300-415 Question 265
Single answerYou are tasked with configuring traffic policing on a Cisco SD-WAN fabric to ensure that specific application traffic does not exceed a committed information rate (CIR). The requirement is to drop packets exceeding the CIR while ensuring that traffic within the CIR is forwarded without any modification. Which configuration approach would best meet this requirement?
- A
Configure a traffic shaping policy in the centralized control policy to limit the application traffic to the desired CIR.
- B
Use a local QoS policy with policing configured on the WAN edge router to enforce the CIR and drop excess traffic.
- C
Implement an application-aware routing policy to direct traffic to a low-bandwidth link, ensuring it stays within the CIR.
- D
Apply a centralized data policy to prioritize traffic and enforce CIR limits directly from the vSmart controller.
Show answer and explanation
Correct answer: B
Explanation
In Cisco SD-WAN, traffic policing is typically implemented using local QoS policies on the WAN edge router. Policing enforces a CIR by discarding traffic that exceeds the specified rate, which aligns with the requirement in the scenario. Other methods, like traffic shaping or application-aware routing, do not achieve the desired outcome of dropping excess traffic.
- A. Incorrect.
Traffic shaping is used to smooth traffic bursts by buffering and delaying packets, not to drop packets exceeding a CIR. This does not meet the requirement to drop excess traffic.
- B. Correct.
Using a local QoS policy with policing on the WAN edge router is the correct method to enforce CIR and drop packets exceeding the specified rate. Policing explicitly limits traffic to the CIR by discarding excess packets.
- C. Incorrect.
Application-aware routing is used to direct traffic based on performance metrics and does not enforce CIR or drop excess traffic. This does not meet the scenario's requirements.
- D. Incorrect.
Centralized data policies prioritize or manage traffic behavior based on rules but do not enforce CIR or handle excess traffic in the required manner.