idnits 2.17.1 draft-scholz-ipfix-rtp-msg-00.txt: Checking boilerplate required by RFC 5378 and the IETF Trust (see https://trustee.ietf.org/license-info): ---------------------------------------------------------------------------- No issues found here. Checking nits according to https://www.ietf.org/id-info/1id-guidelines.txt: ---------------------------------------------------------------------------- No issues found here. Checking nits according to https://www.ietf.org/id-info/checklist : ---------------------------------------------------------------------------- No issues found here. Miscellaneous warnings: ---------------------------------------------------------------------------- == The copyright year in the IETF Trust and authors Copyright Line does not match the current year == The document seems to contain a disclaimer for pre-RFC5378 work, but was first submitted on or after 10 November 2008. The disclaimer is usually necessary only for documents that revise or obsolete older RFCs, and that take significant amounts of text from those RFCs. If you can contact all authors of the source material and they are willing to grant the BCP78 rights to the IETF Trust, you can and should remove the disclaimer. Otherwise, the disclaimer is needed and you can ignore this comment. (See the Legal Provisions document at https://trustee.ietf.org/license-info for more information.) -- The document date (March 5, 2012) is 4434 days in the past. Is this intentional? Checking references for intended status: Informational ---------------------------------------------------------------------------- == Outdated reference: A later version (-08) exists of draft-wu-xrblock-rtcp-xr-quality-monitoring-06 ** Obsolete normative reference: RFC 5101 (Obsoleted by RFC 7011) ** Obsolete normative reference: RFC 5102 (Obsoleted by RFC 7012) -- Obsolete informational reference (is this intentional?): RFC 4566 (Obsoleted by RFC 8866) Summary: 2 errors (**), 0 flaws (~~), 3 warnings (==), 2 comments (--). Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 Network Working Group H. Scholz 3 Internet-Draft VOIPFUTURE GmbH 4 Intended status: Informational March 5, 2012 5 Expires: September 6, 2012 7 RTP Stream Information Export using IPFIX 8 draft-scholz-ipfix-rtp-msg-00 10 Abstract 12 This draft defines a set of Information Elements and matching 13 Templates to convey RTP media stream information in IPFIX packets. 14 The Information Elements describe the RTP header and payload 15 characteristics of the RTP stream either for the entire duration of 16 the monitored stream or for a smaller time slice. 18 Status of this Memo 20 This Internet-Draft is submitted in full conformance with the 21 provisions of BCP 78 and BCP 79. 23 Internet-Drafts are working documents of the Internet Engineering 24 Task Force (IETF). Note that other groups may also distribute 25 working documents as Internet-Drafts. The list of current Internet- 26 Drafts is at http://datatracker.ietf.org/drafts/current/. 28 Internet-Drafts are draft documents valid for a maximum of six months 29 and may be updated, replaced, or obsoleted by other documents at any 30 time. It is inappropriate to use Internet-Drafts as reference 31 material or to cite them other than as "work in progress." 33 This Internet-Draft will expire on September 6, 2012. 35 Copyright Notice 37 Copyright (c) 2012 IETF Trust and the persons identified as the 38 document authors. All rights reserved. 40 This document is subject to BCP 78 and the IETF Trust's Legal 41 Provisions Relating to IETF Documents 42 (http://trustee.ietf.org/license-info) in effect on the date of 43 publication of this document. Please review these documents 44 carefully, as they describe your rights and restrictions with respect 45 to this document. Code Components extracted from this document must 46 include Simplified BSD License text as described in Section 4.e of 47 the Trust Legal Provisions and are provided without warranty as 48 described in the Simplified BSD License. 50 This document may contain material from IETF Documents or IETF 51 Contributions published or made publicly available before November 52 10, 2008. The person(s) controlling the copyright in some of this 53 material may not have granted the IETF Trust the right to allow 54 modifications of such material outside the IETF Standards Process. 55 Without obtaining an adequate license from the person(s) controlling 56 the copyright in such materials, this document may not be modified 57 outside the IETF Standards Process, and derivative works of it may 58 not be created outside the IETF Standards Process, except to format 59 it for publication as an RFC or to translate it into languages other 60 than English. 62 Table of Contents 64 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 5 65 1.1. Use Cases . . . . . . . . . . . . . . . . . . . . . . . . 5 66 1.1.1. Quality of Service (QoS) Monitoring . . . . . . . . . 5 67 1.1.2. Service Level Agreement (SLA) . . . . . . . . . . . . 5 68 1.1.3. Troubleshooting . . . . . . . . . . . . . . . . . . . 5 69 2. Conventions . . . . . . . . . . . . . . . . . . . . . . . . . 6 70 3. Base RTP Information Elements . . . . . . . . . . . . . . . . 6 71 3.1. rtpObservationType . . . . . . . . . . . . . . . . . . . . 6 72 3.2. rtpFlowId . . . . . . . . . . . . . . . . . . . . . . . . 6 73 3.3. rtpStartTime . . . . . . . . . . . . . . . . . . . . . . . 7 74 3.4. rtpEndTime . . . . . . . . . . . . . . . . . . . . . . . . 7 75 3.5. rtpSampleOffset . . . . . . . . . . . . . . . . . . . . . 8 76 3.6. rtpSampleTime . . . . . . . . . . . . . . . . . . . . . . 8 77 3.7. rtpStreamState . . . . . . . . . . . . . . . . . . . . . . 8 78 3.8. rtpProtocolVersion . . . . . . . . . . . . . . . . . . . . 9 79 3.9. rtpPayloadType . . . . . . . . . . . . . . . . . . . . . . 9 80 3.10. rtpMediaType . . . . . . . . . . . . . . . . . . . . . . . 10 81 3.11. rtpMediaSubType . . . . . . . . . . . . . . . . . . . . . 10 82 3.12. rtpIsSRTP . . . . . . . . . . . . . . . . . . . . . . . . 