Alcatel-Lucent 7950 Quality Of Service Manual page 229

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Egress Slope Mapping
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The specified policy contains a value that defines the queue's MBS value (queue-mbs). This is the maximum
depth of the queue specified in bytes where all packets start to discard. The high and low priority RED
slopes provide congestion control mechanisms that react to the current depth of the queue and start a random
discard that increases in probability as the queue depth increases. The start point and end point for each dis-
card probability slope is defined as follows:
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Up to 1024 HSMDA slope policies may be configured on a system.
The system maintains a slope policy named hsmda-default which acts as a default policy when an explicit
slope policy has not been defined for an HSMDA queue. The default policy may be edited, but it cannot be
deleted. If a no slope-policy hsmda-default command is executed, the default slope policy returns to the fac-
tory default settings. The factory default settings are as follows:
High Slope:
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Low Slope:
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Time-Average-Factor: 0
The no form of the command restores the association between the queue and the HSMDA default slope pol-
icy. The command has no immediate effect for queues that have a local override defined for the slope policy.
7950 XRS Quality of Service Guide
Profile-Undefined, High Priority — High Slope
Out-of-Profile Low Slope (priority ignored)
Profile-Undefined, Low Priority — Low Slope
In-Profile from ingress — High Slope
Out-of-Profile from ingress — Low Slope
Start-Utilization — This is defined as percentage of MBS and specifies where the discard
probability for the slope begins to rise above 0%. (A corresponding Start-Probability parameter is
not needed as the start probability is always 0%.
Maximum-Utilization — This is also defined as a percentage of MBS and specifies where (based
on MBS utilized) the discard probability rises to 100%. This is the first portion of the knee
coordinates and is meaningless without the Maximum-Probability parameter.
Maximum-Probability — This is defined as a percentage of discard probability and in conjunction
with maximum-utilization completes the knee coordinate where the discard probability deviates
from the slope and rises to 100%.
Start-Utilization 100%
Max-Utilization 100%
Max-Probability 100%
Shutdown
Start-Utilization 90%
Max-Utilization 90%
Max-Probability 1
No Shutdown
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