关于经营杠杆系数，下列说法中正确的是（）。

A. PIM sparse - dense mode and PIM dense mode require an RP on the network.

B. PIM sparse mode and PIM dense mode require an RP on the network.

C. PIM sparse mode interfaces are always added to the multicast routing table in a router.

D. PIM sparse mode and PIM sparse - dense mode require an RP on the network.

E. PIM dense mode interfaces are always added to the multicast routing table in a router.

F. PIM sparse - dense mode acts as PIM dense mode if an RP is not known.

A．Dense

B．Version1

C．Version2

D．Sparse

A．Link-mode

B． Dense mode

C． Sparse mode

D． Sparse-dense mode

lticasts to hosts connected to multilayer switches 5 and 6. The CMU Multicast Server multicasts to hosts on multilayer switches 1 - 6. Given the number of configuration steps involved, what is the most efficient way to configure the net work while meeting the requirements for multicast data flow？ （）

A. Configure each switch with PIM sparse mode and a separate instance of PIM dense mode.Specify switch 1 as the root for the RPI Multicast Server. Specify switch 2 as the root for the CMU Multicast Server.

B. Configure each switch with PIM sparse mode and a separate instance of PIM dense mode. Leave each multicast server as the root of its own multicast tree.

C. Configure each switch with PIM sparse - dense mode. Configure switch 3 as a ren dezvous point for the RPI multicast stream.

D. Configure each switch with PIM sparse mode and a separate instance of PIM dense mode.Allow the switches to elect their own root for each multicast tree.

E. Configure each switch with PIM sparse mode.

F. Configure each switch with PIM dense mode.

A. Sparse mode multicast uses a pull model to send multicast traffic to where it is requested

B. Dense mode multicast uses a push model to flood traffic throughout the network and then prunes the unwanted traffic

C. Dense mode multicast requires explicit join messa ges from their members

D. Sparse mode uses reverse path forwarding (RPF) to prune off redundant flows

E. The primary use of sparse mode multicast is for test labs and router performance testing