What are the characteristics of a LAN called Ethernet

Ethernet is a baseband LAN standard invented by Xerox. It uses Carrier Supervisory Multiple Access Protocol with Conflict Detection (CSMA/CD) at a rate of 10 Mbps, and the transmission medium is coaxial cable. Ethernet was developed in the 1970s to address sporadic and occasional congestion in networks, and the IEEE 802.3 standard was developed in 1980 based on the original Ethernet technology. The term Ethernet is now used generically to refer to all local area networks that utilize the CSMA/CD protocol. Ethernet version 2.0 was jointly developed by Digital Equipment Corporation, Intel Corporation, and Xerox Corporation, and is compatible with IEEE802.3.

Ethernet and IEEE802.3 are typically implemented by an interface card (NIC) or circuitry on the main circuit board. The Ethernet cable protocol specifies a transceiver to connect the cable to the physical devices of the network. The transceiver performs most of the functions of the physical layer, including conflict detection and the transceiver cable connects the transceiver to the workstation.

IEEE802.3 provides several cable specifications, including 10Base5, which is the closest to Ethernet. In this specification, the connecting cable is referred to as the Attachment Unit Interface (AUI), and the network-connecting device is referred to as the Media Access Unit (MAU) and no longer as a transceiver.

1. How Ethernet and IEEE 802.3 Work

In broadcast-based Ethernet, all workstations can receive an information frame that is sent to the network. Each workstation verifies that the frame is not addressed to itself, and once it has confirmed that it is addressed to itself, it sends it to a higher protocol layer.

In Ethernet with CSMA/CD transport media access, any CSMA/CDLAN workstation can access the network at any moment. Before sending data, the workstation listens for network congestion and can send data only when it detects that the network is free.

In contention-based Ethernet, either workstation can send data as long as the network is free. A conflict occurs when two workstations find the network free and send data at the same time. At this point, both transmission operations are destroyed, and the workstations must retransmit after a certain amount of time, which is determined by a delay algorithm.

2. Differences between Ethernet and IEEE802.3 services

Although there are many similarities between Ethernet and the IEEE802.3 standard, there are some differences. The services provided by Ethernet correspond to Layers 1 and 2 of the OSI reference model, while the services provided by IEEE802.3 correspond to the channel access portion (i.e., a portion of Layer 2) of Layers 1 and 2 of the OSI reference model. IEEE802.3 does not define a logical link control protocol, but defines several different physical layers, while Ethernet defines only one.

Each of the physical layer protocols of IEEE802.3 can be characterized in three ways: the speed of the LAN, the method of signaling, and the type of physical media.