AWS Certified Advanced Networking – Specialty (ANS-C01)Network ImplementationMedium
A company is migrating an on-premises application that relies on multicast communication to discover services. The application will be deployed across multiple EC2 instances in different subnets within a single AWS VPC. Which AWS networking service or feature can enable multicast routing within the VPC?
- ADirect Connect Gateway
- BVPC Peering
- CAWS Transit Gateway
- DVPC Endpoint Services
Show answer & explanationAnswer & explanation
Correct answer: C. AWS Transit Gateway
AWS Transit Gateway supports multicast routing within a single Transit Gateway, allowing multicast traffic to be forwarded between attached VPCs or subnets. Other options do not support multicast.
Why the other options are wrong
- A. Direct Connect Gateway connects on-premises networks to AWS VPCs, and does not inherently support multicast routing within a VPC.
- B. VPC Peering does not support multicast routing.
- D. VPC Endpoint Services are for private access to services, not multicast routing.
Transit Gateway Multicast
AWS Transit Gateway supports multicast routing within a Transit Gateway, allowing multicast traffic to flow between associated subnets or VPCs.
- Enables multicast within a single Transit Gateway
- Requires creating a multicast domain and associating subnets
- Supports IGMP (Internet Group Management Protocol) for group membership
- Useful for legacy applications requiring multicast discovery
Memory trick: Transit Gateway is the only one who can shout to many in the VPC.