11 83 3.13. rtpSSRC . . . . . . . . . . . . . . . . . . . . . . . . . 11 84 3.14. rtpCSRC . . . . . . . . . . . . . . . . . . . . . . . . . 11 85 3.15. rtpTimestamp . . . . . . . . . . . . . . . . . . . . . . . 11 86 4. RTP Payload Information Elements . . . . . . . . . . . . . . . 12 87 4.1. rtpPacketCount . . . . . . . . . . . . . . . . . . . . . . 12 88 4.2. rtpPacketCountLoss . . . . . . . . . . . . . . . . . . . . 12 89 4.3. rtpPacketCountDiscarded . . . . . . . . . . . . . . . . . 13 90 4.4. rtpCodecChange . . . . . . . . . . . . . . . . . . . . . . 13 91 4.5. rtpMarkerBit . . . . . . . . . . . . . . . . . . . . . . . 13 92 4.6. rtpComfortNoise . . . . . . . . . . . . . . . . . . . . . 14 93 4.7. rtpDTMFTones . . . . . . . . . . . . . . . . . . . . . . . 14 94 4.8. rtpPacketization . . . . . . . . . . . . . . . . . . . . . 14 95 4.9. rtpPacketizationChange . . . . . . . . . . . . . . . . . . 14 96 4.10. rtpDSCPChange . . . . . . . . . . . . . . . . . . . . . . 15 98 5. Quality of Service Information Elements . . . . . . . . . . . 15 99 5.1. rtpSenderSynchronization . . . . . . . . . . . . . . . . . 15 100 5.2. rtpSenderRestart . . . . . . . . . . . . . . . . . . . . . 15 101 5.3. rtpSenderJitter . . . . . . . . . . . . . . . . . . . . . 15 102 5.4. rtpNetworkOverload . . . . . . . . . . . . . . . . . . . . 15 103 5.5. rtpOverloadWithPacketLoss . . . . . . . . . . . . . . . . 15 104 5.6. rtpTolerableJitter . . . . . . . . . . . . . . . . . . . . 15 105 5.7. rtpCriticalJitter . . . . . . . . . . . . . . . . . . . . 16 106 5.8. rtpVeryLargeJitter . . . . . . . . . . . . . . . . . . . . 16 107 5.9. rtpTolerablePacketLoss . . . . . . . . . . . . . . . . . . 17 108 5.10. rtpCriticalPacketLoss . . . . . . . . . . . . . . . . . . 17 109 5.11. rtpCriticalLossDensity . . . . . . . . . . . . . . . . . . 18 110 5.12. rtpOverloadWithPacketOrder . . . . . . . . . . . . . . . . 18 111 5.13. rtpDuplicates . . . . . . . . . . . . . . . . . . . . . . 18 112 5.14. rtpPacketOrder . . . . . . . . . . . . . . . . . . . . . . 18 113 5.15. rtpSequenceError . . . . . . . . . . . . . . . . . . . . . 18 114 5.16. rtpLowPacketInterval . . . . . . . . . . . . . . . . . . . 19 115 5.17. rtpNoPacketInterval . . . . . . . . . . . . . . . . . . . 19 116 5.18. rtpBadRTPTimestamp . . . . . . . . . . . . . . . . . . . . 19 117 5.19. rtpMinJitter . . . . . . . . . . . . . . . . . . . . . . . 19 118 5.20. Average Jitter . . . . . . . . . . . . . . . . . . . . . . 19 119 5.20.1. rtpJitterCount . . . . . . . . . . . . . . . . . . . 20 120 5.20.2. rtpJitterSum . . . . . . . . . . . . . . . . . . . . 20 121 5.21. rtpMaxJitter . . . . . . . . . . . . . . . . . . . . . . . 20 122 5.22. Jitter histogram . . . . . . . . . . . . . . . . . . . . . 20 123 5.22.1. rtpJitterBucket0 . . . . . . . . . . . . . . . . . . 21 124 5.22.2. rtpJitterBucket5 . . . . . . . . . . . . . . . . . . 21 125 5.22.3. rtpJitterBucket10 . . . . . . . . . . . . . . . . . . 21 126 5.22.4. rtpJitterBucket15 . . . . . . . . . . . . . . . . . . 22 127 5.22.5. rtpJitterBucket20 . . . . . . . . . . . . . . . . . . 22 128 5.22.6. rtpJitterBucket25 . . . . . . . . . . . . . . . . . . 22 129 5.22.7. rtpJitterBucket30 . . . . . . . . . . . . . . . . . . 22 130 5.22.8. rtpJitterBucket35 . . . . . . . . . . . . . . . . . . 23 131 5.22.9. rtpJitterBucket40 . . . . . . . . . . . . . . . . . . 23 132 5.22.10. rtpJitterBucket45 . . . . . . . . . . . . . . . . . . 23 133 5.22.11. rtpJitterBucket50 . . . . . . . . . . . . . . . . . . 24 134 5.22.12. rtpJitterBucket55 . . . . . . . . . . . . . . . . . . 24 135 5.22.13. rtpJitterBucket60 . . . . . . . . . . . . . . . . . . 24 136 5.22.14. rtpJitterBucket65 . . . . . . . . . . . . . . . . . . 24 137 5.22.15. rtpJitterBucket70 . . . . . . . . . . . . . . . . . . 25 138 5.22.16. rtpJitterBucket75 . . . . . . . . . . . . . . . . . . 25 139 5.22.17. rtpJitterBucket80 . . . . . . . . . . . . . . . . . . 25 140 5.22.18. rtpJitterBucket85 . . . . . . . . . . . . . . . . . . 26 141 5.22.19. rtpJitterBucket90 . . . . . . . . . . . . . . . . . . 26 142 5.22.20. rtpJitterBucket95 . . . . . . . . . . . . . . . . . . 26 143 5.22.21. rtpJitterBucket100 . . . . . . . . . . . . . . . . . 26 144 5.23. rtpDelayType . . . . . . . . . . . . . . . . . . . . . . . 27 145 5.24. rtpDelayOneWay . . . . . . . . . . . . . . . . . . . . . . 27 147 6. MOS measurement . . . . . . . . . . . . . . . . . . . . . . . 28 148 6.1. rtpMOSCAlg . . . . . . . . . . . . . . . . . . . . . . . . 28 149 6.2. rtpMOSClass1 . . . . . . . . . . . . . . . . . . . . . . . 29 150 6.3. rtpMOSClass2 . . . . . . . . . . . . . . . . . . . . . . . 29 151 6.4. rtpMOSClass3 . . . . . . . . . . . . . . . . . . . . . . . 29 152 6.5. rtpMOSClass4 . . . . . . . . . . . . . . . . . . . . . . . 30 153 6.6. rtpMOSClass5 . . . . . . . . . . . . . . . . . . . . . . . 30 154 6.7. rtpMinMOS . . . . . . . . . . . . . . . . . . . . . . . . 30 155 6.8. rtpAvgMOS . . . . . . . . . . . . . . . . . . . . . . . . 31 156 6.9. rtpMaxMOS . . . . . . . . . . . . . . . . . . . . . . . . 31 157 6.10. rtpMinRFactor . . . . . . . . . . . . . . . . . . . . . . 31 158 6.11. rtpAvgRFactor . . . . . . . . . . . . . . . . . . . . . . 31 159 6.12. rtpMaxRFactor . . . . . . . . . . . . . . . . . . . . . . 32 160 7. Recommended Templates . . . . . . . . . . . . . . . . . . . . 32 161 7.1. Entire stream . . . . . . . . . . . . . . . . . . . . . . 32 162 7.2. Time slice . . . . . . . . . . . . . . . . . . . . . . . . 32 163 8. Examples . . . . . . . . . . . . . . . . . . . . . . . . . . . 32 164 9. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 32 165 10. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 32 166 11. Security Considerations . . . . . . . . . . . . . . . . . . . 33 167 12. TODO . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33 168 13. References . . . . . . . . . . . . . . . . . . . . . . . . . . 33 169 13.1. Normative References . . . . . . . . . . . . . . . . . . . 33 170 13.2. Informative References . . . . . . . . . . . . . . . . . . 34 171 Author's Address . . . . . . . . . . . . . . . . . . . . . . . . . 