Implementing Cisco Collaboration Core Technologies (CLCOR) 350-801 Practice Test 38
Question 370
For this Cisco collaboration incident — Calls randomly drop after 30 seconds with RTP continuing until BYE, and the support team blames codec bandwidth. — what test result most directly establishes that the corrective work succeeded?
- RTP quality statistics improve under representative load and speech no longer breaks up.
- The corrected path maintains expected SIP transactions and calls no longer release at the timeout.
- Video loss and artifact rate fall within accepted levels in a sustained test.
- Captured DSCP and queue statistics confirm intended class treatment before and after the carrier handoff.
Explanation
Correct Answer
B:A reproducible 30-second release can be a signaling transaction or ACK problem rather than packet-loss-only QoS. This is decisive because the expected outcome is: The corrected path maintains expected SIP transactions and calls no longer release at the timeout.
Incorrect Answers
A:“RTP quality statistics improve under representative load and speech no longer breaks up” evaluates real-time audio is vulnerable to delay variation and packet loss even while a call remains connected. It would not confirm the collaboration outcome requiring a reproducible 30-second release can be a signaling transaction or ACK problem rather than packet-loss-only QoS.
C:“Video loss and artifact rate fall within accepted levels in a sustained test” evaluates video decoding artifacts can arise from impaired video RTP streams without a full signaling outage. It would not confirm the collaboration outcome requiring a reproducible 30-second release can be a signaling transaction or ACK problem rather than packet-loss-only QoS.
D:“Captured DSCP and queue statistics confirm intended class treatment before and after the carrier handoff” evaluates qoS is end-to-end only if every constrained hop preserves or intentionally maps traffic priority. It would not confirm the collaboration outcome requiring a reproducible 30-second release can be a signaling transaction or ACK problem rather than packet-loss-only QoS.
Question 371
During a collaboration systems review, the following is documented: Audio only fails when a call traverses a particular SBC and its negotiated RTP address is private and unreachable. Which response should engineers prioritize?
- Inspect video stream packet loss, throughput and codec adaptation across the end-to-end path.
- Correlate RF retries, channel contention and WLAN QoS with RTP jitter before changing voice gateways.
- Correct the supported SBC media anchoring or NAT traversal addressing for the affected call leg.
- Classify signaling separately from RTP, using an appropriate signaling class such as CS3 under the QoS design.
Explanation
Correct Answer
C:The SDP media address and the actual translated network path must agree. Apply the specific remedy: Correct the supported SBC media anchoring or NAT traversal addressing for the affected call leg. Verify it by checking: The negotiated media destination is reachable and both endpoints exchange RTP via the approved border.
Incorrect Answers
A:“Inspect video stream packet loss, throughput and codec adaptation across the end-to-end path” concerns video decoding artifacts can arise from impaired video RTP streams without a full signaling outage. The stated collaboration requirement instead depends on the SDP media address and the actual translated network path must agree.
B:“Correlate RF retries, channel contention and WLAN QoS with RTP jitter before changing voice gateways” concerns wireless airtime contention can impair real-time media independently of PSTN routing configuration. The stated collaboration requirement instead depends on the SDP media address and the actual translated network path must agree.
D:“Classify signaling separately from RTP, using an appropriate signaling class such as CS3 under the QoS design” concerns signaling is important but has different delay and throughput characteristics from continuous audio media. The stated collaboration requirement instead depends on the SDP media address and the actual translated network path must agree.
Question 372
A Cisco collaboration operations team is closing a ticket for this requirement: Audio only fails when a call traverses a particular SBC and its negotiated RTP address is private and unreachable. Which result provides the strongest verification?
- Video loss and artifact rate fall within accepted levels in a sustained test.
- Under roaming load, retry rate and RTP loss decrease while call continuity is maintained.
- The negotiated media destination is reachable and both endpoints exchange RTP via the approved border.
- Saturation tests keep voice latency and loss bounded while backup traffic slows.
Explanation
Correct Answer
C:The SDP media address and the actual translated network path must agree. This is decisive because the expected outcome is: The negotiated media destination is reachable and both endpoints exchange RTP via the approved border.
Incorrect Answers
A:“Video loss and artifact rate fall within accepted levels in a sustained test” evaluates video decoding artifacts can arise from impaired video RTP streams without a full signaling outage. It would not confirm the collaboration outcome requiring the SDP media address and the actual translated network path must agree.
B:“Under roaming load, retry rate and RTP loss decrease while call continuity is maintained” evaluates wireless airtime contention can impair real-time media independently of PSTN routing configuration. It would not confirm the collaboration outcome requiring the SDP media address and the actual translated network path must agree.
