Solution to the problem of sticking and unpacking TCP

TCP Solution to the problem of sticking and unpacking

Why? TCP And UDP No glue bag

1️⃣ because udp Packets of have protection boundaries .

2️⃣tcp Is in the form of a byte stream , That is, there is no boundary , Therefore, packet sticking and unpacking may occur when the application layer data is in the transport layer .

The reason for this problem is illustrated

1️⃣ Byte stream can be understood as data flowing in a two-way channel , This data is actually what we often call binary data , In short, it's a lot of 01 strand . these 01 There is no boundary between strings .

2️⃣ Application layer TCP Protocol data , It is not sent to the destination host in the unit of message , Instead, it is sent to the downstream in the form of byte stream , This data may be cut and assembled into various data packets , After receiving these packets, the receiver does not restore the original message correctly , Therefore, the phenomenon of sticking package appears .

Sticking case

Unpacking

unpacking & Sticky package

Solution

Application layer measures

1️⃣ The size of the package .

2️⃣ Add fixed characters to the end of the package , such as ：FTP The solution in ： Add... At the end \r\n

3️⃣ The message header + Message body . There is the length of the message body in the message header .

4️⃣ Customize .

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