单项选择题
A. acts as a meeting place for sources and receivers of multicast traffic
B. used in PIM dense m ode to create a database of all multicast sources
C. used in PIM dense and sparse mode to create a database of all multicast sources
D. acts as the designated router for a broadcast segment when multicast routing is enabled
单项选择题 Refer to the exhibit. IP multicast for group address 224.1.1.1 has been enabled on all router s in the network. Hosts on Network A receive the multicast traffic. However, hosts on Network B do not. On the basis of outputs provided, what could be the cause of the problem? （）
多项选择题 Which two statements are true about Internet Group Management Protocol (IGMP) snooping?（）
多项选择题 Which three statements are true about the Internet Group Management Protocol (IGMP)? （）