Variables Of The Simple Shared Shaper Algorithm; Chapter 11 Configuring Variables In The Simple Shared Shaping Algorithm - Juniper JUNOSE 11.1.X - QUALITY OF SERVICE CONFIGURATION GUIDE 3-21-2010 Configuration Manual

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Variables of the Simple Shared Shaper Algorithm

The formulas the simple shared shaper uses contain values maintained by the simple
shared shaper algorithm, and variables that you configure.
The following factors are maintained by the simple shared shaper algorithm:
You can configure the following variables, which correspond to the commands
described in "Configuring Simple Shared Shaper Algorithm Variables" on page 93.
This section describes the algorithm tasks in detail.
Chapter 11: Configuring Variables in the Simple Shared Shaping Algorithm
Variables of the Simple Shared Shaper Algorithm on page 91
Configuring Simple Shared Shaper Algorithm Variables on page 93
newMeasuredRate Sum of bytes enqueued to non-best-effort constituent queues,
in bps.
oldDynamicRate Dynamic shaping rate from the previous rate period, in
bits-per-second.
sharedShapingRate Configured shared shaper rate, in bps. The shared shaping
rate is the total rate of all constituents of the shared shaper.
convergenceFactor Controls the convergence of the dynamic shaping rate to
the calculated shaping rate, expressed as a percentage of the available bandwidth.
The default value of 50 percent causes the dynamic shaping rate to converge by
half of the available rate each period. For example, when the dynamic rate of a
5 Mbps simple shared shaper is 1 Mbps, and the measured rate goes from 4
Mbps to 0 Mbps, 4 Mbps of bandwidth becomes available. The simple shared
shaper converges from 1 Mbps to 5 Mbps by half of the available bandwidth per
period. In this example, the dynamic shaping rates for several periods are 1
Mbps, 3 Mbps, 4 Mbps, 4.5 Mbps, 4.75 Mbps, and so on.
maximumVOQL Sets the maximum virtual output queue length (VOQL),
expressed in milliseconds (ms) of the shared shaping rate.
The default value of 4000 indicates that a 5 Mbps shared shaper does not allow
the VOQL to exceed 20 Mbps. Smaller values reduce the effect of the VOQL in
the simple shared shaper algorithm.
A maximum VOQL of 0 indicates that the shared shaper ignores the VOQL. This
setting is appropriate for configurations where exceeding the shared shaping
rate for brief periods of time does not cause downstream queuing.
minimumDynamicRate Sets the minimum value for the dynamic shaping rate,
expressed as a percentage of the shared shaping rate. For example, a value of
25 for a 20 Mbps shared shaper specifies that the dynamic shaping rates never
be set to a value less than 5 Mbps. The default value is 0.
reactionFactor Controls how the simple shared shaper reacts to changing rates,
expressed as a percentage. The default value of 200 changes the algorithm to
use 200 percent of the changing rate.
Variables of the Simple Shared Shaper Algorithm
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