Alcatel-Lucent 7450 Quality Of Service Manual page 295

Egress Slope Mapping
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:
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:
Low Slope:
Time-Average-Factor: 0
The no form of the command restores the association between the queue and the HSMDA default slope
policy. The command has no immediate effect for queues that have a local override defined for the
slope policy.
Quality of Service Guide
• 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
Service Egress and Ingress QoS Policies
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