【物联网通信技术】——以太网-海南世电科技

summarize

Ethernet is a wired computer'scommunications interfaceTechnology used to connect devices, including computers, routers, and switches, in wired or wireless networks, Ethernet is the traditional technology for connecting devices in wired local area networks (LAN: local area networks) or wide area networks (WAN: wide area networks). It enables devices to communicate with each other through a protocol, which is a set of rules or a common network language.

Ethernet describes how network devices format and transmit data so that other devices on the same LAN or campus network can recognize, receive, and process the information. Ethernet cables are the physical encapsulated wiring for data transmission. Compared to wireless LAN (WLAN) technology, Ethernet is generally less susceptible to outages. It also provides a greater degree of network security and control than wireless technology because devices must be connected using physical wiring. This makes it difficult for outsiders to access network data or hijack bandwidth from unauthorized devices.

The original 10BASE5 Ethernet used coaxial cable as a shared medium, while newer Ethernet variants use twisted pair and fiber optic links in conjunction with switches. Over the course of its history, Ethernet data rates have increased from the original 2.94 Mbit/s to the latest 400 Gbit/s, with rates of up to 1.6 Tbit/s under development, a process that can be completed in 14 minutes if we have 500 TB of data to send. The Ethernet standard includes several cabling and signaling variants of the OSI physical layer.

Development History

It was inspired byALOHAnet(The ALOHAnet protocol was born in June 1971 at the University of Hawaii's Manoa School of Engineering and is the basis for all wireless communications such as mobile, satellite, cellular and WiFi) Robert Metcalfe studied ALOHAnet in 1973 for his Ph.D. The luminous Ether, after which he was named, was once postulated to be "a ubiquitous, totally passive medium for the propagation of electromagnetic waves"
In 1975 at Xerox (Xerox PARC) was invented by Robert Metcalfe and David Boggs and upgraded from the original 2.94 Mbit/s protocol to the 10 Mbit/s protocol.
Metcalfe left in June 1979XeroxThe establishment of the3ComThe company persuaded Digital Equipment Corporation (DEC, acquired by Compaq in January 1998), Intel and Xerox to work together to promote Ethernet as a standard. As part of this process, Xerox agreed to relinquish its "Ethernet" trademark (anyone and any company can use Ethernet in their products).
The first standard was published on September 30, 1980, with the name explained as "Ethernet, a Local Area Network. Data Link Layer and Physical Layer Specifications"
3Com released the first 10 Mbit/s Ethernet 3C100 NICs in March 1981, and began selling adapters for the PDP-11 and VAX that year, as well as Intel and Sun Microsystems computers based on the Multbus
June 23, 1983Institute of Electrical and Electronics Engineers(IEEE) approved the Ethernet 802.3 standard
Ethernet initially competed with token ring and other proprietary protocols. Ethernet was able to adapt to market demands, with 10BASE2 moving to inexpensive thin coaxial cables and, beginning in 1990, to the now ubiquitous 10BASE-T twisted-pair cable
By the early 1990s, Ethernet became so commonplace that Ethernet ports began to appear on some PCs and most workstations
IEEE 802.3 Working Groupto manage and maintain the various specifications of Ethernet.

Characteristics of the technology

Ethernet has many advantages, which is the main reason why it is quickly gaining customer acceptance in applications.

Relatively low cost.
Backward compatibility.
General noise resistance.
Good quality of data transmission.
Velocity;
Reliability.
Data security, as generic firewalls can be used

Of course, no technology is perfect, and what is one thing can be another.

For smaller, shorter distance networks.
Inconvenient to install, you have to pull the wires to get it ;)
Use of longer cables creates crosstalk.
Not suitable for real-time or interactive applications.
Speed decreases as traffic increases; and
The receiver does not acknowledge receipt of the packet; the
It is not easy to trace the specific cable or node that is causing the problem and troubleshooting is very difficult