Preliminary study on NGN planning method
Http://www.chinatelecom.com.cn June 11, 2003 China Telecom Group Beijing Research Institute Xiong Xiaoming Sun Hongyan
Abstract With the evolution of the network architecture and the development of broadband technology, the evolution of traditional networks to next-generation network (NGN) is an inevitable trend, and the traditional voice business and multimedia business is carried out based on Softswitch's next-generation network. Commercial applications have gradually emerged. Based on the basic architecture of NGN, this paper proposes the basic process of NGN business network planning, and elaborates in detail the basic idea of NGN network planning. Key words NGN Softswitch Planning NGN Planning refers to the determination of the development strategy and development goals of next-generation business networks, as well as material funds and solutions used in achieving goals. NGN's planning method, in solving NGN-related technical problems and explores the NGN large-scale commercial model stage, it also requires key attention. 1 NGN architecture NGN is a broad term that generally refers to a more advanced technology than current networks or a network that provides more advanced services. The NGN discussed herein refers to the next-generation network based on soft exchange technology, and its network architecture can be divided into four main levels according to device functions, as shown in Figure 1. Soft switching equipment is located in the control layer, providing a variety of business connection control, routing, network resource management, billing, certification and other functions. Soft switching equipment and relay media gateway, SIP (SIP (SESSITION INITITION Protocol) terminal, signaling gateway, and other softswitch devices communicate with each other with standard protocols. In the access layer, the function of the signaling gateway is to connect the signal and the packet network, implement the seven signaling of the PSTN / ISDN side and the conversion function of the IP network side signaling; the function of the media gateway is to put various users or networks Access to the core network, transfer the media streams required by the service conversion component network; the SIP terminal is the user agent in the SIP system, which provides voice and data services. In response to interactive multimedia services, it is also necessary to increase the telecommunication-level application server device in the NGN network. 2 NGN planning process is defined according to the CCITT "Communication Network Planning Manual", telecommunications network planning includes four major categories: strategic planning, implementation planning, development planning and technical planning, together with the overall telecommunications network planning, from all aspects Construction and development. The basic flow of the planning of the operator actually deployed the NGN business network as shown in Figure 2. Development strategies include business model and business development strategy, network evolution and network development strategy development, is the overall guideline principle within the planning period; business forecasting is analyzed by market demand, the scale and development goals of market traffic in the planning period; The network plan is based on the business development goal, and the network structure and scale of the planning period are determined to reasonably organize NGN network resources. 2.1 Development Strategies NGN The development strategy mainly includes: NGN business strategy and NGN network strategy. The development of the NGN business is a gradual process. It is mainly driven by market demand and technology development: in the early days of NGN network construction, NGN business is dominated by grouping voice and simple QoS guaranteed multimedia business; with grouping network The continuous improvement, the multimedia business with QoS guarantees is rapidly developed; after the gradual improvement of NGN technology, due to its standardization and open characteristics, business providers provide more business to the network, of which personalized, virtualization is characteristic. The business will become mainstream. Specifically, NGN can also provide voice and telephone network value-added services (such as call forwarding, call waiting, etc.), but also provide rich multimedia services, such as: Instant messaging: integrated text, image or image message business; · Multive media Desktop Access: Users can implement voice, data, and video to desktop through multimedia terminals such as client software, visual calls, or SIP terminals, etc.); • Personalized business: can include dynamic call processing, personal call management, etc. We control the experience of communications.
In the introduction of NGN networks, emerging operators are more concerned about whether grouping networks can provide packet voice services, while traditional operators pay more attention to the network system's ability to provide new services. Therefore, from market demand, based on the development characteristics of operators themselves, develop a practical NGN business development strategy, regardless of emerging operators, or traditional operators, it is important strategic significance. From the perspective of development, NGN is a product that is increasing to IP / ATM-based packet network based public telephone exchange network (PSTN) based on the IP / ATM-based packet network. From the perspective of the network, in a soft exchange as the core, combine the media gateway, signaling gateway interconnection network and packet network to achieve the integration of business layers and the unified management of networks, this superimposed network evolutionary idea will become the domestic next generation The mainstream direction of the network market. From the demand provided by the equipment manufacturers and the domestic market demand, domestic operators implement the NGN network can adopt two introduction strategies: long-distance packet speech network, local grouping voice and multimedia application networking. The long-distance grouping voice network is the use of softswitch technology to replace the existing long-distance telephone network, that is, the so-called long-distance relay, the relay media gateway will implement mutual conversion between circuit switched networks and packet networks; local grouping voice and multimedia The application networking refers to a comprehensive business that combines a combination of a single-use softswitch within a city or cell, and supports diverse user access, including PRI access, V5 access, integrated access device (IAD) Access and various multimedia terminal devices. For operators, based on existing networks and take into account future development needs, reduce costs, increase profits, build high efficiency, easy management, and provide multi-service guarantees, is the ultimate goal of NGN network development strategy. 