Static multicast routes
Configure static multicast routes to control the network paths, administrative distance, and precedence for multicast routes.
Static multicast routes allow you to control the network path used by multicast traffic. Static multicast routes are especially useful when the unicast and multicast topologies of a network are different. By configuring static multicast routes you don't have to make the topologies similar.
In IP multicasting, source IP addresses are unicast addresses while destination IP addresses are multicast (group) addresses. Therefore, in IP multicasting, a route lookup is done for source IP address, rather than its destination IP address.
You can configure more than one static multicast route. The device always uses the most specific route that matches a multicast source address. Thus, if you want to configure a multicast static route for a specific multicast source and also configure another multicast static route for all other sources, you can configure two static routes
Configure the distance keyword in the ip mroute command to specify the administrative distance, which the device uses to determine the best path for a route. When comparing multiple paths for a route, the device prefers the path with the lower administrative distance. To ensure that the default static route is used, configure a low administrative distance value. However, the device prefers directly connected routes over other routes, no matter what the administrative distance.
Configure the route-precedence command to specify a precedence table that dictates how routes are selected for multicast.