Passive Optical Network (PON) Technology Video Surveillance System Solution

Faced with the rapid growth of security services and the Internet of Things, as a large-bandwidth transmission method with low deployment cost and high flexibility, passive optical networks (PON) have been increasingly deployed in transmission access networks around the world, and are showing a trend of replacing traditional switch access networking. Especially in scenarios with long coverage distances such as road monitoring and safe cities, PON is an ideal and economical access method today.

1. Design of monitoring transmission network structure

The main function of the monitoring transmission network system is to access various monitoring resources, provide basic guarantees for various applications of the central management platform, and better serve various users. The network structure is shown in the figure below:

Network topology diagram

1) Core layer

Data Center Core Network

The core layer is mainly composed of core switches. As the brain of the entire network, core switches have high configuration performance. Currently, core switches generally have dual power supplies and dual engines, so core switches generally do not use dual-core switch deployment, but they have high requirements for the backplane bandwidth and processing power of core switches.

2) Access layer

Front-end video resource access

The front-end network uses an independent IP address segment to interconnect multiple front-end monitoring devices. The front-end video resources are accessed through the IP transmission network to the monitoring center or data room for aggregation. There are currently two common methods for front-end network access, usually point-to-point fiber access and point-to-multipoint PON access. The access layer needs to provide support for the network access of the NVR storage device to ensure that the network environment of the NVR storage device is safe and reliable.

User access

For the user-side access switch part, it is necessary to add corresponding user access switches to provide users with Internet access services. The monitoring center deploys access switches and accesses the transmission network through 10G/1G optical fiber links. Ensure the normal applicability of the monitoring center decoder and client

There are two levels of architecture in network design as shown in the figure below. The specific design will not be introduced in detail here.

Secondary network structure design diagram

Network transmission bandwidth requirements

Taking into account the overhead of network transmission and other applications, the theoretical value of the available bandwidth of the link is about 80% of the link bandwidth. To ensure high-quality transmission of video images, it is recommended to use a light-load design when using bandwidth, and the upper limit of the light-load bandwidth is controlled within 50% of the link bandwidth.

3) The network from the core layer switch to the access switch uses optical modules for transmission, and the bandwidth must reach more than 1 Gigabit;

4) The bandwidth between transmission equipment such as optical fiber transceivers and access switches is recommended to reach 100M;

5) The transmission bandwidth between transmission devices such as optical fiber transceivers is recommended to reach 100M;

Networking solution

The video surveillance project uses a 10G backbone ring network and a 1G converged access method to form a three-level image-specific network system, and builds digital video surveillance points through distributed video access and storage.

The front end uses high-definition network cameras for digital video acquisition and transmits the video via PON optical fiber links to the sub-control center for unified access.

As a third-level node in the network, the sub-control center is responsible for all front-end video access to the digital video private network. An integrated network video storage system that combines a video surveillance system and a storage system is deployed in the sub-control center to access, store and forward digital videos, and store images for 30 days.

As the core node of the network, the control center is responsible for real-time video calls of the entire network and real-time monitoring of key monitoring points. As the core management node of the video business, it deploys a video management platform to centrally and uniformly authorize, maintain and manage the equipment and users of the entire network.

The topology diagram is as follows: (PON)

Topology

2. Benefits of using passive optical network transmission for monitoring architecture

1. Network planning of PON equipment - deployment of OLT. In the early stage of xPON construction, it is advisable to adopt centralized settings, and set up OLT nodes at transmission aggregation nodes to cover scattered users in a certain area. In the mature stage of xPON application, it is advisable to adopt the principle of decentralized settings, set up OLT in the room with better wired access or wireless access points, and gradually transition to the unification of access network access and wireless access points to fully realize the comprehensive utilization of basic resources. Use large-capacity OLT equipment to make full use of the distance advantage of optical access, reduce offices, and reduce maintenance costs.

2. Network planning of PON equipment - deployment of splitters. Splitter splitting: Currently, PON can adopt a two-level splitting method to ensure flexible deployment and full utilization of ports; when the user penetration rate increases, the second-level splitting will be adjusted to the first-level splitting; for the current access to the PON network, it is advisable to use the first-level splitting, and try not to exceed two-level splitting. When the user scale is small, the splitter should be set up centrally; when the user scale is large, the splitter can be appropriately dispersed to be as close to the user as possible. Splitter placement location: The splitter can be placed in the handover box, community computer room, corridor, weak current well and other places according to the actual situation of the project.

3. Network planning of PON equipment - deployment of ONU. When building a PON network to implement access network/FTTB, it is advisable to use equipment with built-in voice modules to achieve comprehensive service access. ONU should be set according to the application mode and service requirements of the FTTx network. For access network applications, ONU should be set at the user's home as much as possible, and avoid installation at the door or in the corridor. For ordinary public users, ONU can be set in the user terminal smart box for protection, or placed on the desktop (using optical fiber information socket). For FTTB applications, ONU can be set in different locations such as cabinets in the corridor or shaft of the building, outdoor optical junction boxes, etc. In principle, ONU adopts local power supply, and try not to use remote power supply. In order to ensure the normal development of voice services during power outages, backup power can be provided according to the provided battery module.

4. Network planning and network management of PON equipment. Centrally build the manufacturer's network management and open the northbound interface to facilitate access to the integrated transmission network management.