Figure D-17 Multiple LPARs connected through multiple VLANs Workloads can be logically isolated on separate ISM VCHIDs. Alternatively, workloads can be  isolated by using VLANs. The ISM VLAN definitions are inherited from the associated IP  network (OSA or HiperSockets). The IOCDS (HCD) definitions for ISM PCI VFs are not directly related to the software  (SMC-D) use of ISM (that is, the z/OS TCP/IP and SMC-D implementation and usage are not  directly related to the I/O definition). The user defines a list if ISM FIDs (VFs) in IOCDS (HCD), and z/OS dynamically selects an  eligible FID that is based on the required PNet ID. FIDs or VFs are  not  defined in  Communications Server for z/OS TCP/IP. Instead, z/OS selects an available FID for a specific  PNET. Access to more VLANs does not require configuring extra VFs. Note:  Consider over-provisioning the I/O definitions; for example, consider defining eight  FIDs instead of five. For native PCI devices, FIDs must be defined. Each FID in turn also defines a corresponding  VF. In terms of operating system administration tasks, the administrator typically references  FIDs. VFs (and VF numbers) often are transparent. Configuration considerations D.3.9 Software use of ISM ISM enables SMC-D, which provides SMC capability within the CPC (SMC without requiring  RoCE hardware or network equipment). Host virtual memory is managed by each OS (similar  to SMC-R, logically shared memory) following IBM Z PCI I/O translation architecture.  446  IBM 14 Model ZR1 Technical Guide