need scenario for implementation this user access managment

hi there

i have a problem with how to implementing user and admin access to my application.


[*]want to have some admins in backend that can access to frontend. i mean if they logged in in backend and then go to frontend, the application can specify them and dont need login again

[*]want to have some users in frontend that need login process and their session only known in front end, means if logged in in frontend and try to go to backend, they can not go there.


please tell me only about how to implementing it, i want to do it all alone and if have a problem ask it here again


its better to say frontend users are child of backend users(admins) that can only access to frontend section, but admins can access to the whole site