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Multicast Questions

Here you will find answers to Multicast Questions
Question 1
In PIM-SM what control plane signaling must a multicast source perform before it begins to send multicast traffic to a group?
A. The source must send a PIM Register message to the rendezvous point (RP).
B. The source must first join the multicast group using IGMP before sending.
C. The source must perform a Request to Send (RTS) and Clear to Send (CTS) handshake with the PIM designated router (DR).
D. No control plane signaling needs to be performed; the source can simply begin sending on the local subnet.

Answer: D
Question 2
The ip pim autorp listener command is used to do which of these?
A. enable a Cisco router to “passively” listen to Auto-RP packets without the router actively sending or fotwarding any of the packets 
B. allow Auto-RP packets in groups 224.0.1.39 and 224.0.1.40 to be flooded in dense mode out interfaces configured with the ip pim sparse-mode command
C. enable the use of Auto-RP on a router 
D. configure the router as an Auto-RP mapping agent

Answer: B
Question 3
In order to configure two routers as anycast RPs, which of these requirements, at a minimum, must be satisfied?
A. Multicast Source Discovery Protocol mesh-groups must be configured between the two anycast RPs.
B. The RPs must be within the same IGP domain.
C. Multicast Source Discovery Protocol must be configured between the two anycast RPs.
D. The two anycast RPs must be IBGP peers.

Answer: C
Question 4
Which two of these statements correctly describe classic PIM-SM? (Choose two)
A. The IOS default is for a last-hop router to trigger a switch to the shortest path tree as soon as a new source is detected on the shared tree.
B. The IOS default is for every one of the routers on the shared tree to trigger a switch to the shortest path tree as soon as a new source is detected on the shared tree.
C. The default behavior of switching to the shortest path tree as soon as a new source is detected on the shared tree can be disabled by setting the value in the ip pim spt-threshold command to “infinity”.
D. The default behavior of switching to the shortest path tree as soon as a new source is detected on the shared tree can be disabled by setting the value in the ip pim spt-threshold command to “zero”.

Answer: A C
Question 5
Refer to the exhibit. Router E learned about the PIM RP (designated as 7.7.7.7) from four different sources. Routers A and D advertised the 7.0.0.0 network via EIGRP. Routers B and C advertised the 7.0.0.0 network via OSPF. Considering that all four Ethernet interfaces on router E could potentially lead back to the PIM-RP, when router E receives the first multicast packet down the shared tree, which incoming interface will be used to successfully pass the RPF check?
PIM_RP.jpg
A. E0 
B. E1
C. E2 
D. E3
E. None of these interfaces will be used to successfully pass the RPF check. 
F. All of these interfaces would successfully pass the RPF check.

Answer: A
Question 6
Refer to the exhibit. Two ISPs have decided to use MSDP and configured routers X and Y (both are PIM RPs) as MSDP peers. In the domain of ISP B, PC A has sent an IGMP membership report for the group 224.1.1.1 and PC B has sent an IGMP membership report for the group 224.5.5.5. Assuming that the MSDP peering relationship between routers X and Y is functional, and given the partial configuration output shown from router X, which two of these statements are true? (Choose two)
MSDP.jpg
A. Router X will contain an entry for 224.1.1.1 in its SA cache and will also have an installed (S,G) entry for this in its mroute table
B. Router X will not contain an entry for 224.1.1.1 in its SA cache but will have an installed (*,G) entry for this in its mroute table.
C. Router X will not contain an entry for 224.5.5.5 in its SA cache but will have an installed (S,G) entry for this in its mroute table.
D. Router X will not contain an entry for 224.5.5.5 in its SA cache but will have an installed (*,G) entry for this in its mroute table.
E. Router X will have no entries for 224.5.5.5 in neither its SA cache nor in its mroute table.
F. Router X will have no entries for 224.1.1.1 in neither its SA cache nor in its mroute table.

Answer: A D
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