If you are testing an NG911 IMS call, one of the most important pieces of info that the NG911 network (including LRF, NGCS, PSAP, …) expects from your SoS SIP INVITE is the P-Access-Network-Info or PANI header. This header carries the information about the UE/Subscriber device location.

Ever faced the challenge of deciphering RTP packets nested within another protocol PDU? 🤔 I found myself in this exact situation today. Amidst the lack of a specialized protocol decoder in Wireshark, I decided to roll up my sleeves and craft a nifty RTP packet decoder and encoder using Python.

Really call conferencing is not a feature that I am going to spend time on it to introduce to you or count its pros. We live in the web and cloud era and call/video conferencing, especially over WebRTC is mature enough. But again when you want to touch any feature like this in the 3GPP territory, might it be a little confusing. The idea is simple but it is a habit for some people that make the story complicated when they relate it.

Any telco company and MNO must provide tools or interfaces to third-party companies or government agencies for monitoring or lawful interception (LI) purposes. There are various 3GPP standards for LI systems and their interfaces like X1/2/3 that you can refer to. In addition, sometimes when customers complain about calls and voice qualities, and customer services report it, it is required to have a tool to monitor a specific subscriber or bunch of subscribers to verify what the issue is or what causes that.

If you are following my blog and have read my previous post about testing VoLTE in Samsung and Pixel handsets, I appreciate that, and this post is a quick update. If not, please review the first part VoLTE in Pixel vs Samsung Phones and then return here.