Seven and four floors

TCP/IP protocol stack

OSI seven-layer model

The corresponding relationship between the seventh layer and the fourth layer

Four-tier load balancing

The so-called "four-layer load balancing" refers to the load balancing of back-end servers based on the characteristics of TCP/IP protocol, such as IP address and port number, which works on the transport layer.

Seven-tier load balancing

The so-called "layer 7 load balancer" means that it works on the application layer, sees the HTTP protocol, parses the URI, hostname, resource type and other data in the HTTP message, and then forwards it to the back-end server with appropriate policies.

Data Transmission of TCP/IP Protocol Stack

Can be used to send express delivery, receive express delivery to compare.

Send express delivery, pack from top to bottom, and add tcp header, ip header and Mac header in turn

Receive express delivery, unpack from the bottom up, and remove mac header, ip header and TCP header in turn.

Note:

The four and seven layers mentioned are all for the OSI model.