| In a two-tier system, the client requests a page and the server sends it back. It can either be a pure HTML page or it can be partially or entirely generated by an ASP script. In either case, a pure HTML page is returned to the client which displays it. | |
| In a three-tier system, the server is programmed to access a database -- to update it, retrieve data or both -- under control of an ASP script. The script then formats the result and returns it to the client. Again, a pure HTML page is returned to the client which displays it. | |