I'm introducing some PIM routing into my network to make some multicast traffic available across routers.
I have read a bit on PIM, sparse mode versus dense mode. After reading, I am trying to figure out, under what circumstances would I want to use dense mode?
If I have a simple structure:
[multicast subscriber] <-> [DR router] <-> [DR router] <-> [RP router] <-> [multicast sender]
is it true that using sparse mode from this topology would allow me to expand more efficiently?
How is "time to first packet received" affected by sparse versus dense mode, considering a particular large tree of routers? Are RPs always subscribed to receive multicast?