Exam 300-420 topic 1 question 166 discussion

I too think it's A and B: "The ease of installation and operation of SSM makes it ideal for network operators, especially in those cases where content needs to be forwarded between multiple independent PIM domains (because there is no need to manage MSDP for SSM between PIM domains)." https://www.cisco.com/c/en/us/td/docs/ios-xml/ios/ipmulti_pim/configuration/xe-16/imc-pim-xe-16-book/imc-ssm.html And without IGMPv3 you can't setup PIM-SSM

How about A and E. Using PIM-SSM provides us with the spoofing prevention and efficient bandwidth utilization and MSDP provides us with the inter-domain operability that we need after the merge.

I would say MSDP for sure and, thus, should be also PIM-SM because of the domains that are interconnected.

It is B & D

I think it's A and B. Referring to this: https://www.cisco.com/c/en/us/td/docs/ios/solutions_docs/ip_multicast/Phase_2/mcst_p2.html https://www.researchgate.net/publication/221081564_IGMPv3-Based_Method_for_Avoiding_DoS_Attacks_in_Multicast-Enabled_Networks

https://www.cisco.com/c/en/us/td/docs/ios-xml/ios/ipmulti_pim/configuration/xe-16/imc-pim-xe-16-book/imc-msdp-im-pim-sim.html#GUID-4B201DB3-2C27-4F98-977A-A1AE9DC39C21 MSDP is a mechanism to connect multiple PIM-SM domains. The purpose of MSDP is to discover multicast sources in other PIM domains. The main advantage of MSDP is that it reduces the complexity of interconnecting multiple PIM-SM domains by allowing PIM-SM domains to use an interdomain source tree (rather than a common shared tree).

I would opt for MSDP (for interconnecting multiple domains) and PIM-SM (for efficiency in bandwidth)