System Structure of soft exchange devices in the Next Generation Network

I believe that in the next generation network system, Softswitch device control will continue to be used, and more services will be involved, the video multimedia service provides real-time communication between multiple users in different locations. The content includes high-quality voice with participant image information and other media information. When a conference includes more than two terminals, a multi-point control unit (MCU) is usually required ). All terminals are connected to one MCU. The MCU selects or properly blends signals sent by each user, and controls and manages signaling and optional channels.

Typical applications of video multimedia services include remote meetings among participants, compiling documents, displaying items (such as a new product), commenting, and negotiating contracts, both parties may need to avoid private discussions or invite experts to give suggestions, such as remote teaching and training, remote medical care, and remote item auction. Unlike traditional voice services, video and multimedia services have higher requirements on communication systems, such as support for integration, interactivity, and synchronization. As one of the core devices for voice, data, and video calls, control, and services in the next generation network, Softswitch devices focus on whether Softswitch can inherit traditional voice services, focus on how the softswitch system can better support video and multimedia services, hoping to improve the service capability of the entire network.

Softswitch system structure supporting video and multimedia services

Due to the importance of multimedia services, the softswitch system has taken into account the support for multimedia business applications from several main aspects from the very beginning. First of all, from the network structure perspective, multimedia application processing and calling are separated, and the unique information processing functions of multimedia services are implemented in media servers and smart terminal devices, general call control and service provision are completed in softswitch devices and application servers. Secondly, from the Protocol perspective, the H.323 protocol is developed for multimedia communication, and the SIP protocol is constantly improving its support for multimedia capabilities. As the cornerstone of the softswitch system, the H.248 media gateway protocol has defined a multimedia extension package. At present, the ing between H.324 and H.320 protocols to H.248 protocols is being improved. Finally, from the perspective of business capabilities, the open business generation and provision environment makes the development of multimedia applications richer and faster. Currently, the PARLAY-based API interface specifies the function set of multimedia applications in detail and organically integrates with applications such as voice and data.

The softswitch system that supports multimedia services discards the integrated MCU mode adopted by H.320/H.323 conferencing systems and can adapt to the open features and advantages of the group exchange bearer network. The following two new layered models can be used to better meet the profitability needs of operators. The first mode is the separation scheme of MCU, that is, MCU is mainly composed of MC and MP. MC focuses on the control function and MP focuses on the media processing function. The separation center is MCU split into two parts, and the control part and the media processing part are separated. These two parts originally use internal interfaces, which are actually private interfaces. After the separation, the two parts are implemented using the standard protocol H.248. The second mode is the integration solution, that is, due to the separation of MCU, the MP device can be used as the same media resource as the Media Server. In the next generation network system, it is used under the control of softswitch devices. MC devices and optional GK devices can be completely replaced by Softswitch devices and application servers. Compared with the integration scheme, the softswitch device can completely control the media server. Therefore, this solution provides flexible business development capabilities and makes full use of the open business interfaces provided by Softswitch to facilitate operators to carry out comprehensive video and multimedia services.

The softswitch system structure 1 that supports video multimedia services is shown in. Figure 1 multi-point processor (MP) is mainly responsible for audio, video, and data mixing, switching, and synchronization of multimedia meetings. In addition, it also provides the Conversion Function of Speech Encoding. Multi-Point Controller (MC) is used to control conference calls and video conferences and centrally manage meetings. It can control the coordination capability and priority settings of the multi-point processor and various terminals for voice, video, and data encoding/decoding.

The adaptation gateway is responsible for receiving and processing signaling and audio, video, and other media streams from non-data user terminals. It can process one or more media streams, after processing, it is sent to the corresponding MP or user terminal. The signaling messages sent by the user terminal are mapped to the corresponding messages and forwarded to the softswitch device by the gateway. The Media Server provides dedicated media resources, such as voice notifications and digital receivers. In addition, to meet the new business needs of China Telecom, it also supports personalized dynamic speech programming and dynamic loading and modification of resources. The softswitch system structure that supports video multimedia services can be divided into four layers: Access, transmission, control, and service.

The access layer provides a wide range of network and terminal device access, including H.320 terminals, H.324 terminals, and other types of terminals used in the existing network) smart terminal devices, such as SIP terminals, H.323 terminals, MGCP terminals, H.248 terminals, and soft terminals, as well as media servers. For H.320 and H.324 terminals, the gateway can map the control protocol of the Media Gateway and convert the information format to the information format that can be transmitted on the group network.

The transport layer is a packet exchange network composed of IP routers or ATM switches. It provides a unified transmission platform with high reliability and QoS Assurance for the softswitch system. The control layer is mainly composed of softswitch, which implements call control and connection management, controls network resources, transfers corresponding business processing information, and provides open business interfaces to the business layer.

The business layer mainly refers to the devices that provide various services and services to users. It uses an open and integrated business access platform to provide various value-added services, multimedia services, and third-party services for the Next Generation Network. At the same time, it also has the corresponding business generation and maintenance environment.