In the classical Ethernet the data link layer is divided in two partial layers "Medium Access Control" (MAC; frame processing at sending and receiving, frame transfer to the LLC layer) and "Logical Link Control" (LLC; includes addressing and error checking). In the meantime, there are Ethernet solutions in the metro and terminal area: Ethernet in the First Mile (EFM), Metro Ethernet and midband Ethernet are approaches that are interesting for connecting and metropolitan area networks. In wide area networks (WAN) use Carrier Ethernet, 40-Gbit Ethernet and 100-Gbit Ethernet solutions (400-Gbit under developing), these technology are also used as backplane Ethernet in server systems.
Subcategories of Ethernet:
The Ethernet technology has undergone rapid development. It has established itself in all speed and application areas. The IEEE 802.3 Working Group has the Ethernet specified as follows: "Ethernet is a local area network. Medium equal terminals are connected with the transmission." A maximum of 256 terminals per Ethernet segment can be connected. The functionality of Ethernet is ensured by a layer model (OSI Reference Model).
Apparently restricted applications are found at transfers time-critical signals for example in Internet telephony (VoIP), with live video broadcasts and in the industrial sector. Systems with lowest possible latency were designed for real-time Ethernet and Industrial Ethernet. Ethernet-based techniques with real-time functionality can be found in the production and automation market. Some field-bus systems use Ethernet as a communication infrastructure for the integration of distributed field devices, conditioning modules and control units, named EtherCAT, EtherNet / IP, Ethernet Powerlink and TTEthernet.
The choice of the transmission medium is mostly depending on the required data rate. Copper cables or fiber-optic cable or WiFi are most popular. Ethernet as UTSP-Ethernet (Unshielded Twisted Pair Single) can also be found in the automotive technology. We are working with only one twisted pair.