Service Ingress Qos Policies - Alcatel-Lucent 7950 Quality Of Service Manual

QoS Policies
Color Aware Profiling (Policing)
The normal handling of SAP ingress access packets applies an in-profile or out-of-profile state to
each packet relative to the dynamic rate of the queue as the packet is forwarded towards the egress
side of the system. When the queue rate is within or equal to the configured CIR, the packet is
considered in-profile. When the queue rate is above the CIR, the packet is considered out-of-
profile. (This applies when the packet is scheduled out of the queue, not when the packet is
buffered into the queue.) Egress queues use the profile marking of packets to preferentially buffer
in-profile packets during congestion events. Once a packet has been marked in-profile or out-of-
profile by the ingress access SLA enforcement, the packet is tagged with an in-profile or out-of-
profile marking allowing congestion management in subsequent hops towards the packet's
ultimate destination. Each hop to the destination must have an ingress table that determines the in-
profile or out-of-profile nature of a packet based on its QoS markings.
Color aware profiling adds the ability to selectively treat packets received on a SAP as in-profile
or out-of-profile regardless of the queue forwarding rate. This allows a customer or access device
to color a packet out-of-profile with the intention of preserving in-profile bandwidth for higher
priority packets. The customer or access device may also color the packet in-profile, but this is
rarely done as the original packets are usually already marked with the in-profile marking.
Each ingress access forwarding class may have one or multiple sub-class associations for SAP
ingress classification purposes. Each sub-class retains the chassis wide behavior defined to the
parent class while providing expanded ingress QoS classification actions. Sub-classes are created
to provide a match association that enforces actions different than the parent forwarding class.
These actions include explicit ingress remarking decisions and color aware functions.
All non-profiled and profiled packets are forwarded through the same ingress access queue to
prevent out-of-sequence forwarding. Profiled packets in-profile are counted against the total
packets flowing through the queue that are marked in-profile. This reduces the amount of CIR
available to non-profiled packets causing fewer to be marked in-profile. Profiled packets out-of-
profile are counted against the total packets flowing through the queue that are marked in-profile.
This ensures that the amount of non-profiled packets marked out-of-profile is not affected by the
profiled out-of-profile packet rate.

Service Ingress QoS Policies

Service ingress QoS policies define ingress service forwarding class queues and map flows to
those queues. When a service ingress QoS policy is created by default, it always has two queues
defined that cannot be deleted: one for the default unicast traffic and one for the default multipoint
traffic. These queues exist within the definition of the policy. The queues only get instantiated in
hardware when the policy is applied to a SAP. In the case where the service does not have
multipoint traffic, the multipoint queues will not be instantiated.
Page 38 7950 XRS Quality of Service Guide