Cisco Systems 6921 manual Voice Quality Metrics, Stream

Chapter

Streaming Statistics

Table 8-5	Streaming Statistics Area Items (continued)
Item		Description
Max Jitter		Maximum value of instantaneous jitter, in milliseconds.
Sender Size		RTP packet size, in milliseconds, for the transmitted stream.
Sender Reports Received1		Number of times RTCP Sender Reports have been received.
Sender Report Time		Last time at which an RTCP Sender Report was received.
Received1
Rcvr Size		RTP packet size, in milliseconds, for the received stream.
Rcvr Discarded		RTP packets received from network but discarded from jitter buffers.
Rcvr Reports Received1		Number of times RTCP Receiver Reports have been received.
Rcvr Report Time Received1		Last time at which an RTCP Receiver Report was received.
Voice Quality Metrics
Cumulative Conceal Ratio		Total number of concealment frames divided by total number of speech frames received
		from start of the voice stream.
Interval Conceal Ratio		Ratio of concealment frames to speech frames in preceding 3-second interval of 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 Secs		Number of seconds that have more than 5 percent concealment events (lost 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.

1. When the RTP Control Protocol is disabled, no data generates for this field and thus displays as 0.

Cisco Unified IP Phone 6921, 6941, 6945, and 6961 Administration Guide for Cisco Unified Communications Manager 8.5 (SCCP and SIP)

OL-23769-01 8-11