Физическое подключение
IEEE 802.3 specifies several different physical layers, whereas Ethernet defines only one. Each IEEE 802.3 physical layer protocol has a name that summarizes its characteristics. The coded components of an IEEE 802.3 physical-layer name are shown in Figure
5-1.
Figure 5-1 : IEEE 802.3 Physical-Layer Name Components
A summary of Ethernet Version 2 and IEEE 802.3 characteristics appears in Table 5-1.
| Скорость, Mbps | 10 | 10 | 10 | 1 | 10 | 10 |
| Метод передачи | Baseband | Baseband | Baseband | Baseband | Baseband | Broadband |
| Макс. длина сегмента, м | 500 | 500 | 185 | 250 | 100 | 1800 |
| Среда передачи | 50-Ом коаксиал (толстый) | 50-Ом коаксиал (толстый) | 50-Ом коаксиал (тонкий) | неэкр. витая пара | неэкр. витая пара | 75-ohm coax |
| Топология | Шина | Шина | Шина | Звезда | Звезда | Шина |
Table 5-1 Ethernet Version 2 and IEEE 802.3 Physical Characteristics
Ethernet is most similar to IEEE 802.3 10Base5. Both of these protocols specify a bus topology network with a connecting cable between the end stations and the actual network medium. In the case of Ethernet, that cable is called a transceiver cable. The transceiver cable connects to a transceiver device attached to the physical network medium. The IEEE 802.3 configuration is much the same, except that the connecting cable is referred to as an attachment unit interface (AUI), and the transceiver is called a medium attachment unit (MAU). In both cases, the connecting cable attaches to an interface board (or interface circuitry) within the end station.
