Separates the call control function from the media network (transport layer); it is the core equipment of the next generation packet network

Functions: call control and processing, protocol~, service provision~, service exchange~, interoperability~, resource management~, billing~, authentication/authorization~, address resolution~, voice processing~

Technical features

Achieve the goal: With the cooperation of media equipment and media gateways, protocol conversion of various media streams is realized through computer software programming, and the interconnection of IP, ATM, PSTN network, etc. is realized based on the packet network architecture.

Softswitch network layering: edge access layer (information format conversion), core switching layer (packet technology), network control layer (core layer; softswitching), business management layer

Equipment in Softswitching System

Media Gateway Control Protocol/Bearer Control Protocol=Asymmetric Protocol

Signaling transmission protocol Sigtran (remember the protocol diagram)

call control protocol = peer-to-peer protocol

Other application layer protocols: FTP, RADIUS, PARLAY, SNMP

Core switching layer protocols: Ethernet, MPLS, ATM, TCP/IP, RIP (Dynamic Routing Protocol), OSPF (Open Shortest Path First, the most widely used dynamic routing protocol and a link state protocol) , BGP (Border Gateway Protocol), RSVP (Resource Reservation Protocol)

IMS: A network system framework that provides voice and multimedia services based on IP core network

Comparison between IMS and Softswitch

IMS features: access independent, unified protocol, separation of business and control, separation of user data and exchange control, home service control, horizontal architecture, policy control and QoS guarantee, invisible registration

IMS layered architecture

Protocols in IMS

Advantages of IMS: mobility management, service quality, service control and developer interface