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associated slope policy are immediately applied to the queues using the slope policy.
Within the ingress and egress QoS policies, packets are classified as high priority or low-priority. For color
aware policies, packets are also potentially classified as in-profile, out-of-profile or profile-undefined. Based
on these classifications, packets are mapped to the RED slopes in the following manner:
Ingress Slope Mapping
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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
discard 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
factory default settings. The factory default settings are as follows:
High Slope:
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Low Slope:
7450 ESS OS Quality of Service Guide
In-Profile — High Slope (priority ignored)
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
Operational Commands
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