Example of configuring PIM-DM operation at the VLAN level

The network in the following figure uses VLAN 25 for multicast traffic. However, this VLAN is multinetted and there is only one subnet (10.38.10.x) in VLAN 25 that is common to all three routing switches. Thus, when configuring VLAN 25 on these routing switches to perform multicast routing, it is necessary to use ip pim-dense source-ip-address to designate the common subnet as the source address for outbound multicast traffic on VLAN 25. (If only identical subnets were present in the multinetted VLAN 25 configuration on all three devices, the ip pim-dense ip-addr any command would be used instead.) The other VLANs in the network are not multinetted and therefore do not require the ip pim-dense ip-addr any|source-ip-address option.

For this example, assume that the VLANs and IP addressing are already configured on the routing switch.

Figure 9: Multicast network with a multinetted VLAN

The preceding figure illustrates the steps for configuring multicast routing at the VLAN level for the switch #1.

switch(config)# vlan 25
switch(vlan-25)# ip igmp
switch(vlan-25)# ip rip
switch(vlan-25)# ip pim-dense ip-addr 10.38.10.1
switch(vlan-25-pim-dense)# vlan 27
switch(vlan-27)# ip igmp
switch(vlan-27)# ip rip
switch(vlan-27)# ip pim-dense
switch(vlan-27-pim-dense)# vlan 29
switch(vlan-29)# ip igmp
switch(vlan-29)# ip rip
switch(vlan-29)# ip pim-dense
switch(vlan-29-pim-dense)# write mem
switch(vlan-29-pim-dense)# exit
switch(vlan-29)# exit

Figure 10: Multicast routing configuration on switch #1 in Multicast network with a multinetted VLAN