Brief introduction of Ethernet II Protocol

Ethernet is the most general communication protocol standard used in the existing local area network. The protocol defines the cable types and signal processors used in the local area network.

It consists of a 6-byte destination MAC address, a 6-byte source MAC address, and a 2-byte type field (used to indicate the type of data encapsulated in the Frame).

Then there are 46-1500 bytes of data and 4 bytes of frame check.

Header 8 destination address 6 source address 6 etheric type 2 payload 46mi 1500 frame check sequence 4

Header: 8 bytes, the first seven zero zero 1 alternating bytes (10101010) are used to synchronize the receiving station, and a 1010101011 byte indicates the starting position of the frame.

The header provides receiver synchronization and frame demarcation services.

Destination address: 6 bytes, unicast, multicast or broadcast. The unicast address is called personal, physical, hardware, or MAC address, and the broadcast address is Quan 1pi 0xFF FF FF FF.

Source address: 6 bytes. Indicates the unicast address of the sending node.

Ethernet type: 2 bytes, used to indicate the upper layer protocols contained in the Ethernet frame. That is, the protocol identifier in frame format. For IP messages, the field value is 0x0800.

For ARP information, the value of the etheric type field is 0x0806.

Payload: consists of a protocol data unit PDU of the upper layer protocol. The maximum payload that can be sent is 1500 bytes.

Due to the collision detection feature of Ethernet, the payload is at least 46 bytes. If the upper layer protocol data unit length is less than 46 bytes, it must be added to 46 bytes.

Frame check sequence: 4 bytes. Verify bit integrity.

Destination: destination address is C4:01:20:E8:00:00

SOURCE: source address is c4:02:21:e8:00:00