300-415 Question 271
Single answerYou are configuring a Cisco SD-WAN network to prioritize different types of traffic by marking packets with appropriate DSCP values. A critical video conferencing application requires expedited forwarding (EF) treatment, while normal web traffic should receive best-effort (BE) treatment. During your configuration, which marking configuration would correctly achieve this objective?
- A
Set DSCP value to 46 for video conferencing traffic and 0 for web traffic.
- B
Set DSCP value to 34 for video conferencing traffic and 18 for web traffic.
- C
Set DSCP value to 0 for video conferencing traffic and 46 for web traffic.
- D
Set DSCP value to 26 for both video conferencing traffic and web traffic.
Show answer and explanation
Correct answer: A
Explanation
Marking traffic with appropriate DSCP values is essential in Cisco SD-WAN to ensure proper QoS treatment. Expedited Forwarding (EF) with DSCP value 46 is ideal for real-time traffic such as video conferencing due to its low latency and high priority. Best Effort (BE) with DSCP value 0 is used for non-critical traffic like web browsing, providing lower priority. Correct classification and marking ensure that traffic is treated appropriately based on its requirements.
- A. Correct.
This is correct. DSCP value 46 corresponds to Expedited Forwarding (EF), which is typically used for real-time traffic like video conferencing. DSCP 0 corresponds to Best Effort (BE), which is suitable for normal web traffic.
- B. Incorrect.
This is incorrect. DSCP 34 corresponds to Assured Forwarding (AF41), which is not the standard for real-time traffic. DSCP 18 does not align with Best Effort (BE) classification.
- C. Incorrect.
This is incorrect. DSCP 0 represents Best Effort (BE) and is not suitable for critical video conferencing traffic. DSCP 46, which represents Expedited Forwarding (EF), is incorrectly assigned to web traffic in this option.
- D. Incorrect.
This is incorrect. Assigning DSCP 26 to both traffic types does not provide differentiation between critical and non-critical traffic, which defeats the purpose of marking.