VXLAN QoS

VXLAN quality of service (QoS) provides differentiated service in VXLAN applications. A device implements mapping between QoS priorities in original packets, internal priorities (local precedence assigned by the device to differentiate service classes of packets), and priorities of encapsulated packets. In this way, the switch provides the differentiated QoS service based on original packets.

Figure 1 VXLAN networking

On the network as shown in Figure 1, VXLAN QoS implements mapping between QoS priorities in original packets, internal priorities, and priorities of encapsulated packets according to the following process:

An original packet arrives at a Layer 2 sub-interface on Switch1. Switch1 maps the 802.1p priority of the original packet to the internal priority (PHB and color) based on the DiffServ profile bound to the main interface, and then sends the packet to the specified queue.
After the packet enters the VXLAN tunnel, the VTEP encapsulates the packet and maps the packet's internal priority to the 802.1p priority or DSCP priority based on the default profile in the DiffServ domain. The packet is then transmitted over the VXLAN tunnel based on the 802.1p priority or DSCP priority.
When the packet leaves the tunnel, its 802.1p priority or DSCP priority (depending on which priority is trusted on the tunnel interface) is mapped to the internal priority based on the default profile in the DiffServ domain. The packet then enters the queue matching the internal priority. An Ethernet interface working in Layer 3 mode trusts the DSCP priority only.
Finally, the internal priority is mapped to the 802.1p priority based on the profile in the DiffServ domain bound to the main interface. The packet is transmitted through the outbound interface based on the 802.1p priority.

When the S6720S-EI or S6720-EI is used as the access device, it cannot map the DSCP priority of original packets in the outbound direction but can normally map the packet priority in the inbound direction. Table 1 lists other mapping rules.

**Table 1** Mapping rules in a DiffServ domain applied to an interface when the S6720S-EI or S6720-EI works as the access device
Access Mode to the VXLAN Network	Mapping Rule
By VLAN	Inbound: Performs priority mapping based on the 802.1p priority of packets and the DiffServ domain configured on the interface. Outbound: Modifies the 802.1p priority of packets based on the DiffServ domain configured on the interface.
By the flow encapsulation type default	Inbound: Performs priority mapping based on the priority configured on the main interface by using the port priority priority-value command and the DiffServ domain configured on the interface, if packets do not carry VLAN tags. Performs priority mapping based on the 802.1p priority of packets and the DiffServ domain configured on the interface, if packets carry VLAN tags. Outbound: Does not modify the 802.1p priority of packets.
By the flow encapsulation type untag	Inbound: Performs priority mapping based on the priority configured on the main interface by using the port priority priority-value command and the DiffServ domain configured on the interface. Outbound: Does not modify the 802.1p priority of packets.
By the flow encapsulation type dot1q	Inbound: Performs priority mapping based on the 802.1p priority of packets and the DiffServ domain configured on the interface. Outbound: Modifies the 802.1p priority of packets based on the DiffServ domain configured on the interface.
By the flow encapsulation type qinq	Inbound: Performs priority mapping based on the outer 802.1p priority of packets and the DiffServ domain configured on the interface. Outbound: Modifies the outer 802.1p priority of packets based on the DiffServ domain configured on the interface.

For details, see Configuring Priority Mapping in "Priority Mapping Configuration" in the S2720, S5700, and S6700 V200R019C10 Configuration Guide - QoS.