IEEE 802.3

The frame used in IEEE 802.3 Ethernet networks is shown in Figure 1.

Figure 1. Format of an IEEE 802.3 frame

Diagram of the format of an IEEE 802.2 token-ring frame.

The maximum size of the L-PDU for a 10Mbps network is 1500 bytes. Because 8 bytes are used within the L-PDU for the LLC header, this means that the maximum size of the data field is 1492 bytes. Therefore, set the MTU for IEEE 802.3 networks to 1492 bytes.