Configuring RTCP XR
RTP Control Protocol Extended Reports (RTCP XR) is a VoIP management control that defines a set of metrics containing information for assessing VoIP call quality and for diagnosing problems. RTCP XR (RFC 3611) extends the RTCP reports defined in RFC 3550 by providing additional VoIP metrics (Quality of Experience). RTCP XR information publishing is implemented in the device according to RFC 6035. The draft defines how a SIP User Agent (UA) publishes the detailed information to a defined collector. RTCP XR measures VoIP call quality such as packet loss, delay, signal / noise / echo levels, estimated R-factor, and mean opinion score (MOS). RTCP XR measures these parameters using metrics as listed in the table below. RTCP XR messages containing key call-quality-related metrics are exchanged periodically (user-defined) between the device and the SIP UA. This allows an analyzer to monitor these metrics midstream, or a device to retrieve them through SNMP.
| ● | The RTCP XR feature is available only if the device is installed with a License Key that includes this feature. For installing a License Key, see License Key. |
| ● | If the RTCP XR feature is unavailable (not licensed or disabled), the R-factor VoIP metrics are not provided in CDRs (CDR fields, Local R Factor and Remote R Factor) generated by the device. Instead, these CDR fields are sent with the value 127, meaning that information is unavailable. |
| ● | While the device attempts to determine the signal level, it reports a MOS value of “127 (NA)”. Once it has determined the signal level, it reports the estimated MOS. |
| ● | Packet loss effects voice quality estimation only during periods of voice. During periods of silence, packet loss doesn't effect or degrade voice quality. |
You can configure the device to send RTCP XR to a specific IP Group. The device sends RTCP XR in SIP PUBLISH messages. The PUBLISH message contains the following RTCP XR related header values:
| ■ | From and To: Telephone extension number of the user |
| ■ | Request-URI: IP Group name to where RTCP XR is sent |
| ■ | Event: "vq-rtcpxr" |
| ■ | Content-Type: "application/vq-rtcpxr" |
You can also configure the stage of the call at which you want the device to send RTCP XR:
| ■ | End of the call. |
| ■ | Periodically, according to a user-defined interval between consecutive reports. |
| ■ | (Gateway Application Only) End of a media segment. A media segment is a change in media, for example, when the coder is changed or when the caller toggles between two called parties (using call hold/retrieve). The RTCP XR sent at the end of a media segment contains information only of that segment. For call hold, the device sends RTCP XR each time the call is placed on hold and each time it is retrieved. In addition, the Start timestamp in the RTCP XR indicates the start of the media segment; the End timestamp indicates the time of the last sent periodic RTCP XR (typically, up to 5 seconds before reported segment ends). |
The type of RTCP XR report event (VQReportEvent) supported by the device is VQSessionReport (SessionReport). The device can include local and remote metrics in the RTCP XR. Local metrics are generated by the device while remote metrics are provided by the remote endpoint. The following table lists the supported voice metrics (parameters) published in the RTCP XR.
RTCP XR Published VoIP Metrics
|
Metric |
Parameter |
Description |
|---|---|---|
|
CallID |
- |
Call ID - call ID from the SIP dialog |
|
LocalID |
- |
Local ID - identifies the reporting endpoint for the media session |
|
RemoteID |
- |
Remote ID - identifies the remote endpoint of the media session |
|
OrigID |
- |
Originating ID - Identifies the endpoint which originated the session |
