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Session Initiation Protocol Event Package for Voice Quality Reporting
RFC 6035

Document Type RFC - Proposed Standard (November 2010) Errata
Authors Dr. Henry Sinnreich , Amy Pendleton , Alan Clark , Alan Johnston
Last updated 2015-10-14
RFC stream Internet Engineering Task Force (IETF)
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Additional resources Mailing list discussion
IESG Responsible AD Robert Sparks
Send notices to (None)
RFC 6035
" 1*2DIGIT ]) ;percentage

GapDuration =
 "GD" EQUAL (1*7DIGIT) ;0-3,600,000 -- milliseconds

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MinimumGapThreshold =
 "GMIN" EQUAL (1*3DIGIT) ;1-255

Delay = "Delay" HCOLON
   [ RoundTripDelay WSP ]
   [ EndSystemDelay WSP ]
   [ OneWayDelay WSP ]
   [ SymmOneWayDelay WSP ]
   [ InterarrivalJitter WSP ]
   [ MeanAbsoluteJitter ]
   *(WSP Extension)

; RoundTripDelay SHALL be measured as defined in RFC 3550 [3].

RoundTripDelay = "RTD" EQUAL (1*5DIGIT) ;0-65535

; EndSystemDelay metric is defined in RFC 3611 [4].

EndSystemDelay = "ESD" EQUAL (1*5DIGIT) ;0-65535

; OneWayDelay is defined in RFC 2679 [12].

OneWayDelay = "OWD" EQUAL (1*5DIGIT) ;0-65535

; SymmOneWayDelay is defined as half the sum of RoundTripDelay
; and the EndSystemDelay values for both endpoints.

SymmOneWayDelay = "SOWD" EQUAL (1*5DIGIT); 0-65535

; Interarrival Jitter is calculated as defined RFC 3550 [3]
; and converted into milliseconds.

InterarrivalJitter = "IAJ" EQUAL (1*5DIGIT) ;0-65535 ms

; Mean Absolute Jitter is measured as defined
; by ITU-T G.1020 [9] where it is known as MAPDV.

MeanAbsoluteJitter = "MAJ" EQUAL (1*5DIGIT);0-65535

; Signal metrics definitions are provided in RFC 3611 [4].

Signal = "Signal" HCOLON
   [ SignalLevel WSP ]
   [ NoiseLevel WSP ]
   [ ResidualEchoReturnLoss ]
   *(WSP Extension)

; SignalLevel will normally be a negative value.

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; The absence of the negative sign indicates a positive value.
; Where the signal level is negative, the sign MUST be
; included.  This metric applies to the speech signal decoded
; from the received packet stream.

SignalLevel = "SL" EQUAL ([ "-" ] 1*2DIGIT)

; NoiseLevel will normally be negative and the sign MUST be
; explicitly included.
; The absence of a sign indicates a positive value.
; This metric applies to the speech signal decoded from the
; received packet stream.

NoiseLevel  = "NL" EQUAL ([ "-" ] 1*2DIGIT)

; Residual Echo Return Loss (RERL) is the ratio between
; the original signal and the echo level as measured after
; echo cancellation or suppression has been applied.
; Expressed in decibels (dB).  This is typically a positive
; value.
; This metric relates to the proportion of the speech signal
; decoded from the received packet stream that is reflected
; back in the encoded speech signal output in the transmitted
; packet stream (i.e., will affect the REMOTE user's
; conversational quality).  To support the diagnosis of echo-
; related problems experienced by the local user of the device
; generating a report according to this document, the value of
; RERL reported via the RTCP XR VoIP Metrics payload SHOULD be
; reported in the RemoteMetrics set of data.

ResidualEchoReturnLoss = "RERL" EQUAL (1*3DIGIT)

; Voice Quality estimation metrics.
; Each quality estimate has an optional associated algorithm.
; These fields permit the implementation to use a variety
; of different calculation methods for each type of metric.

QualityEstimates  = "QualityEst" HCOLON
   [ ListeningQualityR WSP ]
   [ RLQEstAlg WSP ]
   [ ConversationalQualityR WSP ]
   [ RCQEstAlg WSP ]
   [ ExternalR-In WSP ]
   [ ExtRInEstAlg WSP ]
   [ ExternalR-Out WSP ]
   [ ExtROutEstAlg WSP ]
   [ MOS-LQ WSP ]
   [ MOSLQEstAlg WSP ]

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   [ MOS-CQ WSP ]
   [ MOSCQEstAlg WSP ]
   [ QoEEstAlg ]
   *(WSP Extension)

ListeningQualityR = "RLQ" EQUAL (1*3DIGIT) ; 0 - 120

RLQEstAlg = "RLQEstAlg" EQUAL word ; "P.564" [10], or other

ConversationalQualityR = "RCQ" EQUAL (1*3DIGIT) ; 0 - 120

RCQEstAlg = "RCQEstAlg" EQUAL word ; "P.564", or other

; ExternalR-In is measured by the local endpoint for incoming
; connection on the "other" side of this endpoint.  For example,
;   Phone A <---> Bridge <----> Phone B
;   ListeningQualityR = quality for Phone A ----> Bridge path
;   ExternalR-In = quality for Bridge <---- Phone B path

ExternalR-In = "EXTRI" EQUAL (1*3DIGIT) ; 0 - 120

ExtRInEstAlg = "ExtRIEstAlg" EQUAL word ; "P.564" or other

; ExternalR-Out is copied from the RTCP XR message received from the
; remote endpoint on the "other" side of this endpoint.  For example,
;   Phone A <---> Bridge <----> Phone B
;   ExternalR-Out = quality for Bridge -----> Phone B path

ExternalR-Out = "EXTRO" EQUAL (1*3DIGIT) ; 0 - 120

ExtROutEstAlg = "ExtROEstAlg" EQUAL word ; "P.564" or other

MOS-LQ = "MOSLQ" EQUAL (DIGIT [ "." 1*3DIGIT ]) ; 0.0 - 4.9

MOSLQEstAlg = "MOSLQEstAlg" EQUAL word ; "P.564" or other

MOS-CQ = "MOSCQ" EQUAL (DIGIT [ "." 1*3DIGIT ])  ; 0.0 - 4.9

MOSCQEstAlg = "MOSCQEstAlg" EQUAL word ; "P.564" or other

; QoEEstAlg provides an alternative to the separate
; estimation algorithms for use when the same algorithm
; is used for all measurements.

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QoEEstAlg = "QoEEstAlg" EQUAL word ; "P.564" or other

; DialogID provides the identification of the dialog with
; which the media session is related.  This value is taken
; from the SIP header.

