Cisco ASR 900 Series Configuration Guide

The classification process selects the traffic to be marked. Classification accomplishes this by partitioning
traffic into multiple priority levels, or classes of service. Traffic classification is the primary component
of class-based QoS provisioning.
•
Police and mark traffic
Policing causes traffic that exceeds the configured rate to be discarded or marked to a different drop
level. Marking traffic is a way to identify packet flows to differentiate them. Packet marking allows you
to partition your network into multiple priority levels or classes of service.
Prerequisites for CEM over MPLS QoS
The device must be configured as an MPLS provider edge (PE) or provider (P) chassis, which can include
the configuration of a valid label protocol and underlying IP routing protocols.
Restrictions for CEM over MPLS QoS
•
MPLS classification and marking can only occur in an operational MPLS Network.
•
MPLS EXP classification and marking is supported on the main chassis interfaces for MPLS packet
switching and imposition (simple IP imposition and Ethernet over MPLS (EoMPLS) imposition) and
on Ethernet virtual circuits (EVCs) or Ethernet flow points (EFPs) for EoMPLS imposition.
•
MPLS EXP topmost classification is not supported for bridged MPLS packets on Ethernet virtual circuits
(EVC) or Ethernet flow points (EFP).
•
MPLS EXP marking in the ingress direction only.
•
If a packet is classified by IP type of service (ToS) or class of service (CoS) at ingress, it cannot be
reclassified by MPLS EXP at egress (imposition case). However, if a packet is classified by MPLS at
ingress it can be reclassified by Quality of Service (QoS) group at egress (disposition case).
•
If a packet is encapsulated in MPLS, the MPLS payload cannot be checked for other protocols such as
IP for classification or marking. Only MPLS EXP marking affects packets encapsulated by MPLS.
How to Classify and Mark MPLS EXP
Classifying MPLS Encapsulated Packets
You can use the match mpls experimental topmost command to define traffic classes based on the packet
EXP values, inside the MPLS domain. You can use these classes to define services policies to mark the EXP
traffic using the police command.
enable
configure terminal
class-map [match-all | match-any] class-map-name
match mpls experimental topmost mpls-exp-value
end
1-Port OC-192 or 8-Port Low Rate CEM Interface Module Configuration Guide, Cisco IOS XE Everest 16.7.x
(Cisco ASR 900 Series)
12
CEM over MPLS QoS
Prerequisites for CEM over MPLS QoS

Cisco ASR 900 Series Specifications

General

Brand	Cisco
Model	ASR 900 Series
Category	Network Router
Language	English