March 20, 2023

Understanding and Troubleshooting SIP | Free Courses –

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This training was created for the IT staff of mobile/telecom providers, ITSPs (Internet Telephony Service Providers), Consultants, Call Centers or any other company using IP telephony.  The performance of these professionals is essential to reduce the churn and the stress of the operation. SIP troubleshooting is a key skill in these scenarios. 

It is a result of years in the frontlines of the tech support of a softs-switch developer, troubleshooting hundreds of deployments.

I have prepared two FREE gifts for this training. The first is a Virtual Machine in open virtualization format with a SIP server running as a Proxy, B2BUA and Redirect.  The second is a list of SIP responses with comments on how to troubleshoot the most common SIP error messages. I sincerely hope you enjoy this training.

There are 5 practical labs to do with your VM and softphones in this training. 


Section 1 – Introduction to SIP

  1. Why is SIP relevant
  2. Introduction to SIP
  3. Complete SIP Proxy free download
  4. SIP Registration Process and Demo
  5. Capturing SIP Packets with wireshark and sngreo
  6. Assignment: Analyzing a SIP registration
  7. Session Setup and Management
  8. SIP trapezoid and ladder
  9. Server Architectures
  10. SIP headers and Body
  11. SIP Call Flow Demo
  12. Assignment: Analyze a SIP Call

Section 2 – SIP Capturing and Filtering

  1. SIP Capture Introduction
  2. Demo context
  3. Demo ngrep
  4. Demo sngrep
  5. Demo wireshark

Section 3 – SIP Dialogs, Transactions and Timers

  1. SIP Transactions and Timers
  2. SIP Dialogs
  3. Assignment: Transactions and Dialogs​

Section 4 – Handling and analyzing Media

  1. Media Encoding
  2. Session Description Protocol
  3. Real Time Protocol and Real Time Control Protocol
  4. Voice Quality
  5. Assignment 4: Analyzing Session Description Protocol

Section 5 – Nat Traversal

  1. NAT Introduction
  2. NAT Types
  3. Manual Configuration
  4. Symmetric Response Routing RFC3581
  5. Application Layer Gateway
  7. STUN
  8. TURN
  9. NAT Conclusion

Section 6- Troubleshooting

  1. Troubleshooting Methodology
  2. Handling Signaling Issues
  3. Handling Media Issues
  4. Handling Billing Issues

​Section 7 – Redundancy and Load Balancing using DNS

  1. SIP Load Balancing and Redundancy using DNS
  2. Redundancy Demo
  3. Redundancy and Load Balancing Summary

Section 8 – Labs

  1. Installing a SIP Proxy
  2. Preparing the environment
  3. Creating domains and users
  4. Download and configure softphones
  5. Capturing a SIP registration
  6. Capturing a SIP Call

Who this course is for:

  • Support Analysts on Internet Telephony Service Providers, Telecom and Mobile companies
  • Support Analysts on companies using VoIP and SIP
  • IT consultants
  • Contact Center IT staff


  • Computer Networks
  • Voice over IP
  • Linux knowledge is not mandatory, but helps.

Last Updated 10/2021

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Understanding and Troubleshooting (3.2 GB) | Mirror

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