Expand Management Programming Manual

EVENT MANAGEMENT
Example of Event-Message Retrieval
EXAMPLE OF EVENT-MESSAGE RETRIEVAL
The following example is presented as modifications to the
example of retrieving event messages in Appendix C of the
Event Management Service (EMS) Manual . To use this example,
you will need to begin with the example in that manual and
its accompanying text. The text below explains the specific
modifications to be made to the basic example so that it
retrieves and handles a particular event message from the EXPAND
subsystem. Following the text are a filter and an event-handling
module to be substituted for the corresponding modules in the
basic example.
For the substitute event-handling module provided below, only TAL
code is given. You could write a TACL or COBOL85 module to
perform the same functions.
The filter in this EXPAND example selects only those event
messages with event number 33, ZEXP-EVT-NET-LINE-QUAL, and the
EXPAND subsystem ID. This event message indicates that a
positive or negative change of 5% or more has occurred in the
transmission quality of an EXPAND line.
This example begins by prompting the operator for a line-quality
threshold value (rather than for a CPU number). Instead of
displaying the retrieved event message, this example checks
whether the reported line quality is less than the operator-
specified threshold value (a typical value might be 60) and, if
so, brings the line down (stops the line) and generates an event
message of its own indicating that it has done so. In stopping
the line, it uses several modules of the example already given in
Section 7.
This example is intended to be an illustration of the basic
programming features one might use in handling an event message
from the EXPAND subsystem; it does not necessarily represent a
reasonable event-handling strategy for any given network. In
reality, you would probably need to use more complex logic. For
instance, you would likely want to do additional checks first to
determine whether the line should really be brought down. If
the line provides the only available path between two nodes, you
might want to use an alternate strategy. There are many other
possible considerations.
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