DialogID  = "DialogID" COLON Call-ID-Parm *(SEMI did-parm)

did-parm  = to-tag / from-tag / word

to-tag    = "to-tag" EQUAL token

from-tag  = "from-tag" EQUAL token

; MetricType provides the metric on which a notification of
; threshold violation was based.  The more commonly used metrics
; for alerting purposes are included here explicitly, using the
; character encoding that represents the parameter in
; this ABNF.  The Extension parameter can be used to provide
; metrics that are not defined by this document.

MetricType = "Type" EQUAL "RLQ" / "RCQ" / "EXTR" /
   "MOSLQ" / "MOSCQ" /
   "BD" / "NLR" / "JDR" /
   "RTD" / "ESD" / "IAJ" /
   "RERL" / "SL" / "NL" / Extension

Direction = "Dir" EQUAL "local" / "remote"
Severity  = "Severity" EQUAL "Warning" / "Critical" /
   "Clear"

Call-ID-Parm =  word [ "@" word ]

; General ABNF notation from RFC 5234.

CRLF =  %x0D.0A
DIGIT =  %x30-39
WSP   =  SP / HTAB ; white space
SP    =  " "
HTAB  =  %x09 ; horizontal tab
HEXDIG =  DIGIT / "A" / "B" / "C" / "D" / "E" / "F" /
             "a" / "b" / "c" / "d" / "e" / "f"
DQUOTE  =  %x22 ; " (Double Quote)
ALPHA   =  %x41-5A / %x61-7A   ; A-Z / a-z

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; ABNF notation from RFC 3261.

alphanum  =  ALPHA / DIGIT
LWS  =  [ *WSP CRLF ] 1*WSP ; linear whitespace
SWS  =  [ LWS ] ; sep whitespace
SEMI =  SWS ";" SWS ; semicolon
EQUAL   =  SWS "=" SWS ; equal
COLON   =  SWS ":" SWS ; colon
HCOLON  =  *( SP / HTAB ) ":" SWS

token       =  1*(alphanum / "-" / "." / "!" / "%" / "*"
                  / "_" / "+" / "`" / "'" / "~" )

IPv4address   =  1*3DIGIT "." 1*3DIGIT "." 1*3DIGIT "." 1*3DIGIT
IPv6address   =  hexpart [ ":" IPv4address ]
hexpart       =  hexseq / hexseq "::" [ hexseq ] / "::"
                      [ hexseq ]
hexseq        =  hex4 *( ":" hex4)
hex4          =  1*4HEXDIG
hex2          =  2HEXDIG

; ABNF notation from RFC 3339.

date-fullyear   = 4DIGIT ; e.g. 2006
date-month      = 2DIGIT ; e.g. 01 or 11
date-mday       = 2DIGIT ; e.g. 02 or 22
time-hour       = 2DIGIT ; e.g. 01 or 13
time-minute     = 2DIGIT ; e.g. 03 or 55
time-second     = 2DIGIT ; e.g. 01 or 59
time-secfrac    = "." 1*DIGIT
time-numoffset  = ("+" / "-") time-hour ":" time-minute
time-offset     = "Z" / time-numoffset
partial-time = time-hour ":" time-minute ":" time-second [ time-secfrac]
full-date    = date-fullyear "-" date-month "-" date-mday
full-time    = partial-time time-offset
date-time    = full-date "T" full-time

; Miscellaneous definitions
;

Extension = word-plus

word  =  1*(alphanum / "-" / "." / "!" / "%" / "*" /
   "_" / "+" / "`" / "'" / "~" /
   "(" / ")" / "<" / ">" /
   ":" / "\" / DQUOTE /
   "/" / "[" / "]" / "?" )

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word-plus =  1*(alphanum /  "-"  /  "."  /  "!"  / "%" / "*" /
   "_"  /  "+"  /  "`"  /  "'"  /  "~"  /
   "("  /  ")"  /  "<"  /  ">"  /  ":"  /
   "\"  /  "/"  /  "["  /  "]"  /  "?"  /
   "{"  /  "}"  /  "="  /  " ")

4.6.2.  Parameter Definitions and Mappings

   Parameter values, codec types, and other aspects of the endpoints may
   change dynamically during a session.  The reported values of metrics
   and configuration parameters SHALL be the current value at the time
   the report is generated.

   The Packet Loss Rate and Packet Discard Rate parameters are
   calculated over the period between the starting and ending timestamps
   for the report.  These are normally calculated from a count of the
   number of lost or discarded packets divided by the count of the
   number of packets, and hence are based on the current values of these
   counters at the time the report was generated.

   Packet delay variation, signal level, noise level, and echo level are
   computed as running or interval averages, based on the appropriate
   standard, e.g., RFC 3550 for Packet Delay Variation (PDV), and the
   sampled value of these running averages is reported.  Delay, packet
   size, jitter buffer size, and codec-related data may change during a
   session and the current value of these parameters is reported as
   sampled at the time the report is generated.

4.6.2.1.  General Mapping Percentages from 8-bit, Fixed-Point Numbers

   RFC 3611 uses an 8-bit, fixed-point number with the binary point at
   the left edge of the field.  This value is calculated by dividing the
   total number of packets lost by the total number of packets expected
   and multiplying the result by 256, and then taking the integer part.

   For any RTCP XR parameter in this format, to map into the equivalent
   SIP vq-rtcpxr parameter, simply reverse the equation, i.e., divide by
   256 and take the integer part.

4.6.2.2.  Timestamps

   Following SIP and other IETF conventions, timestamps are provided in
   Coordinated Universal Time (UTC) using the ABNF format provided in
   RFC 3339 [7].  These timestamps SHOULD reflect, as closely as
   possible, the actual time during which the media session was running
   to enable correlation to related events occurring in the network and
   to accounting or billing records.

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4.6.2.3.  SessionDescription

   The parameters in this field provide a shortened version of the
   session SDP(s), containing only the relevant parameters for session
   quality reporting purposes.  Where values may change during a
   session, for example, a codec may change rate, then the most-recent
   value of the parameter is reported.

4.6.2.3.1.  Payload Type

   This is the "payload type" parameter used in the RTP packets, i.e.,
   the codec.  This field can also be mapped from the SDP "rtpmap"
   attribute field "payload type".  IANA-registered types SHOULD be
   used.

4.6.2.3.2.  Payload Desc

   This parameter is a text description of the codec.  This parameter
   SHOULD use the IANA registry for media-type names where it
   unambiguously defines the codec.  Refer to the "Audio Media Types"
   registry on http://www.iana.org.

4.6.2.3.3.  Sample Rate

   This parameter is mapped from the SDP "rtpmap" attribute field "clock
   rate".  The field provides the rate at which a voice was sampled,
   measured in Hertz (Hz).

