OSI/TS Configuration and Management Manual

Configuring the OSI/TS Subsystem
OSI/TS Configuration and Management Manual—424831-001
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X25AM Subdevice Management
Applications that use X25AM open these subdevices directly and call NonStop Kernel
procedures, such as WRITEREAD, to initiate connections and transfer data across an
X.25 network.
However, when X25AM is to be used exclusively by OSI/TS, you do not need to define
any subdevices. TSP adds subdevices to and deletes subdevices from the I/O processes
dynamically, in response to application requests for services.
Nevertheless, you do need to preconfigure the parameters that the OSI/TS subsystem
uses to create the X.25 subdevices. You define X.25 subdevice parameters in either of
two ways:
•
Use SCF to alter the Layer 3 SERVICE object for your OSI/TS subsystem.
•
Use SCF to add SU objects to your OSI/TS subsystem.
X25AM Subdevice Management
The following information describes how the OSI/TS subsystem names, creates, and
deletes X25AM subdevices.
Naming X25AM Subdevices
When interfacing with X25AM, the TSP process builds an X25AM subdevice name by
using the first four characters of its own TSP process name after the$ sign as the prefix,
followed by a three-character alphanumeric string. This method allows for easy
identification and prevents possible duplicate names created by other TSP processes.
If more than one TSP process is using the same X25AM line across an Expand network,
the first four characters after the $ sign of all the TSP process names must be unique
across that network. Two TSP processes having the same first four characters after the
$ sign in their process names can potentially cause problems–the two processes may
build similar subdevice names, based on their similar process names. In such a case,
one process, while trying to add an X25AM subdevice, may abort a subdevice that is
being used by the other process.
Creating X25AM Subdevices: Connect Requests
When a connect request is received, the TSP process determines whether to create a new
X25AM subdevice or to use an existing subdevice, based on the following criteria:
•
Configured transport class protocol
•
Value of the X25PVC attribute
•
Values of the MULTIPLEX and X25NCONMULTIPLEX attributes
•
Presence of existing but unused network connections (a possibility that is dependent
on the X25DISCONNECTDELAY attribute)