Multicast video program switching architecture. In one embodiment, a user makes a request for service. A controller determines whether the channel is currently broadcast. When the channel is currently broadcast, redirect the user to an address of the channel. When the channel is not currently broadcast, query a storage apparatus to find a currently broadcast channel that has no current viewership, send, a request to a multicast network address translation (MNAT) router comprising a multicast address of the currently broadcast channel and an identifier of the requested channel to modify MNAT settings on the MNAT router and redirect the user to the multicast address, the multicast address associated with the requested channel.