EPON system integratio......

EPON system integration solution

Summary:

System integration includes data, voice, video surveillance and so on as an important part  of security defense system, among which video surveillance is the difficulty in system integration, and it is a comprehensive system with strong defense ability. Video monitoring is widely used in safe cities, railway monitoring, bank remote monitoring, warehouse remote monitoring, construction sites and other occasions because of its intuitive, accurate, timely and rich 

information content. What is particularly prominent is the application of safe city in the whole country, which not only strengthens the construction of urban infrastructure, but more importantly, improves the level of urban security and the handling capacity of major disasters and accidents in cities.

Technology comparison of video surveillance transmission network layer

The transmission network layer technology of video surveillance system mainly includes traditional ADSL, point-to-point fiber transceiver and emerging EPON scheme.

The technologies of the three access platforms are compared as follows:

1. ADSL: at present, a clear monitoring signal needs 300K bandwidth. For the high-definition pictures that need to be transmitted by the public security and financial departments, at least 800K bandwidth is required for each channel. The actual bandwidth provided by

2. ADSL is small, and the IP address assigned after each dial-up is different, so the systemneeds additional devices such as the DNS server to ensure the communication

3. between the monitoring center and each monitoring point.

4. Point-to-point optical transceiver mode: the number of monitoring points in a large monitoring network is very large, and the point-to-point mode needs to occupy a large number of optical cable resources, for the metropolitan area network is generally in short supply of optical cable resources, the implementation of this mode will bring great pressure to operators; Moreover, the optical transceiver only provides a transparent channel, which cannot guarantee the reliability, QoS, security and OAM.

5. EPON mode: EPON (Ethernet passive optical network) is a new type of optical fiber access network technology. It adopts point-to-multipoint structure and passive optical fiber transmission to provide multiple services over the Ethernet. Its physical layer adopts PON technology, Ethernet protocol is used in the link layer, and Ethernet access is realized by using PON topology structure. Therefore, EPON combines the advantages of PON technology and Ethernet technology: low cost; High bandwidth; Strong scalability, flexible and fast service reorganization; Compatibility with existing Ethernet; Convenient management and so on. EPON network structure characteristics of itself, the broadband as special superiority, and with natural organic combination of computer network, the experts all over the world agree that the passive optical network is the realization of "three nets" and solve the information highway "the last kilometer" the best transmission medium, EPON conclude from 2004 standard development up to now, It has become the mainstream broadband access technology at home and abroad.

Compared with the above two schemes, DFLH's EPON-based access platform has the following characteristics:

• It can provide up to 1000M bandwidth. For shopping malls, busy areas and other places

 with intensive monitoring points, each client ONU device can transmit multi-channel high-definition monitoring pictures. Even if monitoring points are added later, there is no bandwidth bottleneck at all;

•EPON point-to-multipoint topology, using a passive optical splitter to share optical fibers at multiple monitoring points, saving a lot of metropolitan area network optical cable resources.

• The circuit of the entire access platform is constructed with passive components, which provides high reliability and easy daily maintenance.

• A wide range of OLT devices meet various service requirements, distribute OLT offices reasonably, use resources more effectively, and save investment.

• Video surveillance dedicated full closed cast aluminum ONU, industrial chip, strong ability to adapt to the environment, easy installation, stable performance.

• DFLH four-port iron shell series, the industry's single PON port power consumption is the lowest, green energy saving.

The EPON access platform networking structure is as follows:

▪ ONU is placed in the front part and the camera is connected below. The analog video at the monitoring point is connected to the ONU through the DVS. The newly created network camera is directly connected to the ONU through the class 5 cable to access the digital video private network.

▪ The optical distributor is mainly placed in the computer room of each police station.

The OLT part is located in the branch room, connected to the switch or metropolitan area network PTN, etc. The specific choice can be made according to the actual situation such as the volume of services.

DFLH intelligent video surveillance EPON access platform design principles are as follows:

-the main way of optical cable is to lay in pipeline

▪ Cable access to all monitoring points

▪ PON system supports network maintainability

▪ OLT key board supports 1+1 backup

▪ Calculate the worst optical power to ensure stable operation

The current EPON protocol stipulates that the longest transmission distance and difference distance of EPON shall not exceed 20km. In the application of intelligent video surveillance, EPON will undoubtedly face the bearing of ultra-remote monitoring points due to the wide and irregular distribution of front endpoints. Therefore, THE DFLH intelligent video surveillance EPON access platform is faced with the burden of ultra-remote monitoring points, and the following optimization schemes are proposed:

▪ Appropriately reduce the splitter ratio to extend the carrying distance, and use the PON 

system to carry the tube-controllable remote broadband access equipment.

▪ For a small number of police stations in the suburbs (the distance is more than 25km), OLT will be sunk without affecting the network level.

▪ Optical fiber transceiver can be used for monitoring points beyond the bearing distance.