Four: load balancing based on IP + port
Seven: to you based on the application layer (url) load balancing information
Four advantages and disadvantages:
Four Faster: processing in kernel space, do not take the user space. Less need to parse
Seven advantages and disadvantages:
Seven more features: The kernel space, user control into the application process forwards. You can achieve more sophisticated control of the load balancing, such as separation based url, session, movement. Cpu takes a lot of time, concurrent bearers less than four
Four sites for large, most distal access layer, used in conjunction with four seven +
Seven for small and medium sites, only seven load balancing
(Four on the front, the back may continue with more complex operations with seven. Generally used in combination)