NonStop S-Series Server Description Manual (G06.24+)

Introduction
HP NonStop S-Series Server Description Manual—520331-003
1-30
Tetrahedral Topology With Four Processor
Enclosures
Tetrahedral Topology With Four Processor
Enclosures
For expansion to a fourth processor enclosure, the enclosures now require full
connection as a tetrahedron. The tetrahedral topology maintains the requirement of
each processor enclosure having direct access to any other processor enclosure in the
configuration.
The cabling depiction for tetrahedral topology is presented in a standard form in
Figure 1-16. The “X” pattern of links in the center of this configuration, plus the outer
square, is equivalent to the three-dimensional drawing shown in Figure 1-14. In both
styles of drawing, each corner router connects to the other three.
Processor enclosures are designated as P/1 through P/4.
The upper part of the figure shows only the X fabric connected, for simplicity. The lower
part shows both fabrics connected. In succeeding diagrams, the connections for the Y
fabric are omitted to reduce complexity. In all cases, the Y-fabric pattern is identical to
what is shown for X-fabric connections.
As previously mentioned, the routers shown are only those on the ServerNet
expansion boards (SEBs).