IBM RS/6000 SP, Handbook

Page: 181 / 480

Chapter 4. Frames
157
4.8.5 Configurations with processor nodes and a switch
Non-switched expansion frames can be added to the Model 500 SP frame
configured with processor nodes and an SPS-8 Switch to take advantage of
unused switch ports.
One example of an under-utilized switch is a Model 500 frame with four wide
nodes and an SP-8 Switch. In this case, the frame is fully populated yet only four
of the eight switch ports are used. In this case, you can add non-switched
expansion frames to the model frame to take advantage of the four unused
switch ports. In these systems, node-to-node data transfers are completed
through the switch.
4.8.6 Configurations with processor nodes only
Non-switched expansion frames can be added to the Model 500 SP frame
configured with processor nodes only (no switch) to take advantage of unused
node slots. Model 500 systems have a capacity for up to eight nodes. If you fill
the model frame by placing two high nodes in that frame, you can install six
additional nodes in the system by using F/C 1500 non-switched expansion
frames. In these systems node-to-node data transfers are completed over the SP
LAN.
Expansion Frame Terminology: Non-switched expansion frames were
sometimes previously referred to as “logical switch expansion frames.”
Both of these terms indicate a shared-switch frame set. The frames of a
shared-switch frame set include the first frame (containing the switch) and one
or more additional frames which do not contain a switch. The additional
frames share the switch of the first frame in the set.
Note: Nodes must be in sequence in this system configuration. Empty node
drawers are not allowed.