Ethernet MAC Frames

As shown in Figure 4.3, an Ethernet MAC frame starts with a header that includes its destination and source MAC addresses. It ends in a frame check sequence (FCS) field that contains a CRC code that is used to detect transmission errors.

Figure 4.3. General format of an Ethernet frame.

Preamble and Start Frame Delimiter Patterns

A station transmits two special bit patterns—a preamble and a start frame delimiter—prior to sending a MAC frame. Figure 4.4 shows a MAC frame preceded by its preamble and start frame delimiter.

Figure 4.4. Preamble, start frame delimiter, and MAC frame.

The preamble pattern tells ...

Get Local Area High Speed Networks now with the O’Reilly learning platform.

O’Reilly members experience books, live events, courses curated by job role, and more from O’Reilly and nearly 200 top publishers.