This Ethernet format is not the IEEE 802.3 frame. This frame was developed in the early 1970s by Digital Equipment Corporation, Intel, and Xerox. In the 1980s this standard was turned over to the IEEE. The IEEE developed the 802.3 standard using Ethernet as the model.
Many companies still use this frame type. The most notable users are running Novell NetWare with IPX protocol.
Novell designation: Ethernet_802.3 frame type.
Cisco designation: novell-ether.
The Ethernet frame length is between 64 and 1518 octets (not bytes - a byte can be either 7 or 8 bits in length, an octet is 8 bits long).
The Internet Standard for Ethernet networks can be found in RFC 894.
Preamble: 101010...1011
Destination:Destination Node (MAC) address.
Source: Source Node (MAC) address
Length: Length of the data field
Data: Higher layer Protocols and information
Frame Check Sequence: CRC (cyclic redundancy check)
A destination address of all ones is a broadcast address.
The destination is a Media Access Control (MAC) address, and is six octets long. This field is the destination of the packet on the local network (or subnet), if the final destination is on a different network this field will contain the address of the router. The ultimate destination, on the larger network, will be found in the data portion of the packet.
This field is also known as the Data Link address, Layer 2 address, MAC address, or hardware address.
The first three octets of a MAC address are assigned to a company by the IEEE. The last three octets are generated by the manufacturer of the network device.
The source is the address of the Ethernet device that sent the packet. It is a Media Access Control (MAC) address, and is six octets long.
This field is also known as the Data Link address, Layer 2 address, MAC address, or hardware address.
The first three octets of a MAC address are assigned to a company by the IEEE. The last three octets are generated by the manufacturer of the network device.
The lenght is the number of octets in the data field.
The data field is variable in length with a minimum of 46 bytes and a maximum of 1498 bytes. The first two octets of data are FFFF which is a null value for the IPX protocol checksum. The remaining octets are IPX data. If one desires to use IPX with checksum enabled, he must choose another frame type. The raw Ethernet frame does not support the IPX checksum feature.
The Frame Check Sequence (FCS) is four octets long, and is a result of a Cyclic Redundancy Check (CRC) performed on the first part of the frame (excluding the preamble).