OSI/TS Configuration and Management Manual

Configuring the OSI/TS Subsystem
OSI/TS Configuration and Management Manual—424831-001
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Connection-Related Attributes
DISCONNECTTIMEOUT Attribute
The DISCONNECTTIMEOUT attribute is similar to CONNECTTIMEOUT it, too,
negatively affects throughput if the value is set too high. This attribute defines the
amount of time TSP waits for a response to a DR-TPDU.
If this value is set too high, connections could be delayed by being unnecessarily tied up
during the connection-release timeout period. If set too low, a user issuing an abort
request or a release response could be disconnected due to the expiration of the timer
instead of the agreement with the remote user. You should be careful, however, to set
the value high enough to allow processing of outstanding data received before the
disconnection is completed.
CLASS Attribute
The CLASS attribute specifies the transport class to be used on the connection. You
should select a transport class that matches the network type. For example, if the
network is extremely reliable, you probably do not need to specify class 4, which incurs
more overhead because of the error-detection procedures. (Of course, if you are using a
LAN, or you are using SNDCF or OSI IP over an X.25 network, you are required to
select class 4.)
In general, class 4 incurs the greatest overhead, class 1 and class 3 incur less overhead,
class 2 incurs even less overhead, and class 0 incurs the least overhead.
CIRCUITS and X25PORT Attributes
The CIRCUITS attribute specifies the total number of circuits allowed on an X25AM
line. It is a SYSGEN attribute. When setting this value, you should consider the
frequency of connections, the amount of traffic involved on the X25AM line, and the
amount of multiplexing of transport connections that may be taking place. If this value
is set too high, the X25AM lines could get overloaded. If multiplexing is not used very
often, the demand for virtual circuits on your network connections increases. You may
need to increase the number of circuits to prevent delays when all the circuits are in use.
See Section 5, OSI Transport Services
for more information on multiplexing.
Use the X25PORT attribute to specify port numbers. Since this attribute directs
connections to specific destination ports, it is useful for controlling traffic and
establishing traffic priorities.
X25PVC Attribute
The X25PVC attribute specifies the logical channel number of the permanent virtual
circuits (PVCs) to which the subdevice is to be bound. You can use PVCs to reduce the
amount of overhead associated with X25AM connection establishment. Be careful,
however, not to overuse this attribute, since PVCs used for relatively infrequent traffic
can negatively affect other users when there is contention for the use of virtual circuits.