[Network Management] difference between full duplex and half duplex

[Network Management] difference between full duplex and half duplex

My colleague said that the network in the new office has been unstable and there is a frequent disconnection delay. Check the incoming line and change the switching network cable. Cannot solve the problem. It is estimated that one or two short circuits are imported into the network cable. Modify the NIC attribute.

Change the adaptive mode to full-duplex 10 M mode and test OK.
Full-duplex transmission
Full-Duplex Transmissions

It means that the switch can receive data while sending data, and the two are synchronized, as if we call each other at ordinary times, while talking, we can also hear the other party's voice. All current vswitches support full duplex.

The advantage of full duplex is low latency and high speed.

The concept of Half Duplex corresponds to the concept that only one action occurs in a period of time. For example, a narrow street in a day can only have one vehicle passing through, when there are currently two vehicles on the road, in this case, only one vehicle is allowed to pass first, and then the other one is driving again. This example shows the principle of half duplex. Early walkie talkie and early hub devices are half duplex products. With the continuous advancement of technology, half duplex will gradually exit the stage of history.

Full Duplex and half duplex
In serial communication, data is usually transmitted between two stations (such as a terminal and a microcomputer). There are three basic transmission modes based on the data stream direction: full duplex, half duplex, and ticket. however, tickets are rarely used currently. The following describes only the first two methods.

1. full duplex)
When data transmission and receiving are distributed by two different transmission lines, both parties can send and receive data at the same time. Such transmission mode is full duplex. in full duplex mode, the sender and receiver are set at each end of the communication system. Therefore, data can be controlled to be transmitted simultaneously in two directions. full-duplex mode does not require any direction switching. Therefore, there is no time delay caused by switching operations, which is applicable to interactive applications that do not have time delay (such as remote monitoring and control systems) very advantageous. this method requires that both parties have a sender and a receiver, and two data lines are required to transmit data signals. (the control line, status line, and ground line may also be required ).

For example, a computer host connects to a display terminal through a serial interface, while a display terminal carries a keyboard. in this way, on the one hand, the characters entered on the keyboard are sent to the host memory; on the other hand, the host memory information can be sent to the screen for display. generally, after one character is entered on the keyboard, It is not displayed first. After receiving the character, the Computer Host immediately returns it to the terminal and then displays the character. in this way, the return process of the first character and the input process of the last character are both carried out, that is, they work in full duplex mode.

2. Semi-dual mode (half duplex)
If the same transmission line is used for both receiving and sending, although data can be transmitted in two directions, the communication parties cannot send and receive data at the same time. This transmission method is half duplex. when the half-duplex mode is used, the sender and receiver at each end of the communication system are switched to the communication line through the receiving/sending switch, which leads to a time delay. the receiving/sending switch is actually an electronic switch controlled by software.
When a Computer Host uses a serial interface to connect to the display terminal, the input and output processes use the same path in the half-duplex mode. some computers and display terminals work in half duplex mode. At this time, the characters entered from the keyboard are sent to the host and displayed on the terminal, instead of sending back, therefore, the receiving and sending processes are avoided at the same time.

Currently, most terminals and serial interfaces provide the reversing capability for the half duplex mode and two independent pins for the full duplex mode. in actual use, it is generally not necessary for both parties to send and receive data at the same time. One-way transmission devices such as printers can be used for half-duplex or even one-time work, and do not need to switch back.

Difference between full duplex mode and half duplex mode in Nic <喎?http: www.bkjia.com kf ware vc " target="_blank" class="keylink"> VcD4KCjxwcmUgY2xhc3M9 "brush: SQL;"> in full duplex mode, eight wires are connected to the corresponding line sequence of the crystal head. In half duplex mode, only four wires are needed, according to the T568B standard, four lines in the order of 1, 2, 3, and 6 are generally used, that is, four lines: White orange, orange, white green, and green; white oranges and oranges are used to send data, while white-green and green are used to receive data. In full duplex mode, the maximum speed of the network cable can reach more than 100 mb. In half duplex mode, the speed of the network cable is usually about 10 MB. Full-duplex Network cables can work in both full-duplex and half-duplex modes. However, full-duplex Network cables cannot work in full-duplex mode. In half-duplex mode, two extra lines can be used to connect telephone lines. For example, the "White-blue and blue" lines can be divided into telephone lines for use. In lan network cabling, this method can reduce cabling costs. A twisted pair is used by both the network cable and telephone line.

Uses the half-duplex network card mode to solve Network Connection faults

If one or more wires in a full-duplex network cable have short circuits or poor contact, such as blue or brown wires, change the NIC to half-duplex mode, you can avoid the use of blue or brown lines with problems, so as to solve Network Connection instability, disconnection and other faults. You can set full or half duplex mode in Nic properties.