What is the difference between unicast, broadcast, and multicast?
A1:
Unicast packets are destined for only one host. Broadcast packets are destined for all hosts on the same segment, regardless of whether the host is interested in the packet. Multicast packets are sent with one copy, and only hosts that are interested in the multicast packet process the packet.
2:
What are the different modes of PIM?
A2:
PIM dense mode and PIM sparse mode are the two modes.
3:
What mechanism does PIM dense mode operate on?
A3:
PIM dense mode operates on the flood-and-prune mechanism. The router first floods the multicast packets on all interfaces, and the neighbors that don't want the multicast packet prune the interface.
4:
What mechanism does PIM sparse mode operate on?
A4:
PIM sparse mode operates on the prune-and-join mechanism. The router won't forward the multicast packet until it receives a PIM join on the interface.
5:
What is the difference between IGMP version 1 and version 2 concerning the group leave mechanism?
A5:
IGMP version 1 doesn't have a specific group leave mechanism. IGMP version 1 group members simply leave the group silently. IGMP version 2 has a specific group leave mechanism in which the host sends a specific IGMP leave message to the router indicating that it's leaving the multicast group.
6:
What multicast address does IGMP use for IGMP queries?
A6:
224.0.0.1 is used.
7:
How does RPF check work?
A7:
When a router receives a multicast packet on an interface, it checks its routing table on the source address of the multicast packet. If the routing table corresponds with the interface from which the multicast packets are received, RPF check succeeds and packets are forwarded; otherwise , multi-cast packets are silently discarded.
8:
What is the rendezvous point (RP)?
A8:
The rendezvous point (RP) is where the multicast sender and receiver meet first before the shortest- path tree is established.
