 | 16-2048 MB | Registration signaling trace file size limit (MB) |
| SS_TRACE_MASK | ERROR | ERROR/DEBUG | Level of debug information to display |
| SS_TRACETOFILE | On | On/Off | Output 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 Method | Location | Information Shown |
|---|---|---|
| Current Call Trace | Current Call > Right-click > Trace | Real-time call signaling for active calls |
| CDR Call Analysis | CDR > Right-click > Call analysis | Complete signaling flow for completed call |
| Registration Analysis | Registration Management > Right-click | Registration message flow and status |
🔧 Interpreting Trace Output
📊 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
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
📊 One-Way Audio Diagnosis (VOS3000 Debug Trace)
| Trace Finding | Meaning | Solution |
|---|---|---|
| SDP shows private IP in c= line | NAT issue – endpoint behind NAT | Enable media proxy, check NAT settings |
| RTP port mismatch between INVITE and 200 OK | SDP negotiation problem | Check codec compatibility, port ranges |
| Contact header has wrong IP | SIP ALG interference | Disable SIP ALG on router |
📊 Registration Failure Analysis
| Trace Finding | Meaning | Solution |
|---|---|---|
| 401 Unauthorized response | Authentication credentials required | Configure correct username/password |
| 403 Forbidden response | Account locked or IP not allowed | Check account status, IP whitelist |
| No response to REGISTER | Network or firewall issue | Check SIP port 5060, firewall rules |
| Authentication retry exceeded | Wrong credentials repeatedly | Verify credentials, check for typos |
📊 Call Drop Investigation
| Trace Finding | Meaning | Solution |
|---|---|---|
| BYE at 30-second interval | NAT binding timeout | Increase NAT keepalive, disable SIP ALG |
| Session timer expiry | Session timer not refreshed | Check SS_SIP_SESSION_TTL setting |
| RTP timeout in trace | No media received for configured time | Check media path, SS_MEDIA_CHECK_TIMEOUT |
| 503 Service Unavailable | Gateway overloaded or down | Check gateway status, line limits |
⚙️ Advanced Trace Configuration (VOS3000 Debug Trace)
📊 Trace Mask Settings
Reference: VOS3000 2.1.9.07 Manual, Section 4.3.5.2 (Page 238)
| Setting | Information Level | When to Use |
|---|---|---|
| ERROR | Errors and warnings only | Normal troubleshooting, production systems |
| DEBUG | Detailed debug information | Complex issues, development testing |
⚙️ Performance Impact
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
| End Reason | Description | Trace Analysis |
|---|---|---|
| Response timeout | No answer before timeout | Check INVITE sent, no 180/183/200 received |
| Connection timeout | No SIP response after retries | Check INVITE sent, check network path |
| Account locked | Account disabled | 403 Forbidden in trace |
| Session timeout | Session timer expired | Check UPDATE/re-INVITE messages |
| No matching rate | No rate for destination | Call rejected before INVITE sent |
| Insufficient balance | Account out of funds | 403 Forbidden after billing check |
| The called not online | No route available | No 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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