We currently have a "mesh" of VPC Peering connections between 10 different VPCs, and it’s becoming a routing nightmare. I’ve heard that AWS Transit Gateway can simplify this by acting as a central hub. What are the performance trade-offs when moving from peering to a transit gateway? Will my data transfer costs increase significantly?
3 answers
Transitioning to AWS Transit Gateway is the move once you exceed three VPCs. It eliminates peering complexity via a hub-and-spoke model where each VPC needs one attachment. While VPC Peering is faster, Transit Gateway simplifies routing and allows for centralized inspection via a security VPC. Regarding costs, you pay an hourly fee per attachment and a processing fee for data. However, the time saved on managing peering routes usually outweighs these costs. One change: you cannot reference security groups across a Transit Gateway, so you must rely on IP-based rules or AWS Network Firewall for control.
How are you planning to handle your "Cross-Region" traffic? Does Transit Gateway support peering between different AWS regions to connect your global offices and data centers seamlessly?
Transit Gateway also supports VPN and Direct Connect attachments, making it the perfect bridge between your on-premise data center and your entire cloud network simultaneously.
That central hub capability is why we moved to it. It simplified our hybrid cloud setup immensely and gave us much better visibility into our traffic flows across the organization.
Comment: Yes, you can peer Transit Gateways across regions! We use this to connect our US-East and EU-West environments. It creates a global private backbone that is much more reliable than using the public internet. The data is encrypted by default as it travels over the AWS fiber, which satisfies our compliance requirements. The management is also centralized, so we can see the entire global network topology from a single dashboard. It’s significantly easier than managing multiple inter-region VPC peering connections.