Exploration and practice of constructing the most

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Exploration and practice of building carrier level VoIP services

VoIP will be one of the largest applications of NGN. How to improve the QoS of the existing VoIP network to the "operator level", while maintaining the low cost of IP services, is a topic that every telecom operator is thinking and exploring. Based on the new technology operation concepts such as Unione (unified service) and misn (Metropolitan integrated service), Shanghai Unicom, based on the in-depth research on the soft switch, mpls/vpn, IPv6 and other related technologies of NGN, and after nearly two years of practice, has found an effective way to improve IP bearing QoS and use soft switch technology to realize centralized service management and control

today, with the rapid development of broadband interconnection, both equipment manufacturers, service providers and telecom operators are focusing on the two core technologies of NGN - soft switch and mpls/vpn, trying to explore solutions to build broadband integrated service communication at the operator level, and looking forward to the ultimate realization of cross network, cross terminal voice The interoperability of video and data services, with the low cost of IP network construction and operation, provides users with carrier level voice (broadband IP), video and other value-added services comparable to PSTN

China Unicom IP has been in operation since June 1999. After the construction of phase I, phase II and phase III projects, at present, the network has covered 329 cities in China, with more than 18000 E1 ports, making it the world's largest IP network. The traffic volume of the network has reached nearly 1billion minutes per month, making it the largest network in the world. The overall IP framework of China Unicom is shown in Figure 1, including IP Bearer Network, service network (including primary dial-up service, secondary dial-up service, group user service and mobile user service), IP network management equipment (such as billing and settlement system, management system, etc.), access customs connected with various local networks, etc

several factors affecting IP QoS

Unicom ipqos index

delayed call

(1) call establishment time. The one-time dialing method is 50%. (2) Landing connection rate. Secondary dialing connection rate>95%; One time dialing connection rate>96%

three factors affecting ipqos

IP Bearer

the main impact of IP Bearer on ipqos includes various delays, jitters, packet loss when hitting high tonnage, insufficient bandwidth, etc

media off

the impact of media off on speech quality is reflected in the following aspects: different speech coding methods, time delay caused by internal speech data processing, echo cancellation, jitter buffer, etc

guard or soft switch CCM

gate keeper (GK) and soft switch CCM (call control manager) have a certain impact on the QoS of IP network. For example, the call setup time has a lot to do with soft switching. Soft switch CCM can improve the QoS performance of IP by using various technical means and strategies. For example, according to the current network situation, soft switch can use the coding with high compression rate when establishing the call under the condition of insufficient bandwidth, make full use of the bandwidth, and maintain the normal voice service capability while ensuring a certain voice quality; When the bandwidth is sufficient, the coding with low compression rate is restored to provide high-quality voice services. Soft switch can also adopt pre-defined rules. For call routes with small network bandwidth, such as long-distance calls, use coding with high compression ratio; On the contrary, use codes with low compression ratio, such as local calls

ip bearer QoS improvement strategy - deploy mpls/vpn

overall development idea of Unicom IP Bearer

China Unicom IP Bearer is divided into two levels of structure: core layer and regional layer. The core layer is composed of seven regional nodes in Beijing, Shanghai, Guangzhou, Shenyang, Wuhan, Xi'an and Chengdu; The regional level is divided into 22 regions according to the regional distribution of each branch. At the initial stage of construction, the bearer adopts atm+ip/vpn to form IP dedicated transmission, so as to ensure the QoS of the IP Bearer layer and the network performance meets the test indicators of China Unicom. In the next stage, the technical evolution route of China Unicom data core is shown in Figure 2. The network will take mpls+atm as the core technology, build a powerful MPLS core network at the seven core nodes, and adopt the two-layer MPLS technology to realize the transparent connection with ATM equipment, so as to build an advanced network with multi protocol and multi services, taking into account the development of ipv4/ipv6. China Unicom's interconnection, data dedicated line, IP, video conference, IPv6 network, CDMA 1X data communication, etc. are all carried on a unified data transmission platform

Shanghai Unicom metro development idea

the overall development idea of Shanghai Unicom Metro is to "focus on NGN and pay equal attention to the integration of data MPLS and transmission MSTP". The network hierarchy is shown in Figure 3. Considering the actual situation of Shanghai Unicom's access in the "last kilometer", the construction of backbone layer and tandem layer is separated from the construction of access layer, and each has its own emphasis. The backbone layer and the tandem layer are collectively referred to as "core", focusing on the transmission capacity of services; In the access layer and user end, we should focus on the access of Unione integrated services, and try to achieve the unity of equipment providers, system integrators, and client application software developers

in the access layer and user layer, the management method of "integrated" construction is adopted to minimize the response time of business plan, technical support and network maintenance, and maximize customer satisfaction; At the same time, in terms of access methods, wired and wireless complement each other, and make full use of the wireless fixed data access advantages of 3.5G, 5.8G, China Unicom CDMA2000 network, as well as WiMAX and other wireless access technologies that will become mature in the future, so as to expand network coverage and business scope

qos improvement strategy for VoIP services - construction and implementation of misn

composition of Shanghai Unicom misn

Shanghai Unicom misn is composed of five parts (see Figure 4): (1) service access control equipment (SACP). From 130 kinds of key materials needed by the national economy in the user's residence to metropolitan areas and bone services, they must pass the access authentication, service access control, network resource management and service quality control of SACP connection. (2) Call management control module (CCM). This module is responsible for the management of user registration; Authentication and control of service access through SACP; Interworking with the backbone service GK to complete the call control of various services; Collect billing information together with SACP; Be responsible for controlling the access of voice and video media streams. (3) Business related. Unicom misn is an IP based packet. When interworking with 193 long-distance backbone based on circuit switching and local PSTN local calls, because the media level and control signaling level are different, it needs to interwork through customs. (4) Bras equipment. Be responsible for connecting the interconnection to 165. (5) Business operation support system. The system includes maintenance management system, user terminal management system, user management (business acceptance, user information management, user business authorization and authentication) and the billing/business accounting system of local misn. Its upper interface is the operation and maintenance support system of each backbone business

sacp's QoS control function

sacp's QoS control function is mainly manifested in four aspects: (1) for call control information flow, different tos/dscp fields can be set according to the called E.164 number and the domain in which the call occurs; (2) For media streams, different tos/dscp fields can be set according to different encoding and decoding methods and the domain in which the call occurs; (3) When information flows between the user's residence and the metropolitan integrated services, QoS markers can be mapped accordingly; (4) Map different streams to different atm/fr-pvc, mplslsp, Ethernet VLAN or SDH virtual containers for transmission

a new generation of operators. At that time, Western powers broke the closed door state-level VoIP network prototype of the Qing government with strong ships and sharp guns.

with the continuous maturity and development of the next generation network technology with soft switch and mpls/vpn as the core, a new generation of operator level VoIP network prototype will be built, as shown in Figure 5

in a word, mpls/vpn improves the QoS of IP Bearer and ensures the quality of service of voice and video services based on IP packets in the metropolitan area; The deployment and implementation of soft switch and China Unicom misn have effectively managed and controlled the different media business flows initiated by Metro users. On this basis, the construction of a new generation of carrier level VoIP services will become a reality. (end)

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