As enterprises expand beyond on-premise data centers, routing traffic efficiently between branch offices, AWS Transit Gateways, and Azure vWANs becomes a massive architectural bottleneck.
The Hairpinning Problem
Legacy hub-and-spoke models force cloud-destined traffic back through an on-premise NGFW for inspection. This creates a "hairpin" effect, drastically increasing latency and overwhelming the core firewall's throughput capacity.
Architecture Solution: Cloud-Native Transit
- AWS Transit Gateway (TGW): Deploy virtualized NGFWs (e.g., VM-Series) in a dedicated Security VPC. Route all East-West (VPC-to-VPC) and North-South (Internet-to-VPC) traffic through this inspection fleet using TGW route tables.
- Azure Virtual WAN (vWAN): Utilize a secured virtual hub. By placing a centralized security appliance within the vWAN hub, you achieve unified routing and security policy enforcement without backhauling to physical data centers.
- BGP Dynamic Routing: Establish BGP over IPSec between your SD-WAN edge and the cloud gateways to ensure dynamic failover and optimal path selection.
Consultant's Note
Always utilize ECMP (Equal-Cost Multi-Path) routing across multiple IPSec tunnels terminating in the cloud to scale beyond the standard 1.25 Gbps tunnel limitation in AWS.