All applicants for Canada immigration must also undergo a background clearance to weed out those who have been, or are involved in espionage, subversion or terrorism. This is to ensure that the safety and order of Canadian society are maintained and protected. Such security screening decisions are made based on information from every available source, which is then carefully weighed to determine whether an applicant is likely to threaten the internal security of Canada. When there is an indication of security concerns, an interview will be scheduled to discuss these findings with the applicant. Anyone who poses such a threat must necessarily be prevented from entering Canada. ( Source: Canadavisa.com)
Standard Background Begins once you have cleared the Medicals: 30 - 120 Days
In - Dept: six months to one year
cheers, I gotta go its 5pm