HP-UX SNAplus2 R7 Administration Guide

Configuring Passthrough Services
Configuring PU Concentration
9.2 Configuring PU Concentration
Normally, a dependent LU session requires a direct communications link to the host computer. However, a node
running SNAplus2 that has a direct communications link to the host can also provide PU concentration facilities to
LUs on downstream computers, enabling them to access the host over the communications link from the SNAplus2
node. The downstream computer must contain an SNA PU type 2.0 or 2.1 to support dependent communication
with the host. For example, the downstream computer could be another computer running SNAplus2 in a standalone
configuration.
Using the PU concentration feature, all the data transferred between the host and the downstream computer is
routed through the SNAplus2 local node. This enables a downstream computer to share a host connection with
SNAplus2 or with other downstream computers, instead of requiring a direct link. For example, you can set up
several downstream computers connected to SNAplus2 over a local token ring network, so that they all access the
same long-distance SDLC leased line from SNAplus2 to the host.
Using PU concentration also simplifies the configuration at the host. The host configuration needs to include only
the SNAplus2 computer and its host communications link; the LUs at the downstream computers are configured as
part of the resources of the SNAplus2 computer. The host computer is not aware that PU concentration is being
used.
Before configuring PU concentration, you must perform the following configuration tasks:
• Define the local node as described in Section 4.2,
Configuring the Node.
• Configure a port and link station for dependent traffic between the local node and the host, as described in
Chapter 5, Defining Connectivity Components. Also, configure ports and link stations for dependent traffic
between the local node and the downstream nodes. For downstream links, you can configure a template on the
port to support implicit downstream LUs (LUs that are not explicitly defined on the local node).
• Define the LUs on the local node that are used for communication with the host (the upstream LUs). Upstream
LUs, including Dependent LU 6.2 LUs, must be defined using the LU Type 0–3 Configuration dialog, specifying
an LU type of unrestricted (unknown). To add the LUs, see Section 6.1, Defining LU Types 0–3.
• If you are going to use any LU pools, define them as described in Section 6.2, Defining LU Pools.
To enable PU concentration, you must configure LUs on the local node to support sessions with downstream
workstations. (If you configured a template on the port to support implicit downstream LUs, you may not need to
define downstream LUs explicitly.) The LUs defined on the local node are referred to as “downstream LUs.” To
configure downstream LUs, you need the LU numbers that are used on the downstream nodes, and the name of the
host LU. (The LUs that are defined on the downstream nodes can be any dependent LU type.)
To configure downstream LUs, use one of the following methods:
Motif administration program
Select
PU concentration
and New downstream LU
from the Services
menu on the Node window.
Command-line administration program
Issue one of the following commands:
define_downstream_lu
define_downstream_lu_range
9.2.1 Downstream LU Configuration Parameters
The following parameters are required for downstream LU configuration:
Downstream LU name
A name for each downstream LU. The LU name is used only to identify the LU locally, and does not need
to match any configuration on the downstream node.
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