Policer Interaction With Initial Profile, Discard Eligibility, And Ingress Priority - Alcatel-Lucent 7450 ESS OS Quality Of Service Manual

Policer Interaction with Initial Profile, Discard Eligibility, and Ingress Priority

Policer Interaction with Initial Profile, Discard Eligibility,
and Ingress Priority
Packets that are offered to an ingress policer may have three different states relative to initial
profile:
•
•
•
Ingress policed packets are not subject to ingress queue CIR profiling within the ingress policer
output queues. While the unicast and multipoint shared queues used by the system for ingress
queuing of policed packets may have a CIR rate defined, this CIR rate is only used for rate based
dynamic priority scheduling purposes. The state of the CIR bucket while forwarding a packet from
a policer-output-queues shared queue will not alter the packets ingress in-profile or out-of-profile
state derived from the ingress policer.
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:
•
•
•
•
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.
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undefined—Either the forwarding class or sub-class associated with the packet is not
explicitly configured as profile in, profile out or de-1-out-profile is enabled and the Dot1P
DE bit is set to zero.
in-profile—The forwarding class or sub-class associated with the packet is configured as
profile in.
out-of-profile—The forwarding class or sub-class associated with the packet is configured
as profile out or de-1-out-profile is enabled and the Dot1P DE bit is set to 1.
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.
7450 ESS OS Quality of Service Guide