CCDE: Cisco Certified Design Expert (Written) — Question 40

You are designing the QoS features for a large enterprise network that includes DMVPN. When would you need to configure QoS preclassify?

Answer options

• A. when you are marking packets with the DSCP bits
• B. when you are marking packets with the TOS bits
• C. when your service provider requires the DSCP bits be set
• D. when the QoS policy cannot be based on DSCP ToS bits

Correct answer: D

Explanation

QoS preclassify is necessary when the QoS policy cannot rely on DSCP or ToS bits due to limitations in how traffic is classified or marked. The other options involve scenarios where QoS policies can be applied based on existing markings, which does not necessitate preclassification.