Fanout Considerations - IBM z13s Technical Manual

Each HCA3-O LR (1xIFB) fanout has an assigned AID number. This number must be used for
definitions in IOCDS to create a relationship between the physical fanout location and the
CHPID number. For more information about AID numbering, see "Adapter ID number
assignment" on page 152.
When STP is enabled, InfiniBand long range (IFB LR) coupling links can be defined as
timing-only links to other z13, z13s, zEC12, zBC12, z196, and z114 CPCs.

4.6.6 Fanout considerations

Fanout slots in each CPC drawer can be used to plug different fanouts. One CPC drawer can
hold up to eight PCIe fanouts and four InfiniBand fanout cards.
For migration purposes, the number of available HCA3-O or HCA3-O LR cards in the z13s
servers can be important (for coupling connectivity to zEC12, zBC12, z196, and z114). The
carry-forward of FICON Express8 features reduces the number of available InfiniBand fanout
slots by two. This limitation can be important for coupling connectivity planning, especially for
a z13s Model N10, as shown in Table 4-3. No more fanout adapter slots are available for an
N10 model after a FICON Express8 feature is carried forward. Table 4-3 shows for the z13s
Models N10 and N20 where the limitation of HCA3-O and HCA3-O LR fanouts that are
caused by carry-forward of FICON Express8 features might require attention during
migration.
For migration considerations, see 4.9.2, "Migration considerations" on page 178.
Table 4-3 CPC drawer InfiniBand fanout availability limitation with carry-forward FICON Express8 features
CPC Model Carry forward
FICON Express8
features
N10 0
1 - 8
N20 0
1 - 8
a. If one I/O drawer is carried forward for a Model N20 with two CPC drawers, only one PCIe I/O drawer can be
installed.
b. The number of FICON Express8 carried forward also affects the maximum number of PCIe I/O features.
Adapter ID number assignment
PCIe and IFB fanouts and ports are identified by an AID that is initially dependent on their
physical locations, unlike channels that are installed in a PCIe I/O drawer or I/O drawer.
Those channels are identified by a physical channel ID (PCHID) number that is related to their
physical location. This AID must be used to assign a CHPID to the fanout in the IOCDS
definition. The CHPID assignment is done by associating the CHPID to an AID port.
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IBM z13s Technical Guide
Resulting Max. number of
number of I/O HCA3-O or
drawers HCA3-O LR
fanout cards
0 2
1 0
0 8
1 6
Max. number of Max. number of
PCIe I/O drawers PCIe I/O features
1 32
1 32
2 64
a b
2 64