Question 1mediummultiple choice
Full question →mediummultiple choiceObjective-mapped
Why might voice traffic be placed in a priority queue on a WAN link?
Answer choices
Why each option matters
Good practice is not just finding the correct option. The wrong answers often show the exact trap the exam wants you to fall into.
A
Distractor review
To increase the TTL value of voice packets
TTL is unrelated to QoS queuing goals.
B
Best answer
To reduce delay and jitter for time-sensitive traffic
Correct. Priority queuing is used to protect time-sensitive traffic such as voice.
C
Distractor review
To change RTP into TCP for reliability
QoS does not convert RTP or UDP traffic into TCP.
D
Distractor review
To avoid assigning IP addresses to phones
IP address assignment is a separate function handled by DHCP or static configuration.
Common exam trap
Common exam trap: answer the scenario, not the keyword
A common exam trap is selecting answers that confuse QoS prioritization with unrelated network functions such as increasing the TTL value of voice packets or converting RTP traffic into TCP. These options are incorrect because QoS focuses on managing packet scheduling and queuing rather than altering packet headers or transport protocols. Another trap is thinking that IP address assignment relates to QoS, which it does not. Recognizing that priority queuing specifically targets delay-sensitive traffic like voice helps avoid these misleading options.
Technical deep dive
How to think about this question
Voice traffic is highly sensitive to delay, jitter, and packet loss because it carries real-time audio communications. Unlike data traffic, which can tolerate some delay and retransmissions, voice requires timely delivery to maintain call quality and intelligibility. Quality of Service (QoS) mechanisms on Cisco devices prioritize voice packets to ensure they receive expedited forwarding and minimal queuing delay on WAN links. Priority queuing places voice traffic in a high-priority queue ahead of other traffic types, reducing latency and jitter by minimizing the time voice packets spend waiting in buffers. Cisco routers and switches use classification and marking techniques such as DSCP or CoS to identify voice packets and apply priority queuing policies. This ensures voice traffic is transmitted promptly even during congestion, maintaining call clarity and reducing echo or dropouts. A common exam trap is confusing QoS prioritization with other unrelated functions like TTL manipulation or protocol conversion. QoS does not alter packet headers to increase TTL or convert RTP to TCP. Instead, it manages packet scheduling and queuing to meet the strict timing requirements of voice. Understanding this distinction helps avoid selecting incorrect answers that describe unrelated network functions.
KKey Concepts to Remember
- Voice traffic requires low latency and minimal jitter to maintain call quality and intelligibility over WAN links.
- Cisco QoS uses priority queuing to place voice packets ahead of other traffic, reducing delay and jitter.
- Priority queuing ensures time-sensitive traffic like voice is forwarded promptly during network congestion.
- Voice packets are identified and classified using DSCP or CoS markings to apply appropriate QoS policies.
- QoS mechanisms do not modify TTL values or convert RTP traffic to TCP for reliability.
- WAN links benefit from QoS prioritization to prevent voice degradation caused by queuing delays.
- Cisco routers and switches implement QoS to protect real-time voice traffic from competing data traffic.
- Understanding the role of priority queuing helps avoid confusing QoS with unrelated network functions.
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.
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More questions from this exam
Keep practising from the same exam bank, or move into a focused topic page if this question exposed a weak area.
Question 1
A router learns the same prefix from both OSPF and EIGRP. Which route is installed by default?
Question 2
A router shows this output: R1#show ip ospf neighbor Neighbor ID Pri State Dead Time Address Interface 10.1.1.2 1 FULL/DR 00:00:34 192.168.12.2 GigabitEthernet0/0 10.1.1.3 1 2WAY/DROTHER 00:00:39 192.168.12.3 GigabitEthernet0/0 Which statement is correct?
Question 3
What is the OSPF metric called?
Question 4
A non-root switch has two uplinks toward the root bridge. One path has a lower total STP cost than the other. What role will the lower-cost uplink have?
Question 5
A router interface applies this ACL inbound: 10 deny tcp any any eq 80 20 permit ip any any A user reports that web browsing to a server by IP address fails, but ping works. Which statement best explains the behavior?
Question 6
A router learns route 198.51.100.0/24 from OSPF with AD 110 and also has a static route to the same prefix configured with AD 150. Which route is installed?
FAQ
Questions learners often ask
What does this 200-301 question test?
Voice traffic requires low latency and minimal jitter to maintain call quality and intelligibility over WAN links.
What is the correct answer to this question?
The correct answer is: To reduce delay and jitter for time-sensitive traffic — Voice traffic is delay-sensitive. Prioritization helps reduce queuing delay and jitter so real-time audio remains intelligible.
What should I do if I get this 200-301 question wrong?
Then try more questions from the same exam bank and focus on understanding why the wrong options are tempting.
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