Configuring Priority Mappings for VLAN Packets

This section describes how to configure priority mappings for VLAN packets and the application environment of this function.

Context

Traffic policy based on BA classification is used to map the precedence of traffic on one type of network to another type. That is, to transmit the traffic in the other network according to the original precedence.

When the NetEngine 8000 F serves as the border router for different networks, the original external priorities (802.1p values) in the VLAN packets that go into the NetEngine 8000 F are all mapped to the internal priorities of the router represented by service classes of DiffServ and colors. When the NetEngine 8000 F sends out the packet, the internal priority is mapped back to the external priority.

If unified scheduling is required for all upstream traffic on an interface, you can run the qos default-service-class command to configure the upstream traffic on the interface to enter the specific queues and provide corresponding services.

After this command is run, other packets cannot be enabled to enter the queues, and BA classification cannot be enabled.

Pre-configuration Tasks

Before configuring traffic shaping, complete the following tasks:

Configuring the physical parameters of interfaces
Configuring the link layer attributes of interfaces to ensure their normal operation
Configuring IP addresses for interfaces
Enabling the routing protocol for communication between devices

This configuration is supported only on the Admin VS.

Procedure

Run system-view
The system view is displayed.
Run diffserv domain { ds-domain-name | default | 5p3d } [ domain-id domain-id-value ]
A DS domain is defined and the DS domain view is displayed.

Define traffic policies on the router based on the actual situation.

To define a traffic policy for incoming VLAN traffic, run the 8021p-inbound 8021p-value phb service-class [ color ] command.
To define a traffic policy for outgoing VLAN traffic, run the 8021p-outbound service-class color map 8021p-value command.

Following DS domain templates are pre-defined by the system for VLAN packets: the 5p3d domain template, and the default domain template.

The 5p3d domain template describes mapping relations from the 802.1 priorities of VLAN packets to the QoS CoSs and colors, or from the QoS CoSs and colors to the 802.1 priorities. You can change the mapping relations in the 5p3d domain template. The 802.1p priorities of the packets from an upstream device are mapped to the QoS CoSs and colors. Their mapping relations are shown in Table 1. The QoS CoSs and colors of the packets going to a downstream device are mapped to the 802.1p priorities. Their mapping relations are shown in Table 2.

**Table 1** Mapping from the 802.1p value to the service-class and color
802.1p	Service	Color
0	BE	Yellow
1	BE	Green
2	AF2	Yellow
3	AF2	Green
4	AF4	Yellow
5	AF4	Green
6	CS6	Green
7	CS7	Green

**Table 2** Mapping from the service-class and color to the 802.1p value
Service	Color	802.1p
BE	Green	1
BE	Yellow	0
BE	Red	0
AF1	Green	1
AF1	Yellow	0
AF1	Red	0
AF2	Green	3
AF2	Yellow	2
AF2	Red	2
AF3	Green	3
AF3	Yellow	2
AF3	Red	2
AF4	Green	5
AF4	Yellow	4
AF4	Red	4
EF	Green	5
EF	Yellow	4
EF	Red	4
CS6	Green, Yellow, Red	6
CS7	Green, Yellow, Red	7

The default domain template describes the default mapping relations from the 802.1p priorities of VLAN packets to the QoS services classes and colors, or from the QoS services classes and colors to the 802.1p priorities. You can change the mapping relations in the default domain template. The 802.1p priorities of the packets from an upstream device are mapped to the QoS CoSs and colors. Their mapping relations are shown in Table 3. The QoS CoSs and colors of the packets going to a downstream device are mapped to the 802.1p priorities. Their mapping relations are shown in Table 4.

