Specifications

System Configuration Files
282 025-9035AA
processed and they should try again later. The call is then terminated as appropriate to the
line type.
If the call is being rejected because of excessive delays at the transmitter (not because of
lack of memory space), PageSaver subscribers may enter owner access mode by
overdialing “0” during the load management prompt.
Alpha entry is handled in a similar manner. Alpha entry logon is not restricted by load
management. After a pager number is entered, the system load is checked; if the page
cannot be accepted, the message “System busy” is displayed on the entry device.
Performance Monitoring
There are two measures of system performance that must be monitored: memory usage
and paging delay time. They differ in that excessive memory usage affects all calls equally
(when there is no memory, no calls may be processed), whereas excessive delay may
occur on one channel while another may be almost unused.
The system monitors memory that is in use and memory that is available. This information
is valuable in making load management decisions.
Paging delay is measured in number of pages queued to a channel. The relationship
between the number of pages queued and the average delay will vary from system to
system depending on the paging formats in use and must be determined by the system
operator.
The destination zone on the channel is not considered in delay calculations. A page on a
low-traffic zone only adds to the delay on a busy zone, so it is important to factor in the
traffic on the busier zones when deciding whether or not to page.
Load Management Parameters
The threshold values that activate load management mechanisms are determined by load
management parameters. There is thus a close correlation between performance
monitoring and the specified parameters. Default values are supplied for parameters not
set by the system operator.
The most important consideration in managing memory usage is to ensure that resources
are always available for Next Out and Breakthrough pages. A sufficient amount of free
memory must be kept in reserve for these high-priority pages. This is specified by an
internal software parameter and is not accessible to the system operator. Note that Next
Out and Breakthrough priorities must be used very cautiously and sparingly for them to
operate correctly.
When a call has been processed to the point where the subscriber has been looked up in the
database and the priority is known, if the priority is less than “Next Out” the free memory
space is checked. If it is less than the reserved amount, the call is rejected.
PageSaver message retrieval uses a large amount of memory while it is in progress. If a
PageSaver subscriber attempts to retrieve messages the free memory is checked again,