Service-gateway access enables a Redis for VMware Tanzu Application Service on-demand service instance to connect to external components that are not on the same foundation as the service instance. These components might be on another foundation or hosted outside of the foundation.
For related procedures, see:
There are multiple use cases for service-gateway access.
Service Gateway access to Redis for Tanzu Application Service instances leverages the TCP Router in TAS for VMs.
Any Redis requests that an app makes are forwarded through DNS to a load balancer that can route traffic from outside to inside the foundation. This load balancer (the TCP Router) opens a range of ports that are reserved for any TAS application traffic. When an app developer creates a service instance on a plan with service-gateway access enabled, a port from such a range is provisioned for that service instance. The load balancer then forwards the requests for this Redis for Tanzu Application Service service instance to the TCP router.