NGN

 

传统电路交换网->智能网->软交换->IMS    (出现的时间先后顺序)

在软交换控制与承载分离的基础上，IMS更进一步地实现了呼叫控制层和业务控制层的分离

IMS全部采用会话初始协议(SIP)作为呼叫控制和业务控制的信令，而在软交换中，SIP只是可用于呼叫控制的多种协议的一种，更多地使用媒体网关控制协议(MGCP)和H.248协议

3GPP (3rd Generation Partnership Project，第三代合作伙伴计划) :是一个成立于1998年12月的标准化机构。目前其成员包括欧洲的ETSI、日本的ARIB和TTC、中国的CCSA、韩国的TTA和北美的ATIS。3GPP的目标是在ITU的IMT-2000计划范围内制订和实现全球性的（第三代）移动电话系统规范。它致力于GSM到UMTS（WCDMA）的演化

3GPP LTE (Long Term Evolution，长期演进) :LTE也被通俗的称为3.9G，具有100Mbps的数据下载能力，被视作从3G向4G演进的主流技术

分组交换(packet switching)

电路交换 (circuit switching)

FMC (Fixed to Mobile Convergence)

----------------------------------------------------------------- IMS -------------------------------------------------------------------

IMS is a global, access-independent and standard-based IP connectivity and service control architecture that enables various types of multimedia services to end-users using common Internet-based protocols.

Call Session Control Functions (CSCF)

Home Subscriber Server (HSS) : the main data storage for all subscriber and service-related data of the IMS. The main data stored in the HSS include user identities, registration information, access parameters and service-triggering information [3GPP TS 23.002].

Subscription Locator Function (SLF) : used as a resolution mechanism that enables the I-CSCF, the S-CSCF and the AS to find the address of the HSS that holds the subscriber data for a given user identity when multiple and separately addressable HSSs have been deployed by the network operator

Multimedia Resource Function Controller (MRFC)

Multimedia Resource Function Processor (MRFP)

Application Server (AS)

IP Multimedia Service Switching Function (IM-SSF)

Media Gateway Control Function (MGCF)

Charging Collection Function (CCF)

DNS (Domain Name System) / ENUM (Telephone E.164 Number Mapping)

----------------------------------------------------------------- 软交换 -------------------------------------------------------------------

软交换 的基本含义就是将呼叫控制功能从媒体网关（传输层）中分离出来，通过软件实现基本呼叫控制功能，包括呼叫选路、管理控制、连接控制（建立/拆除会话）和信令互通，从而实现呼叫传输与呼叫控制的分离，为控制、交换和软件可编程功能建立分离的平面。软交换主要提供连接控制、翻译和选路、网关管理、呼叫控制、带宽管理、信令、安全性和呼叫详细记录等功能。与此同时，软交换还将网络资源、网络能力封装起来，通过标准开放的业务接口和业务应用层相连，从而可方便地在网络上快速提供新业务。

MG,MGW (Media Gateway，媒体网关) ：is a translation device or service that converts digital media streams between disparate telecommunications networks such as PSTN, SS7, Next Generation Networks (2G, 2.5G and 3G radio access networks) or PBX. Media gateways enable multimedia communications across Next Generation Networks over multiple transport protocols such as Asynchronous Transfer Mode (ATM) and Internet Protocol (IP)

Because the media gateway connects different types of networks, one of its main functions is to convert between different transmission and coding techniques

Media gateways are often controlled by a separate Media Gateway Controller which provides the call control and signaling functionality

MGC  (Media Gateway Controller，媒体网关控制器) :An MGC controls a number of dumb terminals, the Media Gateways. The MGC receives signalling information (like dialed digits) from the Media Gateway and can instruct it to alert the called party, to send and receive voice data etc

基采用软交换技术的设备称之为软交换机(Softswitch, SS)，它位于控制层。媒体网关位于接入层。