Policer Interaction with Initial Profile, Discard Eligibility, and Ingress Priority
862 Quality of Service Guide
Priority high and low are used in the child policer’s PIR leaky bucket to choose one of two
discard thresholds (threshold-be-low and threshold-be-high) which are derived from the child
policer’s mbs and high-priority-only parameters. The high threshold is directly generated by
the mbs value. The low threshold is generated by reducing the mbs value by the high-priority-
only percentage. A packet’s priority is determined while the packet is evaluated against the
ingress classification rules in the sap-ingress QoS policy.
Packets that are offered to an egress policer may have four different states relative to initial
profile:
• soft-in-profile—The final result at ingress was in-profile and the profile of the
packet’s profile has not been reclassified at egress.
• soft-out-of-profile—The final result at ingress was out-of-profile and the packet's
profile has not been reclassified at egress.
• hard-in-profile—The profile of the packet has been reclassified at egress as profile in.
• hard-out-of-profile—The profile of the packet has been reclassified at egress as
profile out.
When an egress policer’s CIR rate is set to 0 (or not defined), the policer will have no effect
on the profile of packets offered to the policer. The soft-in-profile and hard-in-profile packets
will remain in-profile while the soft-out-of-profile and hard-out-of-profile packets will
remain out-of-profile.
Setting a non-zero rate for the egress policer’s CIR will modify this behavior for DSCP, prec,
Dot1P, and DEI egress marking purposes. Both soft-in-profile and hard-in-profile retain their
inherent in-profile behavior and the soft-out-of-profile and hard-out-of-profile retain their
inherent out-of-profile behavior.
For egress marking decisions, the hard-in-profile and hard-out-of-profile packets ignore the
egress policer’s CIR state. When the packet state is hard-in-profile, the in-profile Dot1P
marking will be used and when DEI marking is enabled for the packets forwarding class it
will be marked 0. When the packet state is hard-out-of-profile, the out-of-profile Dot1P
marking will be used and when DEI marking is enabled for the packets forwarding class it
will be marked 1.
When the egress packet state is soft-in-profile and soft-out-of-profile and the policer’s CIR is
configured as non-zero, the current CIR state of the policer’s CIR bucket will override the
packets soft profile state. When the policer’s CIR is currently conforming, the output will be
in-profile. When the CIR state is currently exceeding, the output will be out-of-profile. If
enable-exceed-pir is configured, when the PIR state is exceeding, the output will be exceed-
profile. The Dot1P, outerDot1P, and DEI (when DE marking is configured) will reflect the
CIR and PIR derived packet state. If enable-dscp-prec-marking is enabled, the DSCP and
prec will reflect the CIR and PIR derived packet state.
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