Visara LINCS Features - Manual (Page 23)

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3. DSPU Support
Gateway Circuits
PU Passthrough
This feature allows a LINCS node to act as a SNA gateway between Downstream Physical
Units (DSPUs) and an upstream SNA host. Each host PU that is mapped to a DSPU is called
a gateway circuit. SNA data for gateway circuits is passed through the LINCS node but the
link layer connections to the host and the DSPU are maintained as separate logical links.
LINCS does not tunnel any protocol and therefore is not susceptible to link level timeouts,
retries, and lost sessions. All combinations of the upstream and downstream protocols listed
below are supported.
Configuration and Management
Configuration - The following lists the Configuration utilities which are used to define
Gateway Circuits. The “Gateway Menu” in Configuration will guide you through these
configuration utilities.
• The Line Options utility should be used to define the lines you will be using for your
upstream and downstream connections. The appropriate protocols should be enabled on the
Line Options panels.
• A Link Profile should be defined for each protocol you will be using. The profiles are used
to define link parameters which may be shared by any or all of your Gateway Circuits. A
single profile may be assigned to links with the same protocol, thus eliminating the need to
configure this link type information for each upstream and downstream connection.
• A Gateway Circuit panel must be defined for each connection to a DSPU. A line and
link profile must be assigned to each upstream and downstream connection you define.
These panels are used to define unique information for each connection, such as
addressing information.
Management - The “Communications Menu” in Central Control Mode contains many utilities
to help you determine the status of your Gateway Circuits. From this menu, you can determine
the status of your communication lines or of individual Gateway Circuits. Also, depending
upon the protocol(s) being used, you may access one of the protocol submenus (e.g., TCP/IP
Menu, LLC Menu) to get more specific information, please refer to the Communication Menu
in Central Control Mode for more information.
Upstream Protocols
Any of the following protocols can be used as an upstream protocol to connect a PU2.0 SNA
DSPU to a 3270 host:
• Channel (Bus and Tag, or ESCON)
• Frame Relay/LLC
• LAN/LLC
• SDLC
• TCP/IP
• X.25
• APPN DLUR