AWS Certified CloudOps Engineer - Associate
VPC Peering and Transit Gateway
VPC peering is a one to one wire between 2 VPCs with 3 hard limits; Transit Gateway is a regional router that removes all 3 and adds route tables of its own. This lesson covers both, the point where a mesh stops being viable, and how to troubleshoot the 4 layers of routing a transit gateway introduces.
Intermediate 30 minutes 6 Learning Objectives
- Configure a VPC peering connection end to end, including the routes and security group references both sides need
- Explain the 3 limits of VPC peering (no transitive routing, no overlapping CIDRs, no edge to edge routing) and predict which scenarios they break
- Describe how a transit gateway routes traffic using attachments, route table associations, and route propagation
- Build isolated and shared-services segmentation with multiple transit gateway route tables
- Choose between peering and Transit Gateway for a given number of VPCs, cost profile, and routing requirement
- Diagnose connectivity failures across the 4 routing layers a transit gateway introduces, including the Availability Zone attachment rule