Canada Command

Canada Command (CC) was established in February 2006 "to focus on domestic operations and to offer a single point of contact for all domestic and continental defense and security partners." (Source: NORTHCOM website)  As DND explains: "As an integrated national operational command headquarters, CANADA COMMAND will allow the Canadian Forces to bring the best available military resources from across Canada to bear on a crisis or threat, wherever it occurs, nation-wide." (Source)

Weapons systems: CC therefore has under its control and command all of Canada's CF-18 warplanes, missiles, bombs, frigates, destroyers, tanks, artillery and all of its other weapons systems and troops. With the Canadian government's recent decision to spend half a trillion dollars over the next 20 years on the military, the panoply of weapons systems available to CC will only increase. (Source)

CC's counterpart in the US is "U.S. Northern Command" which was formed in "Oct. 1, 2002, to anticipate and conduct homeland defense and civil support operations."
"The two domestic commands established strong bilateral ties well before the signing of the Civil Assistance Plan. The two commanders and their staffs meet regularly, collaborate on contingency planning and participate in related annual exercises." Canadian Air Force Lt.-Gen. Marc Dumais, the commander of CC has said that the two commands, which have a "strong working relationship":
“were created by our respective governments to respond to the defense and security challenges of the twenty-first century, and we both realize that these and other challenges are best met through cooperation between friends.”
(Source: NORTHCOM website)

Canada Command agrees to allow deployment of US troops in Canada
In February 2006, these US and Canadian Commands "signed a Civil Assistance Plan that allows the military from one nation to support the armed forces of the other nation during a civil emergency." (Source: NORTHCOM website)

Two articles by Prof. Michel Chossudovsky are recommended on this:

"The Deployment of US Troops inside Canada" (March 13, 2008)

"Is the Annexation of Canada Part of Bush's Military Agenda?" (November 23, 2004)

CC's Mission

Here's how Canada's Department of National Defence describes CC:
"The creation of CANADA COMMAND means that for the first time, a unified and integrated chain of command at the national and regional levels will have the immediate authority to deploy maritime, land and air assets in their regional areas of responsibility in support of domestic operations." (emphasis added)
(Source)

The CC website sums up its Mission in this way:
"Canada Command will conduct operations to deter, prevent, preempt, and defeat threats and aggression aimed at Canada, within its area of responsibility. When requested, Canada Command will provide military assistance to civil authorities, including consequence management, in order to protect and defend Canada. Canada Command will be the operational link with U.S. Northern Command."
(Source)