In the NGN Architecture, it has two major parts namely WCS (Wireless Call Server) and MGW (Media Gateway). The real intelligent or call processing part is WCS. Different types of
Consider a company where majority of IDD calls are VoIP. For VoIP we use SIP (Session Initiation Protocol). Now companies are using a device called SBC (Session Border Controller) which is regularly deployed in VoIP networks all over the world. SBC will protect the network and devices from malicious attacks and at the same time will allow different parts of the network to communicate through the use of variety of techniques such as NAT (Network Address Translation), SIP, IPV4/6, etc.
Following figure will give you a clear idea on how the previous system was there and how it is replaced now using a SBC.