Expand Configuration and Management Manual (G06.24+)

Planning for ServerNet Clusters
Expand Configuration and Management Manual—523347-008
4-3
ServerNet Clusters Coexisting With FOX Rings
ServerNet Clusters Coexisting With FOX Rings
Interoperability is supported between a ServerNet cluster and a FOX ring containing
ServerNet/FX 2 adapters. This subsection addresses the following topics:
•
Considerations for ServerNet Clusters Coexisting With ServerNet/FX on page 4-3
•
Examples of ServerNet Clusters Coexisting With FOX Rings on page 4-4
For information about ServerNet /FX adapters, see the ServerNet/FX Adapter
Configuration and Management Manual.
Considerations for ServerNet Clusters Coexisting With
ServerNet/FX
•
In general, grouping any NonStop K-series systems on the FOX ring can further
reduce message latencies and minimize use of the FOX ring.
•
When you plan to mix ServerNet clusters with ServerNet/FX, consider the
throughput requirements of networked applications. Since a network can consist of
a combination of data communication methods, having traffic travel along a specific
route can increase network performance by avoiding nodes where increased
processor use would create a bottleneck. A specific route between nodes can be
forced by configuring the LINETF modifier with a different value on each Expand-
over-ServerNet line. Varying the value of the LINETF modifier varies the time factor
(TF) associated with each line.
•
Low message latencies and high performance can be achieved by configuring
systems that communicate often with each other to be part of the same ServerNet
cluster. When systems are part of different ServerNet clusters but connected to the
same FOX ring and need to communicate with each other, the messages bypass
the Expand subsystem and are handled directly by the ServerNet/FX adapters
through the FOX ring.
•
SPEEDK values that are set greater than FOX result in a time factor of 1. For more
information, refer to Routing and Time Factors
on page 18-22.
•
As of G06.20, the Expand routing rules have reverted to the use of simple time
factors. When ServerNet clusters coexist with ServerNet/FX on G06.20 or later
RVUs, you must set the FOX line time factors to 2 or more to avoid a conflict with
the ServerNet cluster time factors (normally set at 1).