4.6.2.3.4.  Packets Per Second

   This parameter is not contained in RTP or SDP but can usually be
   obtained from the device codec.  Packets per second provides the
   (rounded) number of RTP packets that are transmitted per second.

4.6.2.3.5.  Frame Duration

   This parameter is not contained in RTP or SDP but can usually be
   obtained from the device codec.  The field reflects the amount of
   voice content in each frame within the RTP payload, measured in
   milliseconds.  Note that this value can be combined with the
   FramesPerPacket to determine the packetization rate.  Also, where a
   sample-based codec is used, a "frame" refers to the set of samples
   carried in an RTP packet.

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4.6.2.3.6.  Frame Octets

   This parameter is not contained in RTP or SDP but is usually provided
   by the device codec.  The field provides the number of octets in each
   frame within the RTP payload.  This field is usually not provided
   when the FrameDuration is provided.  Also, where a sample-based codec
   is used, a "frame" refers to the set of samples carried in an RTP
   packet.

4.6.2.3.7.  Frames Per Packet

   This parameter is not contained in RTP or SDP but can usually be
   obtained from the device codec.  This field provides the number of
   frames in each RTP packet.  Note that this value can be combined with
   the FrameDuration to determine the packetization rate.  Also, where a
   sample-based codec is used, a "frame" refers to the set of samples
   carried in an RTP packet.

4.6.2.3.8.  FMTP Options

   This parameter is taken directly from the SDP attribute "fmtp"
   defined in RFC 4566.

4.6.2.3.9.  Silence Suppression State

   This parameter does not correspond to SDP, RTP, or RTCP XR.  It
   indicates whether silence suppression, also known as Voice Activity
   Detection (VAD), is enabled for the identified session.

4.6.2.3.10.  Packet Loss Concealment

   This value corresponds to "PLC" in RFC 3611 in the VoIP Metrics
   Report Block.  The values defined by RFC 3611 are reused by this
   recommendation and therefore no mapping is required.

4.6.2.4.  LocalAddr

   This field provides the IP address, port, and synchronization source
   (SSRC) for the session from the perspective of the endpoint that is
   measuring performance.  The IPAddress MAY be in IPv4 or IPv6 format.
   The SSRC is taken from SDP, RTCP, or RTCP XR input parameters.

   In the presence of NAT and where a NAT-traversal mechanism such as
   Session Traversal Utilities for NAT (STUN) [16] is used, the external
   IP address can be reported, since the internal IP address is not
   visible to the network operator.

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4.6.2.5.  RemoteAddr

   This field provides the IP address, port, and SSRC of the session
   peer from the perspective of the remote endpoint measuring
   performance.  In the presence of NAT and where a NAT-traversal
   mechanism such as STUN [16] is used, the external IP address can be
   reported, since the internal IP address is not visible to the network
   operator.

4.6.2.6.  Jitter Buffer Parameters

4.6.2.6.1.  Jitter Buffer Adaptive

   This value corresponds to "JBA" in RFC 3611 in the VoIP Metrics
   Report Block.  The values defined by RFC 3611 are unchanged and
   therefore no mapping is required.

4.6.2.6.2.  Jitter Buffer Rate

   This value corresponds to "JB rate" in RFC 3611 in the VoIP Metrics
   Report Block.  The parameter does not require any conversion.

4.6.2.6.3.  Jitter Buffer Nominal

   This value corresponds to "JB nominal" in RFC 3611 in the VoIP
   Metrics Report Block.  The parameter does not require any conversion.

4.6.2.6.4.  Jitter Buffer Max

   This value corresponds to "JB maximum" in RFC 3611 in the VoIP
   Metrics Report Block.  The parameter does not require any conversion.

4.6.2.6.5.  Jitter Buffer Abs Max

   This value corresponds to "JB abs max" in RFC 3611 in the VoIP
   Metrics Report Block.  The parameter does not require any conversion.

4.6.2.7.  Packet Loss Parameters

4.6.2.7.1.  Network Loss Rate

   This value corresponds to "loss rate" in RFC 3611 in the VoIP Metrics
   Report Block.  For conversion, see Section 4.6.2.1.  A loss rate of
   100% MAY be reported if media packets were expected but none had been
   received at the time of session termination.

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4.6.2.7.2.  Jitter Buffer Discard Rate

   This value corresponds to "discard rate" in RFC 3611 in the VoIP
   Metrics Report Block.  For conversion, see Section 4.6.2.1.

4.6.2.8.  Burst/Gap Parameters

4.6.2.8.1.  Burst Loss Density

   This value corresponds to "burst density" in RFC 3611 in the VoIP
   Metrics Report Block.  For conversion, see Section 4.6.2.1.

4.6.2.8.2.  Burst Duration

   This value corresponds to "burst duration" in RFC 3611 in the VoIP
   Metrics Report Block.  This value requires no conversion; the exact
   value sent in an RTCP XR VoIP Metrics Report Block can be included in
   the SIP vq-rtcpxr parameter.

4.6.2.8.3.  Gap Loss Density

   This value corresponds to "gap density" in RFC 3611 in the VoIP
   metrics Report Block.

4.6.2.8.4.  Gap Duration

   This value corresponds to "gap duration" in RFC 3611 in the VoIP
   Metrics Report Block.  This value requires no conversion; the exact
   value sent in an RTCP XR VoIP Metrics Report Block can be reported.

4.6.2.8.5.  Minimum Gap Threshold

   This value corresponds to "Gmin" in RFC 3611 in the VoIP Metrics
   Report Block.  This value requires no conversion; the exact value
   sent in an RTCP XR VoIP Metrics Report Block can be reported.

4.6.2.9.  Delay Parameters

4.6.2.9.1.  Round-Trip Delay

   This value corresponds to "round trip delay" in RFC 3611 in the VoIP
   Metrics Report Block and may be measured using the method defined in
   RFC 3550.  The parameter is expressed in milliseconds.

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4.6.2.9.2.  End System Delay

   This value corresponds to "end system delay" in RFC 3611 in the VoIP
   Metrics Report Block.  This parameter does not require any
   conversion.  The parameter is expressed in milliseconds.

4.6.2.9.3.  Symmetric One-Way Delay

   This value is computed by adding Round-Trip Delay to the local and
   remote End System Delay and dividing by two.

4.6.2.9.4.  One-Way Delay

   This value SHOULD be measured using the methods defined in IETF RFC
   2679 [12].  The parameter is expressed in milliseconds.

4.6.2.9.5.  Inter-Arrival Jitter

   Inter-arrival jitter is calculated as defined in RFC 3550 and
   converted into milliseconds.

