Exam 300-815 topic 1 question 25 discussion

Answer should be A

Answer should be A, codec mismatch generally drops the call

Answer A (The question mentions Q0S enabled WAN Network, not LAN) B - Call would not work - SDP would not be negotiated Cause=65 (most likely) no audio at all C - Could actually provide those symptoms but, usually complete playback failure. D- COS (Layer 2, think LAN) WAN cares not at L3 (DSCP-IP-Prec) (Put there to trip you up) I would need qos mapping cos to ip prec (old mls qos commands) on L3 Switch. Too much assumption here. Then again were talking Cisco questions, not known for making sense when it comes to testing your actual abilities.

Phone marks the packet witha wrong COS thus QoS is not working

A is correct answer as two different location,

A. missing Call Admission Control

Question states that the WAN is QoS enabled. Answers B and C will not have audio. Answer A still doesn't fix the real root cause. Answer is D, because CoS setting will properly tag audio traffic so that it is prioritized over the WAN.

A. missing Call Admission Control

The question asks about the cause of choppy or clipped audio when a user in location X calls an extension at location Y over a QoS-enabled WAN network. The most likely cause of this issue is: B. codec mismatch Thus, B. codec mismatch is the most plausible cause of choppy or clipped audio in this scenario.

I think answer D. Because A is something that could help to overcome the issue but it's not a route cause of it

Maybe D ? if the phone is not set for trust then there is no QoS markings on the phone which in turn never get prioritized across the WAN. even though QoS is enabled on the WAN

Best Answer would have been if there was something related to QoS misconfigured or missing but Call Admission Control is the closest it gets to QoS. So i agree with you its (A)