300-415 Question 261
Select 3A large enterprise is using Cisco SD-WAN to manage its WAN infrastructure. The IT team notices frequent congestion on specific WAN links during peak hours, resulting in packet drops and degraded application performance. They want to implement traffic shaping to ensure critical applications like voice and video are prioritized while preventing bandwidth over-utilization. Which configuration is required to achieve this goal?
- A
Define a traffic shaping policy using class-based queuing to prioritize critical applications.
- B
Set the traffic shaping rate to a value lower than the physical WAN interface bandwidth.
- C
Enable application-aware routing to dynamically reroute traffic based on link performance.
- D
Configure DSCP-based matching in the shaping policy to categorize traffic for prioritization.
- E
Apply the traffic shaping policy to the outbound direction on the relevant WAN interface.
Show answer and explanation
Correct answers: A, B, E
Explanation
Traffic shaping in Cisco SD-WAN is used to control and prioritize traffic flow to prevent congestion and ensure application performance. By defining a shaping policy with class-based queuing, setting a rate lower than the WAN interface capacity, and applying the policy in the outbound direction, the IT team can effectively manage bandwidth and prioritize critical applications. While application-aware routing and DSCP-based matching are related concepts, they are not directly required for shaping configurations.
- A. Correct.
Defining a traffic shaping policy with class-based queuing allows you to classify and prioritize traffic, ensuring critical applications like voice and video are handled with higher priority.
- B. Correct.
Setting the traffic shaping rate lower than the physical WAN interface bandwidth prevents congestion by capping the maximum traffic rate, ensuring smoother flow and preventing buffer overflows.
- C. Incorrect.
Application-aware routing is not directly related to shaping; it is used for dynamic path selection based on link health metrics rather than controlling traffic rates.
- D. Incorrect.
While DSCP-based matching can help in traffic classification, it is not mandatory for shaping policies. Traffic can also be classified using other methods, such as ACLs or application-based matching.
- E. Correct.
Applying the traffic shaping policy to the outbound direction on the WAN interface ensures that the rate-limiting and prioritization take effect where packets leave the interface.