Overview
Call quality statistics in CUBE, such as packet loss, jitter, and round trip delay can be added to the call detail record (CDR), and these voice metrics can be calculated in IOS. For more information, refer to Voice Quality Enhancements on Cisco Unified Border Element.
The call quality statistics feature is enhanced to provide the following capabilities:
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Enable or disable Quality of Service (QoS) for CUBE.
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Enable or disable Real-time Transport Protocol (RTP) Control Protocol (RTCP) passthrough.
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Configure call quality criteria parameters.
Call quality configuration parameters include max_dropout, max_reorder, and clock_rate. A maximum of three codecs (codec_number, payload_type, clock_rate) per media flow is collected by the PI and sent to CPP, which uses these values in statistics calculation. Calculated statistics such as Jitter, Packet Loss, and Delay are then fetched from the CPP to the CDR. These statistics can be viewed in the command line interface.
The CDR has the following data per call leg of the call:
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Packet Loss-Calculated based on methods shown in RFC3550. The RTCP sender/receiver reports are recalculated, and not just copied from the inbound leg to the outbound leg.
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Delay-Calculated based on timestamp received or timestamp of packets sent.
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Jitter-Variation of delay.
For more information on how to calculate the voice quality metrics related to media(voice) quality, such as conversational mean opinion score (MOS), jitter, and so on, see http://www.cisco.com/c/en/us/td/docs/ios-xml/ios/voice/cube/configuration/cube-book/voi-cube-call-monitoring.html.
The VQM (Voice Quality Monitor) gives information on the voice quality metrics. The VQM on Cisco IOS XE platforms enables statistics gathering based on the received RTCP packets. From these statistics, a voice quality measurement is developed to show the quality of the call. The output is in a simple format, using a system of good, poor, and bad types of ratings.
The following metrics exists in Call Detail Record (CDR) and Management Information Base (MIB) in CUBE, indicating voice quality:
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MOSQe (conversational quality MOS)
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Round-trip-delay.
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Receive-delay (current jitter buffer size).
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Packet-Loss-Rate.
The CDR is sent at the end of a call if AAA accounting is configured.
A CDR example is as follows:
<MOS-Con>4.4072</MOS-Con>
<round-trip-delay>1 ms</round-trip-delay>
<receive-delay>64 ms</receive-delay>
<voice-quality-total-packet-loss>0.0000 %</ voice-quality-total-packet-loss>
VQM Metrics
The following are the metrics exported by VQM:
IOS VQM, Voice/Audio Description Quality Metric |
Description |
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MOS-Con |
The conversational quality MOS. Conversational quality indicates the impact of the quality of the transmission on the dynamics of conversational exchanges between two parties; such metrics take into account delay, echo, and recency. |
round-trip-delay |
The instantaneous round-trip delay. This may be obtained from the RTCP SR reports. |
receive-delay |
The minimum delay that will be applied to the packets received when using an adaptive jitter buffer. |
voice-quality-total-packet-loss |
The total number of packets lost by the jitter buffer in the RTP stream. |
Feature Information
The following table provides release information about the feature or features described in this module. This table lists only the software release that introduced support for a given feature in a given software release train. Unless noted otherwise, subsequent releases of that software release train also support that feature.
Use Cisco Feature Navigator to find information about platform support and Cisco software image support. To access Cisco Feature Navigator, go to www.cisco.com/go/cfn. An account on Cisco.com is not required.
Feature Name |
Releases |
Feature Information |
---|---|---|
Voice Quality Statistics |
Cisco IOS XE Everest 16.5.1b |
Voice quality statistics provides information about the quality of the voice TDM-IP call. This feature is already implemented on ISR-G2, and the feature gap is filled in ISR 4000 series. |
Voice Quality Monitoring |
Cisco IOS XE Denali 16.3.1 |
The Voice Quality Monitoring (VQM) feature provides information on the voice quality metrics related to media (voice) quality, such as conversational mean opinion score (MOS), packet loss rate, and so on. VQM enables you to monitor the quality of calls traversing your VoIP network, and you can diagnose the cause of voice quality issues and troubleshoot them. |