This are the commands that you need to Start and Stop a running Oracle Standby Database in Oracle 11g.
alter database recover managed standby database cancel;
Database altered.
shu immediate;
startup nomount;
ORACLE instance started.
Total System Global Area 3206836224 bytes
Fixed Size 2257520 bytes
Variable Size 1191185808 bytes
Database Buffers 1979711488 bytes
Redo Buffers 33681408 bytes
alter database mount standby database;
Database altered.
alter database recover managed standby database disconnect from session;
Database altered.