Theoretically the network speed of 1000 MB is 125MB/s, but in actual application, factors such as network loss and line attenuation need to be taken into account, so the real download speed cannot reach 125MB/s; therefore, in Under normal circumstances, the actual network speed of 1000M broadband is between 110 and 120MB/S.
#The operating environment of this tutorial: Windows 7 system, Dell G3 computer.
What is the internet speed of 1000 Mbit/s?
The theoretical transmission speed of gigabit broadband is 125MB/s, but in actual applications, factors such as network loss and line attenuation need to be taken into account, so the real download speed cannot reach 125MB/s. Therefore, under normal circumstances, the actual network speed of Gigabit broadband is approximately between 110-120MB/S.
Extension:
Optical fiber is the abbreviation of optical fiber. It is a fiber made of glass or plastic and can be used as a light transmission tool.
The transmission principle is "total reflection of light".
Types of principles
Light and its characteristics:
1. Light is a kind of electromagnetic wave
The wavelength range of the visible light part is: 390~760nm (nanometer). The part greater than 760nm is infrared light, and the part less than 390nm is ultraviolet light. There are three types of optical fibers used: 850nm, 1310nm, and 1550nm.
2. Refraction, reflection and total reflection of light.
Because the propagation speed of light in different materials is different, when light is emitted from one material to another, refraction and reflection will occur at the interface of the two materials. Furthermore, the angle at which light is refracted changes as the angle of incident light changes. When the angle of the incident light reaches or exceeds a certain angle, the refracted light will disappear and all the incident light will be reflected back. This is the total reflection of light. Different substances have different refractive angles for light of the same wavelength (that is, different substances have different refractive indexes), and the same substance also has different refractive angles for light of different wavelengths. Optical fiber communication is based on the above principles.
1. Bare optical fiber is generally divided into three layers: a high-refractive index glass core in the center (the core diameter is generally 50 or 62.5 μm), and a low-refractive index silica glass cladding in the middle (the diameter is generally 125 μm). The outermost layer is a reinforced resin coating. Light is transmitted in the fiber core. When the angle at which the fiber hits the interface between the fiber core and the outer layer is greater than the critical angle for total reflection, the light cannot pass through the interface and will be fully reflected back and continue to transmit forward in the fiber core. The cladding mainly plays the role of to protect.
2. Numerical aperture:
Not all the light incident on the fiber end face can be transmitted by the fiber, only the incident light within a certain angle range can. This angle is called the numerical aperture of the optical fiber. A larger numerical aperture of an optical fiber is beneficial to fiber docking.
Advantages
Low loss
In a system composed of coaxial cables, the best cable has the lowest loss per kilometer when transmitting 800MHz signals All are above 40dB. In comparison, the loss of optical fiber is much smaller. When transmitting 1.31um light, the loss per kilometer is less than 0.35dB. If it transmits 1.55um light, the loss per kilometer is even smaller, up to less than 0.2dB. This is 100 million times less than the power loss of coaxial cable, allowing it to transmit much farther.
In addition, optical fiber transmission loss has two characteristics.
First, it has the same loss in all cable TV channels, and there is no need to introduce an equalizer for equalization like a cable trunk line;
Second, its loss almost does not change with temperature, so there is no need to worry about fluctuations in the mains level caused by changes in ambient temperature.
Light weight
Because the optical fiber is very thin, the diameter of the single-mode optical fiber core is generally 4um~10um, and the outer diameter is only 125um. With the addition of a waterproof layer, reinforcing ribs, sheath, etc., it is used The diameter of the optical cable composed of 4 to 48 optical fibers is less than 13mm, which is much smaller than the standard coaxial cable's diameter of 47mm. In addition, the optical fiber is glass fiber and has a small specific gravity, making it small in diameter and light in weight, making it very easy to install. convenient.
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