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CCNP Practice Question: Which three statements about the classification…
Which three statements about the classification and marking tools in Cisco IOS are true? (Choose three.)
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
The trust boundary can be configured using the 'mls qos trust' command on a switch port to trust the CoS or DSCP value received from an attached device.
Classification identifies traffic based on various fields, while marking sets the QoS value. Trust boundaries determine where marking is honored. NBAR can perform deep packet inspection for classification. CoS is a Layer 2 marking in 802.1Q frames, while DSCP is Layer 3. MPLS uses EXP bits.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
The trust boundary can be configured using the 'mls qos trust' command on a switch port to trust the CoS or DSCP value received from an attached device.
Why this is correct
Correct. The trust boundary is set with 'mls qos trust' to honor incoming markings.
- ✓
NBAR (Network-Based Application Recognition) can classify traffic based on application signatures, including HTTP URLs and SSL certificate fields.
Why this is correct
Correct. NBAR performs deep packet inspection and can match on many application attributes.
- ✓
Layer 2 CoS marking uses a 3-bit field in the 802.1Q tag, providing 8 possible values, while DSCP uses 6 bits for 64 values.
Why this is correct
Correct. CoS is 3 bits (0–7), DSCP is 6 bits (0–63).
- ✗
The 'set dscp' command in a policy map can be used to mark packets with a DSCP value, but only on egress interfaces.
Why it's wrong here
Incorrect. The 'set dscp' command can be used on both ingress and egress policy maps, depending on the platform.
- ✗
MPLS EXP bits are a 3-bit field used for QoS in MPLS networks and are always directly mapped from the IP DSCP value without any configuration.
Why it's wrong here
Incorrect. MPLS EXP bits are 3 bits, but they are not automatically mapped; mapping can be configured using the 'mpls qos' commands.
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JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This 350-401 practice question is part of Courseiva's free Cisco certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the 350-401 exam.