History shows that the development of communication networks, market demand, rising, asked Metro network to provide the corresponding structural adjustment and upgrading.
Since the beginning of China's Internet business in 1994, domestic carriers began to design and build their own metropolitan area network operated, MAN has undergone vigorous development process, the Internet and other data services provide good support. History shows that the development of communication networks, market demand, rising, asked Metro network to provide the corresponding structural adjustment and upgrading.
Actual operating problems Historical and costs, are generally present MAN ATM, SDH and MSTP form of coexistence, as the business development gradually revealed the following:
First, the major network construction business alone, unified bearer network transmission load, add or change the business to bring large-scale metro network construction and structure of a large number of adjustments to project implementation cycle is long, difficult to deal with the community rapidly changing needs. Moreover, multi-service network transmission network on the bearing, making transmission less efficient transport network, can not play the greatest potential for MAN;
Second, metro network onerous complexity of network structure, operators can offer high product cost, can only meet in the high-end customers, on the low-end customer can not provide low-cost access solution;
Third, dense urban areas, from various operators MAN to the user Department needs to complete access by CPN. The use of fiber optic cable construction, construction is slow, long duration, is not conducive to rapid deployment operations. Among them, China Unicom as a large number of building base stations for fixed-line access to provide a different cable for Microwave Access, can provide microwave in every corner of Beijing to deploy, with a certain degree of flexibility.
Various technological bottlenecks MAN Currently, MAN technical problems in the following areas:
1. Based on circuit-switched network, ISDN, DDN, VDSL line can provide a narrow bandwidth, the transmission distance is limited, difficult to set up the scale of enterprise data networks, network hard upgrade. In this way there have been fewer customer acceptance, market, China Telecom, China Netcom, China Railcom to provide such a line;
2.ATM + IP network, although you can guarantee QoS, providing flexible bandwidth allocation, however, expensive access devices, access is limited. Example, a client can access 8E1 or STM-1 / 4 Line of Huawei MA5103, the price of several million. Provides the following ports for the 8E1, or STM-1 / 4, there is no flexibility in the transition bandwidth, the bandwidth easily lead to waste. At the same time, ATM networks need to carry SDH networks, the complexity level, the main provider of the market is China Unicom;
3.PDH, SDH network, can provide N × E1 or STM-1 / 4-port, port type is limited, if the user needs other types of ports, bridges need to install the appropriate equipment, to increase the point of failure . Bandwidth allocation can not be flexible, for small bandwidth, such as the 5E1 line, can still be used to access E1 to Ethernet bridge, for the tens of megabytes of bandwidth, users need to occupy the same STM-1 port, followed by the installation of appropriate equipment income, resulting in a serious waste of bandwidth, the corresponding single node equipment access is so restricted and can not satisfy a large number of different bandwidth networking requirements of users, operators can provide such large green;
4.MSTP network based on SDH technology, drawing Ethernet, ATM, MPLS, RPR (Resilient Packet Ring) technology such as the advantages of the rich interface of the business, and business interface board increase in Ethernet, ATM, MPLS, RPR and other capacity so as to become more business in the near future reunification of multi-service transmission platform. However, due to technical data frame processing MSTP is in the interface board, subject GFP encapsulated into SDH frames, for transmission, processing efficiency is not high. And MSTP built on the basis of SDH technology, limited the deployment of SDH network and bandwidth constraints, although the flexibility to allocate bandwidth, but when a large number of high bandwidth users to access, MSTP equally powerless. China Telecom, China Netcom has been available in some large cities bearing MSTP business, other operators seldom used, in a wait state. The demand for next-generation metro
As the use of DWDM wavelength division multiplexing technology, the national backbone network has been able to achieve Tbit / s transmission rate level; Gigabit Ethernet's advance, local area network can also be expected to provide a good time business support. Therefore, the major network upgrade is the backbone network bottleneck between the MAN and LAN, still can not meet the market and technology development. Based on the above analysis, the next generation metro network should meet the following requirements: I am a professional writer from China Chemicals Products, which contains a great deal of information about promotional folding chair , classic butterfly chair, welcome to visit!
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