Big comparison of packet capture concepts: datagram, data packet, packet
datagram, data packet and packet are three common concepts. Are they the same? If not, what is the difference? The three words are explained in turn below. University Master IT Master
1. Data report: When the application constructs the data to be sent according to the protocol format. The data at this time is called a data message, or simply a data message. The characteristic is that the data has not been sent.
2. Data packet: When the datagram is sent, it will perform specific processing according to network requirements, such as IP fragmentation and TCP fragmentation. The data at this time is the data actually sent, which is called a data packet.
3. Grouping: It is a proprietary term of Wireshark. Wireshark catches the actual transmitted data packets and performs additional processing, such as reorganizing the fragmented packets, and displays the reassembled data in the last fragmented packet. So the packet at this time is not necessarily the data actually transmitted.
To make an analogy: you want to send your wife 20 pounds of apples. According to the standard format, Apple puts it in a carton and writes the sender and receiver information. This is called a datagram. After the delivery company got the piece, it said that 20 pounds was too heavy, and only 5 pounds per package. The courier company repackaged and sent away. This is called a data packet. After your wife received the courier, she took out all the apples and found that they were full, no problem. This is grouping.
Therefore, these three concepts focus differently. According to the situation and understanding of the scene, everyone should choose the correct statement to express and understand.
