IEEE 802.3

During the 90s of last century, many existing protocols and architectures in social networks. Engineers have developed several types of protocols, each for a specific use of disclosure of information such as the transfer of data, voice, broadcasting, data center, and so on. Among them can be found Token Ring, FDDI, ATM and more.

However, due to the simplicity and low cost of Ethernet components, it has prevailed in the end, and is now the most widely used protocol in local area networks (LAN). Faster Ethernet protocol have been defined that can fit many of the above applications and network.

In reality, Ethernet is a family of protocols, each with a different speed, and all are based on packet transfer, as defined by IEEE 802.3 standards group. Today there are Ethernet protocols and components ranging from 10Mbit/sec (10 million bits per second), a 100Mbit/sec (aka Fast Ethernet), 1 Gbit / sec (1 billion bits per second), 10Gbit/sec, 40Gbit / sec and recently 100Gbit/sec.

Ethernet is a protocol physical layer (layer1 and 2 of the 7 levels of the OSI model). It defines the way in which an Ethernet frame (packet) is transferred to the cable / fiber, Ethernet switch and how long the path may lead the structure to its destination.

Ethernet can run on twisted pair copper cables and fiber cables. Copper cables, usually able to transfer Ethernet packets up to 100 meters, and are mainly used in the creation of internal networks. The fiber can reach tens of kilometers and are used to interconnect between campus and down town.

Being a physical layer protocol, Ethernet is a carrier of data for higher level protocols such as IP (Internet Protocol). In fact, most of the cases in which people discuss the IP protocol, Ethernet protocol assumes discussed as a vector. The IP protocol allows communication between two logically separated networks. That is, Ethernet enables direct communication within a logical network, called the VLAN (Virtual LAN), and you must use the IP protocol to route the packet correctly between the Ethernet VLAN.

Most of electronic devices such as personal computers and laptops, to communicate by sending each Ethernet packet. They are identified as Ethernet stations. Each station has a unique address (a unique number consists of 48 bits total). This is called a MAC address. Each station has a network interface card (NIC) that is aware of this issue and would not let an Ethernet packet with a different MAC address to enter the station. Furthermore, this MAC address is added to any packages sent by this network adapter. In the end, each packet contains the unique address of origin in its path.

The main component of an Ethernet network is the Ethernet switch (For clarity we discuss here Switched Ethernet, and an old pattern of ignoring shared Ethernet, which is almost obsolete). A switch is connected to the remote via a copper wire or fiber cable, and can connect to different stations speed. Since all stations, regardless of the speed using the same packet format, the option is active all stations, regardless of their speed interconnect.

As defined by the IEEE 802.3 group, the Ethernet switch is designed to detect the origin of the Ethernet packets (Ethernet Source Address) and the destination of the packet (Ethernet destination address). The destination and source addresses are the first parameters in an Ethernet packet, and are read by the switch. A table of addresses within the switch is constantly learning and maintaining records of addresses that are included in the packets entering the switch in time, and organizes the address table so that each address is tied to the port from which the source address some joined switch. This table is used to route each incoming packet to its appropriate output port, so that the packet should reach its destination at the end.