ServerNet Cluster 6780 Planning and Installation Guide (G06.24+, H06.03+)

Planning for Installation and Migration
ServerNet Cluster 6780 Planning and Installation Guide—527301-004
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Task 10: Plan the Expand-Over-ServerNet Lines
$NCP uses this criteria to select the best-path route to a specific node:
•
The route must have the lowest TF of all possible routes.
•
If two or more routes have the same TF, the route that has the lowest hop count
(HC)—the fewest intervening nodes—is selected. Each path between two nodes is
one hop. For example, a route that includes one passthrough node has a HC of 2.
A route that includes two passthrough nodes has an HC of 3, and so on.
•
If two or more routes have the same TF and HC, the first path that is operational
after the node is started is selected.
For G06.20 and later RVUs on NonStop S-series servers, Super Time Factors are not
used to calculate TFs. As a result, Expand-over-ServerNet and Expand-over-FOX
have a TF of 1 by default. If two systems are linked by more than one type of Expand
line (for example, Expand-over-ServerNet and Expand-over-FOX), use a lower TF to
indicate a more efficient line, path, or route. For ServerNet clusters, HP recommends
that you use a higher TF for the Expand-over-FOX lines. For example, you can use the
time factor of 1 for Expand-over-ServerNet lines (as configured by the Add Node to
ServerNet Cluster action) because of its high bandwidth, a time factor of 2 for Expand-
over-FOX lines, and a time factor of 3 for Expand-over-IP lines.