Oracle Cloud Services with OCI and OCI-classic
Oracle SaaS and Oracle PaaS services are provided based on top the (underlying) Oracle Cloud Infrastructure. This infrastructure comes as either:
Newer PaaS Services like ADW are provided based on OCI → Gen. 2, while other Cloud Services like Fusion Applications or DIPC are built on top of OCI-C → Gen. 1. For End-users or Developers the difference may not be directly apparent, but the underlying capabilities for networking and connectivity will vary greatly both generations. This article will not address the differences between Gen. 2 and Gen. 1, but from an Cloud Architecture point of view it should always be checked what underlying generation is used for the Oracle Cloud Service, because the connection of Services will always be easier if both (or all) are on the same generation of underlying infrastructure.
Connections may still be created between Gen. 1 and Gen. 2 services, but the network performance, network configuration and flexibility will be much better with Gen. 2.