Visara LINCS Configuration - Manual (Page 109)

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5. Gateway Circuits
When entering the Gateway Circuits panel from the Configuration Menu, a gateway circuit
number may be entered as a parameter. Entering a specific circuit number as a parameter will
advance the display directly to that gateway circuit. This is useful if many gateway circuits
are defined and you wish to change a particular circuit.
Note that if gateway circuits are configured for a given line, and the line is taken away using
the Product Description Panel, then the Gateway Circuit panels must be updated to remove
all references to the deleted line.
The Gateway Circuit utility is only displayed if two or more valid lines are configured, and at
least one valid Link Profile is defined.
Gateway Concepts
The gateway function allows LINCS to act as a link between downstream devices and upstream
hosts. A gateway circuit defines a data path through the LINCS node. Each gateway circuit
represents a logical connection from one SNA PU address or LAN line (upstream connection)
to one downstream SNA PU. Gateway circuits are also used to define an upstream IP channel
connection to a LAN card dedicated for downstream IP connections, when the IP Channel
Bridge feature is installed.
A gateway circuit cannot have the upstream and downstream connection through the same
physical interface. If that were the case, the DSPU should access the host directly. For example,
if a host is connected by Token Ring to a gateway LINCS node and another PU, define that
PU as directly connected to the host. One exception to this is if LU to PU Mapping is being
used to communicate with the downstream device.
While defining gateway circuits, you should keep the connection limitations in mind. Refer
to the table Maximum Connection Limitations for a list of these limitations.
The Gateway Circuit diagram indicates the upstream SNA hosts that can be accessed by a
downstream SNA node (DSN) using a gateway circuit.