Mpls Qos Restrictions And Guidelines; Configuring Mpls Qos - Cisco WS-SUP32-GE-3B - Supervisor Engine 32 Software Configuration Manual

Chapter 39

Configuring MPLS QoS

The following commands are not supported:
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MPLS QoS Restrictions and Guidelines

When configuring MPLS QoS, follow these guidelines and restrictions:
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Configuring MPLS QoS
These sections describe how to configure MPLS QoS:
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OL-11439-03
set qos-group
set discard-class
For IP-to-MPLS or EoMPLS imposition when the received packet is an IP packet:
When QoS is disabled, the EXP value is based on the received IP ToS.
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When QoS is queuing only, the EXP value is based on the received IP ToS.
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For EoMPLS imposition when the received packet is a non-IP packet:
– When QoS is disabled, the EXP value is based on the ingress CoS.
– When QoS is queuing only, the EXP value is based on the received IP ToS.
For MPLS-to-MPLS operations:
Swapping when QoS is disabled, the EXP value is based on the original EXP value (in the
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absence of EXP mutation).
– Swapping when QoS is queuing only, the EXP value is based on the original EXP value (in the
absence of EXP mutation).
– Imposing additional label when QoS is disabled, the EXP value is based on the original EXP
value (in the absence of EXP mutation).
Imposing an additional label when QoS is queuing only, the EXP value is based on the original
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EXP value (in the absence of EXP mutation).
Popping one label when QoS is disabled, the EXP value is based on the underlying EXP value.
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Popping one label when QoS is queuing only, the EXP value is based on the underlying EXP
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value.
EXP value is irrelevant to MPLS-to-IP disposition.
The no mls qos rewrite ip dscp command is incompatible with MPLS. The default mls qos rewrite
ip dscp command must remain enabled in order for the PFC3B to assign the correct EXP value for
the labels that it imposes.
The no mls qos mpls trust exp command allows you to treat MPLS packets simiarly to Layer 2
packets for CoS and egress queueing purposes by applying port trust or policy trust instead of the
default EXP value.
Enabling QoS Globally, page 39-18
Enabling Queueing-Only Mode, page 39-19
Configuring a Class Map to Classify MPLS Packets, page 39-20
Configuring the MPLS Packet Trust State on Ingress Ports, page 39-22
Catalyst Supervisor Engine 32 PISA Cisco IOS Software Configuration Guide, Release 12.2ZY
MPLS QoS Restrictions and Guidelines
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