The information in this article applies to:
- Microsoft SNA Server for Windows NT, versions 2.0 and 2.11
SUMMARY
SNA Server for Windows NT supports up to 250 connections (PUs) over a
single SNA Server 802.2 link service, where each connection is
communicating to a different IBM host, peer system (such as AS/400) or
downstream (DSPU) device. However, to communicate to the same SNA
destination, two SNA Server 802.2 link services and connections must
be configured.
MORE INFORMATION
An SNA Server connection is equivalent to an IBM SNA Physical Unit
Type 2.0 or 2.1. When communicating to different destinations (such as
multiple 3745 and AS/400 computers), SNA Server supports up to 250
simultaneous connections over one 802.2 link service.
However, when communicating to the same destination (for example, to
one 3745), two SNA Server 802.2 link services must be defined through
the SNA Server Setup program (each with it's own SAP address), and a
separate 802.2 connection must be defined through the SNA Server Admin
program to use each 802.2 link service. Note that multiple SNA Server
802.2 link services can operate over a single 802.2 adapter, though
each link service must be configured with a unique SAP address.
To define two SNA Server 802.2 link services in the SNA Server Setup
program, do the following:
- From the Setup Option dialog box, Select Configure Link Services.
- Select Add, then highlight SNA DLC 802.2 Link Service and choose
Install.
- Enter a title describing the link service (or leave the default
title), then select the adapter the link service will use.
- Leave the SAP default to 4
- Repeat the previous steps to add the second 802.2 Link Service,
except in step 4, set the SAP value to 8.
To exit Setup, choose Continue repeatedly until Setup displays an
option to exit or start SNA Admin.
To define an SNA Server 802.2 link service in the SNA Server Admin
program, do the following:
- From the SNA Server Admin program, configure both connections with
the appropriate Remote Network Address (which may be the same for
both connections). Note that the Local Node ID will be unique
for each connection, since each connection must refer to a unique
PU at the host (where the Local Node ID must correspond with the
IDBLK + IDNUM parameters on the PU definition in VTAM).
NOTE: VTAM also supports the configuration of a "CPNAME" (control point
name) parameter in the PU definition. This control point name must match
the local control point name in the "Server Properties" dialog in the
SNA Admin program. SNA Server sends the local network name and control
point name to the host in the XID Format 3 message during connection
establishment. However, SNA Server 2.x only supports the configuration
of a single local network name and control point name. If SNA Server is
to support multiple connections (or PUs) to the same host system, and
VTAM is configured with unique "CPNAME" parameters on each PU, the
SNA Server local network name and control point name values in the
server properties dialog must be left blank, and the Local Node ID
configured on the connection dialog must be used to distinguish the
PU to be used. So, in this configuration, VTAM must be configured with
unique IDBLK and IDNUM parameters for each PU that SNA Server is to use.
- Add the required LUs (and optionally, LU pools) and save the
configuration before restarting the SNA Server service.
SNA Server user/group records can be added after the SNA Server
service has been started, though the configuration must be saved
before these additions are available to the SNA Server client
machine(s).
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