Ethernet | Data Link | L2 Header

When a Data is received at Data Link Header with PDu format Packet, Data link layer furthur adds Data link | Ethernet or we can say L2 header to that packet. The size of Ethernet header is of 26 bytes.
L2 Header

The preamble of an Ethernet packet consists of a 56-bit (seven-byte) pattern of alternating 1 and 0 bits, allowing devices on the network to easily synchronize their receiver clocks, which is followed by the SFD to mark a new incoming frame.In general term Preamble is used to distinguish Frames on Media where as SFD tells which part is the header part and which is actual data inside A single Frame. The size of Preamble is 7 byte and SFd is 1 byte.
MAC address is a 6 byte physical address of Device and is presented in Hexadecimal form. In this feild the physical address of destination or receiver device is Mention.
MAC address is a 6 byte physical address of Device and is presented in Hexadecimal form. In this feild the physical address of Source or Sender device is filled.
Type feild consist the value which tells which type of protocol or service is running or encapsulated with. It is of 2 byte.
A frame check sequence (FCS) refers to the extra error-detecting code added to a frame in a communications protocol. Frames are used to send upper-layer data and ultimately the application data from a source to a destination. CRC is run on frame and a value is sent to the destination and when frame are received at destination it again runs CRC and value are compared. if both CRC value are same then frames are received without error and if different frames are discarded.