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VCON Interactive Multicast can work with either Sparse Mode or Dense Mode just fine. However, there would be a preference depending on what the network is used for in a general sense.

Dense Mode - Using PIM Dense Mode, when a multicast is started all routers initially join the multicast tree and then trims back the network links that do not have receivers that subscribe to the multicast. Dense Mode is commonly preferred if the network is centered mostly around videoconferencing (or interactive multicast) or if there are commonly multicast participants in most of the network links.

Sparse Mode - Using PIM Sparse Mode, when a multicast is started, the multicast tree gets built as subscribers actually join the multicast session. Sparse Mode is more typically used on a multiservice network (voice, video, data) where interactive multicasts are not done that often or where the percentage of network segments that will commonly have participants for any given multicast is low (low might mean less than 30% of the network segments).

Again, VCON Interactive Multicast works with either, but above are the general guidelines to follow.