Introduction to SNA Capabilities of Tandem NonStop Systems

Connectivity
Introduction to SNA Capabilities of Tandem NonStop Systems–134597
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Serving SNA Devices Controlled by a Separate SNA
Host
Serving SNA Devices Controlled by a Separate SNA
Host
SNAX/APN and (on K-series servers) SNAX/CDF provide two different solutions for
serving SNA devices that are controlled by a separate SNA host (see Figure 2-4). The
Tandem system and SNA devices can be in the same SNA network, directly connected
SNA networks or remotely-connected SNA networks.
This provides, for example, an easy method of giving an existing network of SNA
devices access to Tandem applications. The SNA devices can log onto, or be acquired
by, applications running anywhere in the Tandem Expand network.
The SNAX/APN solution is called the SNAX/APN extended logon facility (XLF).
Corequisite Software
If you require Tandem applications to be started dynamically when devices log on, you
need Creator software (for SNAX/CDF) or SNAX Creator-2 software (for SNAX/APN).
This software starts the requested Tandem application, typically a TACL process or a
Pathway application that uses one of the SNAX/CDF or SNAX/APN APIs.
To allow the SNA devices to log on, the SNAX/APN XLF solution requires the Tandem
Logon Manager for IBM Systems (ILOGMGR) software running on the SNA host.
SNAX/CDF requires EnvoyACP/XF software to handle physical connections. To allow
communication across SNA networks, SNAX/CDF requires that the networks be
bridged using SNA network interconnect (SNI).
Comparing the Solutions
The main differences between the solutions are indicated below:
SNAX/APN XLF Solution SNAX/CDF Solution
Easier to configure or reconfigure because
devices are dynamically configured
More difficult to configure or reconfigure,
because you must define routing in the SNA
subarea network
Uses open architecture (APPN) Uses IBM-proprietary architecture
(subarea networking)
Supports several types of connections to
SNA networks (switched or nonswitched
SDLC, X.25 PVCs, and Token-Ring)
Supports only one type of connection to SNA
networks (nonswitched SDLC)
Requires Tandem software (ILOGMGR) on
the SNA host
No Tandem software on the SNA host
Communication across SNA networks
possible without using SNA network
interconnect (SNI)
Communication across SNA networks
requires that the networks be bridged using
SNA network interconnect (SNI)