PIM-DM Application in a Single AS
Figure 4-17 shows multicast services deployed on a small-scale network. The Interior Gateway Protocol (IGP) protocol is running on the network and all network segments are reachable. Multicast group members are densely distributed. Hosts on this network want to receive video on demand (VoD) information, and network bandwidth needs to be used efficiently.
Implementation Plan
As shown in Figure 4-17, HostA, HostB, and HostC are receivers of multicast video streams. The entire PIM domain runs PIM-DM. RouterA connects to the multicast source (Source); RouterB connects to the network segment of HostA; RouterD and RouterF connect to the network segment of HostB and HostC.
The network deployment must meet the following requirements:
PIM-DM is enabled on all router interfaces.
IGMP runs between the routers and hosts on a shared network segment (between RouterB and HostA, and between RouterD/RouterF and HostB/HostC).
All router interfaces on the same network segment must run the same IGMP protocol version (IGMPv2 is recommended) and be configured with the same parameters, such as the interval for querying IGMP packets and hold time for memberships. If IGMP versions or parameters are inconsistent, IGMP member relationships on routers are different.
After the network is deployed, HostA, HostB, and HostC can receive multicast data from Source, and the users can watch the video programs they request.
It is recommended that members be statically added to a multicast group at the network border. This improves the stability of multicast services.
