Profile Preferred Mode Root Policers
870 Quality of Service Guide
Egress supported stat-modes are:
• no-stats
• minimal - default
• offered-profile-no-cir
• offered-profile-cir
• offered-total-cir
• offered-limited-capped-cir
• offered-profile-capped-cir
• offered-total-cir-exceed
Details of the output showing the stat-modes for ingress and egress child policers can be
found in the Class Fair Hierarchical Policing for SAPs section of the SR OS Advanced
Configuration Guide.
Profile Preferred Mode Root Policers
The profile-preferred option ensures that the root policer provides a preference to consume
its PIR bucket tokens at a given priority level to packets which have their profile state been
set to in-profile by the output of the child policer CIR bucket.
When this option is selected, all child policers parented to a root policer will have their FIR
bucket track the state of the CIR bucket. In other words, a green packet will always be blue
and a yellow packet will always be orange. When admitting packets from the child policers
within a given priority level, orange packets will be allowed up to the "discard-unfair"
threshold while blue packets will be allowed up to the "discard-all" threshold. The operation
is unchanged if a child policer is configured to forward traffic exceeding its PIR, specifically,
the exceed profile traffic is treated in the same way as yellow/orange (out of profile) packets.
HPOL will no longer set the FIR bucket of the child policer based on fair share calculation.
Instead, the ‘profile-preferred’ option forces the FIR bucket to track the CIR bucket’s
decrement rate and the threshold chosen for the CIR bucket would also be used in the FIR
bucket (instead of using the threshold associated with the PIR bucket).
The green/yellow output from the policer would be used for packet marking decisions. The
blue/orange child policer input to the parent policer would chose the discard-orange or
discard-all thresholds for the child policer’s priority level within the parent policer.
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