Configuring Mpls Qos; Overview; Feature And Hardware Compatibility - HP FlexNetwork MSR Series Configuration Manuals

Configuring MPLS QoS

Overview

MPLS uses 3 bits, called EXP bits, to carry class-of-service information to provide support for
DiffServ. MPLS QoS identifies different traffic flows with different EXP bits and implements
differentiated services. MPLS QoS can guarantee low delay and low packet loss ratio for critical
service traffic, such as voice and video traffic. For more information about MPLS, see MPLS
Configuration Guide.
MPLS QoS supports CAR and priority marking. MPLS QoS provides the following functions:
•
Classify traffic on the PE and apply differentiated QoS strategies for different traffic classes. For
example, MPLS QoS can organize packets with EXP value 1 into a class and packets with EXP
value 2 into another class. Then it performs traffic policing and priority marking for each class of
packets.
•
When a PE labels a packet, it maps the IP precedence to the EXP field of the label. In this way,
the class information carried in the IP header is carried in the label.
The EXP field in an MPLS label is processed according to the following rules:
•
The device re-sets the EXP field of only the topmost label.
•
During label encapsulation, the ToS field of the IP packet is directly changed into the EXP field
of the MPLS label.
•
The EXP field remains unchanged when label swapping is performed.
•
During a label push operation, the EXP field of the newly pushed outer label inherits the EXP
field of the inner label.
•
After a label pop operation for a packet, the following rules apply:
If the packet is still an MPLS packet, the EXP field of the popped label is not copied to the

inner label.
If the packet is an IP packet, the EXP field of the popped label is not copied to the ToS field

of the IP packet.

Feature and hardware compatibility

The following matrix shows the feature and hardware compatibility:
Hardware
MSR954 (JH296A/JH297A/JH298A/JH299A/JH373A)
MSR958 (JH300A/JH301A)
MSR1002-4/1003-8S
MSR2003
MSR2004-24/2004-48
MSR3012/3024/3044/3064
MSR4060/4080
118
MPLS QoS compatibility
No
No
Yes
Yes
Yes
Yes
Yes