Svc Sharing Considerations - HP Spooler FASTP Manual

Installation and Configuration Considerations for
FASTPX25

The NUA can be configured in the FASTCNFG configuration file using the X25NUA
parameter in a DEVICE entry. When the NUA is configured using the X25NUA
parameter, one SVC per printer can be configured or several printers can share a
pool of X.25 subdevices (SVCs).
Note that for devices configured using the X25NUA parameter, FASTPX25 uses
the SPI interface to solicit subdevice information from X25AM. A Subsystem
Control Process (SCP) must therefore be running in the system. FASTPX25
assumes that an SCP process named $ZNET is running. You can change this
default by adding a suitable DEFINE before starting the Spooler supervisor. For
example:
>ADD DEFINE =SCP, FILE $ZSCP.#ZSPI
Note that the process qualifier #ZSPI is mandatory.

SVC Sharing Considerations

You can specify a pool of SVCs by using either the SVCLIST or SVCMACRO modifier
in a FASTCNFG DEVICE entry. Either of these modifiers allows FASTPX25 to select a
free SVC from a pool before establishing a connection to the remote NUA which
permits effective sharing of a smaller number of SVCs by a larger number of Spooler
devices. When either of these modifiers is used, the NUA must be configured by using
the X25NUA attribute in a FASTCNFG DEVICE entry.
Using SVC sharing can provide a degree of security against problems in lines between
the HP host and the X.25 network. By specifying SVCs from different lines in the same
list, FASTPX25 can print even if an entire X.25 line is down.
Each SVC list can contain up to 256 entries, but the total number of unique SVCs
known to a single FASTPX25 print process must also not exceed 256. The same SVCs
can be referenced by different FASTPX25 print processes, however, collisions are only
noticed when an open fails with Guardian error 12. Although collisions do not prevent
jobs being printed, CPU costs increase because of the failed opens; therefore,
whenever possible, you should configure a distinct pool of SVCs for each FASTPX25
print process.
When FASTPX25 opens a device that is configured for SVC sharing, it searches for
the first SVC in the list that is not known to be busy with another Spooler device.
FASTPX25 then attempts to open this SVC in order to establish the connection and
print the job.
If the open fails for any reason, FASTPX25 moves onto the next SVC known to be free.
If the open fails for any other reason than FEINUSE (12), FASTPX25 logs a warning
message to $0. If the open fails with FEINUSE (12), FASTPX25 assumes that another
process is using the SVC and moves onto the next SVC in the list without printing a
warning.
If the job fails to print for any reason, FASTPX25 starts the search for a free SVC from
the next SVC in the list when the Spooler supervisor instructs FASTPX25 to open the
device once again.
Spooler FASTP Network Print Processes Manual — 427528-006
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SVC Sharing Considerations