China: Real-Time Data Transmission Makes Convenient Network Management for Shanxi Province

---H3C Tackles Shanxi Province's Expressway Network Interconnection Project

In recent years, the expressway construction in Shanxi Province has witnessed rapid development. Till the Dayun expressway opens to traffic in September, 2003, the total expressway mileage has amounted to over 1200 kilometers, one of the longest in China. The framework of the expressway network has come into being, reaching the highroads in all directions.

The rapid development of expressway construction calls for highly efficient transportation management. According to the traditional practice, numerous toll gates have to be set up along each expressway respectively and the inefficient manual operation has produced much difficulty in management and control. The traffic department leaders of Shanxi Province have shown their great foresight in addressing this issue. Seeing the importance in the information construction of the transportation network, they have proposed the principle of "unified planning and design, uniform standard, forward thinking, step-by-step implementation" and they implemented such a strategy in the road construction that "once a section is built, it is added to the expressway network till the network covers all the expressways to implement the ultimate goal of uniform traffic monitoring, electronic charging, resource sharing and one-card service."

Multiservice and reliable expressway network platform

The construction of the information platform is an essential step in the information development progress of modern transportation management. The importance of construction of the supporting network system itself is obvious enough. Each computer network must be able to carry and exchange information. In case of an expressway network, the platform to implement online charging and to transmit charging data, traffic monitoring data and road images, the requirement is much higher and the network must still guarantee the operations of key users and tasks.

Shanxi Province presently has over 100 expressway toll gates. To transport the video information of all these toll gates at the same time, the network must have outstanding performance. In addition, the network is not only required to meet the current service demands but also required to accommodate at least five years of future service development, like functions related to weather forecast, accident prevention, vehicle navigation and logistic information. To this aim, the network should be able to support smooth upgrade and be able to protect investment at times of new technology adoptions by leveraging the existing equipment. The charge settlement directly affects revenues of the related companies. The monitoring data determines the safety in driving and the quality of traffic control. And the system relies on the various road images, in particular, the dynamic video data, to conduct appropriate charging and traffic monitoring operations. In this case, not a slight delay is allowed and not a little bit of data loss is allowable, because that would be sufficient to generate the Mosaic phenomenon, resulting in blurred display. The consequences could be serious. Therefore, the network must be able to transport all kinds of information correctly, safely and reliably.

After multiple times of debates and equipment selection, the whole series of Huawei-3Com's network products are finally chosen to construct the network

Three-layer hierarchy

Based on the real situation of the expressway construction in Shanxi Province, H3C has specially worked out a network solution that features high reliability, high performance, high security, easy management and great expansibility to meet the strict network demands of this project. The entire network will consist of two parts: the provincial WAN and the LAN system of the provincial charge monitoring center.

According to the scheme, the provincial WAN owns a three-layer hierarchy, implementing the analog transmission from the toll gates to the regional monitoring centers and the digital transmission from regional monitoring centers to the provincial center. The provincial monitoring center manages the expressways of the entire province by regions. And there are totally nine regions in the province, each under the governance of a regional monitoring center. The first network layer (core layer) is the provincial monitoring center, the second (convergent layer} are the regional monitoring centers, and the third (access layer) are toll gates. For each network layer, a router is configured (but the provincial monitoring center has two). The backbone of the communication system is constructed by 2.5G broadband links to fulfill the upstream and downstream data transmission. The network reliability is guaranteed by the alternative and backup transmission routes.

The major data communication equipments at all network layers are totally provided by H3C. As the data forwarding and access center of the entire network, the provincial monitoring center uses two suits of the high-end carrier-class reliable network equipment-- the core router NetEngine 80 and the core multi-layer routing switch S8016. For the video LAN switch at the provincial center, the S6506 (H3C S7506)  routing switch is adopted. And for the traffic monitoring LAN switch, the charging management LAN switch, the IC card management switch, and the bill management LAN switch for the provincial center, the S3526E series switches are adopted. The various regional monitoring centers all adopt the NetEngine05 and AR2880E routers to converge and forward the monitoring data sent by toll gates. And at each toll gate, the AR2809 router is adopted. All the above-mentioned network equipment will be uniformly managed on the multifunctional GUI network management system, which will greatly reduce the workload of the maintenance staff and enhance the network management and maintenance efficiency.

Impressive implementation effect

This network solution has taken various means to guarantee the performance, reliability and expansibility of the network. The network system can afford a 24-hours-a-day availability all year round. The interconnection between the S8016 routing switch and the core router NetEngine80 are implemented via dual links. All vital parts are configured in hot backup mode. All boards are hot swappable. Hence, services are totally free of interruption. In addition, the backbone bandwidth of the NetEngine80 and S8016 equipment is as high as 256G, able to forward packets at wire speed of 96Mpps. As a result, the network equipment will never be the bottleneck of service processing and forwarding. What's more, all the core equipment are based on a slot design and a modular structure to be flexibly expansible. They can not only satisfy the current needs of charging and traffic monitoring, but also adapt to the future network expansion and service development in the coming three years.

The high-bandwidth demand of real-time video transmission is also sufficiently guaranteed. The NetEngine80, S8016 and S6506 (H3C S7506) equipment produced by H3C can afford full QOS support and powerful flow classification function, able to upload data and video information in real-time and guarantee the high-quality video service in priority. At the same time, the provincial video system has been running the controllable multicast service to avoid repeated generation of the same video stream. This operable and manageable multicast solution provides functions like multicast source management, multicast user management and multicast security control to enhance the efficiency in bandwidth usage, to lower the network load and to guarantee the clearness and continuity of the video display.

Facilitated by this dedicated network platform, Shanxi Province's expressway management will further advance from the primitive electronic processing to intelligent transportation management, providing services like vehicle navigation, consultation service and logistic information. And the network will ultimately grow into an intelligent transportation network with integrated functions, including charging, monitoring, communication, logistics and first aid. Till then, the information level of expressway management will have progressed to a new stage with more benefits to the society