As the technology of fiber optic communication gets better and better, it can be said that optical fiber has been involved in all aspects of our work and life, such as intelligent home, office automation, industrial control network, onboard vehicle and military communication network and other fields. Optical fiber in the data center connects ports of switches and transceivers.
What is the meaning of electric and optical ports in a switch?
Electric Port: the port (network cable) where twisted pair wires are inserted. The speed is 10M or 100M in general and 1000M in some cases.
Optical port:
Optical Modules are required, and then optical fiber is inserted.
Both are used for primary transmission. The longest distance of the electric port is 100 meters, while the optical port can reach 5KM to 100KM, depending on the type of fiber.
How to use the fiber optic interface of the switch?
In a word, light meets light and electricity meets electricity. For example, the general computer network card is the electrical port, so to connect to the exchange of mechanical and electrical port, with the general twisted pair connection can. If both switches have optical ports, or if your computer is an optical network card, you can use optical ports to interconnect, with optical cables in between. If the two devices are close to each other, you can connect them directly with light jumper wires.
Of course, the production of optical connectors is rather troublesome and the tools needed are expensive, so they are all bought ready-made. Their appearance is mostly LC, and the older switches have SC. Long - distance connection to carry out cable laying, and at both ends of the production of light distribution box. Then connect to the device using light jumper wires. The interface shapes on the optical distribution box are generally ST and FC. When purchasing optical jumper, be sure to distinguish the external types of both ports.
Generally, the bandwidth of optical port is more than 1000M, and the power port is 100M. Of course, many laptop network CARDS are 1000M.
Electric interface connection is simple, basically all RJ45 standard modules. The optical port needs to consider the matching of modules and optical cables as well as the matching of optical modules at both ends, so the so-called optical port on general equipment is actually just a base that can be inserted into the module. The base can be plugged into electrical module, multi-mode optical module, single-mode optical module. Depending on the switch's bandwidth support for this base port, it can be divided into 100M, 1000M, 10000M and so on. Most importantly, the module types should be consistent at both ends. The types here mainly refer to multiple/single mode, bandwidth and distance.
When the SFP optical module is connected to the switch, the optical signal strength is the key parameter to ensure the normal operation of the whole connection.
Connection between 2 switches
In general, two switches are required to meet the following conditions:
1.Single or double fiber is unified under the same mode fiber. If single or double fiber is connected, a single or double fiber converter should be added in the middle.
2.The optical fiber mode is unified into single mode or multi-mode. If the single-mode and multi-mode optical fiber are connected in the case of double fiber, a single-mode multi-mode converter shall be added in the middle.
3.The wavelength of dual fiber shall be unified (850nm, 1310nm, 1550nm), and the wavelength of transceiver of single fiber shall be unified (for example, the sending wavelength shall be 1310nm, and the receiving wavelength shall be 1550m or other wavelength).
4.The sending light power and the light receiving sensitivity need to be in the same range.
5.Whether the transmission distance of optical modules is the same. If all the above five conditions are met, the short distance between the two optical modules can be usedIt is necessary to pay attention to whether the light receiving sensitivity of the long distance optical module when it reaches the opposite end is greater than the minimum overload point.
6. The optical module rate and duplex mode should be set to mandatory 100 MB, gigabit full duplex or self-negotiation. If one end is self-negotiation and the other end is mandatory 100 MB and gigabit full duplex, the 100 MB-1G light port cannot be linked up.
CCTV network Solution overview
A) network
The overall network architecture is divided into two layers, core layer and access layer.Considering the stability of the network system, the core layer adopts the main and backup mode, and a total of 2 core switches are deployed.
Two core switches are deployed in the central control room, and the monitoring server is connected by 10 megapixel multimode fiber jumper, and the digital video matrix is connected by the gigabit network cable.
Seven 24-port gigabit switches in the access layer are deployed in the machine room. Each switch is configured with gigabit single-mode optical module, which is connected to the core switch in the central control room through gigabit single-mode optical cable. The network camera on the monitoring pole converts electrical signals into optical signals through optical fiber transceivers, and USES gigabit single-mode optical cable to connect with the access switch in the machine room.
B) optical cable
Each monitoring pole converts electrical signal into optical signal through optical fiber transceiver, adopts 4-core single-mode optical cable, and uses 2-core standby.
Every 3 monitoring poles converge to form a 12-core single-mode optical cable, and every 4 groups of 12-core single-mode optical cables converge to form a 48-core single-mode optical cable.
At the end of the machine room, 48-core single-mode fiber optic cable converts optical signals into electrical signals through optical transceivers and connects to switches.
Requirement of devices getting higher
Video security monitoring system optical cable transmission structure is a more complex, large scale system. In the security communication network, the determination of network signal transmission mode, mainly according to the distance of transmission, the number of monitoring points and other related requirements and determine.
Generally speaking, when the distance between the monitoring point and the monitoring center is within a few hundred meters, video baseband transmission mode is adopted.When the location of the camera is far away from the monitoring center, the cable transmission of radio frequency or optical fiber transmission mode can be adopted.And use optical cable instead of coaxial cable to carry out video signal transmission, video monitoring system provides a high quality, long distance advantage, its transmission characteristics and multi-function is incomparable by other transmission methods.Advanced transmission means, stable performance, perfect reliability and multifunctional information exchange network lay a good foundation for the information highway in the future.
In video monitoring practical construction application, the application of optical fiber, optical cable for trunk transmission system capacity, two-way transmission, good system indicators, high safety and reliability, has a better effect. In order to achieve the transmission effect of all-optical network, the system still needs to realize the transformation and upgrading of corresponding supporting facilities. At the same time, it is faced with the problem of increasing operation cost in the later period.
In the process of realizing the transmission of all-optical network, the transformation of supporting facilities is faced with great pressure. Video monitoring system not only needs to realize the transformation of transmission lines, but also needs to realize the replacement of all-optical network access equipment and transmission relay devices, which will increase the cost of the whole project. In fact, this is similar to the current video monitoring HD popularization.
When installing the optical splitter box, it is necessary to ensure stability.
In addition, there are still many problems in the construction process of optical fiber. Very complete design and construction drawings must be available to facilitate construction and future inspections. The turning radius of the fiber should be 20 times larger than the diameter of the fiber itself. When the optical fiber goes through the wall or floor, it shall add plastic pipe with mouth guard and fill the pipe with flame retardant filler.
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