34 173 1. Introduction 175 IPFIX [RFC5101] and [RFC5102] defines a framework allowing to export 176 arbitrary data from so called IPFIX exporters. One type of IPFIX 177 exporter may be co-located or passively observe Session Initiation 178 Protocol (SIP) [RFC3261] based VoIP calls. The signaling messages 179 can be exported using [I-D.trammell-ipfix-sip-msg] which leaves the 180 Real Time Protocol (RTP) [RFC3550] media streams unmonitored. This 181 document defines a set of additional IPFIX Information Elements (IEs) 182 to describe RTP streams on various levels. These layers include the 183 IP transport, RTP header information as well as Quality of Service 184 (QoS) information of monitored streams. 186 1.1. Use Cases 188 RTP stream flow information contained in IPFIX flow records can be 189 used for various tasks such as Quality of Service (QoS) monitoring, 190 Service Level Agreement (SLA) validation and general troubleshooting 191 of VoIP networks. 193 1.1.1. Quality of Service (QoS) Monitoring 195 Aggregated to higher-level metrics the in-depth information provided 196 by the RTP (and optionally SIP) flow records allows service providers 197 to gauge the overall quality of their network in terms of the quality 198 of experience (QoE). On this level an individual call is less 199 important but the overall quality (e.g. amount of minutes meeting 200 certain quality standards) can be used to get a quick overview on the 201 network and service performance. 203 1.1.2. Service Level Agreement (SLA) 205 SLAs are typically used as part of contracts between two network 206 operators. The requirements on the reliability of the data may be 207 higher compared to QoS Monitoring as the failure to meet 208 contractually agreed quality standards often has a direct commercial 209 impact. 211 1.1.3. Troubleshooting 213 An active network component (SIP proxy, B2BUA, media server) may not 214 have the capabilities to store session related information for a long 215 time to facilitate troubleshooting capabilities (e.g. due to missing 216 harddisk). Such a system or a group of systems may run the metering 217 process and export the data to a collector for processing or 218 troubleshooting purposes. 220 2. Conventions 222 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 223 "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this 224 document are to be interpreted as described in RFC 2119 [RFC2119]. 226 3. Base RTP Information Elements 228 The base RTP Information Elements cover information transported 229 outside the Real Time Protocol [RFC3550] or defined by the Metering 230 Process. 232 3.1. rtpObservationType 234 Description: The rtpObservationType is similar to the 235 sipObservationType from [I-D.trammell-ipfix-sip-msg]. 237 0: unknown: The Metering Process does not specify the observation 238 type 240 1: receiver: The Metering Process is, or is co-located with, the 241 receiver of the RTP stream. 243 2: sender: The Metering Process is, or is co-located with, the 244 sender of the RTP stream. 246 3: passive: The Metering Process passively observed the RTP 247 stream. 249 4: rtcp: TBD 251 Data Type: unsigned8 253 Data Type Semantics: identifier 255 PEN (provisional): xxx 257 ElementId (provisional): xxx 259 3.2. rtpFlowId 261 The rtpFlowId field is used to identify the RTP stream covered in 262 this flow record. It shall be used to correlate the RTP stream to 263 IPFIX SIP sessions. The rtpFlowId is calculated using a 5-tuple of 264 source IP, source port, destination IP, destination port and 265 transport protocol. Additionally the RTP SSRC is added. The exact 266 calculation method is up for discussion. VOIPFUTURE uses a 64Bit 267 hash value. 269 Description: Hash value identifying the observed RTP stream. 271 Data Type: unsigned64 273 Data Type Semantics: identifier 275 PEN (provisional): xxx 277 ElementId (provisional): xxx 279 3.3. rtpStartTime 281 Description: Start time of the RTP stream in milliseconds since 0000 282 UTC Jan 1, 1970. The time is taken from the local clock and not 283 from the RTP stream timestamp field. The local clock SHALL be NTP 284 synchronized. If this flow record covers only part of an RTP 285 stream the start time must be set to the start time of the 286 observation time/interval. 288 Data Type: dateTimeMilliseconds 290 Data Type Semantics: identifier 292 PEN (provisional): xxx 294 ElementId (provisional): xxx 296 3.4. rtpEndTime 298 Description: End time of the RTP stream in milliseconds since 0000 299 UTC Jan 1, 1970. The time is taken from the local clock and not 300 from the RTP stream timestamp field. The local clock SHALL be NTP 301 synchronized. If this flow record covers only part of an RTP 302 stream the end time must be set to the end time of the observation 303 time/interval. 305 Data Type: dateTimeMilliseconds 307 Data Type Semantics: identifier 309 PEN (provisional): xxx 311 ElementId (provisional): xxx 313 3.5. rtpSampleOffset 315 Description: Offset of the observation interval contained in this 316 flow record. The value is measured in milliseconds and contains 317 the offset of the beginning of the flow record from the beginning 318 of the RTP stream. 320 Data Type: unsigned32 322 Data Type Semantics: identifier 324 PEN (provisional): xxx 326 ElementId (provisional): xxx 328 3.6. rtpSampleTime 330 An IPFIX observer may generate and export a flow record for the 331 entire duration of an RTP stream or for a specific part, e.g. a fixed 332 time slice of 10 seconds. In case a single flow record is created 333 the rtpSampleTime equals the RTP stream duration in milliseconds. In 334 either case the rtpStreamState IE should be set to true if this flow 335 record describes an ended RTP stream. 337 Description: Duration of the observation time of this flow record 338 measured in milliseconds. 340 Data Type: unsigned32 342 Data Type Semantics: deltaCounter 344 PEN (provisional): xxx 346 ElementId (provisional): xxx 348 3.7. rtpStreamState 350 Using the rtpSampleOffset and rtpSampleTime IEs flow entries may be 351 generated which describe only part of an RTP stream. This IE is used 352 to describe the state of the observed stream, e.g. to indicate the 353 reception of the last flow record belonging to a single RTP stream. 