Cisco Systems 8945, 8941 manual Voice Quality Metrics, Mos Lqk

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Table 7-4 Call Statistics Items for the Cisco Unified Phone 8941 and 8945

Item	Description
Avg Jitter	Estimated average RTP packet jitter (dynamic delay that a packet encounters when
	going through the network) observed since the receiving voice stream was opened.
Max Jitter	Maximum jitter observed since the receiving voice stream was opened.
Rcvr Discarded	Number of RTP packets in the receiving voice stream that have been discarded
	(bad packets, too late, and so on).
	Note The phone will discard payload type 19 comfort noise packets that are
		generated by Cisco Gateways, which will increment this counter.
Rcvr Lost Packets	Missing RTP packets (lost in transit).
Voice Quality Metrics
Cumulative	Total number of concealment frames divided by total number of speech frames
Conceal Ratio	received from start of the voice stream.
Interval Conceal	Ratio of concealment frames to speech frames in preceding 3-second interval of
Ratio	active speech. If using voice activity detection (VAD), a longer interval might be
	required to accumulate 3 seconds of active speech.
Max Conceal Ratio	Highest interval concealment ratio from start of the voice stream.
Conceal Secs	Number of seconds that have concealment events (lost frames) from the start of
	the voice stream (includes severely concealed seconds).
Severely Conceal	Number of seconds that have more than 5 percent concealment events (lost
Secs	frames) from the start of the voice stream.
Latency	Estimate of the network latency, expressed in milliseconds. Represents a running
	average of the round-trip delay, measured when RTCP receiver report blocks are
	received.
MOS LQK	Objective estimate of the Mean Opinion Score (MOS) for Listening Quality
	(LQK) that ranks audio quality from 5 (excellent) to 1 (bad). This score is based
	on audible-concealment events due to a frame loss in the preceding 8 seconds of
	the voice stream.
	Note The MOS LQK score can vary based on the type of codec that the
		Cisco Unified IP Phone uses.
Avg MOS LQK	Average MOS LQK score for the entire voice stream.
Min MOS LQK	Lowest MOS LQK score from the start of the voice stream.
Max MOS LQK	Baseline or highest MOS LQK score from the start of the voice stream.
	The following codecs provide the corresponding maximum MOS LQK scores
	under normal conditions with no frame loss:
	•	G.711: 4.5
	•	G.722: 4.5
	•	G.728/iLBC: 3.9
	•	G729A/AB: 3.7
MOS LQK Version	Version of the Cisco-proprietary algorithm used to calculate the MOS LQK
	scores.

Cisco Unified IP Phone 8941 and 8945 Administration Guide for Cisco Unified Communications Manager 8.5 (SCCP and SIP)

OL-20851-01 7-9