Softswitch

Soft switch is a functional entity for the next generation network NGN with real-time business call control and connection control functions, is the next generation network call control core.Simply look soft switching is to realize traditional PBX" call control function entity, but the traditional" call control function and business together, different business needs call control function is different, and the soft switch is independent of service, the requirement of soft exchange for call control function is a variety of business basic call control.

Soft exchange concept originated in the United States.At that time in the enterprise under the environment of the network, the user based on the Ethernet telephone, through a set of PC server call control software ( Call Manager, Call Server), PBX ( Private Branch eXchange, user level switch) function ( IP PBX).For such a device, system does not need to lay a network, but only through shared with the LAN can realize the uniform management and maintenance, integrated cost is far lower than the traditional PBX.Because the enterprise network environment on equipment reliability, billing and management requirements are not high, mainly used to meet the communication needs of equipment of low threshold, many devices are available to provide such solutions, so the IP PBX application gained huge success.By IP PBX success inspired, in order to improve the comprehensive benefit of operation of network, network development tend to be more rational, open, better services to users.The industry raised such a thought : the traditional switching equipment parts, divided into call control and media processing, between the two using a standard protocol ( MGCP, H248) and basically using pure software processing, and Soft Switch (soft exchange) technology emerge as the times require.

According to the international Soft Switch ISC Soft Switch is defined, based on the packet network by programmed software to provide call control and media processing phase separation equipment and systems.Therefore, the basic meaning of the softswitch call control function from a media gateway (transport layer ) separated by software to achieve the basic call control function, so as to realize the separation of call transfer and call control, as control, switching and software programmable function to establish a separate plane.Soft switch provides the connection control, translation and routing, gateway management, call control, bandwidth management, signalling, safety and call detail records and other functions.At the same time, softswitch will also cyber source, network capability package together, through the standard open service interface and business application layer is connected, can be conveniently on the network quickly provide new business.

Yin Kang points out, China's telecom industry has always been the noun attribute, equipment category switch translated as " switch ", and the noun attribute switching translated as " exchange ".X25 switch for X25 switch, ATM switch for ATM switch, L2 / L3 switch for two / three layer switch.So he suggested, for academic discussions of the seriousness of the soft switch should be more correctly translated as " soft switch ."This is the concept of translation on the issue.However, on the one hand, for the concept of soft switching fuzzy, also reflects the industry for the soft exchange knowledge in some aspects still exist deviations, there is too much emphasis on one aspect ability, or exaggerated the soft switching function.Even in a very long period of time, the soft exchange was artificially "myth ", it is considered to be a representative of the communications industry in the future, seems to be equal to anything technical.

Soft switch is a developing concept, contains many features.Its core is a using standardized protocols and application programming interface ( API) and open system structure.This is the third party to develop new applications and new business opens the door.Soft exchange system structure of other important features include application of separation ( de-coupling of applications), call control and bearer control.