RTP Control Protocol Extended Reports (RTCP XR)

Publisher

IETF / RFC Editor

URL

https://www.rfc-editor.org/rfc/rfc3611.html

Published

2003-11-01

Updated

unknown

Accessed

2026-09-24

HTTP status

200

License

IETF Trust Legal Provisions; no-redistribution; short excerpts and locators only

Source notes citing this source

• RTCP XR end system delay is a 16-bit value in milliseconds covering encoding, jitter buffer, decoding and playout delay; round trip delay is a separate 16-bit millisecond field. in context
• RTCP XR loss rate and discard rate are 8-bit fixed-point fractions (binary point at the left edge), computed as lost or discarded packets over expected packets times 256, capped at 255. in context
• RTCP XR MOS-CQ is an estimated conversational-quality MOS that includes the effects of delay and other factors affecting conversation. in context
• RTCP XR MOS-LQ is an estimated listening-quality MOS on a 1 to 5 scale that excludes the effects of delay. in context
• RTCP XR encodes MOS-LQ and MOS-CQ as integers from 10 to 50 equal to MOS times 10, with 127 meaning unavailable. in context
• In the RTCP XR VoIP Metrics block the R factor is an integer from 0 to 100, where 94 corresponds to toll quality, 50 or less is regarded as unusable, and 127 means unavailable. in context
• RTCP XR carries per-call voice quality in the VoIP Metrics Report Block, block type 7. in context
• RFC 3611 states that for a VoIP gateway the source of echo is typically line echo occurring at 2-4 wire conversion points in the network. in context
• In RFC 3611 an RERL value of 127 means the parameter is unavailable. in context
• The RTCP XR VoIP Metrics block carries an 8-bit residual echo return loss (RERL) field, measured directly by the endpoint's echo canceller or estimated by adding its reported ERL and ERLE. in context
• RFC 3611 (November 2003) defines the RTCP Extended Report packet with seven report block types, of which the VoIP Metrics Report Block in section 4.7 is intended for monitoring VoIP calls. in context
• RFC 3611 (RTCP Extended Reports) is a Standards Track RFC dated November 2003. in context
• RFC 3611 defines seven RTCP XR report block types: Loss RLE (1), Duplicate RLE (2), Packet Receipt Times (3), Receiver Reference Time (4), DLRR (5), Statistics Summary (6) and VoIP Metrics (7). in context
• The RTCP XR VoIP Metrics block reports burst and gap durations as mean durations in milliseconds and burst and gap densities as 8-bit fixed-point fractions. in context
• The RTCP XR VoIP Metrics block carries round trip delay and end system delay as 16-bit values in milliseconds. in context
• RFC 3611 recommends a Gmin gap threshold value of 16 for distinguishing bursts from gaps in VoIP Metrics reporting. in context
• The RTCP XR VoIP Metrics block reports jitter buffer nominal, maximum and absolute maximum delay as 16-bit values in milliseconds. in context
• In the RTCP XR VoIP Metrics block, loss rate and discard rate are 8-bit fixed-point fractions computed as packets lost or discarded divided by packets expected, multiplied by 256 and capped at 255. in context
• The RTCP XR VoIP Metrics MOS-LQ and MOS-CQ fields carry MOS multiplied by 10 as an integer from 10 to 50, with 127 meaning unavailable. in context
• In RFC 3611, MOS-LQ is a listening-quality estimate that excludes delay effects, while MOS-CQ is a conversational-quality estimate that includes them. in context
• The RTCP XR VoIP Metrics R factor and external R factor are integers from 0 to 100, with 127 meaning unavailable. in context

Cite this source record

APA

WarmTransfer. (2003, November 1). RTP Control Protocol Extended Reports (RTCP XR). WarmTransfer. https://warmtransfer.net/knowledge/sources/rfc-3611-rtcp-xr

BibTeX

@misc{warmtransfer-rfc-3611-rtcp-xr,
  title  = {RTP Control Protocol Extended Reports (RTCP XR)},
  author = {{WarmTransfer}},
  year   = {2003},
  url    = {https://warmtransfer.net/knowledge/sources/rfc-3611-rtcp-xr},
  note   = {IETF / RFC Editor, accessed 2026-09-24}
}