|
LocalAddr |
- |
Local Address - IP address, port, and SSRC of the endpoint/UA which is the receiving end of the stream being measured |
|
RemoteAddr |
- |
Remote Address - IP address, port, and SSRC of the source of the stream being measured |
|
LocalGroup |
- |
Local Group ID - identification for the purposes of aggregation for the local endpoint |
|
RemoteGroup |
- |
Remote Group ID - identification for the purposes of aggregation for the remote endpoint |
|
LocalMAC |
- |
Media Access Control (MAC) address of the local SIP device |
|
Timestamps |
START |
Start time of the media session |
|
STOP |
End time of the media session |
|
|
SessionDesc |
PT |
Payload Type - 'payload type' parameter in the RTP packets (i.e., the codec). |
|
PD |
Payload Description - description of the codec |
|
|
SR |
Sample Rate - rate at which the voice was sampled |
|
|
FD |
Frame Duration (msec) - packetization rate |
|
|
FO |
Frame Octets - number of octets in each frame per RTP packet |
|
|
FPP |
Frames per Packets - number of frames per RTP packet |
|
|
PLC |
Packet Loss Concealment - indicates whether a PLC algorithm was used for the session ("0" - unspecified; "1" - disabled; "2" - enhanced; "3" - standard) |
|
|
SSUP |
Silence Suppression State - indicates whether silence suppression, also known as Voice Activity Detection (VAD) is enabled ("on" or "off") |
|
|
JitterBuffer
|
JBA |
Jitter Buffer Adaptive - indicates the jitter buffer in the endpoint ("0" - unknown; "1" - reserved; "2" - non-adaptive; "3" - adaptive) |
|
JBR |
Jitter Buffer Rate |
|
|
JBN |
Jitter Buffer Nominal |
|
|
JBM |
Jitter Buffer Max |
|
|
JBX |
Jitter Buffer Abs Max |
|
|
PacketLoss |
NLR |
Network Packet Loss Rate |
|
JDR |
Jitter Buffer Discard Rate |
|
|
BurstGapLoss |
BLD |
Burst Loss Density |
|
BD |
Burst Duration |
|
|
GLD |
Gap Loss Density |
|
|
GD |
Gap Duration |
|
|
GMIN |
Minimum Gap Threshold |
|
|
Delay |
RTD |
Round Trip Delay (msec) |
|
ESD |
End System Delay (msec) |
|
|
OWD |
One Way Delay (msec) |
|
|
IAJ |
Inter-Arrival Jitter (msec) |
|
|
MAJ |
Mean Absolute Jitter (msec) |
|
|
Signal |
SL |
Signal Level (dB) - ratio of the signal level to a 0 dBm0 reference |
|
NL |
Noise Level (dB) - ratio of the silent period background noise level to a 0 dBm0 reference |
|
|
RERL |
Residual Echo Return Noise (dB) - ratio between the original signal and the echo level as measured after echo cancellation or suppression has been applied |
|
|
QualityEst |
RLQ |
Listening Quality R - listening quality expressed as an R factor (0-95 for narrowband calls and 0-120 for wideband calls) |
|
RLQEstAlg |
RLQ Est. Algorithm - name (string) of the algorithm used to estimate RLQ |
|
|
RCQ |
Conversational Quality R - cumulative measurement of voice quality from the start of the session to the reporting time (R is 0-95 for narrowband calls and 0-120 for wideband calls) |
|
|
RCQEstAlg |
RCQ Est. Algorithm - name (string) of the algorithm used to estimate RCQ |
|
|
EXTRI |
External R In - voice quality as measured by the local endpoint for incoming connection on "other" side (R is 0-95 for narrowband calls and 0-120 for wideband calls) |
|
|
ExtRIEstAlg |
Ext. R In Est. Algorithm - name (string) of the algorithm used to estimate EXTRI |
|
|
EXTRO |
External R Out - value is copied from RTCP XR received from the remote endpoint on the "other" side of this endpoint (R is 0-95 for narrowband calls and 0-120 for wideband calls) |
|
|
ExtROEstAlg |
Ext. R Out Est. Algorithm - name (string) of the algorithm used to estimate EXTRO |
|
|
MOSLQ |
MOS-LQ - estimated mean opinion score for listening voice quality on a scale from 1 to 5, in which 5 represents excellent and 1 represents unacceptable |
|
|
MOSLQEstAlg |
