Queue-Types; Color Aware Profiling - Alcatel-Lucent 7450 Quality Of Service Manual

Queue Parameters

Queue-Types

The expedite, best-effort and auto-expedite queue types are mutually exclusive to each
other. Each defines the method that the system uses to service the queue from a hardware
perspective. While parental virtual schedulers can be defined for the queue, they only enforce
how the queue interacts for bandwidth with other queues associated with the same scheduler
hierarchy. An internal mechanism that provides access rules when the queue is vying for
bandwidth with queues in other virtual schedulers is also needed.

Color Aware Profiling

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.
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• Counters for packets and octets transmitted out-of-profile
Quality of Service Guide