D:“Saturation tests keep voice latency and loss bounded while backup traffic slows” evaluates real-time audio requires predictable low-delay handling when competing data traffic fills a constrained link. It would not confirm the collaboration outcome requiring the SDP media address and the actual translated network path must agree.
Question 373
During a collaboration systems review, the following is documented: Call quality degrades only on one Wi-Fi access point when many clients roam into the area. Which response should engineers prioritize?
- Correlate RF retries, channel contention and WLAN QoS with RTP jitter before changing voice gateways.
- Inspect video stream packet loss, throughput and codec adaptation across the end-to-end path.
- Isolate acoustic or hybrid echo paths and inspect endpoint echo cancellation or gateway media characteristics.
- Use a supported assured-forwarding video class and measured bandwidth policy distinct from strict-priority voice.
Explanation
Correct Answer
A:Wireless airtime contention can impair real-time media independently of PSTN routing configuration. Apply the specific remedy: Correlate RF retries, channel contention and WLAN QoS with RTP jitter before changing voice gateways. Verify it by checking: Under roaming load, retry rate and RTP loss decrease while call continuity is maintained.
Incorrect Answers
B:“Inspect video stream packet loss, throughput and codec adaptation across the end-to-end path” concerns video decoding artifacts can arise from impaired video RTP streams without a full signaling outage. The stated collaboration requirement instead depends on wireless airtime contention can impair real-time media independently of PSTN routing configuration.
C:“Isolate acoustic or hybrid echo paths and inspect endpoint echo cancellation or gateway media characteristics” concerns echo relates to delayed audio reflection or leakage rather than SIP registration. The stated collaboration requirement instead depends on wireless airtime contention can impair real-time media independently of PSTN routing configuration.
D:“Use a supported assured-forwarding video class and measured bandwidth policy distinct from strict-priority voice” concerns video generally needs managed bandwidth without starving other traffic through unrestricted priority treatment. The stated collaboration requirement instead depends on wireless airtime contention can impair real-time media independently of PSTN routing configuration.
Question 374
A Cisco collaboration operations team is closing a ticket for this requirement: Call quality degrades only on one Wi-Fi access point when many clients roam into the area. Which result provides the strongest verification?
- Under roaming load, retry rate and RTP loss decrease while call continuity is maintained.
- Video loss and artifact rate fall within accepted levels in a sustained test.
- An echo test shows the reflected signal is acceptably attenuated on the affected leg.
- Packet captures show control traffic receives the designed signaling marking and call setup stays reliable.
Explanation
Correct Answer
A:Wireless airtime contention can impair real-time media independently of PSTN routing configuration. This is decisive because the expected outcome is: Under roaming load, retry rate and RTP loss decrease while call continuity is maintained.
Incorrect Answers
B:“Video loss and artifact rate fall within accepted levels in a sustained test” evaluates video decoding artifacts can arise from impaired video RTP streams without a full signaling outage. It would not confirm the collaboration outcome requiring wireless airtime contention can impair real-time media independently of PSTN routing configuration.
C:“An echo test shows the reflected signal is acceptably attenuated on the affected leg” evaluates echo relates to delayed audio reflection or leakage rather than SIP registration. It would not confirm the collaboration outcome requiring wireless airtime contention can impair real-time media independently of PSTN routing configuration.
D:“Packet captures show control traffic receives the designed signaling marking and call setup stays reliable” evaluates signaling is important but has different delay and throughput characteristics from continuous audio media. It would not confirm the collaboration outcome requiring wireless airtime contention can impair real-time media independently of PSTN routing configuration.
Question 375
During a collaboration systems review, the following is documented: A collaboration WAN treats voice and bulk backups identically during saturation. Which response should engineers prioritize?
- Classify audio media into an appropriate expedited forwarding class and preserve a controlled priority queue.
- Align WLAN multimedia access categories and supported QoS markings with the wired end-to-end policy.
- Agree the provider QoS class mapping and reclassify at supported trust boundaries where necessary.
- Size LLQ priority bandwidth to measured admitted voice traffic and prevent unbounded queue domination.
Explanation
Correct Answer
A:Real-time audio requires predictable low-delay handling when competing data traffic fills a constrained link. Apply the specific remedy: Classify audio media into an appropriate expedited forwarding class and preserve a controlled priority queue. Verify it by checking: Saturation tests keep voice latency and loss bounded while backup traffic slows.
