Example 1: Calculate the maximum frame rate of a node on an Ethernet LAN.

The minimum frame payload is 46 Bytes (dictated by the slot time of the Ethernet LAN architecture). The maximum frame rate is achieved by a single transmitting node which does not therefore suffer any collisions. This implies a frame consisting of 72 Bytes (see table above) with a 9.6 µs inter-frame gap (corresponding to 12 Bytes at 10 Mbps). The total utilised period (measured in bits) corresponds to 84 Bytes.

 Frame Part Minimum Size Frame
 Inter Frame Gap (9.6µs)
MAC Preamble (+ SFD)
 MAC Destination Address  
 MAC Source Address
 MAC Type (or Length)
Payload (Network PDU)
 Check Sequence (CRC)
 Total Frame Physical Size

Example 2: Calculate the maximum throughput of the link service provided by Ethernet

 Frame Part Maximum Size Frame
 Inter Frame Gap (9.6µs)
MAC Preamble (+ SFD)
 MAC Destination Address
 MAC Source Address
 MAC Type (or Length)
Payload (Network PDU)
 Check Sequence (CRC)
 Total Frame Physical Size

Example 3: One node transmits 100 B frames at 10 frames per second, another transmits 1000 B frames at 2 frames per second, calculate the utilisation of the Ethernet LAN.

 Frame Part Frame 1 Frame 2
 Inter Frame Gap (9.6µs)
MAC Preamble (+ SFD)
 MAC Destination Address
 MAC Source Address
 MAC Type (or Length)
Payload (Network PDU)
 Check Sequence (CRC)
 Total Frame Physical Size