2.2 Business Forecast Business Forecast is the premise of network planning, the basis and basis of the quantitative data and qualitative development of the entire plan, and its accuracy will directly affect the scale, development and practicality of planning. The key issues involved in the prediction are how to use the scientific prediction method for practical calculation and operation, and judging the rationality of the forecast results according to the development trend of technology, business, market, and makes the necessary corrections. Regardless of the NGN business model, its business forecasts include three most basic content: users prediction, traffic prediction, and flow flow. The number of users predicts the judgment of the potential user market in the planning period; the business quantity prediction is based on the business scale calculated by user characteristics, business characteristics, etc.; the flow flow direction is determined by end-to-end traffic distribution. Business prediction should be based on business development strategies, closely rounding business development strategies, and analyzes the key business within the planning period. Parameters that may involve in the NGN business prediction include: number of telephone users, number of enterprise users, terminal type, and device number, business and user's penetration, user characteristics, service characteristics, business geographic distribution characteristics, traffic flow flow characteristics. For its specific operators' business forecast, it should also be combined with its market competitiveness, considering various business market share of operators. 2.3 Network Planning NGN Network Planning is a planning and design of the structural organization and network scale of the NGN network. Network structural planning includes softswitch, signaling gateway, and media gateway device setting mode, as well as routing structures; equipment capacity calculations are the NGN network equipment in capacity demand scale, device number setting, board quantity configuration, etc. Calculation; bandwidth capacity measurement is concerned about the bandwidth requirements of media streams and signaling streams to the packet network; construction and investment programs are preliminary estimates for NGN overall network deployment and NGN network equipment investment. In addition, NGN network plan also includes contents such as network management, QoS, and address resource allocation. By analyzing the development goals of NGN within the planning period, network planning can provide operators with appropriate network construction programs, realizing rational organization and utilization of NGN network resources, and maximizing resources.
(1) The focus of network structural planning network structure planning should be solved is the topology setting of network equipment. Soft exchange, signaling gateway and media gateway equipment should be used in principle, setting with local networks, but in the initial NGN construction, according to business conditions, network equipment settings can consider implementing multiple local network coverage: one Soft exchange can cover multiple local networks, called softswitch service area; a signaling gateway can also cover multiple local networks, called signaling gateway service area; a media gateway can overwrite multiple POP points (operator network connection Point). NGN network structure planning is shown in Figure 3. The first is to set the POP point range based on the network coverage, and determine the number of each POP point media gateway device based on the user size and predictive traffic of the POP point access. For softswitch and signaling gateway devices, depending on NGN service and device performance, the number of regions of the softswitch service area and the signaling gateway service area, the service area covers the POP point range, and the number of devices in each service area. The network scale capacity measurement result can provide quantitative basis for the NGN network structure scheme, providing quantitative basis: If the network calculation capacity is small, the range of the POP point service area covered by the device can be increased; if the network measurement capacity is relatively large It can reduce the range of the POP point service area covered by the device, or directly increase the number of network devices, increasing processing power. When the measurement capacity scale can ensure the full utilization of existing equipment, it can meet the simpleness and manageability of the network structure layout, it can be obtained by relatively reasonable structural solutions. (2) Equipment capacity measurement in NGN network planning, all network element devices have problems with equipment capacity, and the most important types of devices are soft exchange, signaling gateways, and media gateways. The ultimate goal of the equipment capacity measurement is to achieve reasonable organization and utilization of NGN network resources to facilitate management and maintenance. The basic step of network device capacity measurement is shown in Figure 4. The first step in calculating the capacity (processing power) demand for network devices. Different network devices, their capacity demand is different, and the processing power of soft switching devices can be represented by BHCA (busy call), the processing power of the signaling gateway device can be represented by the number of BHCA or the signal link. The processing power of the media gateway device can be measured by the number of relay port DS0 (Digital Signal 0). Regardless of the type of target network equipment, the basic premise of its measurement includes three types of parameters: business characteristic parameters, traffic flow flow to parameters and network structural parameters. Business characteristics are parameters related to NGN business characteristics, such as the average call duration of the voice service; traffic flow flow to parameters is a representation of end-to-end traffic size; network structural parameters refer to parameters related to network structure, such as soft exchange The service area covers the POP point range, the number of soft exchanges, and the like. The second step of calculating the specific configuration of the network device, including the number of devices and board configurations. Step 2 The planning target object is a specific equipment manufacturer's device. The device performance parameters refer to the measurement parameters of the maximum processing capabilities provided by different vendors, and device configuration information refers to information such as the maximum processing board number, single board processing performance. According to the measurement result of the step, the final configuration size of the network device can be calculated in consideration of the redundancy of the partial device. (3) The flow rate between the bandwidth capacity measurement NGN access layer is mainly the pathfinding path of the related equipment, the establishment of voice media links, and the transmission of speech and multimedia data, not only for transmission of safety, low time delay requirements. High, and it is also high for transmission bandwidth. Only the network provides the necessary bandwidth and QoS guarantee to achieve a soft exchange-based voice service and multimedia business to achieve perfect implementation. To achieve the guarantee of QoS and necessary bandwidth of the packet network, in addition to introducing new QoS mechanisms, reasonable network resource allocation is based, including packet network node device processing capabilities, port resource allocation, and relay circuit bandwidth allocation, etc. .
