Configuring MPLS Public QoS
After you configure MPLS Public QoS, differentiated services are provided for different services on the MPLS public network based on the service priorities.
Pre-configuration Tasks
Before configuring MPLS QoS, complete the following tasks:
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Configure IP addresses for interfaces to ensure that neighboring nodes are reachable at the network layer.
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Configure an IGP to advertise the network segments connecting to interfaces on each node and the routes of hosts with LSR IDs.
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Configure MPLS and MPLS LDP.
Context
To implement certain QoS functions on an MPLS network, devices on the network need to determine the packet priorities based on the MPLS labels. Therefore, you need to map the MPLS labels to EXP priorities.
MPLS QoS can differentiate different services on an MPLS network. If you want to retain priorities carried in original packets regardless of the change in the EXP field, set the DiffServ mode to short pipe. If you set the DiffServ mode to uniform, priorities carried in original packets may be changed. In uniform mode, the egress node determines the per-hop behavior (PHB) based on EXP priorities of packets. In short pipe mode, the egress node determines the PHB based on Differentiated Service Code Point (DSCP) priorities of packets.
The MPLS DiffServ mode configured on a transit device does not take effect.
Procedure
- Run system-view
The system view is displayed.
- Create a DiffServ domain and configure priority mapping.
For details, see Priority Mapping Configuration in CloudEngine 12800 and 12800E Series Switches Configuration Guide - QoS.
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Performing the following steps on the ingress:
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Run diffserv domain ds-domain-name
A DiffServ domain is created and the DiffServ domain view is displayed.
The default domain defines default mappings from packet priorities to PHBs. You can modify the mapping defined in the default domain but cannot delete the default domain. In addition to the DiffServ domain default, a maximum of six user-defined DiffServ domains can be created.
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Run mpls-exp-outbound dscp-value map exp-value
The DSCP priority is mapped to the EXP priority of MPLS packets in the outbound direction of an interface.
For details on the default mapping from the DSCP priority to the EXP priority, see mpls-exp-outbound.
The DSCP priority in this command is the priority carried in packets of a device's outbound interface.
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Run quit
Return to the system view.
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Performing the following steps on the egress:
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Run diffserv domain ds-domain-name
A DiffServ domain is created and the DiffServ domain view is displayed.
The default domain defines default mappings from packet priorities to PHBs. You can modify the mapping defined in the default domain but cannot delete the default domain. In addition to the DiffServ domain default, a maximum of six user-defined DiffServ domains can be created.
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Run mpls-exp-inbound exp-value phb service-class
The EXP priority of MPLS packets is mapped to the PHB in the inbound direction of an interface.
For details on the default mapping from the EXP priority to the PHB, see mpls-exp-inbound.
The EXP priority of MPLS packets is mapped to green in the inbound direction of an interface.
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Run quit
Return to the system view.
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To apply a user-defined DiffServ domain to a Layer 3 interface on the ingress node receiving the packets or a Layer 3 interface on the egress node receiving the packets, run the trust upstream ds-domain-name command in the Layer 3 interface view.
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- Configure the MPLS DiffServ mode.
Run mpls mode { short-pipe [ ttl ttl-value exp exp-value | domain ds-name ] | uniform [ domain ds-name ] }
The MPLS DiffServ mode is set.
By default, the MPLS DiffServ mode is uniform.
When running the mpls mode short-pipe ttl ttl-value exp exp-value command, specify the same EXP value for the outer and inner MPLS labels. If the parameter exp is not specified, the inbound interface performs priority mapping for incoming packets based on the original priorities.
When the MPLS DiffServ mode is uniform, the egress node maps EXP priorities of packets to DSCP priorities. To map PHBs to DSCP priorities, configure the qos phb marking dscp enable command in the system view.
- Run commit
The configuration is committed.