Licensing Requirements and Limitations for Priority Mapping (CE12800E)

Involved Network Elements

Other network elements are not required.

Licensing Requirements

Priority mapping is a basic feature of a switch and is not under license control.

Version Requirements

Feature Limitations

Default Trusted Priority

• Layer 3 physical interfaces trust DSCP priorities. This cannot be modified.

Limitations on Priority Mapping

• The default DiffServ domain is default. In addition to this domain, the device supports a maximum of seven DiffServ domains. You can change the mapping in the DiffServ domain default, but cannot delete the domain.
• Colors are used to determine whether the packets are discarded during congestion avoidance and are independent of the mapping between internal priorities and queues.
• Only queues 0, 1, 2, and 6 are available for unknown unicast packets, broadcast packets, and multicast packets on the configured with ED-E, EG-E, and EGA-E series cards.

Limitations on Interface Priority

• The priority of a Layer 3 physical interface is 0 and cannot be configured.
• If no DiffServ domain is applied to an inbound interface and the interface priority is configured, the device adds a VLAN tag to received packets, uses the interface priority as the packet priority, and sends packets to queues based on the interface priority.
• The priority cannot be configured for Eth-Trunk member interfaces.

Limitations When Priority Mapping Is Used with Other Services

• You can create a DiffServ domain, enable the mapping between PHBs and DSCP/802.1p priorities in the outbound direction, and configure the mapping between CoS values and queue indexes only in the Admin-VS in port mode. The configurations take effect for other VSs in port mode.

• You can create a DiffServ domain, enable the mapping between PHBs and DSCP/802.1p priorities in the outbound direction, and configure the mapping between CoS values and queue indexes in all VSs in group mode. The configurations take effect for the local VS.

• When FCF or NPV is configured, the mapping from PHBs to 802.1p priorities in the outbound direction cannot be disabled. Otherwise, the device cannot send backpressure signals.

• For the CE12800E equipped with ED-E, EG-E, and EGA-E series cards, when 10GE interfaces numbered 1 to 12 are used to form a stack, stacking packets enter the interface queue corresponding to priority 7, and non-stacking packets with priority 7 enter the interface queue corresponding to priority 6. In this case, the interface queue corresponding to priority 6 is congested and packets are lost. When the CE12800E is used in a stack, 40GE/100GE interfaces are recommended. If 10GE interfaces are used, 10GE interfaces numbered 13 to 48 are recommended.

• The default priority mapping behaviors for packets forwarded through VXLAN tunnels in VXLAN scenarios are as follows:

  1. After an original packet arrives at a Layer 2 sub-interface on the switch, the switch maps the 802.1p or DSCP value of the original packet to the internal priority (PHB and color) based on the DiffServ domain applied to the Layer 2 sub-interface, and then sends the packet to a specified queue.

  2. The switch encapsulates the packet into a VXLAN packet and forwards it to the VXLAN tunnel. The following table describes the QoS priorities of the encapsulated packet.

     Device Model	802.1p Value of the Encapsulated Packet	DSCP Value of the Encapsulated Packet
     CE12800	By default, the outer 802.1p value of the encapsulated packet is mapped from the internal priority, and the inner 802.1p value of the encapsulated packet remains unchanged. After the qos phb marking 8021p disable command is configured in the system view, the outer 802.1p value is 2, and the inner 802.1p value remains unchanged.	For a VXLAN-encapsulated packet forwarded at Layer 3: By default, the outer DSCP value of the encapsulated packet is mapped from the internal priority, and the inner DSCP value of the encapsulated packet is mapped from the internal DSCP value on the switch. After the qos phb marking dscp enable command is configured in the system view, both the outer and inner DSCP values are mapped from the internal priority. For a VXLAN-encapsulated packet forwarded at Layer 2: By default, the outer DSCP value of the encapsulated packet is mapped from the internal priority, and the inner DSCP value of the encapsulated packet remains unchanged. After the qos phb marking dscp enable command is configured in the system view, the preceding mappings are not changed.
     CE12800E (configured with ED-E, EG-E, and EGA-E series cards)	By default, the outer 802.1p value of the encapsulated packet is mapped from the internal priority, and the inner 802.1p value of the encapsulated packet remains unchanged. After the qos phb marking 8021p disable command is configured in the Ethernet interface view, the outer 802.1p value is 0, and the inner 802.1p value remains unchanged.	By default, the outer DSCP value of the encapsulated packet is 0, and the inner DSCP value of the encapsulated packet remains unchanged. After the qos phb marking dscp enable command is configured in the Ethernet interface view, the outer DSCP value is mapped from the internal priority, and the inner DSCP value remains unchanged.
     CE12800E (configured with FD-X series cards)	By default, the outer 802.1p value of the encapsulated packet is mapped from the internal priority, and the inner 802.1p value of the encapsulated packet remains unchanged. After the qos phb marking 8021p disable command is configured in the Ethernet interface view, the preceding mappings are not changed.	By default, the outer DSCP value of the encapsulated packet is mapped from the internal priority, and the inner DSCP value of the encapsulated packet remains unchanged. After the qos phb marking dscp enable command is configured in the Ethernet interface view, the preceding mappings are not changed. After the qos phb marking dscp disable command is configured in the NVE interface view, the outer DSCP value is the same as the DSCP value of the original packet, and the inner DSCP value remains unchanged.

  3. When the packet leaves the tunnel, its 802.1p or DSCP value (depending on which value is trusted on the tunnel interface) is mapped to the internal priority based on the configured DiffServ domain (based on only the default DiffServ domain for the CE12800). The packet then enters the queue matching the internal priority. An Ethernet interface working in Layer 3 mode only trusts the DSCP value.

  4. The internal priority is mapped based on the DiffServ domain applied to the Layer 2 sub-interface or physical outbound interface. The packet is then transmitted based on the mapped priority.