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Wu 6 Huawei 7 April 1, 2013 9 RTP Control Protocol (RTCP) Extended Report (XR) Blocks for 10 Synchronization Delay and Offset Metrics Reporting 11 draft-ietf-xrblock-rtcp-xr-synchronization-03 13 Abstract 15 This document defines two RTP Control Protocol (RTCP) Extended Report 16 (XR) Blocks that allow the reporting of synchronization delay and 17 offset metrics for use in a range of RTP applications. 19 Status of this Memo 21 This Internet-Draft is submitted in full conformance with the 22 provisions of BCP 78 and BCP 79. 24 Internet-Drafts are working documents of the Internet Engineering 25 Task Force (IETF). Note that other groups may also distribute 26 working documents as Internet-Drafts. The list of current Internet- 27 Drafts is at http://datatracker.ietf.org/drafts/current/. 29 Internet-Drafts are draft documents valid for a maximum of six months 30 and may be updated, replaced, or obsoleted by other documents at any 31 time. It is inappropriate to use Internet-Drafts as reference 32 material or to cite them other than as "work in progress." 34 This Internet-Draft will expire on October 3, 2013. 36 Copyright Notice 38 Copyright (c) 2013 IETF Trust and the persons identified as the 39 document authors. All rights reserved. 41 This document is subject to BCP 78 and the IETF Trust's Legal 42 Provisions Relating to IETF Documents 43 (http://trustee.ietf.org/license-info) in effect on the date of 44 publication of this document. Please review these documents 45 carefully, as they describe your rights and restrictions with respect 46 to this document. Code Components extracted from this document must 47 include Simplified BSD License text as described in Section 4.e of 48 the Trust Legal Provisions and are provided without warranty as 49 described in the Simplified BSD License. 51 Table of Contents 53 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 54 1.1. Synchronization Delay and Offset Metrics Reporting 55 Blocks . . . . . . . . . . . . . . . . . . . . . . . . . . 3 56 1.2. RTCP and RTCP XR Reports . . . . . . . . . . . . . . . . . 3 57 1.3. Performance Metrics Framework . . . . . . . . . . . . . . 3 58 1.4. Applicability . . . . . . . . . . . . . . . . . . . . . . 3 59 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 4 60 2.1. Standards Language . . . . . . . . . . . . . . . . . . . . 4 61 3. RTP Flows Initial Synchronization Delay Report Block . . . . . 5 62 3.1. Metric Block Structure . . . . . . . . . . . . . . . . . . 5 63 3.2. Definition of Fields in RTP Flow Initial 64 Synchronization Delay Metrics Block . . . . . . . . . . . 6 65 4. RTP Flows Synchronization Offset Metrics Block . . . . . . . . 7 66 4.1. Metric Block Structure . . . . . . . . . . . . . . . . . . 7 67 4.2. Definition of Fields in RTP Flow General 68 Synchronization Offset Metrics Block . . . . . . . . . . . 8 69 5. SDP Signaling . . . . . . . . . . . . . . . . . . . . . . . . 9 70 5.1. SDP rtcp-xr-attrib Attribute Extension . . . . . . . . . . 9 71 5.2. Offer/Answer Usage . . . . . . . . . . . . . . . . . . . . 10 72 6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 10 73 7. Security Considerations . . . . . . . . . . . . . . . . . . . 11 74 8. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 11 75 9. References . . . . . . . . . . . . . . . . . . . . . . . . . . 11 76 9.1. Normative References . . . . . . . . . . . . . . . . . . . 11 77 9.2. Informative References . . . . . . . . . . . . . . . . . . 12 78 Appendix A. Metrics represented using RFC6390 Template . . . . . 12 79 Appendix B. Change Log . . . . . . . . . . . . . . . . . . . . . 13 80 B.1. draft-ietf-xrblock-rtcp-xr-syncronization-03 . . . . . . . 13 81 B.2. draft-ietf-xrblock-rtcp-xr-syncronization-02 . . . . . . . 13 82 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 14 84 1. Introduction 86 1.1. Synchronization Delay and Offset Metrics Reporting Blocks 88 This draft defines two new block types to augment those defined in 89 [RFC3611], for use in a range of RTP applications. 91 The first new block type supports reporting of Initial 92 Synchronization Delay to establish multimedia session. Information 93 is recorded about time difference between the start of RTP sessions 94 and the time the RTP receiver acquires all components of RTP sessions 95 in the multimedia session [RFC6051]. 97 The second new block type supports reporting of the relative 98 synchronization offset time of two arbitrary streams (e.g., between 99 audio and video streams), with the same RTCP CNAME included in RTCP 100 SDES packets [RFC3550]. 102 These metrics belong to the class of transport level metrics defined 103 in [RFC6792]. 105 1.2. RTCP and RTCP XR Reports 107 The use of RTCP for reporting is defined in [RFC3550]. [RFC3611] 108 defined an extensible structure for reporting using an RTCP Extended 109 Report (XR). This document defines a new Extended Report block for 110 use with [RFC3550] and [RFC3611]. 