Materials for studying "gatekeeper" (gatekeeper) in IP-telephony?

Question

Telephony

Nowhere can I find a normal material on this topic, even in English. There is usually only a theory, but how to set it up to understand how it works - there is no such thing. Does anyone have the sources or the title of any books?

Answer 1

I may be wrong, but it looks like you are looking for information on the SBC implementation.
If you search for this term, you will find more information, including in Russian:

1. https://ru.wikipedia.org/wiki/Session_Border_Controller
   
2. https://wiki.merionet.ru/ip-telephoniya/51/chto-ta...
   

If we talk about practical implementation, I recommend looking at the project - https://github.com/voiceboys/sbcOS