Detailed Explanation of Networking Media and Equipment

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1. Network card

Network cards are divided into three categories: wired network cards , wireless network cards , and optical fiber network cards

1. Wired network card

Most desktop computers come with it, using RJ-45 standard interface

• Transfer data to the network (other hosts) via twisted pair
• Receive data sent to this machine from the network (other hosts) through a twisted pair

2. Wireless card

Usually the notebook comes with it, and the desktop needs to be added by itself

• Transfer data to the network (other hosts) via wireless signals
• Receive data sent to this machine from the network (other hosts) through wireless signals

3. Optical network card

Not commonly used, using fiber optic interface, expensive

• Transmit data to the network (other hosts) through fiber optic jumpers
• Receive data sent to this machine from the network (other hosts) through fiber optic jumpers

Two, network cable

There are two types of network cables: twisted pair , optical cable

1. Twisted pair

Currently the most widely used and most cost-effective transmission medium

• It consists of 8 copper core wires, which are divided into 4 pairs and twisted in pairs
• Including UTP (unshielded twisted pair), STP (shielded twisted pair)

Line sequence specification

• T568A: white green, green, white orange, blue, white blue, orange, white brown, brown
• T568B: white orange, orange, white green, blue, white blue, green, white brown, brown

注意：现在基本使用T568B线序规范

According to the transmission speed supported by the twisted pair

• Effective transmission distance < 100 meters
• At present, Category 5e and Category 6 twisted pair cables are more commonly used

2. Optical cable

Suitable for ultra-high-speed, long-distance (> 100 meters) transmission

• The core of the optical cable is made of high-transparency glass
• Data transmission through optical pulse signal, strong anti-interference

According to the core wire thickness and precision requirements are different

• Divided into multimode fiber and single mode fiber
• Multi-mode: transmission distance 550m
• Single mode: transmission distance 5/10/40/70km

Fiber Jumper

• Refers to the finished optical cable used to connect optical network card, optical switch/optical modem equipment
• Because receiving/sending signals need to be completed by different optical fibers, jumpers generally appear in pairs

3. Switch

1. What is a switch

switch

• Used to connect multiple computers/switches together to form a network
• The switch is responsible for providing exclusive lines for any two computers to communicate

2. Switch classification

There are two types of switches: unmanaged switches and managed switches

Unmanaged switches (also known as plug-and-play switches)

• Plug and play, no device configuration required (and not supported)
• Cheap to use and cheap (hundreds of dollars)

Managed switches (also known as smart switches)

• It can realize more advanced functions such as network segment division and flow control
• Supports advanced configuration of equipment, and the price is also more expensive (thousands of yuan, tens of thousands of yuan)