忘不了Optical fiber access network technology
The entire telecommunication network according to network function is divided into three ctions: switching, transmission,and access. Access to telecommunications business transparent to urs, transmit specific, access to local switch and the ur that the connection between the parts, usually include subscriber line transmission system, reu equipment, crossing connection device or ur/network terminal equipment. And actually pick for business entity is business nodes. 工地安全
1. Access network development process凉拌鸡肉
1.1 Access Network (AN: Access by business) refers to a node interface (SNI) and related urs Network interface (UNI) between a ries of transmit entity (such as line facilities and transmission facilities) for transmission consisting of telecommunication business provide the required transmit load capacity, implementation system configurations percentile management interface via and management. Access can be en as with business and application irrelevant transmission network, mainly finish cross
ing connection, reu and transmission function, it is transparent to urs of signaling.
Bad on modern of telecommunication network access network is integrated rvice access, simple local voice access will be increasingly cannot meet the requirements, the voice, data and image comprehensive access is becoming access network development trend. After years of development, access network define though does not change, but its connotation and forms has changed significantly. Superior traditional access network integrated optical fiber access network will be urs access the future developing trend.
Optical fiber access from SNI to UNI refers to all or part of the access network by using optical fiber as medium. ITU - T about access network recommendations indicate that fiber, ur access system is compod of three parts: optical line terminal(OLT), optical distribution network (ODN) and optical network unit (ONU). 轮岗方案
1.2According to the requirement of system access framework and the important characteristics, access network can be summarized as the following:
1.2.1 Access to access business provides bearing capacity, achieve business transparent transfer.
1.2.2. The access is transparent to urs signaling, except for some urs signaling format conversion outside, signaling and business processing function is still in business node.
1.2.3 The introduction of should not be restricted access all kinds of existing access types and business, access network should through the limited standardization interface and business node connected.
1.2.4Access network have independent from the business node in the network management system, this system through the standardized interfaces connected TMN, access network operation for implementation TMN, maintenance and management.
2 .fiber structure
2.1general linear structure. Refer to the public bus, fiber as each ur terminals through d环世界多少钱
irect connect with bus coupler network structure. Its characteristic is sharing backbone fiber, save lines to remove node investment, the demand is higher, dynamic range, interfere with each other effect is small. Defect is loss of accumulation, the backbone fiber ur acceptance dependence is strong.
行政是干嘛的2.2 ring structure. Refers to all share a fiber optic link node, fiber optic link its end to end the clod loop network structure. Characteristic is lf-healing, namely can be realized without intervention, the network can be in a relatively short period of time to recover from failure have preached business, high reliability. Defect is hanged by the number of urs of monocylic limited, polycyclic interchange is relatively complex, not suitable for CATV, etc FenPeiXing business.
2.3star structure. This structure is actually point-to-point way, each ur terminals in the central node through with control and switch functions of the astral couplers exchange information. Characteristics of simple structure, maintenance is convenient and easy to upgrade and expansion between, each ur relatively independent, good crecy, busine
ss adaptability. Defect is higher, networking required fiber cost of poor flexibility, high reliability requirements of central node.
2.4 tree structure. Similar to the branches, a hierarchical structure, shape in transfer boxes and FenXianHe place adopts multiple optical distributor, will signal filtering down top end innings allocation, have strong control coordination. Characteristic is suitable for broadcasting business. Defect is power loss is bigger, two-way communication difficulty bigger.
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