Hi sailaja,
I think you are not maintaining any session in your application.
If you are then you need to check the session variable at _layout.cshtml file.
If the session is empty then redirect to login page.
Same as you implement in asp.net traditional page.
You can refer this
link[
^] for reference.
Note: Different browsers wont share common sessions as far as I know.
Hope this helps you a bit.
Regards,
RK