Solution : https://service.sap.com/sap/support/notes/1609304 (SAP Service marketplace login required)
Summary :
For SAP systems prior to NetWeaver 7.3 and specific versions on Windows, ASCS instances were deployable predominantly for HA configurations with Microsoft Failover Clustering. Standalone ASCS installations were not supported in non-HA or non-cluster setups. From NetWeaver 7.3 onwards, SAP introduced support for standalone ASCS instances on non-HA systems, offering flexibility for deployment either with other instances on one host or separately. This flexibility does, however, introduce more complexity in RFC connections and could necessitate additional reconfiguration for system upgrades or using the EHPI installer. For non-HA environments, SAP suggests co-locating the ASCD instance with the primary application server to maintain traditional RFC configuration behavior. In HA setups using Microsoft Failover Clustering, it is recommended that the primary application server instance and additional identically configured application server instances be locally installed on cluster nodes.
Key words :
identically configured additional application server instance locally, primary application server instance locally, abap central services instance reason, abap primary application server instance -, traditional primary application server, primary application server instance, newer sap system versions, standalone ascs instance leads, -party high-availability scenarios, primary application server