4.6.2.9.6.  Mean Absolute Jitter

   It is recommended that MAJ be measured as defined in ITU-T G.1020
   [9].  This parameter is often referred to as MAPDV (Mean Absolute
   Packet Delay Variation).  The parameter is expressed in milliseconds.

4.6.2.10.  Signal-Related Parameters

4.6.2.10.1.  Signal Level

   This field corresponds to "signal level" in RFC 3611 in the VoIP
   Metrics Report Block.  This field provides the voice signal relative
   level is defined as the ratio of the signal level to a 0 dBm0
   reference, expressed in decibels.  This value can be used directly
   without extra conversion.

4.6.2.10.2.  Noise Level

   This field corresponds to "noise level" in RFC 3611 in the VoIP
   Metrics Report Block.  This field provides the ratio of the silent
   period background noise level to a 0 dBm0 reference, expressed in
   decibels.  This value can be used directly without extra conversion.

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4.6.2.10.3.  Residual Echo Return Loss (RERL)

   This field corresponds to "RERL" in RFC 3611 in the VoIP Metrics
   Report Block.  This field provides the ratio between the original
   signal and the echo level in decibels, as measured after echo
   cancellation or suppression has been applied.  This value can be used
   directly without extra conversion.

4.6.2.11.  Quality Scores

4.6.2.11.1.  ListeningQualityR

   This field reports the listening quality expressed as an R factor
   (per G.107).  This does not include the effects of echo or delay.
   The range of R is 0-95 for narrowband calls and 0-120 for wideband
   calls.  Algorithms for computing this value SHOULD be compliant with
   ITU-T Recommendations P.564 [10] and G.107 [11].

4.6.2.11.2.  RLQEstAlg

   This field provides a text name for the algorithm used to estimate
   ListeningQualityR.  This field will be free form text and not
   necessarily reflective of any standards or recommendations.

4.6.2.11.3.  ConversationalQualityR

   This field corresponds to "R factor" in RFC 3611 in the VoIP Metrics
   Report Block.  This parameter provides a cumulative measurement of
   voice quality from the start of the session to the reporting time.
   The range of R is 0-95 for narrowband calls and 0-120 for wideband
   calls.  Algorithms for computing this value SHOULD be compliant with
   ITU-T Recommendations P.564 and G.107.  Within RFC 3611, a reported R
   factor of 127 indicates that this parameter is unavailable; in this
   case, the ConversationalQualityR parameter MUST be omitted from the
   vq-rtcpxr event.

4.6.2.11.4.  RCQEstAlg

   This field provides a text name for the algorithm used to estimate
   ConversationalQualityR.  This field will be free form text and not
   necessarily reflective of any standards or recommendations.

4.6.2.11.5.  ExternalR-In

   This field corresponds to "ext. R factor" in RFC 3611 in the VoIP
   Metrics Report Block.  This parameter reflects voice quality as
   measured by the local endpoint for incoming connection on "other"
   side (refer to RFC 3611 for a more-detailed explanation).  The range

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   of R is 0-95 for narrowband calls and 0-120 for wideband calls.
   Algorithms for computing this value SHOULD be compliant with ITU-T
   Recommendations P.564 and G.107.  Within RFC 3611, a reported R
   factor of 127 indicates that this parameter is unavailable; in this
   case, the ConversationalQualityR parameter MUST be omitted from the
   vq-rtcpxr event.

4.6.2.11.6.  ExtRInEstAlg

   This field provides a text name for the algorithm used to estimate
   ExternalR-In.  This field will be free-form text and not necessarily
   reflective of any standards or recommendations.

4.6.2.11.7.  ExternalR-Out

   This field corresponds to "ext. R factor" in RFC 3611 in the VoIP
   Metrics Report Block.  Here, the value is copied from RTCP XR message
   received from the remote endpoint on the "other" side of this
   endpoint; refer to RFC 3611 for a more detailed explanation).  The
   range of R is 0-95 for narrowband calls and 0-120 for wideband calls.
   Algorithms for computing this value SHOULD be compliant with ITU-T
   Recommendations P.564 and G.107.  Within RFC 3611, a reported R
   factor of 127 indicates that this parameter is unavailable; in this
   case, the ConversationalQualityR parameter SHALL be omitted from the
   vq-rtcpxr event.

4.6.2.11.8.  ExtROutEstAlg

   This field provides a text name for the algorithm used to estimate
   ExternalR-Out.  This field will be free-form text and not necessarily
   reflective of any standards or recommendations.

4.6.2.11.9.  MOS Reporting

   Conversion of RFC 3611 reported mean opinion scores (MOSs) for use in
   reporting MOS-LQ and MOS-CQ MUST be performed by dividing the RFC
   3611 reported value by 10 if this value is less than or equal to 50
   or omitting the MOS-xQ parameter if the RFC 3611 reported value is
   127 (which indicates unavailable).

4.6.2.11.9.1.  MOS-LQ

   This field corresponds to "MOSLQ" in RFC 3611 in the VoIP Metrics
   Report Block.  This parameter is the estimated mean opinion score for
   listening voice quality on a scale from 1 to 5, in which 5 represents
   "Excellent" and 1 represents "Unacceptable".  Algorithms for

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   computing this value SHOULD be compliant with ITU-T Recommendation
   P.564 [10].  This field provides a text name for the algorithm used
   to estimate MOS-LQ.

4.6.2.11.9.2.  MOS-CQ

   This field corresponds to "MOSCQ" in RFC 3611 in the VoIP Metrics
   Report Block.  This parameter is the estimated mean opinion score for
   conversation voice quality on a scale from 1 to 5, in which 5
   represents excellent and 1 represents unacceptable.  Algorithms for
   computing this value SHOULD be compliant with ITU-T Recommendation
   P.564 with regard to the listening quality element of the computed
   MOS score.

4.6.2.11.9.3.  MOSCQEstAlg

   This field provides a text name for the algorithm used to estimate
   MOS-CQ.  This field will be free-form text and not necessarily
   reflective of any standards or recommendations.

4.6.2.11.10.  QoEEstAlg

   This field provides a text description of the algorithm used to
   estimate all voice quality metrics.  This parameter is provided as an
   alternative to the separate estimation algorithms for use when the
   same algorithm is used for all measurements.  This field will be
   free-form text and not necessarily reflective of any standards or
   recommendations.

4.7.  Message Flow and Syntax Examples

   This section shows a number of message flow examples showing how the
   event package works.

