Alcatel-Lucent 7450 Quality Of Service Manual page 341

Service Egress and Ingress QoS Policies
Context config>qos
Description
This command is used to create or edit a Service Egress QoS policy. The egress policy defines the
Service Level Agreement (SLA) for service packets as they egress on the SAP.
Policies in effect are templates that can be applied to multiple services as long as the scope of the policy
is template. The queues defined in the policy are not instantiated until a policy is applied to a service.
A sap-egress policy differs from sap-ingress policies in the complexity of the QoS parameters that can
be defined. At ingress, policies determine queue mappings based on ingress DSCP, Dot1P and IP or
MAC match criteria. Multiple queues can be created per forwarding class and each queue can have
different CIR or PIR parameters.
At egress, the policies are much simpler, as the forwarding class and in or out of profile determination
happened way back at the original service ingress SAP. Egress SAP QoS policies allow the definition
of queues and the mapping of forwarding classes to those queues. Each queue needs to have a relative
CIR for determining its allocation of QoS resources during periods of congestion. A PIR can also be
defined that forces a hard limit on the packets transmitted through the queue. When the forwarding
class is mapped to the queue, a Dot1p value can optionally be specified. If specified and the SAP has
a Dot1q encapsulation type, the Dot1p value will be used for all packets that egress on that forwarding
class. If the Dot1p value is not specified, a Dot1p value of zero will be used. If the SAP is null
encapsulated, or on a SONET/SDH interface, the Dot1p value has no meaning.
A default-action parameter is required to specify the default queue used by all forwarding classes not
specifically mapped within the queue parameters. A sap-egress policy will be considered incomplete,
if it does not include definition of at least one queue and does not specify the default action. Incomplete
sap-egress policies cannot be applied to services.
The sap-egress policy with policy-id 1 is the default sap-egress QoS policy and is applied to service
egress SAPs when an explicit policy is not specified or removed. The system sap-egress policy can be
modified but not deleted. Using the no sap-egress command on policy-id 1 causes it to revert to its
factory default parameters.
The factory default settings for sap-egress policy-id 1 define a single queue with PIR set to the
maximum value and a CIR set to 25. The single queue is the default queue and all forwarding classes
will map to it. Packets being tagged according to the SAP encapsulation defined will have the Dot1p
bits set to zero.
Any changes made to an existing policy, using any of the sub-commands, will be applied immediately
to all egress SAPs where this policy is applied. For this reason, when many changes are required on a
policy, it is highly recommended that the policy be copied to a work area policy-id. That work-in-
progress policy can be modified until complete and then written over the original policy-id. Use the
config qos copy command to maintain policies in this manner.
The no form of this command to deletes the sap-egress policy. A policy cannot be deleted until it is
removed from all service SAPs where it is applied. When a sap-egress policy is removed from a SAP,
the SAP will revert to the default sap-egress policy-id 1.
The system default sap-egress policy is a special case. The no command restores the factory defaults
to policy-id 1.
Quality of Service Guide 341