Managing Superdome Complexes: A Guide for HP-UX System Administrators

Planning Superdome Configurations
Building Blocks and Definitions
Appendix A314
The two XBCs in a cabinet are connected to each other and, in a
64-way-capable system, to the two XBCs in the other cabinet as well.
These connections allow cells to communicate and to share memory both
within and across crossbars, allowing partitions comprising more than
four cells.
You need to be careful when configuring partitions that cross crossbar
boundaries; not all configurations which are physically possible are
supported. See “Choosing Cells for Partitions” on page 325.
Crossbar Connections
Three of the ports on a crossbar controller (XBC) are reserved for
connections to other XBCs on other crossbars in the complex. One of
these ports is used to connect to the other XBC in the same cabinet. This
is a direct crossbar-to-crossbar connection (set in etch on the board) and
is not configurable:
Direct Link
+------+
| |
| XBC0 |
| |
+------+
|
|
+------+
| |
| XBC4 |
| |
+------+
The direct XBC-XBC link between crossbars in a cabinet.