CIT’s Ethernet Troubleshooting

## Copyright © 1999 Boson Software

Written by kevin@boson.com

PACKET SIZES:

- Packets larger than 1,518 Bytes are called "Giants." Packets less than 64 Bytes are called "Runts."

ETHERNET FRAME COMPONENTS:

- In an Ethernet frame; the Preamble is 8 bytes; the Source and Destination Addresses are each 6 bytes; the Type field is 2 bytes; and the FCS field is 4 bytes.

- The preamble is an alternating series of 1s and 0s at the beginning of Ethernet and IEEE 802.3 frames. The Preamble announces that a frame is coming.

- Ethernet frames contain a TYPE field, whereas an IEEE 802.3 frame contains a LENGTH field.