User guide

Packet Over SONET Module Installation and User Guide 3-91
Configuring and Monitoring APS Functions
Configuring APS Timers
To set the values of the timers used in the APS hello protocol that is exchanged between
the working and protection switches for an APS group, use the following command:
config aps <group#> timers <seconds> <consecutive_misses>
The group# parameter is an integer in the range from 1 to 65535 that identifies the APS
group to which this configuration command applies.
The
seconds parameter is an integer in the range from 1 to 300 that specifies the
amount of time the protection switch waits between transmissions of hello packets to
the working switch. The default value is 1.
The
consecutive_misses parameter is an integer in the range from 1 to 100 that
controls the time interval the protection switch waits before assuming that the working
switch has failed. If the working switch does not respond within
consecutive_misses
hello intervals, or (
consecutive_misses * seconds) seconds, the protection switch
assumes that the working switch has failed and initiates a line switch. The default value
is 5.
In some cases, even if the working switch and working line are both operational,
congestion might temporarily slow the response time of the working switch to the
point that the protection switch assumes the working switch has failed, causing
premature or unnecessary line switches. While setting larger values for
seconds
and
consecutive_misses will protect against premature or unnecessary line
switches, they can also delay a line switch when an actual switch failure occurs.
This command applies only to SONET ports performing the protection line
function.
The following command example configures the timers for APS group 1001 to 1 second
and 3 consecutive misses.
config aps 1001 timers 1 3