355 Description: 357 0: undefined: The state of the stream is not known. 359 1: running: The Metering Process expects more RTP packets or has 360 already received packets for this RTP stream which are outside 361 the scope of this flow record. 363 2: ended: The Metering Process determined that the RTP stream 364 ended. Information sources could be signaling information or 365 the fact that no RTP media has been received for a longer 366 period of time. 368 3: no packets: The Metering Process has not received any RTP 369 packets for this RTP stream in the observation interval but the 370 stream has not ended. A VoIP endpoint may have requested the 371 media stream to be suspended, i.e. put 'on hold' (tbd:reference 372 to sendonly ..) 374 Data Type: unsigned8 376 Data Type Semantics: identifier 378 PEN (provisional): xxx 380 ElementId (provisional): xxx 382 3.8. rtpProtocolVersion 384 Description: Value of the RTP version taken from the RTP header. 385 For RFC 3550 [RFC3550] RTP packets this will typically be set to 386 2. 388 Data Type: unsigned8 390 Data Type Semantics: identifier 392 PEN (provisional): xxx 394 ElementId (provisional): xxx 396 3.9. rtpPayloadType 398 Description: Payload Type (PT) as conveyed in RTP header 400 Data Type: unsigned8 402 Data Type Semantics: identifier 403 PEN (provisional): xxx 405 ElementId (provisional): xxx 407 3.10. rtpMediaType 409 Every RTP stream falls into a certain category, e.g. audio or video. 410 These RTP media types have been defined in [RFC4566] and are carried 411 in this Information Element. A Metering Process may learn these 412 based on the information in the RTP stream alone or (e.g. when co- 413 located with a SIP Metering Process) based on signaling information. 414 New media types may be defined in the registry created by [RFC3840]. 416 Description: 418 0: unknown: unknown media type 420 1: audio: audio RTP stream 422 2: video: video RTP stream 424 3: text: text session 426 4: application: tbd 428 5: message: tbd 430 Data Type: unsigned8 432 Data Type Semantics: identifier 434 PEN (provisional): xxx 436 ElementId (provisional): xxx 438 3.11. rtpMediaSubType 440 The string value for this IE can be found in the IANA registry for 441 'RTP Payload Format MIME types' on 442 http://www.iana.org/assignments/rtp-parameters 444 Description: Media subtype based on IANA registry 446 Data Type: string 447 Data Type Semantics: identifier 449 PEN (provisional): xxx 451 ElementId (provisional): xxx 453 3.12. rtpIsSRTP 455 tbd: The tri-state rtpIsSRTP will be set if SRTP is used/not used or 456 the content is not known. Might require the RTP Metering Process to 457 be co-located with a signaling process. 459 3.13. rtpSSRC 461 Description: SSRC field as conveyed in RTP header. The SSRC field 462 identifies the synchronization source. 464 Data Type: unsigned32 466 Data Type Semantics: identifier 468 PEN (provisional): xxx 470 ElementId (provisional): xxx 472 3.14. rtpCSRC 474 Description: Convey the CSRCs as RFC6313 basicList? To be discussed 476 Data Type: basicList 478 Data Type Semantics: identifier 480 PEN (provisional): xxx 482 ElementId (provisional): xxx 484 3.15. rtpTimestamp 486 Description: Timestamp value as conveyed in RTP header. The 487 timestamp is taken from the first RTP packet if multiple RTP 488 packets are covered in this flow record. 490 Data Type: unsigned32 491 Data Type Semantics: identifier 493 PEN (provisional): xxx 495 ElementId (provisional): xxx 497 4. RTP Payload Information Elements 499 This section defines additional Information Elements which describe 500 RTP streams based on their IP transport and RTP header parameters. 501 Complicated metrics may be subject to different measurement methods. 502 In order to prevent data from being unusable due to incompatible 503 formats or measurement methods most Information Elements are counter 504 values which allow calculation of metrics on mediator or collector 505 systems. Additionally this allows matching flow records to be 506 aggregatd by addition, e.g. addition of the rtpPacketCount values of 507 multiple observation intervals. 509 4.1. rtpPacketCount 511 Description: Number of RTP packets covered in this flow record. 512 This includes observed duplicate packets. 514 Data Type: unsigned32 516 Data Type Semantics: deltaCounter 518 PEN (provisional): xxx 520 ElementId (provisional): xxx 522 4.2. rtpPacketCountLoss 524 Description: Number of RTP packets lost in the duration covered by 525 this flow record. The number of lost packets SHOULD be calculated 526 using the RTP sequence numbers. 528 Data Type: unsigned32 530 Data Type Semantics: deltaCounter 532 PEN (provisional): xxx 534 ElementId (provisional): xxx 536 4.3. rtpPacketCountDiscarded 538 Passive monitoring equipment shall assume a fixed 40 millisecond 539 jitter buffer (TODO: add reference to TM Forum/ITU). A packet 540 observed later than the expected packet inter-arrival time plus the 541 40ms is assumed to be received by the RTP receiver too late to be 542 played out. Even though the packet may be received by the RTP 543 receiver it will be discarded which has the same effect as packet 544 loss. 546 Description: Number of RTP packets discarded in the duration covered 547 by this flow record. 549 Data Type: unsigned32 551 Data Type Semantics: deltaCounter 553 PEN (provisional): xxx 555 ElementId (provisional): xxx 557 4.4. rtpCodecChange 559 Description: The codec used in the observed RTP stream may change 560 throughout an observation interval. This value indicates the 561 number of changes identified by changing RTP header Payload Type 562 (PT) values. 564 Data Type: unsigned32 566 Data Type Semantics: deltaCounter 568 PEN (provisional): xxx 570 ElementId (provisional): xxx 572 4.5. rtpMarkerBit 574 Description: The RTP Marker Bit may be set on one or more packets 575 within the observation interval. This value indicates the number 576 of unique packets which had the Marker Bit set. Duplicate packets 577 MUST be ignored for this calculation. 