Alvarion BreezeACCESS EZ AU-EZ, System Manual

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Chapter 4 - Operation and Administration Menus and Parameters
BreezeACCESS EZ AU-EZ 117 System Manual
Under normal conditions, the actual Information Rate (IR) is between the 0 to the
MIR values, based on the formula IR= K*MIR.
In this formula K is between 0 and 1 and is determined dynamically by the AU
according to overall demand in the cell and the prevailing conditions that
influence the performance of the wireless link.
The MIR/CIR algorithm uses buffers to control the flow of data. To balance the
performance over time, a special Burst Duration algorithm is employed to enable
higher transmission rates after a period of inactivity. If no data intended for a
certain SU is received from the Ethernet port during the last N seconds, the unit is
allowed to transmit to this destination N times its allowed IR value without any
delay. For example, if the Burst Duration is set to 0.5 second (or more), then after
a period of inactivity of 0.5 seconds up to 128 Kbits x 0.5 = 64 Kbits may be
transmitted to a unit whose IR is 128 Kbps, without any delay (provided overall
conditions in the wireless link allow this burst).
The MIR and CIR parameters are
4.2.6.6.2.1 MIR: Downlink for SU-EZ
Sets the Maximum Information Rate of the downlink from the AU to each of the
SUs.
Available values range is from 128 to 12032 (Kbps)
The default value is 12032 (Kbps).
The actual value will be the entered value rounded to the nearest multiple of 128
(N*128).
4.2.6.6.2.2 Maximum Burst Duration
Sets the maximum time for accumulating burst transmission rights according to
the Burst Duration algorithm.
Available values range from 0 to 2000 (milliseconds).
The default value is 5 (milliseconds), enabling a maximum burst of (0.005 X CIR)
Kbps after a period of inactivity of 5 milliseconds or more.
4.2.6.6.2.3 Graceful Degradation Limit
Sets the limit on using the graceful degradation algorithm. In cases of over
demand, the performance of all SUs is degraded proportionally to their CIR
(IR=(100%-k%) x CIR). The graceful degradation algorithm is used as long as k

K, where K is the Graceful Degradation Limit. Beyond this point, the simple "brute
force" algorithm is used. The Graceful Degradation Limit should be raised in
proportion to the demand in the cell. The higher the expected demand in a cell,
the higher the value of the Graceful Degradation Limit. Higher demand can be