- A
The class-map uses 'match-all' but the engineer intended to use 'match-any'.
Correct because if the class-map uses 'match-all', all match conditions must be true; if the traffic matches only one condition, it will not be classified.
- B
The access-list used for matching is not applied to the correct interface.
Why wrong: Incorrect because the access-list is used within the class-map, not applied directly to the interface.
- C
The router does not support matching on both IP and port in the same class-map.
Why wrong: Incorrect because routers support matching on multiple fields.
- D
The class-map must be applied to the interface before it can match traffic.
Why wrong: Incorrect because the class-map itself does not need to be applied; the policy-map containing the class-map must be applied.
Quick Answer
The answer is that the class-map likely uses 'match-all' when the engineer intended to use 'match-any'. When a class-map is configured with match-all, every single match condition—such as both the destination IP address and the port—must be true for a packet to be classified, making it highly restrictive. If the goal was to match traffic based on either the destination IP address or the port, match-any is the correct choice, as it classifies a packet if any one condition is satisfied. On the ENCOR 350-401 exam, this distinction tests your understanding of QoS classification logic and is a common trap where candidates overlook the default behavior of class-maps. A reliable memory tip is to think of match-all as requiring a perfect "AND" relationship, while match-any works like an "OR"—if you want flexibility, remember that "any" means "any one is enough."
CCNP QoS Architecture Practice Question
This 350-401 practice question tests your understanding of qos architecture. Read the scenario carefully and evaluate each option against the stated constraints before committing to an answer. After answering, compare your reasoning against the explanation and wrong-answer breakdown below. Once you have made your selection, read the full explanation to reinforce the concept and understand why each distractor is designed to mislead on exam day.
A network engineer is configuring QoS on a Cisco router to prioritize business-critical applications. The engineer creates a class-map that matches traffic based on the destination IP address and port. However, the class-map does not match the expected traffic. What is the most likely reason?
Clue words in this question
Noticing these words before you look at the options changes how you read each choice.
Clue:
"most likely"Why it matters: Probability qualifier — the question wants the most probable cause or outcome, not a guaranteed one. Eliminate low-probability options.
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 class-map uses 'match-all' but the engineer intended to use 'match-any'.
Option A is correct because when a class-map uses 'match-all', all match conditions must be true for a packet to be classified. If the engineer intended to match traffic based on either the destination IP address OR the port, using 'match-any' would allow the class-map to match if any single condition is met. The mismatch occurs because the class-map is too restrictive, requiring both conditions to be satisfied simultaneously.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
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 class-map uses 'match-all' but the engineer intended to use 'match-any'.
Why this is correct
Correct because if the class-map uses 'match-all', all match conditions must be true; if the traffic matches only one condition, it will not be classified.
Clue confirmation
The clue word "most likely" in the question point toward this answer.
Related concept
Read the scenario before looking for a memorised answer.
- ✗
The access-list used for matching is not applied to the correct interface.
Why it's wrong here
Incorrect because the access-list is used within the class-map, not applied directly to the interface.
- ✗
The router does not support matching on both IP and port in the same class-map.
Why it's wrong here
Incorrect because routers support matching on multiple fields.
- ✗
The class-map must be applied to the interface before it can match traffic.
Why it's wrong here
Incorrect because the class-map itself does not need to be applied; the policy-map containing the class-map must be applied.
Common exam traps
Common exam trap: answer the scenario, not the keyword
Cisco often tests the subtle difference between 'match-all' (default) and 'match-any' in class-maps, trapping candidates who assume that multiple match conditions automatically use OR logic.
Detailed technical explanation
How to think about this question
Under the hood, class-maps use a match-sequential logic: 'match-all' requires all conditions to be true (logical AND), while 'match-any' requires at least one condition to be true (logical OR). In real-world scenarios, business-critical applications often use multiple ports or IP ranges, so using 'match-any' is common to avoid missing traffic that matches only one criterion. The 'match-all' default can cause silent classification failures that are difficult to troubleshoot without careful verification of the match logic.
KKey Concepts to Remember
- Read the scenario before looking for a memorised answer.
- Find the constraint that changes the correct option.
- Eliminate answers that are true in general but not in this case.
TExam Day Tips
- Watch for words such as best, first, most likely and least administrative effort.
- Review why wrong options are wrong, not only why the correct option is correct.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
How this comes up in practice
A small business has 20 workstations on the 192.168.1.0/24 network and one public IP from its ISP. The router uses PAT (NAT overload) so all 20 devices share one public address using different source ports. NAT questions test whether you understand the four address terms and which direction each translation applies.
What to study next
Got this wrong? Here's your next step.
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
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QoS Architecture — study guide chapter
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FAQ
Questions learners often ask
What does this 350-401 question test?
QoS Architecture — This question tests QoS Architecture — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: The class-map uses 'match-all' but the engineer intended to use 'match-any'. — Option A is correct because when a class-map uses 'match-all', all match conditions must be true for a packet to be classified. If the engineer intended to match traffic based on either the destination IP address OR the port, using 'match-any' would allow the class-map to match if any single condition is met. The mismatch occurs because the class-map is too restrictive, requiring both conditions to be satisfied simultaneously.
What should I do if I get this 350-401 question wrong?
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
Are there clue words in this question I should notice?
Yes — watch for: "most likely". Probability qualifier — the question wants the most probable cause or outcome, not a guaranteed one. Eliminate low-probability options.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
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Last reviewed: Jun 24, 2026
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.
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