I have enabled multicast routing in the core switch to allow multicast streams to be routed to the ops network from the auxilliary network (between VLAN 20 and 106) - this is to support the upcoming digital video system.  The Loopback0 interface has been created in the switch to act as the PIM RP[1] for the CDS network, with address 172.17.2.1/32.  Interfaces Vlan20 and Vlan106 are configured to use 'ip pim sparse-dense-mode'.  No other VLANS are currently configured to route multicast traffic.

[1] Protocol Independent Multicast Rendezvous Point