AWS::EC2::TransitGateway

• Transitive peering between thousand VPCs and on-premises
• Hub and Spoke model (star)
• Route Tables limit the connection between the VPCs
• Supports IP Multicast

Properties

• https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/aws-resource-ec2-transitgateway.html

Type: AWS::EC2::TransitGateway
Properties:
  AmazonSideAsn: Integer
  AssociationDefaultRouteTableId: String
  AutoAcceptSharedAttachments: String
  DefaultRouteTableAssociation: String
  DefaultRouteTablePropagation: String
  Description: String
  DnsSupport: String
  MulticastSupport: String
  PropagationDefaultRouteTableId: String
  SecurityGroupReferencingSupport: String
  Tags:
    - Tag
  TransitGatewayCidrBlocks:
    - String
  VpnEcmpSupport: String

• Shared services VPC
• Share VPCs across accounts

VpnEcmpSupport

• Site-To-Site VPN ECMP
• Increases the bandwidth of the s2s connections using ECMP (Equal Cost Multipath routing)
• Forwards the traffic over multiple best path (multiple tunnels at the same time)