Wireless bridge

Release date:

2019-08-14

Viewed:

Foreword:


There are more and more wireless bridges used, especially the wiring is not convenient. The place where the construction environment is not good is widely used. Is it a wireless bridge? How to choose a good wireless bridge? How to apply it?


text:


First, what is a wireless bridge


Network Architecture

As the name suggests, wireless bridges are the bridges of wireless networks. They use wireless transmission to bridge the communication between two or more networks. Wireless bridges are divided into circuit-type bridges and data-type bridges from the communication mechanism. The circuit-type bridge wireless transmission mechanism adopts the PDH/SDH microwave transmission principle, and the interface protocol is implemented by the bridge principle. It has the characteristics of stable data rate and small transmission delay, and is suitable for the multimedia network network solution. It is suitable for 3G/4G. Interconnection of mobile communication base stations.

The data-type bridge adopts the IP transmission mechanism, and the interface protocol is implemented by the bridge principle. It has the characteristics of flexible networking and low cost, and is suitable for network data transmission and low-level monitoring image transmission. It is widely used in various data based on pure IP architecture. Network solution.


Second, how to choose a wireless bridge

  A wireless bridge is a wireless monitoring device widely used in the field of wireless monitoring. Although it is a wireless device like a wireless AP or a wireless router, it is not used to build wifi, but is used to wirelessly transmit video data. Like the switch in wired monitoring, the wireless bridge is an important transmission device in wireless monitoring, and its importance can be seen.


       There are many types of wireless bridges on the market, so people don't know where to choose, and they don't know how to choose high quality and most suitable.

Technical indicators to be considered when selecting a wireless bridge (for users and users):


Working frequency

       There are two working frequencies of the wireless bridge, 2.4G and 5.8G, and the characteristics of the two bridges are different. In general, the 2.4G wireless bridge is the mainstream frequency band, with good compatibility and good diffraction ability, but the anti-interference is relatively poor. The 5.8G wireless bridge is relatively clean, the anti-interference ability is better, the transmission distance is far, but the diffraction ability is poor.


2. Transmission rate

       Wireless bridges have a variety of transmission rates, such as 150Mbps, 3000Mbps, 450Mbps, 600Mbps, 900Mbps, etc. How to rate, according to wireless monitoring requirements.


3. Antenna

       The antenna is an important accessory for wireless bridges. It is used to transmit and receive wireless signals. Without an antenna, the wireless bridge cannot communicate. There are many types of antennas, such as omnidirectional antennas and directional antennas, and the larger the antenna gain, the better the performance of the wireless bridge.


4. Power supply mode

       Because it is mostly used outdoors, such as reservoirs, forests, etc., if power wiring is not available, other power supply methods are needed. The bridge that generally supports PoE power supply is the best.


5. Security

       Like wireless routers and wireless APs, wireless bridges also need to set passwords or encrypt wireless signals. Otherwise, there will be many terminals access, which will affect wireless monitoring transmission.


6. Waterproof, heat resistant

       The wireless bridge works mostly outdoors, and the environment is changeable. The following are rain, rain, snow, high temperature, etc. The first requirement is waterproof, dustproof, heat resistant and anti-condensation. A 'quality' is a must for a qualified wireless bridge.


7. Stability

       The stability of the wireless bridge is very important. If it runs normally, it will crash, and the rate will slow down. So what is the monitoring? This is related to the hardware of the wireless bridge, such as chips, motherboards, memory, cache, and so on. Of course, in a stable wireless bridge, if it is not done in the later installation, it is also a no-brainer.


8. Transmission distance

       Wireless monitoring projects need to transmit at different distances. There are many transmission distances for wireless bridges. Some transmissions are 1 to 3 kilometers, some are transmitted 3 to 5 kilometers, some are transmitted 5 to 10 kilometers, and some are transmitted 20 More than the kilometer, it must be determined according to the monitored transmission distance. As far as possible, the maximum transmission distance of the bridge is greater than the monitoring transmission distance.


Third, the application of wireless bridge

   How the wireless bridge will be erected in practice, and then several recommended erection schemes are recommended:


1, point to point mode

    Point-to-point (PTP), or 'direct transmission.' Wireless bridge devices can be used to connect two fixed networks in different buildings. They generally consist of a pair of bridges and a pair of antennas. The two antennas must be placed in opposite orientations, and the outdoor antenna is connected to the bridge in the room by a cable, and the bridge is physically connected to the network.


2, relay mode

    That is, 'indirect transmission.' Between the two points of BC is not visible, but the two can be indirectly visible through an A building. And AC two points, the two points between the BA meet the requirements of bridge equipment communication. The relay mode can be adopted, and the A building is used as a relay point. Each bridge is placed in the BC, and the antenna is directional. The A point options are as follows: I place a bridge and an omnidirectional antenna. This method is suitable for the case where the transmission bandwidth is not high and the distance is relatively close; II, if the point A is a single-point to multi-point wireless The bridge can insert two wireless network cards on the wireless bridge of the central point A. The two wireless network cards respectively connect two antennas through the feeder, and the two antennas respectively point to the B network and the C network; III places two bridges and two sides are oriented. antenna


3, point-to-multipoint transmission

Since wireless bridges often have special requirements when building networks, it is difficult to find power supply nearby. Therefore, it is very important to have PoE (Power over Ethernet) capability, such as Ethernet power supply that can support 802.3af international standard, and can provide 12V DC power to the bridge through the Category 5 line. General bridges can be managed via the web or managed via SNMP. It also has advanced link integrity detection capability. When it is used as an AP, it can automatically detect whether the uplink Ethernet connection is working properly. Once the uplink connection is found to be disconnected, it will automatically disconnect the wireless connection. Workstations, such disconnected workstations can be discovered in time, and search for other available APs, significantly improving the reliability of the network connection, and also facilitate the timely locking and troubleshooting. In short, with the maturity and popularity of wireless networks, the application of wireless bridges will also be greatly popularized.


The following is the application of wireless bridge in the monitoring system.

Network Architecture