Expand Configuration and Management Manual (G06.24+)

Subsystem Description
Expand Configuration and Management Manual—523347-008
18-74
Multi-CPU Feature
Multi-CPU Feature
The Expand multi-CPU feature enables you to spread the communications load over
multiple processors by connecting multiple Expand line-handler process, each in a
separate processor, between two adjacent nodes. The Expand multi-CPU feature
significantly increases the maximum throughput of an Expand path, especially for
Expand-over-IP connections, because an Expand-over-IP line-handler process and its
associated NonStop TCP/IP process must be configured in the same processor pair.
This subsection describes briefly how the Expand multi-CPU feature works so that you
can effectively configure and use this feature in your network. It includes the following:
•
Multi-CPU Paths on page 18-74
•
Multi-CPU Configuration on page 18-74
•
Multi-CPU Considerations on page 18-75
Multi-CPU Paths
The multi-CPU path is the fundamental component of the Expand multi-CPU feature. A
multi-CPU path can consist of up to 16 individual Expand paths, including multi-line
paths. Each Expand line-handler process (or multi-line path) that is a member of a
multi-CPU path can be configured in a different processor.
In order to guarantee message order, one Expand line-handler process at each source
node and one Expand line-handler process at each destination node are paired; all
messages between that source and destination node are sent through this Expand
line-handler pair.
Multi-CPU Configuration
You configure an Expand line-handler process (or a path logical device, in the case of
a multi-line path) as member of a multi-CPU path using the SUPERPATH_ON modifier.
The SUPERPATH_OFF modifier indicates that the path is not part of a the multi-CPU
path. The default is SUPERPATH_OFF.
When a path comes up and any number of other paths to the same destination node
are already up, the action of $NCP is determined by the configuration of the new path.
If it is configured with the SUPERPATH_OFF modifier, then the new path becomes a
redundant normal path to the node. If it is configured with the SUPERPATH_ON
Note. For more information about Expand-over-IP line-handler processes, refer to Expand-to-
IP Interface on page 18-54.
Note. For detailed information about the formation about Expand line-handler pairs, refer to
Multi-CPU Paths
on page 18-31.
Note. The SUPERPATH_ON and SUPERPATH_OFF modifiers are described in detail in
Section 17, Expand Modifiers
.