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Examine the exhibit below. You are configuring Class of Service on a WAN-facing network interface, and you want to perform DSCP rewrite on the packets that are forwarded to the WAN. However, you are not able to turn on DSCP rewrite. Referring to the exhibit, what is the cause of this issue?
In the exhibit, the Add Associate Interface/Network window has Interface selected, and the interface name is set to vni-0/0. The DSCP rewrite option is not available because rewrite behavior is intended to be applied at the network association level for the WAN network, not directly while associating only the physical/logical interface. For WAN-facing CoS, the scheduler and shaping parameters can be attached to an interface, but DSCP rewrite policies are applied to remark traffic as it exits through a network context.
Versa SD-WAN design documentation explains that QoS rewrite rules rewrite packet QoS attributes as packets leave the VOS device, and that rewrite rules can modify IEEE 802.1p bits, IPv4 TOS/DSCP bits, and IPv6 traffic class bits. It also explains that a rewrite policy is commonly applied on a WAN network to remark traffic based on the forwarding class and loss priority assigned by QoS or App QoS policies. In the design example, Versa explicitly describes applying a QoS propagation or rewrite policy on the MPLS WAN network to remark traffic to a DSCP value. Therefore, the issue is the association type: it is set to Interface, not Network.