**Table 3** Default mapping from the IP Precedence/MPLS EXP/802.1p to the service-class and color
IP Precedence/MPLS EXP/802.1p	Service	Color
0	BE	Green
1	AF1	Green
2	AF2	Green
3	AF3	Green
4	AF4	Green
5	EF	Green
6	CS6	Green
7	CS7	Green

**Table 4** Default mapping from the service-class and color to IP Precedence/MPLS EXP/802.1p
Service	Color	IP Precedence/MPLS EXP/802.1p
BE	Green, Yellow, Red	0
AF1	Green, Yellow, Red	1
AF2	Green, Yellow, Red	2
AF3	Green, Yellow, Red	3
AF4	Green, Yellow, Red	4
EF	Green, Yellow, Red	5
CS6	Green, Yellow, Red	6
CS7	Green, Yellow, Red	7

(Optional) Run field dei enable vlan { { vlan-id1 [ to vlan-id2 ] }&<1-10> | all } in the interface view.
The DEI capability for a range of VLANs on an interface is specified. After you enable DEI for a VLAN and configure simple traffic classification, packets enter queues based on CoSs and are marked with different colors based on the values of their CFI fields.

The DEI function takes effect only after simple traffic classification is configured and trust priority of 802.1p.
Run commit
The configuration is committed.
Run quit
Return to the system view.
Perform the following operations based on the interfaces on which a traffic policy will be used:
- Apply a traffic policy to VLAN packets on a Layer 3 sub-interface.
  1. To enter the sub-interface view, run the interface gigabitethernet interface-number.subnumber command.
  2. Bind the sub-interface to a DS domain.
    
    You can use either the qos phb enable command or trust upstream command to bind a Layer 3 sub-interface to a DS domain and map priorities for packets. The qos phb enable command, however, maps priorities only for downstream traffic. To map priorities for both upstream and downstream traffic, run the trust upstream command.
    - To bind the sub-interface to a DS domain and map priorities for packets, run the trust upstream { 5p3d | ds-domain-name | default } command.
    - To bind the sub-interface to a DS domain and map priorities only for downstream packets, run the qos phb enable { ds-domain-name | default } command.
      
      The undo qos phb disable command is mutually exclusive to the trust upstream.
  3. To enable 802.1 priority-based BA classification, run the trust { 8021p | inner-8021p | outer-8021p } [ inbound | outbound ] command.
    
    Before running the trust 8021p command on a sub-interface, use the trust upstream command to bind the sub-interface to a DS domain. Otherwise, the trust 8021p configuration does not take effect.
    
    After you add an interface to a DiffServ domain, the traffic policy configured for the domain automatically takes effect for the incoming and outgoing traffic on the interface.
- Apply a traffic policy to VLAN packets on a Layer 2 interface.
  1. To enter the view of a Layer 3 interface, run the interface gigabitethernet interface-number command.
  2. To change the interface mode from Layer 3 to Layer 2, run the portswitch command.
  3. To add the Layer 2 interface to specific VLANs in tagged mode, run the port trunk allow-pass vlan { { vlan-id1 [ to vlan-id2 ] } &<1-10> | all } command.
  4. Bind the Layer 2 interface to a DS domain.
    
    You can use either the qos phb enable vlan command or trust upstream vlan command to bind a Layer 2 interface to a DS domain and map priorities for packets. The qos phb enable vlan command, however, maps priorities only for downstream traffic. To map priorities for both upstream and downstream traffic, run the trust upstream vlan command.
    - To bind the Layer 2 interface to a DS domain and map priorities for packets, run the trust upstream { 5p3d | ds-domain-name | default } [ inbound | outbound ] vlan { vlan-id1 [ to vlan-id2 ] } &<1-10> ] command.
    - To bind the Layer 2 interface to a DS domain and map priorities only for downstream packets, run the qos phb enable { ds-domain-name | default | 5p3d } [ vlan { vlan-id1 [ to vlan-id2 ] } &<1-10> ] command.
      
      The qos phb enable command is mutually exclusive to the trust upstream vlan and qos phb disable commands on the Layer 2 interface.
  5. To enable 802.1 priority-based BA classification, run the trust 8021p [ inbound | outbound ] vlan { vlan-id1 [ to vlan-id2 ] } command.
Run commit
The configuration is committed.

Verifying the Configuration

Run the following commands to check the previous configuration.

Run the display diffserv domain [ ds-domain-name ] [ 8021p | dscp | exp ] [ inbound | outbound ] command to display the configurations of a DS domain.
Run the display diffserv domain application ds-domain-name command to display the interface list applied to a DS domain.