300-430 · Question #311
An engineer implements QoS on an AireOS WLC v8.3. When configuring AVC on a WLAN, the engineer must configure the appropriate AVC profile for a Cisco Wireless IP Phone 8821, Which command must be…
The correct answer is C. config avc profile AUTOQOS-AVC-PROFILE rule add application cisco-phone-audio mark 46. Voice traffic for the Cisco Wireless IP Phone 8821 must be marked with DSCP 46 (EF - Expedited Forwarding) to receive proper low-latency QoS treatment in an AireOS AVC profile.
Question
An engineer implements QoS on an AireOS WLC v8.3. When configuring AVC on a WLAN, the engineer must configure the appropriate AVC profile for a Cisco Wireless IP Phone 8821, Which command must be used?
Options
- Aconfig avc profile AUTOQOS-AVC-PROFILE rule add application cisco-phone-audio mark 41
- Bconfig avc profile AUTOQOS-AVC-PROFILE rule add application cisco-phone-audio mark 56
- Cconfig avc profile AUTOQOS-AVC-PROFILE rule add application cisco-phone-audio mark 46
- Dconfig avc profile AUTOQOS-AVC-PROFILE rule add application cisco-phone-audio mark 48
How the community answered
(26 responses)- A4% (1)
- B4% (1)
- C85% (22)
- D8% (2)
Why each option
Voice traffic for the Cisco Wireless IP Phone 8821 must be marked with DSCP 46 (EF - Expedited Forwarding) to receive proper low-latency QoS treatment in an AireOS AVC profile.
DSCP 41 is not a recognized standard marking for voice bearer traffic and does not appear in Cisco AutoQoS AVC profiles for voice phones.
DSCP 56 maps to CS7, which is reserved for network routing control traffic such as BGP, not for voice media streams.
DSCP 46 corresponds to the Expedited Forwarding (EF) per-hop behavior defined in RFC 3246, which is the industry standard marking for voice bearer traffic. The Cisco AutoQoS AVC profile marks the cisco-phone-audio application with DSCP EF (46) to ensure the low-latency, low-jitter queuing treatment required for voice RTP streams on the Wireless IP Phone 8821.
DSCP 48 maps to CS6, which is assigned to network control protocols, not to voice bearer traffic.
Concept tested: AVC profile DSCP EF marking for wireless voice
Source: https://www.cisco.com/c/en/us/td/docs/wireless/controller/8-3/config-guide/b_cg83/avc.html
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