By Yi Liang
The next-generation network is a high speed packet or cell based network which can provide multiple services such as voice, data, video and multimedia. It has a high bandwidth multi-service core and intelligent edge. It provides quick service delivery and provisioning. Next-generation networks are based on internet technologies including Internet Protocol (IP), Multiprotocol Label Switching (MPLS), and Session Initiation Protocol (SIP).
Network convergence is one of the key subjects in the next-generation network. The goal is to bring together voice, data and video at the network level, at the system level, at the application level, and at the device level. Convergence in transport means all traffic sharing a common packet-based network which is usually IP based. At the system level, the softswitch will replace the traditional circuit switch. It enables voice communication over the IP backbone. IP PBX and multi-service devices enable the enterprise to access the network easily and reduce cost. More and more applications will be developed to use the new infrastructure. These new applications integrate voice, data and video at the desktop as well as in the server. Examples of this include multimedia conferencing, multimedia messaging etc.
The IP Multimedia Subsystem (IMS) is a standardized NGN architecture originally developed by the 3G Partnership Project (3GPP). It defines a generic architecture that offers VoIP and other multimedia services within wireless and wireline infrastructures. The IMS architecture is divided into three layers: service (application), control and transport (access). Following diagram is a simplified view of the layered architecture of IMS. Major vendors like Ericsson, Lucent, Nortel and Siemens have made substantial investment in IMS software. There are a lot of challenges and also a lot of opportunities in this technology evolution process.
