In this case, the router is not given the responsibility of forwarding multicast streams. Instead, the service provider arranges for the router to receive the multicast streams so the router can detect the flow and perform QoS adjustment. An OIF map is installed that maps the traffic streams to a loopback interface configured for MLD version passive. This means that when the traffic is received, a null mroute is installed (that is, an mroute with an empty OIF list) and the router applies the QoS adjustment to the join interface. See Figure 16.
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Note: Ensure that PIM-SM (or any other upstream multicast protocol) is informed of the group (or source-group) interest. |
Figure 16: Multicast Traffic Receipt Without Forwarding
