| Abstract In this paper, fixed NGN and IMS technology, | | | | physical realization of interworking function by the |
| technical characteristics are compared, and the | | | | MGCF / MGW implementation, user data stored in the |
| evolution of the existing fixed NGN to IMS | | | | HSS, the network is more distributed, logical entity does |
| demonstration program were analyzed, obtained | | | | not necessarily correspond to physical implementation. |
| feasible evolution program. | | | | Network capabilities help network expansion and |
| 1, background IMS (IPMultimediaSubsystem, IP | | | | modular business integration, facilitating the centralized |
| Multimedia Subsystem) is the version proposed by | | | | network. Softswitch and IMS layered architecture as |
| 3GPP in Release5 support IP Multimedia Subsystem | | | | shown in Table 1 compared. |
| business, its core features with SIP protocol and has | | | | 2.1.3 businesses Fixed NGN for the operations of the |
| nothing to do with the access of, the development | | | | following ways. |
| trend of network convergence , 3GPP, ETSI and | | | | SoftSwitch provided directly by the business, which |
| ITU-T are working on IMS-based network integration | | | | provides basic telephone services, supplementary |
| program, to achieve the fixed network and mobile | | | | services, etc.; SoftSwitch with SSP capabilities and |
| network convergence. Therefore, IMS is considered | | | | current network by SG SCP exchange to offer the |
| the ideal goal of the next generation network | | | | intelligent network services; SoftSwitch and the |
| architecture. | | | | application server through the SIP, H. 323, Radius, etc. |
| 2, fixed NGN to IMS evolution of feasibility analysis | | | | protocol interworking; by Parlay-GW/OSA-GW |
| 2.1IMS comparison with the fixed NGN | | | | provide API interface, to provide business development |
| 2.1.1 Technical characteristics Compared with the fixed | | | | platform for third parties. |
| softswitch technology, IMS has the following technical | | | | Thus, fixed NGN business logic found in AS and SS, |
| advantages. | | | | the soft switch. The IMS control of operations and |
| Access independence; more thorough separation; | | | | separate all the business logic in business layer to |
| network more standard and uniform. | | | | achieve, S-CSCF session control function only |
| Addition to the above characteristics, the fixed NGN | | | | completed, the business concentrated in AS, by and |
| and IMS, in particular the integration of IMS-based | | | | between the AS and the control layer to provide an |
| systems and some other key technical differences, | | | | open service interface, so IMS is more conducive to |
| including registration, QoS, roaming, security, and so on. | | | | the development of third-party business. |
| 2.1.2 Network Element Set | | | | IMS business provides as follows. |
| On the network architecture, NGN and IMS networks | | | | IMS through the IM-SSF and traditional intelligence |
| have adopted a hierarchical structure of the network is | | | | services (CAMEL, INAP, etc.) of the exchange, have |
| divided into business layer, control layer and bearer | | | | the intelligence to achieve business succession; IMS |
| layer and access layer. The main difference is fixed | | | | AS can provide through the SIP-based services, such |
| NGN focus on physical implementation, the control | | | | as IM, Poc, Presence, etc.; IMS through Parlay-GW |
| layer functions concentrated in the soft-switch, | | | | OSA-GW (OpenServicesAccess-Gate-way) to |
| soft-switching network, only a central control point; the | | | | provide API interfaces to provide business |
| IMS control layer functions by a number of logic | | | | development platform for third parties. |
| function modules, such as the CSCF session control | | | | |