579 Data Type: unsigned32 580 Data Type Semantics: deltaCounter 582 PEN (provisional): xxx 584 ElementId (provisional): xxx 586 4.6. rtpComfortNoise 588 Description: RTP packets of the observed RTP stream may be Comfort 589 Noise packets. This value indicates the number of unique Comfort 590 Noise packets in this observation interval. Duplicate packets 591 MUST be ignored for this calculation. 593 Data Type: unsigned32 595 Data Type Semantics: deltaCounter 597 PEN (provisional): xxx 599 ElementId (provisional): xxx 601 4.7. rtpDTMFTones 603 tbd: # of DTMF tones observed in interval, e.g. PT 101. May also 604 include in-band if possible by observation method. 606 4.8. rtpPacketization 608 Description: The packetization time of the data contained in the RTP 609 packets in milliseconds. If a packetization time change occured 610 during the monitoring interval described by this flow record the 611 rtpPacketization value SHALL be set to the interval used for most 612 of the packets. If no packetization time can be determined the 613 value MUST be set to 0. 615 Data Type: unsigned8 617 Data Type Semantics: quantity 619 PEN (provisional): xxx 621 ElementId (provisional): xxx 623 4.9. rtpPacketizationChange 624 Description: The packetization time of RTP packets may change 625 throughout a single RTP stream. Endpoints may use the ptime SDP 626 parameter to indicate/request changes or change the packetization 627 time without advance notice if allowed by the codec. This value 628 indicates the number of packetization time changes in this 629 observation interval. 631 Data Type: unsigned8 633 Data Type Semantics: deltaCounter 635 PEN (provisional): xxx 637 ElementId (provisional): xxx 639 4.10. rtpDSCPChange 641 tbd: should be transport based - # of changes of DSCP/ToS bits on IP 642 layer. Alternative: basicList of seen DSCP classes. 644 5. Quality of Service Information Elements 646 5.1. rtpSenderSynchronization 648 tbd: VOIPFUTURE specific 650 5.2. rtpSenderRestart 652 tbd: VOIPFUTURE specific, can be incorporated into rtpSequenceError 654 5.3. rtpSenderJitter 656 tbd: VOIPFUTURE specific 658 5.4. rtpNetworkOverload 660 tbd: VOIPFUTURE specific 662 5.5. rtpOverloadWithPacketLoss 664 tbd: VOIPFUTURE specific 666 5.6. rtpTolerableJitter 668 TM Forum and ITU recommend that monitoring equipment such as the 669 IPFIX Metering Process should assume a jitter buffer with a fixed 670 size of 40 milliseconds. Based on this value we consider jitter as 671 tolerable if the inter-arrival time between to packets does not 672 exceed these 40 milliseconds. Based on a 20 millisecond 673 packetization time (as conveyed in rtpPacketInterval) a jitter of 674 less than 20 milliseconds can be considered as tolerable. TBD: 675 define jitter measurement method, most likely something better than 676 RFC3550. 678 Description: The number of RTP packets with a tolerable jitter as 679 defined above. Duplicate packets MUST be ignored for this 680 calculation. 682 Data Type: unsigned32 684 Data Type Semantics: deltaCounter 686 PEN (provisional): xxx 688 ElementId (provisional): xxx 690 5.7. rtpCriticalJitter 692 Based on the rtpTolerableJitter definition this Information Element 693 describes the number of RTP packets which arrived with a critical 694 value for the packet inter-arrival time, i.e. more than 40 695 milliseconds after the previous packet. 697 Description: The number of RTP packets with a critical jitter as 698 defined above. Duplicate packets MUST be ignored for this 699 calculation. 701 Data Type: unsigned32 703 Data Type Semantics: deltaCounter 705 PEN (provisional): xxx 707 ElementId (provisional): xxx 709 5.8. rtpVeryLargeJitter 711 RTP packets observed with a packet inter-arrival time of more than 80 712 milliseconds above the indicated packetization time (e.g. >100ms in 713 case of a 20ms packetization time) are counted in this very large 714 jitter category. Often RTP packets will match this property if 715 network buffering occurred during the observation interval. 717 Description: The number of RTP packets with a very large jitter as 718 defined above. Duplicate packets MUST be ignored for this 719 calculation. 721 Data Type: unsigned32 723 Data Type Semantics: deltaCounter 725 PEN (provisional): xxx 727 ElementId (provisional): xxx 729 5.9. rtpTolerablePacketLoss 731 RTP packet loss can be detected using the RTP sequence number. A 732 loss event is considered tolerable if only one packet is lost before 733 the RTP stream continues. 735 Description: The number of tolerable packet loss events as defined 736 above observed in the observation interval. 738 Data Type: unsigned32 740 Data Type Semantics: deltaCounter 742 PEN (provisional): xxx 744 ElementId (provisional): xxx 746 5.10. rtpCriticalPacketLoss 748 RTP packet loss can be detected using the RTP sequence number. A 749 loss event is considered critical if more than one packet is lost 750 before the RTP stream continues. 752 Description: The number of critical packet loss events as defined 753 above observed in the observation interval. 755 Data Type: unsigned32 757 Data Type Semantics: deltaCounter 759 PEN (provisional): xxx 761 ElementId (provisional): xxx 763 5.11. rtpCriticalLossDensity 765 VOIPFUTURE needs to describe, should be kept in. We need to cover 766 burst-loss 768 5.12. rtpOverloadWithPacketOrder 770 VOIPFUTURE needs to describe, optional 772 5.13. rtpDuplicates 774 Description: Duplicate RTP packets may be observed and identified 775 based on the RTP sequence number. This counter indicates the 776 number of observed duplicate packets in the observation interval. 778 Data Type: unsigned32 780 Data Type Semantics: deltaCounter 782 PEN (provisional): xxx 784 ElementId (provisional): xxx 786 5.14. rtpPacketOrder 788 RTP packets may be re-ordered during transmission, e.g. due to 789 routing changes. This Information Element indicates the number of 790 RTP packets which are received out of order during the observation 791 interval. 