4.7.1.  End of Session Report Using NOTIFY

Pendleton, et al.            Standards Track                   [Page 29]
RFC 6035         SIP Package for Voice Quality Reporting   November 2010

       Alice            Proxy/Registrar        Collector             Bob
       |                    |                    |                    |
       |                    |                    |                    |
       | REGISTER Allow-Event:vq-rtcpxr F1       |                    |
       |------------------->|                    |                    |
       |      200 OK F2     |                    |                    |
       |<-------------------|                    |                    |
       |                    |  SUBSCRIBE Event:vq-rtcpxr F3           |
       |                    |<-------------------|                    |
       | SUBSCRIBE Event:vq-rtcpxr F4            |                    |
       |<-------------------|                    |                    |
       |     200 OK F5      |                    |                    |
       |------------------->|                    |                    |
       |                    |   200 OK F6        |                    |
       |                    |------------------->|                    |
       |      INVITE F7     |                    |                    |
       |------------------->|                    |                    |
       |                    |      INVITE F8     |                    |
       |                    |---------------------------------------->|
       |                    |      200 OK F9     |                    |
       |                    |<----------------------------------------|
       |     200 OK F10     |                    |                    |
       |<-------------------|                    |                    |
       |        ACK F11     |                    |                    |
       |------------------->|                    |                    |
       |                    |      ACK F12       |                    |
       |                    |---------------------------------------->|
       |        RTP         |                    |                    |
       |<============================================================>|
       |        RTCP, RTCP XR                    |                    |
       |<============================================================>|
       |                    |                    |                    |
       |    BYE F13         |                    |                    |
       |------------------->|      BYE F14       |                    |
       |                    |---------------------------------------->|
       |                    |     200 OK F15     |                    |
       |                    |<----------------------------------------|
       |     200 OK F16     |                    |                    |
       |<-------------------|                    |                    |
       |  NOTIFY Event:vq-rtcpxr F17             |                    |
       |------------------->|                    |                    |
       |                    | NOTIFY Event:vq-rtcpxr F18              |
       |                    |------------------->|                    |
       |                    |     200 OK F19     |                    |
       |                    |<-------------------|                    |
       |     200 OK F20     |                    |                    |
       |<-------------------|                    |                    |

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RFC 6035         SIP Package for Voice Quality Reporting   November 2010

   Figure 1. Summary report with NOTIFY sent after session termination.
   In the call flow depicted in Figure 1, the following message format
   is sent in F17:

       NOTIFY sip:collector@example.org SIP/2.0
       Via: SIP/2.0/UDP pc22.example.org;branch=z9hG4bK3343d7
       Max-Forwards: 70
       To: <sip:collector@example.org>;tag=43524545
       From: Alice <sip:alice@example.org>;tag=a3343df32
       Call-ID: 1890463548
       CSeq: 4321 NOTIFY
       Contact: <sip:alice@pc22.example.org>
       Allow: INVITE, ACK, CANCEL, OPTIONS, BYE, REFER,
        SUBSCRIBE, NOTIFY
       Event: vq-rtcpxr
       Accept: application/sdp, message/sipfrag
       Subscription-State: active;expires=3600
       Content-Type: application/vq-rtcpxr
       Content-Length: ...

       VQSessionReport: CallTerm
       CallID: 6dg37f1890463
       LocalID: Alice <sip:alice@example.org>
       RemoteID: Bill <sip:bill@example.net>
       OrigID: Alice <sip:alice@example.org>
       LocalGroup: example-phone-55671
       RemoteGroup: example-gateway-09871
       LocalAddr: IP=10.10.1.100 PORT=5000 SSRC=1a3b5c7d
       LocalMAC: 00:1f:5b:cc:21:0f
       RemoteAddr:IP=11.1.1.150 PORT=5002 SSRC=0x2468abcd
       RemoteMAC: 00:26:08:8e:95:02
       LocalMetrics:
       Timestamps:START=2004-10-10T18:23:43Z STOP=2004-10-01T18:26:02Z
       SessionDesc:PT=0 PD=PCMU SR=8000 FD=20 FO=160 FPP=1 PPS=50
                       PLC=3 SSUP=on
       JitterBuffer:JBA=3 JBR=2 JBN=40 JBM=80 JBX=120
       PacketLoss:NLR=5.0 JDR=2.0
       BurstGapLoss:BLD=0 BD=0 GLD=2.0 GD=500 GMIN=16
       Delay:RTD=200 ESD=140 SOWD=200 IAJ=2 MAJ=10
       Signal:SL=-18 NL=-50 RERL=55
       QualityEst:RLQ=88 RCQ=85 EXTRI=90 MOSLQ=4.1 MOSCQ=4.0
         QoEEstAlg=P.564
       RemoteMetrics:
       Timestamps:START=2004-10-10T18:23:43Z STOP=2004-10-01T18:26:02Z
       SessionDesc:PT=0 PD=PCMU SR=8000 FD=20 FO=160 FPP=1 PPS=50
                       PLC=3 SSUP=on
       JitterBuffer:JBA=3 JBR=2 JBN=40 JBM=80 JBX=120
       PacketLoss:NLR=5.0 JDR=2.0

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RFC 6035         SIP Package for Voice Quality Reporting   November 2010

       BurstGapLoss:BLD=0 BD=0 GLD=2.0 GD=500 GMIN=16
       Delay:RTD=200 ESD=140 SOWD=200 IAJ=2 MAJ=10
       Signal:SL=-21 NL=-45 RERL=55
       QualityEst:RLQ=90 RCQ=85 EXTRI=90 MOSLQ=4.3 MOSCQ=4.2
         QoEEstAlg=P.564
       DialogID:1890463548@alice.example.org;to-tag=8472761;
         from-tag=9123dh311

4.7.2.  Midsession Threshold Violation Using NOTIFY

   Alice            Proxy/Registrar        Collector             Bob
    |                    |                    |                    |
    |                    |                    |                    |
    | REGISTER Allow-Event:vq-rtcpxr F1       |                    |
    |------------------->|                    |                    |
    |      200 OK F2     |                    |                    |
    |<-------------------|                    |                    |
    |                    |  SUBSCRIBE Event:vq-rtcpxr F3           |
    |                    |<-------------------|                    |
    | SUBSCRIBE Event:vq-rtcpxr F4            |                    |
    |<-------------------|                    |                    |
    |     200 OK F5      |                    |                    |
    |------------------->|                    |                    |
    |                    |   200 OK F6        |                    |
    |                    |------------------->|                    |
    |      INVITE F7     |                    |                    |
    |------------------->|                    |                    |
    |                    |      INVITE F8     |                    |
    |                    |---------------------------------------->|
    |                    |      200 OK F9     |                    |
    |                    |<----------------------------------------|
    |     200 OK F10     |                    |                    |
    |<-------------------|                    |                    |
    |        ACK F11     |                    |                    |
    |------------------->|                    |                    |
    |                    |      ACK F12       |                    |
    |                    |---------------------------------------->|
    |        RTP         |                    |                    |
    |<============================================================>|
    |        RTCP, RTCP XR                    |                    |
    |<============================================================>|
    |  NOTIFY Event:vq-rtcpxr F13             |                    |
    |------------------->|                    |                    |
    |                    | NOTIFY Event:vq-rtcpxr F14              |
    |                    |------------------->|                    |
    |                    |     200 OK F15     |                    |
    |                    |<-------------------|                    |
    |     200 OK F16     |                    |                    |

