What is the purpose of the VMware Cloud on AWS Compute Gateway (CGW)?

Compute Gateway (CGW) The CGW is a Tier 1 router that handles network traffic for workload VMs connected to routed compute network segments. Compute gateway firewall rules, along with NAT rules, run on the Tier 0 router. In the default configuration, these rules block all traffic to and from compute network segments (see Configure Compute Gateway Networking and Security).

https://docs.vmware.com/en/VMware-Cloud-on-AWS/services/vmc-on-aws-networking-security.pdf

The CGW is a Tier 1 router that handles network traffic for workload VMs connected to routed compute network segments. Compute gateway firewall rules, along with NAT rules, run on the Tier 0 router.