The hottest IP solution for urban traffic informat

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IP is the solution for urban traffic information system.

IP is the internetprotocol, which is the basis of the Internet services we usually use, such as WWW browsing, e-mail, Telnet, FTP, gopher directory services and other applications, which are implemented on IP. The Internet has developed at an amazing speed. From 89 to 99, the number of hosts has increased tenfold every three years. So far, there are more than 200 million people in the world. The infinite business opportunities brought by interconnection drive the rapid expansion of the entire IT industry. On the one hand, the commercial success of interconnection is that the design of tcp/ip adheres to the principle of "network hardware independence", which shows superior performance in crossing the limitations of network hardware platform. On the other hand, it benefits from the openness of interconnection. Today, IP has become a standard that must be supported by various network technologies. For example, in order to make ATM better support IP, the ATM Forum and the Internet Engineering Task Force (IETF) have developed at least three schemes: local area simulation (Lane), ATM multi protocol (MPOA) and ipoveratm. Whether it can support fast transmission of IP has become an important indicator to evaluate a new network technology. Some networks for the purpose of directly transmitting IP, such as Cisco's dynamic packet transmission (DPT), IP@DTM , also came into being to compete for a place in the highly competitive network market

At the beginning of the emergence of ATM, because it provided 155m and 622m high-speed connections and support for multi service QoS, there was no other technology that could surpass it at that time, so it caused a sensation. However, the IP packet routing switching technology based on ASIC chip soon appeared, which directly switched and routed IP packets at a high speed, exposing the inherent shortcomings of ATM. First, ATM technology is too complex and difficult to configure and manage; Second, the price is too high. The price of 622m ATM port is much higher than that of 1000m Ethernet port; Third, when ATM transmits IP, it needs to split packets into cells for transmission, and the efficiency is only about 80%; Fourth, ATM does not support IPmulticast, and the ATM Forum has no standard to support IPmulticast. These defects make ATM in a passive position in the competition with IP packet routing switching technology

similarly, IP packet switching has many obvious advantages over synchronous digital sequence (SDH), which is often used in highway construction in China

first, the self-healing ring of SDH requires redundant optical fiber backup. These backup optical fibers are not used during the normal operation of SDH. In fact, it is a waste of active temperature sensitive optical fibers. Under any reasonable topology, IP packet switching will use all optical fibers to transmit data and automatically balance the communication load of different optical fibers

second, once SDH allocates a logical channel for two-point communication, even if there is no data transmission between the two points, the logical signal cannot be used for other data communication that requires bandwidth. IP packet switching will not allocate fixed channels for communication, and all communications share high-speed bandwidth, which greatly improves the efficiency of network communication

third, SDH is based on time division and has no switching function. If you want to add voice switching to SDH, you need to access the SPC exchange. Even for the two adjacent communications, the voice must first go to the SPC exchange through the meridians, and then return along the line, wasting bandwidth in vain. IP packet switching has the ability of route identification and can automatically find the shortest path. It avoids wasting bandwidth on local voice data

fourth, the roads in the future must be crisscross, and the corresponding traffic information networks are crisscross. In this environment with extremely complex topological relations, the network interconnection based on IP routing is extremely convenient, and it can make full use of the redundant routes. In the case of partial failure of roads or nodes, the normal communication of other nodes can still be maintained. For SDH, this is unimaginable

of course, IP can also run on SDH. Currently, graphene is the only physical method, but some performance based on "interconnection +" should be sacrificed

its is @a panel display function itsolutions, and the mainstream of it is IP. Therefore, taking IP as the solution of urban traffic information system (MTIs) is in line with the trend of it development and has technical foresight. From the previous analysis, it can be seen that MTIs includes a violation inspection and punishment system, which requires that MTIs support other applications to connect to the traffic dynamic database wirelessly; MTIs needs to connect the commercial vehicle operation system and public transport operation system invested by other users, which requires MTIs to support all connections suitable for users, including DDN, frame relay (FR), N-ISDN, dial-up, etc; MTIs needs to exchange data with other dynamic databases outside the system, such as 119 fire alarm database, which requires that the network protocol of MTIs itself is universal and standard. The network environment of MTIs is so complex and the connections are so diverse, but the dilemma of MTIs is exactly what the Internet has faced in the past and has been successfully solved. The solution is IP

the traffic information system based on IP has many advantages that cannot be compared with other platforms:

first, the most scarce resource of its is standards, and it is a "standard" network protocol. IP protocol is supported by almost all network manufacturers and mainstream products, and is recognized as a protocol independent of hardware platform. Using IP as the basis of building traffic information system, there is a large choice in software and hardware, which can well reduce technical risks. At the same time, IP can pass unimpeded between different networks, saving the software and hardware investment of protocol conversion

secondly, Internet has profoundly affected our lives. Today's communication system, communication media and public focus have a trend towards Internet. Especially in Shanghai, CDPD, China's first wireless device supporting internet access, and China's first accessible two-way paging system also appeared here. Now WAP enabled

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