19. Web Server
Apache httpd, Nginx, etc
Serving static contents
html, js/css, jpg/png, ...
Reverse proxy for dynamic contents
session control
load balancing
authentication
caching
server
web server
server
application
server
appli
ser
server
database server
20. Application Server
Server process executes application code
html, HTTP API endpoint
generating views
calling SQL
calling external api
referring caches
server
web server
server
application
server
appli
ser
server
database server
21. Database Server
MySQL, PostgreSQL, Oracle DB, MS
SQLServer, ... (MongoDB, Cassandra, Redis, ...)
storing data
search/respond data
server
web server
server
application
server
appli
ser
server
database server