Configuring MPLS Public QoS (CE Switches Excluding CE6870EI and CE6875EI)
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 pipe or short pipe. If you set the DiffServ mode to uniform, priorities carried in original packets may be changed. In uniform and pipe modes, 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.
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 8800, 7800, 6800, and 5800 Series Switches Configuration Guide - QoS.
A DiffServ domain comprises the connected DiffServ nodes, which use the same service policy and implement the same PHBs.
When traffic enters a device, the device maps packet priorities to PHBs and colors, and performs congestion management based on PHBs and congestion avoidance based on colors. When traffic flows out of the device, the device maps PHBs and colors of packets to priorities. The downstream device provides QoS services based on packet priorities.
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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 seven user-defined DiffServ domains can be created.
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Define a traffic policy on the device.
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Run exp-inbound exp-value phb service-class color
The EXP priority of MPLS packets is mapped to the PHB and color in the inbound direction of an interface.
For details on the default mapping from EXP priorities of MPLS packets to PHBs and colors in the inbound direction of an interface in a DiffServ domain, see exp-inbound.
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Run exp-outbound service-class color map exp-value
The PHB and color in original packets are mapped to the EXP priority of MPLS packets in the outbound direction of an interface.
For details on the default mapping from PHBs and colors in original packets to EXP priorities of MPLS packets in the outbound direction of an interface in a DiffServ domain, see exp-outbound.
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Run quit
Return to the system view.
To apply a user-defined DiffServ domain to a Layer 2 interface on the ingress node receiving the packets or a Layer 2 interface on the egress node receiving the packets, run the trust upstream ds-domain-name command in the Layer 2 interface view.
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- Configure the MPLS DiffServ mode.
To map priorities of incoming packets to PHBs and colors based on the mappings defined in a DiffServ domain, bind the DiffServ domain to the inbound interface of the packets. The system then maps priorities of packets to PHBs and colors based on the mappings in the DiffServ domain.
To map PHBs and colors of outgoing packets to priorities based on the mappings defined in a DiffServ domain, bind the DiffServ domain to the outbound interface of the packets. The system then maps PHBs and colors of outgoing packets to priorities based on the mappings in the DiffServ domain.
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Run mpls
The MPLS view is displayed.
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Run mpls ldp qos-mode { pipe exp exp-value | short-pipe [ exp exp-value ] | uniform } [ domain ds-name ]
The MPLS DiffServ mode is set.
By default, the MPLS DiffServ mode is uniform.
If no DiffServ domain name is specified, the default domain is used.
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When running the mpls ldp qos-mode { pipe exp exp-value | short-pipe exp exp-value } command, specify the EXP value for MPLS labels. When the DiffServ mode is short pipe and the expexp-value parameter is not specified, the device maps the original priorities of packets on the inbound interface to the EXP values.
- If the DiffServ mode of the MPLS network is set to uniform, you need to run the qos phb marking dscp enable command on the penultimate hop in a PHP scenario and the egress node in a non-PHP scenario; otherwise, the EXP values of packets cannot be mapped to DSCP priorities.
- If the DiffServ mode of the MPLS network is set to pipe, DSCP priorities of original packets may be changed if the qos phb marking dscp enable command is configured on the outbound interface of the egress node. The changed value is determined by the DiffServ domain in use.
- In an implicit PHP scenario, the egress does not implement MPLS QoS on the packets. To use MPLS QoS in pipe or uniform mode in this scenario, it is recommended that you configure related configurations on the penultimate hop instead of the egress node, or configure the egress node to allocate an explicit null label to the penultimate hop.
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- Run commit
The configuration is committed.
