Transit Gateway
Definition
AWS networking hub that connects multiple networks together through a central point, simplifying network management and enhancing connectivity.
Use Cases
- Amazon: Connecting multiple AWS VPCs and on-premises networks for large-scale internal services and shared platforms — Uses hub-and-spoke network designs in AWS with centralized routing and shared services VPCs; Transit Gateway is commonly used in AWS reference architectures to interconnect many VPCs and hybrid connectivity via VPN/Direct Connect attachments (Reduces the operational overhead of managing many point-to-point peering links, centralizes routing control, and improves scalability as the number of VPCs grows)
- Netflix: Segmenting and connecting multiple AWS environments (e.g., shared services, tooling, and application VPCs) while maintaining centralized network governance — Adopts hub-and-spoke networking patterns on AWS for multi-VPC connectivity and centralized controls; Transit Gateway is a common building block for these patterns alongside routing policies and security controls (Simplifies multi-VPC connectivity and helps enforce consistent network policies across many environments)
Provider Equivalents
- AWS: AWS Transit Gateway
- Azure: Azure Virtual WAN
- GCP: Network Connectivity Center
- OCI: OCI Cloud Router
Frequently Asked Questions
- What's the difference between Transit Gateway and VPC peering?
- VPC peering is a direct, one-to-one connection between two VPCs. If you have many VPCs, peering can turn into a complex mesh with lots of connections and route updates. Transit Gateway acts like a central hub: each VPC connects once to the hub, and the hub routes traffic between them, which scales better for dozens or hundreds of networks.
- When should I use Transit Gateway?
- Use Transit Gateway when you need to connect many VPCs, multiple AWS accounts, or hybrid networks (site-to-site VPN and/or Direct Connect) and want centralized routing and simpler operations. It’s especially useful for hub-and-spoke designs, shared services VPCs, multi-account landing zones, and environments where the number of network connections would otherwise grow quickly with VPC peering.
- How much does Transit Gateway cost?
- Pricing is mainly based on (1) attachments (each VPC/VPN/Direct Connect association to the Transit Gateway) and (2) data processing through the Transit Gateway, plus standard data transfer charges depending on traffic patterns (for example, cross-AZ or inter-region if you use inter-region peering). Exact rates vary by region, so you should estimate using the AWS Pricing page and the AWS Pricing Calculator with your expected number of attachments and monthly GB processed.
Category: networking
Difficulty: advanced
Related Terms
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