Control Layer
Main task of management layer is to control other layers. It is liable for correct functioning of management of transport layer (MGW/SGW). It controls service calling (application layer) and also manages user profiles (access layer).

One of the main principles of NGN architecture is it's division of management functions from connection hardware. In traditional telephony, connection functions of transport layer and functions of management layer, were supported by one device - exchange. In NGN, elements MGW/SGW are used as connection and routing function of exchange (switching network, interface and signaling). Servers for controling of calling (Softswitch) are replacing controling functions of exchange (processors and memories). This division with use of packet network, primarily for data transfers, is used also for voice and multimedia communication in real time. This is demanding a new management protocols.

 

These protocols we can divide into three groups:

 

  • Signalling protocols for call control, which allows establishment, controlling, and termination of session. (SIP protocol and recommendation
  • Protocols for MGW/SGW management, with use of softswitches. Mainly it is protocols type of Master/Slave H.248/MEGACO and MGCP.
  • Signaling protocols between softswitches. There is debate about protocols BICC, SIP-T (protokol SIP for telephony) and SIGTRAN.