🧭 Connect Multiple VPCs and On-Premises Networks using AWS Transit Gateway
AWS Transit Gateway (TGW) is a central hub that simplifies network connectivity between multiple VPCs, on-premises networks, and AWS accounts.
It uses a hub-and-spoke (star) topology to eliminate the need for complex VPC peering meshes.
🧩 Architecture Diagram
| Feature | Description |
|---|---|
| Scalability | Connect thousands of VPCs |
| Centralized Management | Manage all connectivity in one place |
| Multi-Account Sharing | Share via AWS Resource Access Manager (RAM) |
| Routing Control | Custom route tables for segmentation |
| Inter-Region Peering | Connect TGWs across regions |
| High Bandwidth | Up to 50 Gbps per attachment (aggregate) |
🧮 Comparison Table
| Use Case | Recommended Service |
|---|---|
| Connect 2 VPCs | VPC Peering |
| Connect On-Prem to AWS | Site-to-Site VPN / Direct Connect |
| Connect Many VPCs + On-Prem | ✅ Transit Gateway |
🧠 Exam Tip
If a question says:
“You need to connect hundreds of VPCs and on-premises data centers efficiently.”
→ The correct answer is AWS Transit Gateway.
✅ Summary
- Transit Gateway = Centralized hub for network interconnectivity.
- Replaces VPC Peering Meshes.
- Works with VPCs, VPNs, and Direct Connect Gateways.
- Supports multi-account, multi-region, and segmented routing.