793 Description: Number of out-of-order RTP packets observed. Duplicate 794 packets must not count towards this value. 796 Data Type: unsigned32 798 Data Type Semantics: deltaCounter 800 PEN (provisional): xxx 802 ElementId (provisional): xxx 804 5.15. rtpSequenceError 806 The RTP header sequence numbers increases monotonically throughout an 807 RTP session. A forward or backward jump in sequence numbers or a 808 reset of the sequence number observed indicates problems on the 809 sender side. Additionally the receiver of the RTP stream may suffer 810 as handling these situations is not defined. 812 Description: Number of RTP sequence error events observed. 813 Duplicate packets must not count towards this value. 815 Data Type: unsigned32 817 Data Type Semantics: deltaCounter 819 PEN (provisional): xxx 821 ElementId (provisional): xxx 823 5.16. rtpLowPacketInterval 825 to be defined by VOIPFUTURE 827 5.17. rtpNoPacketInterval 829 to be defined by VOIPFUTURE 831 5.18. rtpBadRTPTimestamp 833 to be defined by VOIPFUTURE 835 5.19. rtpMinJitter 837 Description: The minimum jitter value is defined as the minimal 838 packet inter-arrival time in milliseconds in the observation 839 interval. 841 Data Type: unsigned8 843 Data Type Semantics: quantity 845 PEN (provisional): xxx 847 ElementId (provisional): xxx 849 5.20. Average Jitter 851 Calculating and transporting an average jitter value makes little 852 sense if the data should be aggregated at a later stage, e.g. by a 853 mediator, collector or an application processing the data. To remedy 854 this both the number of packet inter-arrival times and the sum of the 855 packet inter-arrival times in milliseconds are counted. 857 The average jitter value can be calculated by dividing rtpJitterSum 858 by rtpJitterCount. 860 An average jitter value for multiple flow records can be calculated 861 by dividing the sum of all rtpJitterSum values by the sum of all 862 rtpJitterCount values. 864 5.20.1. rtpJitterCount 866 Description: The number of packet inter-arrival times observed. 868 Data Type: unsigned16 870 Data Type Semantics: deltaCounter 872 PEN (provisional): xxx 874 ElementId (provisional): xxx 876 5.20.2. rtpJitterSum 878 Description: The sum of all packet inter-arrival times in 879 milliseconds. 881 Data Type: unsigned32 883 Data Type Semantics: quantity 885 PEN (provisional): xxx 887 ElementId (provisional): xxx 889 5.21. rtpMaxJitter 891 Description: The maximum jitter value is defined as the maximal 892 packet inter-arrival time in milliseconds in the observation 893 interval. 895 Data Type: unsigned8 897 Data Type Semantics: quantity 899 PEN (provisional): xxx 901 ElementId (provisional): xxx 903 5.22. Jitter histogram 905 In order to display and aggregate detailed jitter information of the 906 observed RTP stream additional Information Elements are required. 907 The Metering Process observing an RTP stream analyses the packet 908 inter-arrival times without needing to know the agreed packetiziation 909 time. The following calculations are only made for packets with 910 consecutive RTP sequence numbers. From 250 received RTP packets in 911 an observation interval a Metering Process can calculate 249 packet 912 inter-arrival times. In case of packet loss (i.e. missing sequence 913 number in the packet stream) no packet inter-arrival time is 914 calculated. Based on the calculated inter-arrival time the counters 915 in the buckets listed below are increased. All counters start at 916 zero per observation interval. Inter-arrival times have a 917 millisecond granularity. 919 5.22.1. rtpJitterBucket0 921 Description: Number of packet inter-arrival times between 0 and 922 lower than 2.5 milliseconds. 924 Data Type: unsigned16 926 Data Type Semantics: deltaCounter 928 PEN (provisional): xxx 930 ElementId (provisional): xxx 932 5.22.2. rtpJitterBucket5 934 Description: Number of packet inter-arrival times starting at 2.5 935 and lower than 7.5 milliseconds. 937 Data Type: unsigned16 939 Data Type Semantics: deltaCounter 941 PEN (provisional): xxx 943 ElementId (provisional): xxx 945 5.22.3. rtpJitterBucket10 947 Description: Number of packet inter-arrival times starting at 7.5 948 and lower than 12.5 milliseconds. 950 Data Type: unsigned16 952 Data Type Semantics: deltaCounter 953 PEN (provisional): xxx 955 ElementId (provisional): xxx 957 5.22.4. rtpJitterBucket15 959 Description: Number of packet inter-arrival times starting at 12.5 960 and lower than 17.5 milliseconds. 962 Data Type: unsigned16 964 Data Type Semantics: deltaCounter 966 PEN (provisional): xxx 968 ElementId (provisional): xxx 970 5.22.5. rtpJitterBucket20 972 Description: Number of packet inter-arrival times starting at 17.5 973 and lower than 22.5 milliseconds. 975 Data Type: unsigned16 977 Data Type Semantics: deltaCounter 979 PEN (provisional): xxx 981 ElementId (provisional): xxx 983 5.22.6. rtpJitterBucket25 985 Description: Number of packet inter-arrival times starting at 22.5 986 and lower than 27.5 milliseconds. 988 Data Type: unsigned16 990 Data Type Semantics: deltaCounter 992 PEN (provisional): xxx 994 ElementId (provisional): xxx 996 5.22.7. rtpJitterBucket30 997 Description: Number of packet inter-arrival times starting at 27.5 998 and lower than 32.5 milliseconds. 1000 Data Type: unsigned16 1002 Data Type Semantics: deltaCounter 1004 PEN (provisional): xxx 1006 ElementId (provisional): xxx 1008 5.22.8. rtpJitterBucket35 1010 Description: Number of packet inter-arrival times starting at 32.5 1011 and lower than 37.5 milliseconds. 1013 Data Type: unsigned16 1015 Data Type Semantics: deltaCounter 1017 PEN (provisional): xxx 1019 ElementId (provisional): xxx 1021 5.22.9. rtpJitterBucket40 1023 Description: Number of packet inter-arrival times starting at 37.5 1024 and lower than 37.5 milliseconds. 1026 Data Type: unsigned16 1028 Data Type Semantics: deltaCounter 1030 PEN (provisional): xxx 1032 ElementId (provisional): xxx 1034 5.22.10. rtpJitterBucket45 1036 Description: Number of packet inter-arrival times starting at 42.5 1037 and lower than 47.5 milliseconds. 