TGW Connect Attachment and Multicast Routing

Question

Hi, Can the topology mentioned in the link below:
https://docs.aws.amazon.com/vpc/latest/tgw/tgw-connect.html
![TGW-Connect-Topology](/media/postImages/original/IMJQa5pFhDToat_VpJvUlgZQ)

be used to send the multicast traffic between the VPC like from VPC A and VPC C ? When creating TGW enable Multicast and Create a Connect attachment to create a GRE tunnel to transport the multicast traffic ?

Answer

Hello,

Unfortunately Multicast over TGW connect attachmnt is not supported, see the below comment from the documentation:

> Multicast routing is not supported over AWS Direct Connect, Site-to-Site VPN, peering attachments, or transit gateway **Connect attachments**.

See the complete list of considerations for Multicast on transit gateways [here](https://docs.aws.amazon.com/vpc/latest/tgw/tgw-multicast-overview.html)

TGW Connect Attachment and Multicast Routing

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