Network Protocols - Ethernet

July 27, 2022

Operates on the physical and data link layers of the OSI model and Network Access/Link layer of the TCP/IP model
Minimum frame size is 64 bytes, maximum is 1518 bytes
Preamble field not included in frame size
Any frame less than 64 bytes or greater than 1518 bytes is discarded
Preamble & SFD (start of frame delimiter) fields are 7 and 1 bytes in size, respectively and are used for synchronisation between devices.
Destination MAC address field used to identify recipient
Source MAC address field used to identify NIC where frame originated. Can only be unicast (to one address)
Type/length field identifies the upper layer protocol encapsulated in the Ethernet frame (2 bytes in size)
Data field contains encapsulated frame from a higher layer. 46-1500 bytes in in size
Frame check sequence field used to detect errors (4 bytes)