Shulou(Shulou.com)06/01 Report--

Coaxial cable-as shown

Coaxial cable is a kind of early network transmission medium, which can be divided into thick coaxial cable and thin coaxial cable according to its diameter. The name of coaxial cable is related to its structure, which is composed of inner conductor, outer conductor, insulating medium and protective sleeve. The corresponding standards are 10BASE2 and 10BASE5 (that is, thin coaxial cable and thick coaxial cable), the transmission distances are 185m and 500m respectively, and also support 10Mbps transmission rate. Now it has been basically eliminated and is no longer used in enterprise networks.

Because of the structure of the coaxial cable, only half-duplex communication is allowed, sending and receiving are allowed, but not at the same time. And a network device connected by a coaxial cable is located in a collision domain, which means that these devices use cables to transmit data at the same time, resulting in conflicts. In this case, CSMA/CD (Carrier sense Multipoint access / collision Detection) is generally used to solve the communication conflict problem. Another half-duplex network, WLAN, uses CSMA/CA (Carrier sense multiple access / collision avoidance).

Twisted pair-as shown

Twisted pair is the most commonly used network transmission medium for network wiring, which is composed of four groups of copper wires. Compared with coaxial twisted pair, the manufacturing cost and deployment cost are lower, but the network transmission performance is higher. There are a variety of Ethernet standards for twisted pair, from the original Category 3 10BASE-T standard to now super Category 6, Category 7 gigabit and 10 gigabit standards, the network speed is not the same as that of coaxial cable.

There are two standards for twisted pair on-line arrangement, which are 568a and 568b respectively. The line sequence of 568a is white-green, green, white-orange, blue, white-blue, orange, white-brown, brown; the line sequence of 568b is white-orange, orange, white-green, blue, white-blue, green, white-brown, brown. And the equipment should be connected in accordance with the principle of "crossing for the same kind of equipment and straight-through for different devices". If two routers need to be connected by a crossover, a router and a switch are connected by a straight-through line. In addition, routers and PCs belong to the same device, HUB and switches belong to the same device.

Optical fiber-as shown in the picture

Optical fiber is the abbreviation of optical fiber, which is a kind of fiber made of glass or plastic, which can be used as a light conduction tool. The transmission principle is' total reflection of light'. Optical fiber has the advantages of fast transmission speed, high transmission reliability and strong anti-interference ability, but the price of optical fiber is more expensive than twisted pair, and the application of enterprise network is less. It can be divided into single-mode fiber and multimode fiber. Compared with multimode fiber, single-mode fiber has better performance and is more suitable for long-distance transmission, but it is also more expensive than multimode fiber.

Optical fiber is divided into SC interface and LC interface according to the difference of connector part. SC is 1Gb interface and LC is 2Gb interface. According to the shape, it can be divided into FC round with thread (the most used on the distribution frame), ST clamping circle, PC microsphere grinding and polishing, SC clamping square (the most used on router switches), MT-RJ square.

Serial cable-as shown in the figure

Serial port cables can be divided into v.24 and v.35. The commonly used serial port cable standard is RS-232, which is also the recommended standard for serial port cables. the distance of the transmission cable is only 6m, while some standards support the transmission distance as far as 1200m. Serial port protocols include PPP (Point to Point), HDLC (Advanced data Link Control Protocol), FR (frame Relay Protocol) and ATM (Asynchronous transfer Mode).

Nowadays, the serial port cable is mostly used to connect the routing switching equipment.

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