Incorrect Answers
B:“Align WLAN multimedia access categories and supported QoS markings with the wired end-to-end policy” concerns wireless WMM queues and wired DSCP treatment must map coherently across the access boundary. The stated collaboration requirement instead depends on real-time audio requires predictable low-delay handling when competing data traffic fills a constrained link.
C:“Agree the provider QoS class mapping and reclassify at supported trust boundaries where necessary” concerns qoS is end-to-end only if every constrained hop preserves or intentionally maps traffic priority. The stated collaboration requirement instead depends on real-time audio requires predictable low-delay handling when competing data traffic fills a constrained link.
D:“Size LLQ priority bandwidth to measured admitted voice traffic and prevent unbounded queue domination” concerns low-latency queuing needs capacity control as well as preferential service. The stated collaboration requirement instead depends on real-time audio requires predictable low-delay handling when competing data traffic fills a constrained link.
Question 376
An assessor is validating a change intended to fix: A collaboration WAN treats voice and bulk backups identically during saturation. Which observed result is most decisive?
- WLAN captures and controller counters show consistent voice prioritization through the air and LAN.
- Captured DSCP and queue statistics confirm intended class treatment before and after the carrier handoff.
- Saturation tests keep voice latency and loss bounded while backup traffic slows.
- Visitor data is reset to approved classes while legitimate managed-phone RTP remains EF.
Explanation
Correct Answer
C:Real-time audio requires predictable low-delay handling when competing data traffic fills a constrained link. This is decisive because the expected outcome is: Saturation tests keep voice latency and loss bounded while backup traffic slows.
Incorrect Answers
A:“WLAN captures and controller counters show consistent voice prioritization through the air and LAN” evaluates wireless WMM queues and wired DSCP treatment must map coherently across the access boundary. It would not confirm the collaboration outcome requiring real-time audio requires predictable low-delay handling when competing data traffic fills a constrained link.
B:“Captured DSCP and queue statistics confirm intended class treatment before and after the carrier handoff” evaluates qoS is end-to-end only if every constrained hop preserves or intentionally maps traffic priority. It would not confirm the collaboration outcome requiring real-time audio requires predictable low-delay handling when competing data traffic fills a constrained link.
D:“Visitor data is reset to approved classes while legitimate managed-phone RTP remains EF” evaluates blindly trusting all endpoint DSCP markings lets untrusted devices consume protected network queues. It would not confirm the collaboration outcome requiring real-time audio requires predictable low-delay handling when competing data traffic fills a constrained link.
Question 377
During a migration-readiness audit, the assessor records: Cisco SIP call-control traffic is marked as voice RTP, using the same strict-priority class. Which implementation meets the constraint?
- Align WLAN multimedia access categories and supported QoS markings with the wired end-to-end policy.
- Use a supported assured-forwarding video class and measured bandwidth policy distinct from strict-priority voice.
- Classify signaling separately from RTP, using an appropriate signaling class such as CS3 under the QoS design.
- Measure RTP loss, jitter and delay under congestion and repair the bottleneck or QoS treatment.
Explanation
Correct Answer
C:Signaling is important but has different delay and throughput characteristics from continuous audio media. Apply the specific remedy: Classify signaling separately from RTP, using an appropriate signaling class such as CS3 under the QoS design. Verify it by checking: Packet captures show control traffic receives the designed signaling marking and call setup stays reliable.
Incorrect Answers
A:“Align WLAN multimedia access categories and supported QoS markings with the wired end-to-end policy” concerns wireless WMM queues and wired DSCP treatment must map coherently across the access boundary. The stated collaboration requirement instead depends on signaling is important but has different delay and throughput characteristics from continuous audio media.
B:“Use a supported assured-forwarding video class and measured bandwidth policy distinct from strict-priority voice” concerns video generally needs managed bandwidth without starving other traffic through unrestricted priority treatment. The stated collaboration requirement instead depends on signaling is important but has different delay and throughput characteristics from continuous audio media.
D:“Measure RTP loss, jitter and delay under congestion and repair the bottleneck or QoS treatment” concerns real-time audio is vulnerable to delay variation and packet loss even while a call remains connected. The stated collaboration requirement instead depends on signaling is important but has different delay and throughput characteristics from continuous audio media.
Question 378
An assessor is validating a change intended to fix: Cisco SIP call-control traffic is marked as voice RTP, using the same strict-priority class. Which observed result is most decisive?
- Packet captures show control traffic receives the designed signaling marking and call setup stays reliable.
- WLAN captures and controller counters show consistent voice prioritization through the air and LAN.
