Alvarion BreezeACCESS II, System Manual

Page: 156 / 324

2-26
BreezeACCESS Version 4.5 Operations and Administration
Manual Revision: 1.0
In addition, the Average Rate is also calculated for each of the above
traffic statistics rates, using the formula Ra(t)=[Rc*1 +Ra(t-1)*5]/6,
where:
Rc - Current Rate
Ra(t) - The new value of the Average Rate for the applicable rate.
Ra(t-1) - the previous Average Rate of the applicable rate.
For the first test cycle after reset (or after enabling the AU Alarms
Option ), Ra= Rc.
For each traffic statistics type, three values can be configured:
a. Minor Alarm Threshold - The threshold for decision on a
minor severity alarm for the applicable traffic statistics type.
b. Major Alarm Threshold - The threshold for decision on a
major severity alarm for the applicable traffic statistics type.
c. Minimum Minor Alarm Delta - serves in the minor alarm
decision process, as described below.
A minor severity alarm is generated if both of the following conditions
are met:
a. The Current Rate of the applicable rate exceeds the Minor
Alarm Threshold for this traffic statistics type.
b. The Current Rate is higher than the Average Rate by at
least the value of the Minimum Minor Alarm Delta ,
indicating a rapid decrease in performance.
A minor severity alarm will also be generated if the Current Rate
dropped below the applicable Major Alarm Threshold but is still higher
than the applicable Minor Alarm Threshold . (Alarm status changed
from major to minor).
A major severity alarm is generated if the Current Rate has increased
above the Major Alarm Threshold for the applicable traffic statistics
type.
Power Tests
Each test cycle, the AU transmits a multicast SNAP (Sub Network
Access Protocol) polling message to its associated SUs. The SUs must
respond to this message within a given time frame. The response
message includes the last RSSI level at which the SU receives
transmissions from the AU.