Measure the test taker's knowledge about the comprehensive application of layer-3 switches in TMIS.

Mainstream layer-3 switches support security level and virtual subnet division. Today we will mainly explain some comprehensive applications of layer-3 switches in TMIS networks. With the rapid development of China's economy, the transportation volume of Railways has increased significantly, requiring the transition from experience management to modern management. Management personnel must have a complete information system to obtain timely, accurate, and complete information and provide decision-making support.

The Ministry of Railways's transportation management information system (TMIS) was proposed against this background. The TMIS network adopts the advanced layer-3 switch technology, ATM technology, and fast Ethernet technology to form a large network system covering the whole country.

According to Guo Yanjin, deputy director of the electronic computing Technology Center of the Ministry of Railways, the application of computers in railway operation management in China has been around for more than 30 years. However, due to the low development level of computer hardware and software, scattered development of various applications, lack of unified planning, resulting in low-level repeated development, low level of information sharing, and unbalanced development. In general, a complete system cannot be formed. In this context, the Ministry of Railways proposed the idea of building a railway operation management information system (OIS). Its core is the transportation management information system (TMIS ). TMIS consists of the central database system, station segment system, department, bureau, branch application system, and computer network system. The network system integrates the first three parts into a whole. The TMIS network system is centered on the ATM backbone network of the Ministry of Railways and is connected with 12 large regions and 58 branches nationwide, covering more than two thousand stations and sections across the country.

6 CoreBuilder 7000HD high-density trunk switches of 3Com are used in the ATM backbone network of the Ministry of Railways. The main feature of CoreBuilder7000HD is a 5.0Gbps backbone network engine, which uses interfaces with high-density 8 ports, the vswitch can provide up to 32 non-blocking 155Mbps ports. The CoreBuilder 7000HD switch comes with an enhanced i960 processor. It provides fast signaling rate, extended memory, and high-performance LAN simulation services. It is a complete, standard-based ATM solution.

Director Li Yucai of the Implementation Department of the Ministry of Railways electronic computing center said: "the ATM network scheme is mainly used to meet the needs of multimedia transmission with high quality requirements, such as voice, images and future video conferences. "The second-level trunk and Working Group networks use CoreBuilder 3500 layer-3 Switch and edge switch SuperStack Ⅱ Switch3300, and adopt dual-machine redundant backup in the building and redundant link connection between the buildings, this not only improves the reliability, but also plays a role in load balancing. The ingress and branch LAN also use 3Com's full-line network products, including third-layer switch CoreBuilder 3500 and edge switch SuperStack Ⅱ Switch3300, HUB and nic. According to director Li, TMIS actually unified the original independent small network into a layered and large physical network. The reason for choosing the layer-3 switch is as follows, it mainly solves the performance, reliability, and security and confidentiality issues in large networks.

The CoreBuilder 3500 switch uses advanced distributed ASIC + RISC technology to provide Layer 2 and Layer 3 Switch communication capabilities for line speed. The total data throughput can exceed 4 million packets per second. Because a policy-based service mechanism is used to support QoS and CoS, the dynamic traffic classification PACE technology and resource retention Protocol (RSVP) are used ), the vswitch supports real-time multimedia network communication to improve throughput, reduce latency, and ensure security. At the same time, because the switch, HUB, and nic adopt a unified system environment, the performance of the switch is brought to full play, and image transmission can be supported in the Ethernet environment. "In many cases, switch performance cannot be fully realized due to inconsistent terminals," said Li. "

In large networks, especially for a large transportation management information system such as TMIS, security is critical. CoreBuilder 3500 layer-3 switches support security level and virtual subnet division. Considering that a department may be dispersed in different buildings, the virtual network in vswitch 3500 is divided not by location, but by Application Department, and the security level of each subnet is different, departments with high security levels are allowed to access those with low security levels. Otherwise, they are not allowed. This not only enables information flow by department, but also enables traffic control and security isolation.

Director Li said: "If a centralized route processing can also achieve virtual subnet division, there are two problems: one is that trunk line redundancy is too large, and the other is that Wan and LAN routes are implemented by a router, you cannot perform hierarchical management. "In addition, the 3COM device has the anti-theft function. You can disable unused interfaces through the network management to prevent network attacks by using the protocol analyzer and prevent leakage of confidential information.

TMIS is a large-scale network system, which is an important part of network management. Because the TMIS system is very large, in order to better monitor the network operation, A three-level distributed network management system is composed of the Ministry of Railways, the Ministry of Railways, and the branch offices to achieve hierarchical management. The Branch is used as the basic management point to monitor and manage the network operation of each station, while the Ministry of Railways and the Bureau know the situation of each station through the branch. Each network management station has its own network management permissions, handle problems. The network management platform selects the Sun Net Manager intelligent network management system.

The Platform also runs network management applications such as 3Com Transcend Enterprise Manager. After a problem occurs in a traditional network management system, the common method is to find the problem and solve the problem through queries. The Neural Network Intelligent Network Management can define the regular working method as a logical relationship, it is automatically implemented on the network through development and training.

The establishment of the TMIS system will achieve significant economic and social benefits, provide accurate, timely and complete vehicle flow information for transport Production Scheduling and command personnel, and accelerate the rolling stock turnover, it greatly improves the customer's service status and provides accurate information for the maintenance, finance, statistics, material transfer and other departments of locomotives and vehicles; it provides various decision-making support schemes for the Ministry of Railways and the State Planning Commission to formulate medium-and long-term railway development plans and annual plans.