Figure 1 shows a point-to-point topology. In point-to-point networks, data can flow in one of two ways:
- Half-duplex communication: Both devices can both transmit and receive on the media but cannot do so simultaneously. Ethernet has established arbitration rules for resolving conflicts arising from instances when more than one station attempts to transmit at the same time. Figure 2 shows half-duplex communication.
- Full-duplex communication: Both devices can transmit and receive on the media at the same time. The data link layer assumes that the media is available for transmission for both nodes at any time. Therefore, there is no media arbitration necessary in the data link layer. Figure 3 shows full-duplex communication.