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Cisco 7600 Series Router Cisco IOS Software Configuration Guide, Release 12.2SX
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Chapter 42 Configuring PFC3BXL or PFC3B Mode MPLS QoS
Understanding PFC3BXL or PFC3B Mode MPLS QoS
Classification for MPLS-to-IP PFC3BXL or PFC3B Mode MPLS QoS
PFC3BXL or PFC3B mode MPLS QoS at the ingress to PE2 supports matching on the EXP value and
the
police
command.
PFC3BXL or PFC3B mode MPLS QoS at the egress of PE2 supports matching on IP precedence or
DSCP values or filtering with an access group and the
police
command.
Classification at MPLS-to-IP Ingress Port
LAN port classification is based on the EXP value. OSM and FlexWAN interfaces classify traffic using
the
match mpls experimental
command. The
match mpls experimental
command matches on the EXP
value in the received topmost label.
Classification at MPLS-to-IP Egress Port
Note
The egress classification queuing is different for LAN and WAN ports.
Classification for MPLS-to-IP is the same as it is for IP-to-IP.
The LAN interface classification is based on the egress CoS. The OSM and WAN interfaces classify
traffic on information in the transmitted IP header.
Note
You can use PFC3BXL or PFC3B QoS features or OSM QoS features in an output policy; however, you
cannot use both in the same output policy.
If the egress port is a trunk, the LAN ports and OSM GE-WAN ports copy the egress CoS into the egress
802.1Q field.
Note
For MPLS to IP, egress IP ACL or QoS is not effective on the egress interface if the egress interface has
MPLS IP (or tag IP) enabled. The exception is a VPN CAM hit, in which case the packet is classified on
egress as IP.
MPLS VPN
The information in this section also applies to an MPLS VPN network.
The following PE MPLS QoS features are supported for MPLS VPN:
•
Classification, policing, or marking of CE-to-PE IP traffic through the VPN subinterface
•
Per-VPN QoS (per-port, per-VLAN, or per-subinterface)
For customer edge (CE)-to-PE traffic, or for CE-to-PE-to-CE traffic, the subinterface support allows you
to apply IP QoS ingress or egress policies to subinterfaces and to physical interfaces. Per-VPN policing
is also provided for a specific interface or subinterface associated with a given VPN on the CE side.
In situations when there are multiple interfaces belonging to the same VPN, you can perform per-VPN
policing aggregation using the same shared policer in the ingress or egress service policies for all similar
interfaces associated with the same PFC3BXLs or PFC3Bs.
For aggregate VPN labels, the EXP propagation in recirculation case may not be supported because
MPLS adjacency does not know which egress interface the final packet will use.
