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

Planning Superdome Configurations
Building Blocks and Definitions
Appendix A 315
In a 64-way-capable-system, another of these three ports connects the
crossbar to the corresponding XBC in the other cabinet:
Direct and Flex Links (64-way-capable-system)
+------+ +------+
| | B | |
| XBC0 |----------| XBC8 |
| | | |
+------+ +------+
|A |A
| |
+------+ +------+
| | B | |
| XBC4 |----------|XBC12 |
| | | |
+------+ +------+
This figure shows the XBC-XBC links between crossbars (A) and the flex
links between corresponding XBCs in two cabinets (B).
This leaves one more port for an XBC connection. The way this last port
is connected defines the difference between a U-Turn and a Cross-Flex
connection.
Cross-Flex and U-Turn
• If the last port is connected to the other XBC in the same cabinet
(that is, a second XBC-XBC connection to the second XBC in the same
cabinet), this is a U-Turn connection.
• If the connection is to the other XBC in another cabinet (such that
XBC 0 is cabled to XBC 12), this is a Cross-Flex connection.