Service Egress and Ingress QoS Policies
322
Quality of Service Guide
3HE 11014 AAAC TQZZA Edition: 01
For service egress queues, the PIR defines the maximum rate that the queue can transmit
packets out an egress interface.
When the PIR is set to max on a SAP-ingress queue, the max value defaults to the physical
port line rate. On a SAP-egress queue, the PIR is set to the physical port line rate.
The no form of the command returns all queues created with the queue-id by association with
the QoS policy to the default PIR and CIR parameters (max, 0).
Default rate max cir 0 (this default specifies the amount of bandwidth in kb/s. The max value and the
pir-rate value are mutually exclusive.)
Parameters pir-rate — defines the administrative PIR rate, in kb/s, for the queue. When the rate
command is executed, a valid PIR setting must be explicitly defined. When the rate
command has not been executed, the default PIR of max is assumed. Fractional
values are not allowed and must be given as a positive integer. The PIR rate has a
minimum value of 8 kb/s.
The actual PIR rate is dependent on the queue’s adaptation-rule parameters and the
actual hardware where the queue is provisioned.
Values 1 to 100000000 | max
Default max
Caution: The rate command can be executed at any time but should be executed during a
maintenance window because the command can be service-affecting. Altering the PIR and
CIR rates affects all queues created through the association of the service ingress or service
egress QoS policy with the queue-id.
Note: The ingress traffic to an Epipe, Ipipe, IES, VPLS, and VPRN service may be shaped
to a lower rate than the PIR and CIR values configured in the SAP ingress policy.
At SAP ingress, the CIR and PIR settings under rate include both payload (customer) traffic
and overhead traffic, which affects the shaping rate internally. Additional overhead bytes
include the internal fabric header minus any bytes that have been removed from the original
packet (such as the four-byte FCS).
At SAP ingress, the actual shaping rate is related to the service rate (PIR or CIR) specified
in the SAP ingress QoS policy, as shown below:
Shaping rate (actual) = (PIR or CIR) / ratio
where ratio = (customer packet size + additional bytes - removed headers -
4 byte FCS) / (customer packet size)
At SAP egress, shaping does not include the FCS, so the actual shaping rate is a bit higher
than the PIR/CIR ratio configured in the QoS policy.
Shaping rate (actual) = (PIR or CIR) / ratio
where ratio = (customer packet size - 4 byte FCS) / (customer packet size)
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