Egress Forwarding Class Override; Service Egress Qos Policies; Figure 2: Egress Forwarding Class Override - Alcatel-Lucent 7950 Quality Of Service Manual

QoS Policies

Egress Forwarding Class Override

Egress forwarding class override provides additional QoS flexibility by allowing the use of a
different forwarding class at egress than was used at ingress.
The ingress QoS processing classifies traffic into a forwarding class (or sub-class) and by default
the same forwarding class is used for this traffic at the access or network egress. The ingress
forwarding class or sub-class can be overridden so that the traffic uses a different forwarding class
at the egress. This can be configured for the main forwarding classes and for sub-classes, allowing
each to use a different forwarding class at the egress.
The buffering, queuing, policing and remarking operation at the ingress and egress remain
unchanged. Egress reclassification is possible. The profile processing (in/out) is completely
unaffected by overriding the forwarding class.
When used in conjunction with QPPB (QoS Policy Propagation Using BGP), a QPPB assigned
forwarding class takes precedence over both the normal ingress forwarding class classification
rules and any egress forwarding class overrides.
Ingress (Service 1):
EF
AF21
AF11
BE
Ingress (Service 2):
EF
CP3
Classification
CP2
CP1
BE
Figure 2
for the network egress, while it also shows ingress service 2 using forwarding classes L1, AF, and
L2 that are overridden to AF for the network egress.

Service Egress QoS Policies

Service egress queues are implemented at the transition from the service core network to the
service access network. The advantages of per-service queuing before transmission into the access
network are:
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FC EF
FC AF
FC L1
FC BE
FC EF
FC L2
FC AF
FC L1
FC BE

Figure 2: Egress Forwarding CLass Override

shows the ingress service 1 using forwarding classes AF and L1 that are overridden to L1
These 2 AF classes are
combined and use FC
L1 across the core
Egress (Network):
These 3 CP classes are
combined and use FC
L1 across the core
7950 XRS Quality of Service Guide
FC EF
FC L1
FC AF
FC BE
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