1039 Data Type: unsigned16 1041 Data Type Semantics: deltaCounter 1042 PEN (provisional): xxx 1044 ElementId (provisional): xxx 1046 5.22.11. rtpJitterBucket50 1048 Description: Number of packet inter-arrival times starting at 47.5 1049 and lower than 52.5 milliseconds. 1051 Data Type: unsigned16 1053 Data Type Semantics: deltaCounter 1055 PEN (provisional): xxx 1057 ElementId (provisional): xxx 1059 5.22.12. rtpJitterBucket55 1061 Description: Number of packet inter-arrival times starting at 52.5 1062 and lower than 57.5 milliseconds. 1064 Data Type: unsigned16 1066 Data Type Semantics: deltaCounter 1068 PEN (provisional): xxx 1070 ElementId (provisional): xxx 1072 5.22.13. rtpJitterBucket60 1074 Description: Number of packet inter-arrival times starting at 57.5 1075 and lower than 62.5 milliseconds. 1077 Data Type: unsigned16 1079 Data Type Semantics: deltaCounter 1081 PEN (provisional): xxx 1083 ElementId (provisional): xxx 1085 5.22.14. rtpJitterBucket65 1086 Description: Number of packet inter-arrival times starting at 62.5 1087 and lower than 67.5 milliseconds. 1089 Data Type: unsigned16 1091 Data Type Semantics: deltaCounter 1093 PEN (provisional): xxx 1095 ElementId (provisional): xxx 1097 5.22.15. rtpJitterBucket70 1099 Description: Number of packet inter-arrival times starting at 67.5 1100 and lower than 72.5 milliseconds. 1102 Data Type: unsigned16 1104 Data Type Semantics: deltaCounter 1106 PEN (provisional): xxx 1108 ElementId (provisional): xxx 1110 5.22.16. rtpJitterBucket75 1112 Description: Number of packet inter-arrival times starting at 72.5 1113 and lower than 77.5 milliseconds. 1115 Data Type: unsigned16 1117 Data Type Semantics: deltaCounter 1119 PEN (provisional): xxx 1121 ElementId (provisional): xxx 1123 5.22.17. rtpJitterBucket80 1125 Description: Number of packet inter-arrival times starting at 77.5 1126 and lower than 82.5 milliseconds. 1128 Data Type: unsigned16 1130 Data Type Semantics: deltaCounter 1131 PEN (provisional): xxx 1133 ElementId (provisional): xxx 1135 5.22.18. rtpJitterBucket85 1137 Description: Number of packet inter-arrival times starting at 82.5 1138 and lower than 87.5 milliseconds. 1140 Data Type: unsigned16 1142 Data Type Semantics: deltaCounter 1144 PEN (provisional): xxx 1146 ElementId (provisional): xxx 1148 5.22.19. rtpJitterBucket90 1150 Description: Number of packet inter-arrival times starting at 87.5 1151 and lower than 92.5 milliseconds. 1153 Data Type: unsigned16 1155 Data Type Semantics: deltaCounter 1157 PEN (provisional): xxx 1159 ElementId (provisional): xxx 1161 5.22.20. rtpJitterBucket95 1163 Description: Number of packet inter-arrival times starting at 92.5 1164 and lower than 97.5 milliseconds. 1166 Data Type: unsigned16 1168 Data Type Semantics: deltaCounter 1170 PEN (provisional): xxx 1172 ElementId (provisional): xxx 1174 5.22.21. rtpJitterBucket100 1175 Description: Number of packet inter-arrival times starting at 97.5 1176 milliseconds. 1178 Data Type: unsigned16 1180 Data Type Semantics: deltaCounter 1182 PEN (provisional): xxx 1184 ElementId (provisional): xxx 1186 5.23. rtpDelayType 1188 The RTP one-way delay is the time RTP packets need to travel from the 1189 source (RTP sender) to the destination (RTP receiver). This value 1190 may be obtained from RTCP reports generated by RTP receivers or by 1191 actively using ICMP ping requests to obtain a rough approximation of 1192 the delay. ICMP based delay calculation is not encouraged. In any 1193 use case the observed or measured one-way delay is only a single data 1194 point which does not match the observation interval defined by the 1195 rtpSampleTime and rtpSampleOffset. TBD: discuss this, esp whether to 1196 move this in a separate section. 1198 Description: 1200 0: unknown: unknown delay measurement 1202 1: rtcp: delay value taken from RTCP report 1204 2: rtcp-xr: delay value taken from RTCP-XR report 1206 3: ping: active ICMP ping 1208 4: endpoint: mouth to ear delay 1210 Data Type: unsigned8 1212 Data Type Semantics: identifier 1214 PEN (provisional): xxx 1216 ElementId (provisional): xxx 1218 5.24. rtpDelayOneWay 1219 Description: One way RTP delay in milliseconds. 1221 Data Type: unsigned16 1223 Data Type Semantics: identifier 1225 PEN (provisional): xxx 1227 ElementId (provisional): xxx 1229 6. MOS measurement 1231 A multitude of Mean opinion score (MOS) assessment algorithms have 1232 been defined of which only one or few may be available to an IPFIX 1233 Metering Process. The quality (i.e. accuracy) of these algorithms 1234 varies and has to be noted when transporting MOS values. 1236 An IPFIX Metering Process may use these Information Elements to 1237 convey information on the duration of the stream in which the quality 1238 fell into the respective category as well as the measurement 1239 algorithm used to obtain the information. 1241 6.1. rtpMOSCAlg 1243 The values carried in this IE are taken from the "RTCP XR QoE metric 1244 block - Calculation Algorithm" sub-registry of the "RTP Control 1245 Protocol Extended Reports (RTCP XR) Block Type Registry" as defined 1246 in [I-D.wu-xrblock-rtcp-xr-quality-monitoring]. 1248 Description: The calculation algorithm (CAlg) used by the Metering 1249 Process to calculate the MOS value. 1251 0: undefined: The algorithm is not known/specified. 1253 1: ITU-T P.564 1255 2: G.107 1257 3: G.107 / ETSI TS 101 329-5 Annex E 1259 4: ITU-T P.NAMS 1261 5: ITU-T P.NBAMS 1262 6: RTCP - Real Time Control Protocol (not defined in registry!) 1264 Data Type: unsigned8 1266 Data Type Semantics: identifier 1268 PEN (provisional): xxx 1270 ElementId (provisional): xxx 1272 The MOS values calculated are separated into MOS classes based on the 1273 ITU-T G.107 classes. 