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RFC 6035         SIP Package for Voice Quality Reporting   November 2010

    |<-------------------|                    |                    |
    |                    |                    |                    |
    |    BYE F17         |                    |                    |
    |------------------->|      BYE F18       |                    |
    |                    |---------------------------------------->|
    |                    |     200 OK F19     |                    |
    |                    |<----------------------------------------|
    |     200 OK F20     |                    |                    |
    |<-------------------|                    |                    |
    |  NOTIFY Event:vq-rtcpxr F21             |                    |
    |------------------->|                    |                    |
    |                    | NOTIFY Event:vq-rtcpxr F22              |
    |                    |------------------->|                    |
    |                    |     200 OK F23     |                    |
    |                    |<-------------------|                    |
    |     200 OK F24     |                    |                    |
    |<-------------------|                    |                    |

   Figure 2.  An alert report is sent during the session.
   In the call flow depicted in Figure 2, the following message
   format is sent in F13:

       NOTIFY sip:collector@example.org SIP/2.0
       Via: SIP/2.0/UDP pc22.example.org;branch=z9hG4bK3343d7
       Max-Forwards: 70
       To: <sip:proxy@example.org>
       From: Alice <sip:alice@example.org>;tag=a3343df32
       Call-ID: 1890463548
       CSeq: 4331 PUBLISH
       Allow: INVITE, ACK, CANCEL, OPTIONS, BYE, REFER,
        SUBSCRIBE, NOTIFY
       Event: vq-rtcpxr
       Accept: application/sdp, message/sipfrag
       Content-Type: application/vq-rtcpxr
       Content-Length: ...

       VQAlertReport: Type=NLR Severity=Critical Dir=local
       CallID: 6dg37f1890463
       LocalID: Alice <sip:alice@example.org>
       RemoteID: Bill <sip:bill@example.org>
       OrigID: Alice <sip:alice@example.org>
       LocalGroup: example-phone-55671
       RemoteGroup: example-gateway-09871
       LocalAddr:IP=10.10.1.100 PORT=5000 SSRC=0x2468abcd
       LocalMAC: 00:1f:5b:cc:21:0f

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RFC 6035         SIP Package for Voice Quality Reporting   November 2010

       RemoteAddr:IP=11.1.1.150 PORT=5002 SSRC=1357efff
       RemoteMAC: 00:26:08:8e:95:02
       LocalMetrics:
       Timestamps:START=2004-10-10T18:23:43Z STOP=2004-10-01T18:26:02Z
       SessionDesc:PT=18 PD=G729 SR=8000 FD=20 FO=20 FPP=2 PPS=50
                       FMTP="annexb=no" PLC=3 SSUP=on
       JitterBuffer:JBA=3 JBR=2 JBN=40 JBM=80 JBX=120
       PacketLoss:NLR=10.0 JDR=2.0
       BurstGapLoss:BLD=0 BD=0 GLD=2.0 GD=500 GMIN=16
       Delay:RTD=200 ESD=140 SOWD=200 IAJ=2 MAJ=10
       Signal:SL=-21 NL=-50 RERL=55
       QualityEst:RLQ=80 RCQ=85 EXTRI=90 MOSLQ=3.5 MOSCQ=3.7
                        QoEEstAlg=P.564
       RemoteMetrics:
       Timestamps:START=2004-10-10T18:23:43Z STOP=2004-10-01T18:26:02Z
       SessionDesc:PT=18 PD=G729 SR=8000 FD=20 FO=20 FPP=2 PPS=50
                       FMTP="annexb=no" PLC=3 SSUP=on
       JitterBuffer:JBA=3 JBR=2 JBN=40 JBM=80 JBX=120
       PacketLoss:NLR=5.0 JDR=2.0
       BurstGapLoss:BLD=0 BD=0 GLD=2.0 GD=500 GMIN=16
       Delay:RTD=200 ESD=140 SOWD=200 IAJ=2 MAJ=10
       Signal:SL=-21 NL=-45 RERL=55
       QualityEst:RLQ=90 RCQ=85 MOSLQ=4.3 MOSCQ=4.2 QoEEstAlg=P.564
       DialogID:1890463548@alice.example.org;to-tag=8472761;
          from-tag=9123dh311

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RFC 6035         SIP Package for Voice Quality Reporting   November 2010

4.7.3.  End of Session Report Using PUBLISH

      Alice            Proxy/Registrar        Collector              Bob
       |                    |                    |                    |
       |                    |                    |                    |
       | REGISTER Allow-Event:vq-rtcpxr  F1      |                    |
       |------------------->|                    |                    |
       |      200 OK F2     |                    |                    |
       |<-------------------|                    |                    |
       |      INVITE F3     |                    |                    |
       |------------------->|                    |                    |
       |                    |      INVITE F4     |                    |
       |                    |---------------------------------------->|
       |                    |      200 OK F5     |                    |
       |                    |<----------------------------------------|
       |     200 OK F6      |                    |                    |
       |<-------------------|                    |                    |
       |        ACK F7      |                    |                    |
       |------------------->|                    |                    |
       |                    |      ACK F8        |                    |
       |                    |---------------------------------------->|
       |        RTP         |                    |                    |
       |<============================================================>|
       |        RTCP        |                    |                    |
       |<============================================================>|
       |                    |                    |                    |
       |    BYE F9          |                    |                    |
       |------------------->|      BYE F10       |                    |
       |                    |---------------------------------------->|
       |                    |     200 OK F11     |                    |
       |                    |<----------------------------------------|
       |     200 OK F12     |                    |                    |
       |<-------------------|                    |                    |
       |  PUBLISH Event:vq-rtcpxr F13            |                    |
       |------------------->|                    |                    |
       |                    | PUBLISH Event:vq-rtcpxr F14             |
       |                    |------------------->|                    |
       |                    |     200 OK F15     |                    |
       |                    |<-------------------|                    |
       |     200 OK F16     |                    |                    |
       |<-------------------|                    |                    |

   Figure 3. End of session report sent after session termination.
   In the message flow depicted in Figure 3, the following message is
   sent in F13.

