Specifications

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 Configuration Procedure
 Configure Switch A:
Step Operation Description
1 Configure interface.
Configure IP addresses and subnet masks of VLAN interfaces 1, 2
and 3 on Routing→ Interface→Interface Config page.
2 Configure routing
protocol.
Configure the routing entries via static route or dynamic routing
protocol like OSPF, and make sure all the switches can
communicate with each other and update the routing information
through a unicast routing protocol dynamically.
3 Enable multicast
routing and PIM DM
Enable multicast routing on Multicast Routing→Global Config
page. Enable PIM DM on VLAN interfaces 1, 2 and 3 on Multicast
Routing→PIM DM→PIM DM Interface page.
 Configure Switch B and C:
Step Operation Description
1 Configure interface Configure IP addresses and subnet masks of VLAN interfaces 2, 3,
4 and 5 on Routing→Interface→Interface Config page.
2 Configure routing
protocol
Configure the routing entries via stat
ic route or dynamic routing
protocol like OSPF, and make sure all network can communicate
with each other.
3 Enable multicast
routing and PIM DM
Enable multicast routing on Multicast Routing→Global Config
page. Enable PIM DM on VLAN interfaces 2, 3, 4 and 5 on
Multicast Routing→PIM DM→PIM DM Interface page.
4 Enable IGMP Enable IGMP on the VLAN interfaces 4 and 5 which connect to the
receivers on Multicast Routing→IGMP→Interface Config page.
11.4 PIM SM
PIM DM uses the “flood-and-prune” mode to create the SPT for transferring multicast data.
Although SPT has the short path, its building-up process is of low efficiency and does not apply to
the large and medium-sized network.
PIM SM is a multicast routing protocol in sparse mode. It uses the “Pull Mode” to transfer multicast
data and usually applies to large and medium-sized network with relatively sparse multicast group
members.
The working mechanism of PIM SM is illustrated as below:
 PIM SM assumes that no hosts need to receive the multicast data, the multicast data will not be
forwarded to the host unless there is an explicitly request for the traffic. The core task of PIM
SM to realize multicast forwarding is to build and maintain the RPT (Rendezvous Point Tree).
RPT selects a certain router in the PIM domain as the public RP (rendezvous point), through
which the multicast data is transferred along the RPT to the receivers.