D.3.8 Software Exploitation Of Ism - IBM z13s Technical Manual

Configuration considerations
The IOCDS (HCD) definitions for ISM PCI VFs are not directly related to the software
(SMC-D) exploitation 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 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
additional VLANs does not require configuration of additional VFs.
Note: Consider over-provisioning the I/O definitions (e.g.consider defining eight FIDs
instead of 5.
For native PCI devices, FIDs need to be defined. Each FID in turn will also define a
corresponding VF. In terms of operating system administration tasks, the administrator will
typically reference FIDs. Usually VFs (and VF numbers) are transparent.

D.3.8 Software exploitation of ISM

ISM enables SMC-D, which provides SMC capability within the CPC (SMC without requiring
RoCE hardware/network equipment). Host virtual memory is managed by each OS (similar to
SMC-R, logically shared memory) following existing z Systems PCI I/O translation
architecture. Only minor changes required for z/VM guests. An OS can be enabled for both
SMC-R and SMC-D. SMC-D is used when both peers are within the same CPC (and ISM
PNet and VLAN). After the ISM HCD configuration is complete, SMC-D can be enabled in
z/OS with a single TCP/IP parameter (GLOBALCONFIG SMCD). ISM FIDs must be
associated with an IP network. The association is accomplished by matching PNet IDs (for
example HiperSockets and ISM).
Note: ISM FIDs must be associated with HiperSockets or with an OSA adapter by using a
PNet ID. It cannot be associated to both.
D.3.9 SMC-D over ISM prerequisites
SMC-D over ISM has these prerequisites:
z13s or z13 server (Driver 27):
– HMC/SE for ISM vPCI Functions.
At least two z/OS V2.2 systems in two LPARs on the same CPC with required service
installed:
– SMC-D can only communicate with another z/OS V2.2 instance and peer hosts must
be on the same CPC and ISM PNet.
– SMC-D requires an IP Network with access through OSA or HiperSockets that has a
defined PNet ID that matches the ISM PNet ID.
If running as a z/OS guest under z/VM, z/VM 6.3 with APAR VM65716, including APARs is
required for guest access to RoCE (Guest Exploitation only).
Linux support is planned for a future deliverable.
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IBM z13s Technical Guide