300-415 Question 268
Select 2An enterprise is deploying Cisco SD-WAN and wants to implement QoS policies to ensure that high-priority traffic, such as voice and video, is treated appropriately across the network. The administrator decides to use traffic marking to prioritize traffic based on DSCP values. In which scenario would traffic marking occur within the Cisco SD-WAN solution?
- A
Traffic marking is applied at the vSmart controller before transmitting the policy to vEdge routers.
- B
Traffic marking is applied at the ingress interface of the vEdge or cEdge router.
- C
Traffic marking is applied at the egress interface of the vEdge or cEdge router.
- D
Traffic marking is performed at the transport layer between SD-WAN tunnels.
- E
Traffic marking can only be applied by the upstream device before reaching the SD-WAN fabric.
Show answer and explanation
Correct answers: B, C
Explanation
Traffic marking in a Cisco SD-WAN solution occurs at the edge routers (vEdge or cEdge) and can be applied either at the ingress or egress interface, depending on the QoS policy configuration. The vSmart controller distributes the policies but does not perform the actual marking. Marking ensures that traffic is properly prioritized as it traverses the network, both within the SD-WAN fabric and beyond.
- A. Incorrect.
Traffic marking is not applied at the vSmart controller. The vSmart controller is responsible for distributing policies to the edge routers, but actual marking happens at the routers.
- B. Correct.
Traffic marking can occur at the ingress interface of a vEdge or cEdge router, where packets are classified and DSCP values can be set based on QoS policies.
- C. Correct.
Traffic marking can occur at the egress interface of a vEdge or cEdge router to ensure that traffic leaving the router is properly marked for downstream devices.
- D. Incorrect.
Traffic marking is not performed at the transport layer between SD-WAN tunnels. Marking happens at the interface level of the routers, not at the tunnel level.
- E. Incorrect.
Traffic marking can be applied within the SD-WAN fabric and does not rely solely on the upstream device. The SD-WAN routers have mechanisms to classify and mark traffic.