IBM RS/6000 SP Handbook page 322

Placement rules for switches
Switch configuration rule 1:
An eight port switch does not support PCI high nodes, I/O Expansion units, or
SP-attached servers.
All eight port switches do not support PCI high nodes, I/O expansion units, or
SP-attached servers. As for the limited scalability of the eight port switches, they
support up to a maximum of eight nodes.
Switch configuration rule 2:
HiP Switch is compatible with MCA nodes only.
HP Switch requires HP Switch adapter-2 (F/C 4018) in an SP node, which is only
available for for MCA, so HP Switch is only compatible with MCA nodes.
Furthermore, HiP Switch is not supported in PSSP Version 3.1 or later.
Switch configuration rule 3:
SP Switch is compatible with both MCA and PCI nodes.
The SP Switch (F/C 4011) can be used with both MCA and PCI nodes. A mixed
environment of MCA nodes and PCI nodes is supported by SP Switch. However,
as PSSP V3.1 is required for PCI POWER3 nodes, the coexistence of PSSP
versions should be considered carefully when upgrading the SP system.
Switch configuration rule 4:
The SP Switch (F/C 4011) only can be used with the SP-attached Servers and
Clustered Enterprise Servers.
The SP Switch (F/C 4011) only can be used with the SP-attached Servers and
Clustered Enterprise Servers. For the Clustered Enterprise Servers you have to
configure 9076-555 Standalone Switch for Clustered Nodes with one up to two
F/C 4011.
Switch configuration rule 5:
SP Switch2 is compatible with PCI high nodes only (requires PSSP Version
3.2).
298 RS/6000 SP and Clustered IBM ^ pSeries Systems Handbook