Pendleton, et al.            Standards Track                   [Page 35]
RFC 6035         SIP Package for Voice Quality Reporting   November 2010

       PUBLISH sip:collector@example.org SIP/2.0
       Via: SIP/2.0/UDP pc22.example.org;branch=z9hG4bK3343d7
       Max-Forwards: 70
       To: <sip:proxy@example.org>
       From: Alice <sip:alice@example.org>;tag=a3343df32
       Call-ID: 1890463548
       CSeq: 4331 PUBLISH
       Allow: INVITE, ACK, CANCEL, OPTIONS, BYE, REFER,
        SUBSCRIBE, NOTIFY
       Event: vq-rtcpxr
       Accept: application/sdp, message/sipfrag
       Content-Type: application/vq-rtcpxr
       Content-Length: ...

       VQSessionReport: CallTerm
       CallID: 6dg37f1890463
       LocalID: Alice <sip:alice@example.org>
       RemoteID: Bill <sip:bill@example.net>
       OrigID: Alice <sip:alice@example.org>
       LocalGroup: example-phone-55671
       RemoteGroup: example-gateway-09871
       LocalAddr: IP=10.10.1.100 PORT=5000 SSRC=1a3b5c7d
       LocalMAC: 00:1f:5b:cc:21:0f
       RemoteAddr:IP=11.1.1.150 PORT=5002 SSRC=0x2468abcd
       RemoteMAC: 00:26:08:8e:95:02
       LocalMetrics:
       Timestamps:START=2004-10-10T18:23:43Z STOP=2004-10-01T18:26:02Z
       SessionDesc:PT=18 PD=G729 SR=8000 FD=20 FO=20 FPP=2 PPS=50
                       FMTP="annexb=no" PLC=3 SSUP=on
       JitterBuffer:JBA=3 JBR=2 JBN=40 JBM=80 JBX=120
       PacketLoss:NLR=5.0 JDR=2.0
       BurstGapLoss:BLD=0 BD=0 GLD=2.0 GD=500 GMIN=16
       Delay:RTD=200 ESD=140 SOWD=200 IAJ=2 MAJ=10
       Signal:SL=-21 NL=-50 RERL=55
       QualityEst:RLQ=90 RCQ=85 EXTRI=90 MOSLQ=4.2 MOSCQ=4.3
         QoEEstAlg=P.564
       RemoteMetrics:
       Timestamps:START=2004-10-10T18:23:43Z STOP=2004-10-01T18:26:02Z
       SessionDesc:PT=18 PD=G729 SR=8000 FD=20 FO=20 FPP=2 PPS=50
                       FMTP="annexb=no" PLC=3 SSUP=on
       JitterBuffer:JBA=3 JBR=2 JBN=40 JBM=80 JBX=120
       PacketLoss:NLR=5.0 JDR=2.0
       BurstGapLoss:BLD=0 BD=0 GLD=2.0 GD=500 GMIN=16
       Delay:RTD=200 ESD=140 SOWD=200 IAJ=2 MAJ=10
       Signal:SL=-21 NL=-45 RERL=55
       QualityEst:RLQ=90 RCQ=85 MOSLQ=4.3 MOSCQ=4.2 QoEEstAlg=P.564
       DialogID:1890463548@alice.example.org;to-tag=8472761;
          from-tag=9123dh311

Pendleton, et al.            Standards Track                   [Page 36]
RFC 6035         SIP Package for Voice Quality Reporting   November 2010

4.7.4.  Alert Report Using PUBLISH

       Alice            Proxy/Registrar        Collector             Bob
       |                    |                    |                    |
       |      INVITE F1     |                    |                    |
       |------------------->|                    |                    |
       |                    |      INVITE F2     |                    |
       |                    |---------------------------------------->|
       |                    |      200 OK F3     |                    |
       |                    |<----------------------------------------|
       |     200 OK F4      |                    |                    |
       |<-------------------|                    |                    |
       |        ACK F5      |                    |                    |
       |------------------->|                    |                    |
       |                    |      ACK F6        |                    |
       |                    |---------------------------------------->|
       |        RTP         |                    |                    |
       |<============================================================>|
       |        RTCP        |                    |                    |
       |<============================================================>|
       |  PUBLISH Event:vq-rtcpxr F7             |                    |
       |------------------->|                    |                    |
       |                    | PUBLISH Event:vq-rtcpxr F8              |
       |                    |------------------->|                    |
       |                    |     200 OK F9      |                    |
       |                    |<-------------------|                    |
       |     200 OK F10     |                    |                    |
       |<-------------------|                    |                    |
       |                    |                    |                    |
       |      BYE F11       |                    |                    |
       |------------------->|      BYE F12       |                    |
       |                    |---------------------------------------->|
       |                    |     200 OK F13     |                    |
       |                    |<----------------------------------------|
       |     200 OK F14     |                    |                    |
       |<-------------------|                    |                    |

   Figure 4. Alert report message flow

      In the message flow depicted in Figure 4, the following message is
      sent in F7:

       PUBLISH sip:collector@example.org SIP/2.0
       Via: SIP/2.0/UDP pc22.example.org;branch=z9hG4bK3343d7
       Max-Forwards: 70
       To: <sip:collector@example.org>
       From: Alice <sip:alice@example.org>;tag=a3343df32
       Call-ID: 1890463548

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RFC 6035         SIP Package for Voice Quality Reporting   November 2010

       CSeq: 4321 PUBLISH
       Allow: INVITE, ACK, CANCEL, OPTIONS, BYE, REFER,
        SUBSCRIBE, NOTIFY
       Event: vq-rtcpxr
       Accept: application/sdp, message/sipfrag
       Content-Type: application/vq-rtcpxr
       Content-Length: ...

