Hi Nabin
1. Multilog is possible. I mean if any user log in through GUI in desktop or laptop, and he trying to log in through browser, 2 connection parallely connected. IN SM04 its showing two connection with the same user name.. But in SAP profile multi gui login has been disable. (Through GUI multilogin not possible)
Yes it will show two connection, 1. GUI & 2. http
2. When user log in through browser (Android device), he log out from sap, but in SM04 t-code sap shows the user still log in to the system.
For this you have define the profile parameters for HTTP ideal time out settings for this refer the SAP Note
3. Check this SAP Note 1728946 - Central Browser Note for NetWeaver
Regards
Sriram