AWS Transit Gateway deep dive: route tables, segmentation and scale

Transit Gateway is the backbone of any serious AWS network. The route table model — not VPC peering — is what makes it scale.

Concepts

• Attachments, route tables, association vs propagation.
• Multi-account via Resource Access Manager (RAM).

Segmentation

• One TGW route table per security zone.
• Production, dev, shared services as separate tables.

Inter-region

• TGW peering for region-to-region.
• Cloud WAN for multi-region segmentation policy.

Hybrid

• Direct Connect Gateway + Transit VIF.
• Site-to-site VPN as backup.

Pitfalls

• Bandwidth per attachment is not unlimited.
• Quota: routes per table; plan early.

Train cloud routing reasoning in a TechLeague tournament.