       VQAlertReport: Type=RLQ Severity=Warning Dir=local
       CallID: 6dg37f1890463
       LocalID: Alice <sip:alice@example.org>
       RemoteID: Bill <sip:bill@example.org>
       OrigID: Alice <sip:alice@example.org>
       LocalGroup: example-phone-55671
       RemoteGroup: example-gateway-09871
       LocalAddr: IP=10.10.1.100 PORT=5000 SSRC=1a3b5c7d
       LocalMAC: 00:1f:5b:cc:21:0f
       RemoteAddr:IP=11.1.1.150 PORT=5002 SSRC=0x2468abcd
       RemoteMAC: 00:26:08:8e:95:02
       Metrics:
       Timestamps:START=2004-10-10T18:23:43Z STOP=2004-10-01T18:26:02Z
       SessionDesc:PT=0 PD=PCMU SR=8000 FD=20 FO=160 FPP=1 PPS=50
                       PLC=3 SSUP=on
       JitterBuffer:JBA=3 JBR=2 JBN=40 JBM=80 JBX=120
       PacketLoss:NLR=5.0 JDR=2.0
       BurstGapLoss:BLD=0 BD=0 GLD=2.0 GD=500 GMIN=16
       Delay:RTD=200 ESD=140 SOWD=200 IAJ=2 MAJ=10
       Signal:SL=-12 NL=-30 RERL=55
       QualityEst:RLQ=60 RCQ=55 EXTR=90 MOSLQ=2.4 MOSCQ=2.3
          QoEEstAlg=P.564
       RemoteMetrics:
       Timestamps:START=2004-10-10T18:23:43Z STOP=2004-10-01T18:26:02Z
       SessionDesc:PT=0 PD=PCMU SR=8000 FD=20 FO=160 FPP=1 PPS=50
                       PLC=3 SSUP=on
       JitterBuffer:JBA=3 JBR=2 JBN=40 JBM=80 JBX=120
       PacketLoss:NLR=5.0 JDR=2.0
       BurstGapLoss:BLD=0 BD=0 GLD=2.0 GD=500 GMIN=16
       Delay:RTD=200 ESD=140 SOWD=200 IAJ=2 MAJ=10
       Signal:SL=-23 NL=-60 RERL=55
       QualityEst:RLQ=90 RCQ=85 EXTRI=90 MOSLQ=4.2 MOSCQ=4.3
          QoEEstAlg=P.564
       DialogID:1890463548@alice.example.org;to-tag=8472761;
               from-tag=9123dh3111

Pendleton, et al.            Standards Track                   [Page 38]
RFC 6035         SIP Package for Voice Quality Reporting   November 2010

4.8.  Configuration Dataset for vq-rtcpxr Events

   It is the suggestion of the authors that the SIP configuration
   framework [15] be used to establish the necessary parameters for
   usage of vq-rtcpxr events.  A dataset for this purpose should be
   designed and documented in a separate document upon completion of the
   framework.

5.  IANA Considerations

   This document registers a new SIP Event Package and a new media type.

5.1.  SIP Event Package Registration

      Package name: vq-rtcpxr
      Type: package
      Contact: Amy Pendleton <aspen@telchemy.com>
      Published Specification: This document

5.2.  application/vq-rtcpxr Media Type Registration

   Type name: application
   Subtype name: vq-rtcpxr
   Required parameters: none
   Optional parameters: none
   Encoding considerations: 7 bit
   Security considerations: See next section.
   Interoperability considerations: none.
   Published specification: This document.

   Applications that use this media type: This document type is
      being used in notifications of VoIP quality reports.

   Additional Information:

      Magic Number: None
      File Extension: None
      Macintosh file type code: "TEXT"

   Person and email address for further information: Amy Pendleton
      <aspen@telchemy.com>

   Intended usage: COMMON

   Author / Change controller: The IETF.

Pendleton, et al.            Standards Track                   [Page 39]
RFC 6035         SIP Package for Voice Quality Reporting   November 2010

6.  Security Considerations

   RTCP reports can contain sensitive information since they can provide
   information about the nature and duration of a session established
   between two or more endpoints.  As a result, any third party wishing
   to obtain this information SHOULD be properly authenticated by the
   SIP UA using standard SIP mechanisms and according to the
   recommendations in [5].  Additionally, the event content MAY be
   encrypted to ensure confidentiality; the mechanisms for providing
   confidentiality are detailed in [2].

7.  Contributors

   The authors would like to thank Rajesh Kumar, Dave Oran, Tom Redman,
   Shane Holthaus, and Jack Ford for their comments and input.

8.  References

8.1.  Normative References

   [1]   Bradner, S., "Key words for use in RFCs to Indicate Requirement
         Levels", BCP 14, RFC 2119, March 1997.

   [2]   Rosenberg, J., Schulzrinne, H., Camarillo, G., Johnston, A.,
         Peterson, J., Sparks, R., Handley, M., and E. Schooler, "SIP:
         Session Initiation Protocol", RFC 3261, June 2002.

   [3]   Schulzrinne, H., Casner, S., Frederick, R., and V. Jacobson,
         "RTP: A Transport Protocol for Real-Time Applications", STD 64,
         RFC 3550, July 2003.

   [4]   Friedman, T., Caceres, R., and A. Clark, "RTP Control Protocol
         Extended Reports (RTCP XR)", RFC 3611, November 2003.

   [5]   Roach, A., "Session Initiation Protocol (SIP)-Specific Event
         Notification", RFC 3265, June 2002.

   [6]   Crocker, D. and P. Overell, "Augmented BNF for Syntax
         Specifications: ABNF", STD 68, RFC 5234, January 2008.

   [7]   Klyne, G., Ed. and C. Newman, "Date and Time on the Internet:
         Timestamps", RFC 3339, July 2002.

   [8]   Niemi, A., "Session Initiation Protocol (SIP) Extension for
         Event State Publication", RFC 3903, October 2004.

   [9]   ITU-T G.1020, "Performance parameter definitions for quality of
         speech and other voiceband applications utilizing IP networks".

Pendleton, et al.            Standards Track                   [Page 40]
RFC 6035         SIP Package for Voice Quality Reporting   November 2010

   [10]  ITU-T P.564, "Conformance testing for voice over IP
         transmission quality assessment models".

   [11]  ITU-T G.107, "The E-model, a computational model for use in
         transmission planning".

   [12]  Almes, G., Kalidindi, S., and M. Zekauskas, "A One-way Delay
         Metric for IPPM", RFC 2679, September 1999.

8.2.  Informative References

   [13]  Westerlund, M. and S. Wenger, "RTP Topologies", RFC 5117,
         January 2008.

   [14]  Hilt, V., Noel, E., Shen, C., and A. Abdelal, "Design
         Considerations for Session Initiation Protocol (SIP) Overload
         Control", Work in Progress, July 2009.

   [15]  Petrie, D. and S. Channabasappa, "A Framework for Session
         Initiation Protocol User Agent Profile Delivery", Work
         in Progress, October 2010.

   [16]  Rosenberg, J., Mahy, R., Matthews, P., and D. Wing, "Session
         Traversal Utilities for NAT (STUN)", RFC 5389, October 2008.

Authors' Addresses

   Amy Pendleton
   Telchemy Incorporated
   EMail: aspen@telchemy.com

   Alan Clark
   Telchemy Incorporated
   EMail: alan.d.clark@telchemy.com

   Alan Johnston
   Avaya
   St. Louis, MO  63124
   EMail: alan.b.johnston@gmail.com

   Henry Sinnreich
   Unaffiliated
   EMail: henry.sinnreich@gmail.com

Pendleton, et al.            Standards Track                   [Page 41]