Although using different technology and approach, some of the same component concepts that make up the PSTN also create VOIP networks. There are three major pieces to VOIP networks.
-VOIP networks
-media gateways/signalling controllers
-media gateways
Media gateways are responsible for call origination, call detection, analog-to-digital conversion of voice, and creation of voice packets (CODEC functions).
Typically, each conversation (call) [...]