MOS-LQ Est. Algorithm - name (string) of the algorithm used to estimate MOSLQ |
|
|
MOSCQ |
MOS-CQ - estimated mean opinion score for conversation voice quality on a scale from 1 to 5, in which 5 represents excellent and 1 represents unacceptable |
|
|
MOSCQEstAlg |
MOS-CQ Est. Algorithm - name (string) of the algorithm used to estimate MOSCQ |
|
|
QoEEstAlg |
QoE Est. Algorithm - name (string) of the algorithm used to estimate all voice quality metrics |
|
|
DialogID |
- |
Identification of the SIP dialog with which the media session is related |
Below shows an example of a SIP PUBLISH message sent with RTCP XR and QoE information:
PUBLISH sip:172.17.116.201 SIP/2.0
Via: SIP/2.0/UDP 172.17.116.201:5060;branch=z9hG4bKac2055925925
Max-Forwards: 70
From: <sip:172.17.116.201>;tag=1c2055916574
To: <sip:172.17.116.201>
Call-ID: 20559160721612201520952@172.17.116.201
CSeq: 1 PUBLISH
Contact: <sip:172.17.116.201:5060>
Allow: REGISTER,OPTIONS,INVITE,ACK,CANCEL,BYE,NOTIFY,PRACK,REFER,INFO,SUBSCRIBE,UPDATE
Event: vq-rtcpxr
Expires: 3600
User-Agent: device/7.40A.600.203
Content-Type: application/vq-rtcpxr
Content-Length: 1066
VQSessionReport
CallID=20328634741612201520943@172.17.116.201
LocalID: <sip:1000@172.17.116.201>
RemoteID: <sip:2000@172.17.116.202;user=phone>
OrigID: <sip:1000@172.17.116.201>
LocalAddr: IP=172.17.116.201 Port=6000 SSRC=0x54c62a13
RemoteAddr: IP=172.17.116.202 Port=6000 SSRC=0x243220dd
LocalGroup:
RemoteGroup:
LocalMAC: 00:90:8f:57:d9:71
LocalMetrics:
Timestamps: START=2015-12-16T20:09:45Z STOP=2015-12-16T20:09:52Z
SessionDesc: PT=8 PD=PCMA SR=8000 FD=20 PLC=3 SSUP=Off
JitterBuffer: JBA=3 JBR=0 JBN=7 JBM=10 JBX=300
PacketLoss: NLR=0.00 JDR=0.00
BurstGapLoss: BLD=0.00 BD=0 GLD=0.00 GD=6325 GMIN=16
Delay: RTD=0 ESD=11
Signal: SL=-34 NL=-67 RERL=17
QualityEst: RLQ=93 MOSLQ=4.1
MOSCQ=4.10
RemoteMetrics:
Timestamps: START=2015-12-16T20:09:45Z STOP=2015-12-16T20:09:52Z
JitterBuffer: JBA=3 JBR=0 JBN=0 JBM=0 JBX=300
PacketLoss: NLR=0.00 JDR=0.00
BurstGapLoss: BLD=0.00 BD=0 GLD=0.00 GD=0 GMIN=16
Delay: RTD=65535 ESD=0
QualityEst:
DialogID: 20328634741612201520943@172.17.116.201;to-tag=1c1690611502;from-tag=1c2032864069
| ➢ | To configure RTCP XR: |
| 1. | Open the RTP/RTCP Settings page (Setup menu > Signaling & Media tab > Media folder > RTP/RTCP Settings). |
| 2. | Under the RTCP-XR group, configure the following: |
| ● | 'Enable RTCP XR' (VQMonEnable) - enables voice quality monitoring and RTCP XR. |
| ● | 'Tx RTCP Packets Interval' (RTCPInterval) - defines the time interval between adjacent RTCP reports. |
| ● | 'Disable RTCP XR Interval Randomization' (DisableRTCPRandomize) - determines whether RTCP report intervals are randomized or whether each report interval accords exactly to the parameter RTCPInterval. |
| ● | 'Burst Threshold' (VQMonBurstHR) - defines the voice quality monitoring excessive burst alert threshold. |
| ● | 'Delay Threshold' (VQMonDelayTHR) - defines the voice quality monitoring excessive delay alert threshold. |
| ● | 'R-Value Delay Threshold' (VQMonEOCRValTHR) - defines the voice quality monitoring end of call low quality alert threshold. |
| ● | 'Minimum Gap Size' (VQMonGMin) - defines the voice quality monitoring minimum gap size (number of frames). |
| 3. | Under the RTCP-XR Collection Server group, configure the following: |
| ● | 'Publication IP Group ID' (PublicationIPGroupID): Configures the IP Group to where you want the device to send RTCP XR reports. |
| ● | (Gateway Application Only) 'Gateway RTCP XR Report Mode' (RTCPXRReportMode): Enables the sending of RTCP XR reports and configures at what stage of the call they are sent. |
| ● |
|
| 4. | Click Apply, and then restart the device with a save-to-flash for your settings to take effect. |