1275 6.2. rtpMOSClass1 1277 Description: Number of seconds the monitored stream had a MOS 1278 quality lower than 3.10 1280 Data Type: float32 1282 Data Type Semantics: deltaCounter 1284 PEN (provisional): xxx 1286 ElementId (provisional): xxx 1288 6.3. rtpMOSClass2 1290 Description: Number of seconds the monitored stream had a MOS 1291 quality larger than or equal 3.10 and lower than 3.60 1293 Data Type: float32 1295 Data Type Semantics: deltaCounter 1297 PEN (provisional): xxx 1299 ElementId (provisional): xxx 1301 6.4. rtpMOSClass3 1303 Description: Number of seconds the monitored stream had a MOS 1304 quality larger than or equal 3.60 and lower than 4.03 1306 Data Type: float32 1307 Data Type Semantics: deltaCounter 1309 PEN (provisional): xxx 1311 ElementId (provisional): xxx 1313 6.5. rtpMOSClass4 1315 Description: Number of seconds the monitored stream had a MOS 1316 quality larger than or equal 4.03 and lower than 4.34 1318 Data Type: float32 1320 Data Type Semantics: deltaCounter 1322 PEN (provisional): xxx 1324 ElementId (provisional): xxx 1326 6.6. rtpMOSClass5 1328 Description: Number of seconds the monitored stream had a MOS 1329 quality larger than or equal 4.34 1331 Data Type: float32 1333 Data Type Semantics: deltaCounter 1335 PEN (provisional): xxx 1337 ElementId (provisional): xxx 1339 6.7. rtpMinMOS 1341 Description: Minimum MOS value measured in the monitoring interval. 1343 Data Type: float32 1345 Data Type Semantics: quantity 1347 PEN (provisional): xxx 1349 ElementId (provisional): xxx 1351 6.8. rtpAvgMOS 1353 Description: Average MOS value measured in the monitoring interval. 1355 Data Type: float32 1357 Data Type Semantics: quantity 1359 PEN (provisional): xxx 1361 ElementId (provisional): xxx 1363 6.9. rtpMaxMOS 1365 Description: Maximum MOS value measured in the monitoring interval. 1367 Data Type: float32 1369 Data Type Semantics: quantity 1371 PEN (provisional): xxx 1373 ElementId (provisional): xxx 1375 6.10. rtpMinRFactor 1377 Description: Minimum R-Factor measured in the monitoring interval. 1379 Data Type: float32 1381 Data Type Semantics: quantity 1383 PEN (provisional): xxx 1385 ElementId (provisional): xxx 1387 6.11. rtpAvgRFactor 1389 Description: Average R-Factor measured in the monitoring interval. 1391 Data Type: float32 1393 Data Type Semantics: quantity 1395 PEN (provisional): xxx 1396 ElementId (provisional): xxx 1398 6.12. rtpMaxRFactor 1400 Description: Maximum R-Factor measured in the monitoring interval. 1402 Data Type: float32 1404 Data Type Semantics: quantity 1406 PEN (provisional): xxx 1408 ElementId (provisional): xxx 1410 7. Recommended Templates 1412 The defined RTP stream IPFIX templates must support both IPv4 and 1413 IPv6 transport. They need to carry either flow information regarding 1414 the entire duration of an RTP stream or specific to a shorter 1415 observation interval. 1417 7.1. Entire stream 1419 tbd 1421 7.2. Time slice 1423 tbd, based on previous template. Split a single RTP stream in three 1424 flow records as example including (empty) 'RTP stream ended' flow 1425 record. 1427 8. Examples 1429 9. Acknowledgements 1431 tbd 1433 10. IANA Considerations 1435 tbd 1437 11. Security Considerations 1439 tbd 1441 12. TODO 1443 QUESTION-1: Should we try to take a biflow approach and join both 1444 stream directions of a call in a single flow record? I assume this 1445 would not give any big advantage and complicates scenarios in which 1446 Service Level Agreements are done on a per direction basis. 1448 QUESTION-2: Should we define the CSRCs as RFC6313 basicList? 1450 QUESTION-3: Should we degrade rtpPacketOrder or rtpSequenceError to a 1451 boolean? 1453 QUESTION-4: Should rtpPacketCount include duplicate packets? 1455 QUESTION-5: How about 'packet errors', e.g. packets which could not 1456 be processed properly? 1458 QUESTION-6: Should we include a standard deviation value for 1459 rtpAvgJitter and other average values? 1461 QUESTION-7: (from MK@VOIPFUTURE): It has to be possible to send an 1462 empty flow record indicating the end of an RTP stream. 1464 QUESTION-8: should we reduce these deltaCounters to 16 Bit (now: 1465 32Bit)? rtpCodecChange, rtpMarkerBit, rtpComfortNoise, 1466 rtpPacketIntervalChange, rtpSequenceError, rtp*Jitter 1468 QUESTION-9: should we add direction indicators? E.g. caller-to- 1469 callee or callee-to-caller? 1471 QUESTION-10: should we use milliseconds or seconds for the MOS class 1472 slots? 1474 13. References 1476 13.1. Normative References 1478 [I-D.trammell-ipfix-sip-msg] 1479 Claise, B., Trammell, B., Kaplan, H., and S. Niccolini, 1480 "SIP Message Information Export using IPFIX", 1481 draft-trammell-ipfix-sip-msg-02 (work in progress), 1482 October 2011. 1484 [I-D.wu-xrblock-rtcp-xr-quality-monitoring] 1485 Hunt, G., Clark, A., Wu, W., Schott, R., and G. Zorn, 1486 "RTCP XR Blocks for QoE metric reporting", 1487 draft-wu-xrblock-rtcp-xr-quality-monitoring-06 (work in 1488 progress), December 2011. 1490 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 1491 Requirement Levels", BCP 14, RFC 2119, March 1997. 1493 [RFC5101] Claise, B., "Specification of the IP Flow Information 1494 Export (IPFIX) Protocol for the Exchange of IP Traffic 1495 Flow Information", RFC 5101, January 2008. 1497 [RFC5102] Quittek, J., Bryant, S., Claise, B., Aitken, P., and J. 1498 Meyer, "Information Model for IP Flow Information Export", 1499 RFC 5102, January 2008. 1501 13.2. Informative References 1503 [RFC3261] Rosenberg, J., Schulzrinne, H., Camarillo, G., Johnston, 1504 A., Peterson, J., Sparks, R., Handley, M., and E. 1505 Schooler, "SIP: Session Initiation Protocol", RFC 3261, 1506 June 2002. 1508 [RFC3550] Schulzrinne, H., Casner, S., Frederick, R., and V. 1509 Jacobson, "RTP: A Transport Protocol for Real-Time 1510 Applications", STD 64, RFC 3550, July 2003. 1512 [RFC3840] Rosenberg, J., Schulzrinne, H., and P. Kyzivat, 1513 "Indicating User Agent Capabilities in the Session 1514 Initiation Protocol (SIP)", RFC 3840, August 2004. 1516 [RFC4566] Handley, M., Jacobson, V., and C. Perkins, "SDP: Session 1517 Description Protocol", RFC 4566, July 2006. 1519 Author's Address 1521 Hendrik Scholz 1522 VOIPFUTURE GmbH 1523 Wendenstrasse 4 1524 Hamburg 20097 1525 Germany 1527 Phone: +49 40 688 900 100 1528 Email: hscholz@voipfuture.com 1529 URI: http://www.voipfuture.com/