112 1.3. Performance Metrics Framework 114 The RTP Monitoring Architectures [RFC6792] provides guideline for 115 reporting block format using RTCP XR. The new report block described 116 in this memo is in compliance with the monitoring architecture 117 specified in [RFC6792]. 119 1.4. Applicability 121 When joining each session in layered video sessions [RFC6190] or the 122 multimedia session, a receiver may not synchronize playout across the 123 multimedia session or layered video session until RTCP SR packets 124 have been received on all components of RTP sessions. The component 125 RTP session are referred to as each RTP session for each media type 126 in multimedia session or separate RTP session for each layer in the 127 layered video session. For multicast session, the initial 128 synchronization delay metric varies with the session bandwidth, the 129 number of members, and the number of senders in the session. The RTP 130 flow Initial synchronization delay block defined in this document can 131 be used to report such metric, i.e., the initial synchronization 132 delay to receive all the RTP streams belonging to the same multimedia 133 session or layered video session. In the absence of packet loss, the 134 initial synchronization delay equals to the average time taken to 135 receive the first RTCP packet in the RTP session with the longest 136 RTCP reporting interval. In the presence of packet loss, the media 137 synchronization should rely on the in-band mapping of RTP and NTP- 138 format timestamps [RFC6051] or wait until the reporting interval has 139 passed, and the next RTCP SR packet is sent. 141 Receivers of the RTP flow initial synchronization delay block could 142 use this metric to compare with targets (i.e., Service Level 143 Agreement or thresholds of the system) to help ensure the quality of 144 real-time application performance. 146 In an RTP multimedia session, there can be an arbitrary number of 147 streams carried in different RTP sessions, with the same RTCP CNAME. 148 These streams may be not synchronized with each other. For example, 149 one audio stream and one video stream belong to the same session, and 150 the audio stream is transmitted lagging behind video stream for 151 multiple tens of milliseconds [TR-126]. The RTP Flows 152 Synchronization Offset block can be used to report such 153 synchronization offset between video stream and audio stream. This 154 block is also applied to the case where an RTP session can contain 155 media streams with media from multiple media types. The metrics 156 defined in the RTP flows synchronization Offset block can be used by 157 network manager for trouble shooting and dealing with user experience 158 issues. 160 2. Terminology 162 2.1. Standards Language 164 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 165 "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this 166 document are to be interpreted as described in RFC 2119 [RFC2119]. 168 In addition, the following terms are defined: 170 Initial Synchronization Delay: 172 A multimedia session comprises a set of concurrent RTP sessions 173 among a common group of participants, using one RTP session for 174 each media type. The initial synchronization Delay is the average 175 time for receiver to synchronize all components of a multimedia 176 session [RFC6051]. 178 Synchronization Offset: 180 Synchronization between two media streams must be maintained to 181 ensure satisfactory QoE. Two media streams can be of the same or 182 different media type belonging to one RTP session or in different 183 media types belonging to one multimedia session. The 184 Synchronization Offset is the relative time difference of the two 185 media streams that need to be synchronized. 187 3. RTP Flows Initial Synchronization Delay Report Block 189 This block is sent by RTP receivers and reports Initial 190 synchronization delay beyond the information carried in the standard 191 RTCP packet format. Information is recorded about time difference 192 between the start of multimedia session and the time when the RTP 193 receiver acquires all components of RTP sessions [RFC6051] measured 194 at the receiving end of RTP stream. 196 Instances of this Block refer by Synchronization source (SSRC) to the 197 separate auxiliary Measurement Information block [RFC6776] which 198 describes measurement periods in use (see [RFC6776] section 4.2). 199 This metrics block relies on the measurement period in the 200 Measurement Information block indicating the span of the report and 201 SHOULD be sent in the same compound RTCP packet as the measurement 202 information block. If the measurement period is not received in the 203 same compound RTCP packet as this Block, this Block MUST be 204 discarded. 206 3.1. Metric Block Structure 208 The RTP Flows Initial Synchronization Delay Report Block has the 209 following format: 211 0 1 2 3 212 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 213 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 214 | BT=RFISD | I | Reserved | Block length=2 | 215 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 216 | SSRC of Source | 217 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 218 | Initial Synchronization Delay | 219 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 221 3.2. Definition of Fields in RTP Flow Initial Synchronization Delay 222 Metrics Block 224 Block type (BT): 8 bits 226 The RTP Flows Initial Synchronization Delay Report Block is 227 identified by the constant . 