- Under load the meeting has bounded video loss and voice priority remains protected.
- The corrected path maintains expected SIP transactions and calls no longer release at the timeout.
Explanation
Correct Answer
A:Signaling is important but has different delay and throughput characteristics from continuous audio media. This is decisive because the expected outcome is: Packet captures show control traffic receives the designed signaling marking and call setup stays reliable.
Incorrect Answers
B:“WLAN captures and controller counters show consistent voice prioritization through the air and LAN” evaluates wireless WMM queues and wired DSCP treatment must map coherently across the access boundary. It would not confirm the collaboration outcome requiring signaling is important but has different delay and throughput characteristics from continuous audio media.
C:“Under load the meeting has bounded video loss and voice priority remains protected” evaluates video generally needs managed bandwidth without starving other traffic through unrestricted priority treatment. It would not confirm the collaboration outcome requiring signaling is important but has different delay and throughput characteristics from continuous audio media.
D:“The corrected path maintains expected SIP transactions and calls no longer release at the timeout” evaluates a reproducible 30-second release can be a signaling transaction or ACK problem rather than packet-loss-only QoS. It would not confirm the collaboration outcome requiring signaling is important but has different delay and throughput characteristics from continuous audio media.
Question 379
During a migration-readiness audit, the assessor records: HD meeting video and voice share a WAN, but all video is discarded during routine traffic bursts. Which implementation meets the constraint?
- Classify signaling separately from RTP, using an appropriate signaling class such as CS3 under the QoS design.
- Align WLAN multimedia access categories and supported QoS markings with the wired end-to-end policy.
- Use a supported assured-forwarding video class and measured bandwidth policy distinct from strict-priority voice.
- Add an appropriate priority class with a bounded allocation in the IOS XE policy-map.
Explanation
Correct Answer
C:Video generally needs managed bandwidth without starving other traffic through unrestricted priority treatment. Apply the specific remedy: Use a supported assured-forwarding video class and measured bandwidth policy distinct from strict-priority voice. Verify it by checking: Under load the meeting has bounded video loss and voice priority remains protected.
Incorrect Answers
A:“Classify signaling separately from RTP, using an appropriate signaling class such as CS3 under the QoS design” concerns signaling is important but has different delay and throughput characteristics from continuous audio media. The stated collaboration requirement instead depends on video generally needs managed bandwidth without starving other traffic through unrestricted priority treatment.
B:“Align WLAN multimedia access categories and supported QoS markings with the wired end-to-end policy” concerns wireless WMM queues and wired DSCP treatment must map coherently across the access boundary. The stated collaboration requirement instead depends on video generally needs managed bandwidth without starving other traffic through unrestricted priority treatment.
D:“Add an appropriate priority class with a bounded allocation in the IOS XE policy-map” concerns lLQ scheduling follows the queue configuration in the policy-map, not classification alone. The stated collaboration requirement instead depends on video generally needs managed bandwidth without starving other traffic through unrestricted priority treatment.
Question 380
An assessor is validating a change intended to fix: HD meeting video and voice share a WAN, but all video is discarded during routine traffic bursts. Which observed result is most decisive?
- Packet captures show control traffic receives the designed signaling marking and call setup stays reliable.
- WLAN captures and controller counters show consistent voice prioritization through the air and LAN.
- Under load the meeting has bounded video loss and voice priority remains protected.
- A capture confirms bidirectional RTP packets at both endpoints and two-way audio is restored.
Explanation
Correct Answer
C:Video generally needs managed bandwidth without starving other traffic through unrestricted priority treatment. This is decisive because the expected outcome is: Under load the meeting has bounded video loss and voice priority remains protected.
Incorrect Answers
A:“Packet captures show control traffic receives the designed signaling marking and call setup stays reliable” evaluates signaling is important but has different delay and throughput characteristics from continuous audio media. It would not confirm the collaboration outcome requiring video generally needs managed bandwidth without starving other traffic through unrestricted priority treatment.
B:“WLAN captures and controller counters show consistent voice prioritization through the air and LAN” evaluates wireless WMM queues and wired DSCP treatment must map coherently across the access boundary. It would not confirm the collaboration outcome requiring video generally needs managed bandwidth without starving other traffic through unrestricted priority treatment.
D:“A capture confirms bidirectional RTP packets at both endpoints and two-way audio is restored” evaluates one-way audio often means one RTP direction is blocked or misaddressed despite healthy SIP signaling. It would not confirm the collaboration outcome requiring video generally needs managed bandwidth without starving other traffic through unrestricted priority treatment.
