AWS Certified Advanced Networking – Specialty (ANS-C01) — Question 38

A company is deploying a new application on AWS. The application uses dynamic multicasting. The company has five VPCs that are all attached to a transit gateway Amazon EC2 instances in each VPC need to be able to register dynamically to receive a multicast transmission.
How should a network engineer configure the AWS resources to meet these requirements?

Answer options

• A. Create a static source multicast domain within the transit gateway. Associate the VPCs and applicable subnets with the multicast domain. Register the multicast senders' network interface with the multicast domain. Adjust the network ACLs to allow UDP traffic from the source to all receivers and to allow UDP traffic that is sent to the multicast group address.
• B. Create a static source multicast domain within the transit gateway. Associate the VPCs and applicable subnets with the multicast domain. Register the multicast senders' network interface with the multicast domain. Adjust the network ACLs to allow TCP traffic from the source to all receivers and to allow TCP traffic that is sent to the multicast group address.
• C. Create an Internet Group Management Protocol (IGMP) multicast domain within the transit gateway. Associate the VPCs and applicable subnets with the multicast domain. Register the multicast senders' network interface with the multicast domain. Adjust the network ACLs to allow UDP traffic from the source to all receivers and to allow UDP traffic that is sent to the multicast group address.
• D. Create an Internet Group Management Protocol (IGMP) multicast domain within the transit gateway. Associate the VPCs and applicable subnets with the multicast domain. Register the multicast senders' network interface with the multicast domain. Adjust the network ACLs to allow TCP traffic from the source to all receivers and to allow TCP traffic that is sent to the multicast group address.

Correct answer: C

Explanation

The correct answer is C because it specifies the creation of an IGMP multicast domain, which is essential for dynamic registration of multicast receivers. Options A and B incorrectly suggest a static source multicast domain, which does not support dynamic registration. Option D also incorrectly uses TCP instead of UDP, which is necessary for multicast traffic.