Monitoring dedicated and traditional switch comparison

Full-line switch configuration uplink Gigabit optical port

1) The monitoring industry usually uses non-network management switches as camera access. Ordinary non-network management switches are designed for PC networks. Therefore, ordinary non-network management switches are not equipped with optical ports, but the basic items for monitoring security are basically It is necessary to connect the optical port to the equipment room, so only one pair of photoelectric converters can be added. A pair of photoelectric converters (must be used in pairs) Taobao buys more than 100 to 200 pieces, all made by the Shenzhen cottage factory, the failure rate is very high, the wiring is still chaotic, to connect 1 power supply, 1 twisted pair Line, 1 fiber line. Our approach is: all the monitoring switches are configured with fiber interfaces, all of which are Gigabit.

2) Gigabit models are equipped with 2 ports, which can be used to facilitate one optical port to be connected to one switch below, and the other optical port is used to connect to the machine room.

3) Now the resolution of the camera is getting higher and higher, and the traffic is getting bigger and bigger. The traditional 100M non-network management switches are all equipped with 100-megabit ports. Because the traffic in the PC network is relatively small, many projects use video cards after discovery. Time, delay, etc., so now everyone uses all Gigabit. But in fact, the flow of a camera does not exceed 2-8M (1 megapixel 2-4 megabytes, 2 megapixels 4-6M, 3 megapixels 6-8M), 100 megabit access must be enough, the problem is If you still use hundreds of megabytes in the uplink, it must not be enough (for example, 10 channels of 3 million pixels, the average flow rate is 80M, considering that the camera has sudden traffic, most of them are not enough), so we configure all on the 100M switch. Gigabit on the link.

Large cache design

Many people use TP or D-Link switches in the project, which is obviously Gigabit. It only takes 3-5 channels. Why is there a delay? What about Caton? This has nothing to do with switching capacity, backplane, and packet forwarding rate. The core reason is the internal cache size. Many switches of TP and D-link are home-class. Although it is Gigabit, the cache is very small, usually around 512K. Although the average traffic of the camera is 2-8M, there will be a burst of traffic at intervals (one customer will doubt this, the burst traffic is determined by the H.264 compression technology of the monitoring, very very certain, in the laboratory The actual capture can be seen, have confidence).

The switch does not handle this burst of traffic, it will put the cache for a while and then send it again. The home switch cache is too small, which will cause the cache to be full, the data will be discarded, and the camera needs to be sent again, so the image is seen on the monitor. The delay is long (image delay is a very common problem of monitoring, and in a severe case it is delayed by a dozen seconds). Our approach is: So the monitoring switch, except the lowest 2 are 2M cache, the other is 4M cache. Basically able to solve this delay problem.

Adapt to harsh environments

The monitoring switch is used in engineering projects, the environment is actually worse than the PC network, but the ordinary PC network switch also reduces the quality requirements in order to reduce the cost. For example, the normal 1 year warranty, 0-40 degree working range, our monitoring switch is 0. -50 degree working range, 3 year warranty, the product is also designed within a ratio of 3 years within the failure rate (usually within 0.5%).

Flow control switch design

Flow control is not very useful in video surveillance, but it is recommended to open it in the visual access control. After opening, the switch will open the flow control function to ensure the unlocking command transmission function and avoid the situation that remote unlocking cannot occur. If an ordinary corridor switch is used, the visual intercom traffic is large. In some occasions, the command to open the door will be discarded in the transmission. When the user presses the door open button, the door of the stairway cannot be opened, and the owner complains.