What is AWS networking with Transit Gateway and PrivateLink?

Advanced AWS networking services for complex enterprise architectures: AWS Transit Gateway (TGW): a regional network transit hub connecting multiple VPCs and on-premises networks. Eliminates complex VPC peering (peering doesn't scale — N VPCs requires N*(N-1)/2 peering connections; TGW requires N connections to one hub). Features: up to 5,000 VPC attachments per TGW; route tables for segmentation (dev VPCs can't reach prod); Inter-Region peering between TGWs; VPN and Direct Connect attachments; multicast support; Network Manager (visual topology). Use case: hub-and-spoke network topology — all VPCs attach to TGW, routing centralized. AWS PrivateLink (VPC Endpoint Services): expose your service to other VPCs or accounts privately without internet or VPC peering. Service provider creates a Network Load Balancer → creates endpoint service → consumers create interface VPC endpoints → private DNS resolution → secure communication. Use cases: expose internal microservices to partner accounts; access AWS services privately (ECR, S3, KMS — no internet required); shared services VPC (security, logging) connected to multiple workload VPCs. AWS Direct Connect: dedicated network connection from on-premises to AWS (1Gbps or 10Gbps). Consistent, low-latency, private — no internet. Hosted connections (smaller bandwidth via partners). Direct Connect Gateway for multiple regions. Virtual Interfaces: private (VPC), public (AWS public services like S3), transit (Transit Gateway). Site-to-Site VPN: IPSec encrypted tunnel over internet from on-premises to AWS (cheaper than Direct Connect, higher latency, variable bandwidth). Accelerated VPN uses AWS Global Accelerator for lower latency. Combine Direct Connect (primary) + VPN (backup) for resilient hybrid connectivity.