229 Interval Metric Flag (I): 2 bits 231 This field is used to indicate whether the Burst/Gap Discard 232 Summary Statistics metrics are Sampled, Interval or Cumulative 233 metrics: 235 I=10: Interval Duration - the reported value applies to the 236 most recent measurement interval duration between successive 237 metrics reports. 238 I=11: Cumulative Duration - the reported value applies to the 239 accumulation period characteristic of cumulative measurements. 240 I=01: Sampled Value - the reported value is a sampled 241 instantaneous value. 243 In this document, the value I=00 is the reserved value and MUST 244 NOT be used. 246 Reserved: 6 bits 248 This field is reserved for future definition. In the absence of 249 such a definition, the bits in this field MUST be set to zero and 250 MUST be ignored by the receiver. 252 Block length: 16 bits 254 The constant 2, in accordance with the definition of this field in 255 Section 3 of RFC 3611 [RFC3611]. 257 SSRC of source: 32 bits 259 The SSRC of the media source SHALL be set to the value of the SSRC 260 identifier carried in any arbitrary component of RTP sessions 261 belonging to the same multimedia session. 263 Initial Synchronization Delay: 32 bits 265 The average delay, expressed in units of 1/65536 seconds, from the 266 beginning of multimedia session [RFC6051] to the time when RTCP 267 packets are received on all of the components RTP sessions. It is 268 recommended that the beginning of multimedia session is chosen as 269 the time when the receiver has joined the first RTP session of the 270 multimedia session. The value of the initial synchronization 271 delay is calculated based on received RTCP SR packets or the RTP 272 header extension containing in-band mapping of RTP and NTP-format 273 timestamps [RFC6051]. If there is no packet loss, the initial 274 synchronization delay is expected to be equal to the average time 275 taken to receive the first RTCP packet in the RTP session with the 276 longest RTCP reporting interval or the average time taken to 277 receive the first RTP header extension containing in-band mapping 278 of RTP and NTP- format timestamps. 280 If the measurement is unavailable, the value of this field with 281 all bits set to 1 MUST be reported. 283 4. RTP Flows Synchronization Offset Metrics Block 285 In the RTP multimedia sessions or one RTP session, there can be an 286 arbitrary number of Media streams and each media stream (e.g., audio 287 stream or video stream) is sent in a separate RTP stream. In case of 288 one RTP session, each media stream or each medium uses different 289 SSRC. The receiver associates RTP streams to be synchronized by 290 means of RTCP CNAME contained in the RTCP Source Description (SDES) 291 packets [RFC3550]. 293 This block is sent by RTP receivers and reports synchronization 294 offset of two arbitrary RTP streams that needs to be synchronized in 295 the RTP multimedia session. Information is recorded about the 296 relative average time difference between two arbitrary RTP streams 297 with the same CNAME and measured at the receiving end of RTP stream. 299 Instances of this Block refer by Synchronization source (SSRC) to the 300 separate auxiliary Measurement Information block [RFC6776] which 301 describes measurement periods in use (see [RFC6776] section 4.2). 302 This metrics block relies on the measurement period in the 303 Measurement Information block indicating the span of the report and 304 SHOULD be sent in the same compound RTCP packet as the measurement 305 information block. If the measurement period is not received in the 306 same compound RTCP packet as this Block, this Block MUST be 307 discarded. 309 4.1. Metric Block Structure 311 The RTP Flow General Synchronization Offset Report Block has the 312 following format: 314 0 1 2 3 315 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 316 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 317 | BT=RFSO | I | Reserved | Block length=4 | 318 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 319 | SSRC of source | 320 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 321 | Synchronization Offset, most significant word | 322 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 323 | Synchronization Offset, least significant word | 324 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 326 4.2. Definition of Fields in RTP Flow General Synchronization Offset 327 Metrics Block 329 Block type (BT): 8 bits 331 The RTP Flow General Synchronization Offset Report Block is 332 identified by the constant . 334 Interval Metric Flag (I): 2 bits 336 This field is used to indicate whether the Burst/Gap Discard 337 Summary Statistics metrics are Sampled, Interval or Cumulative 338 metrics: 340 I=10: Interval Duration - the reported value applies to the 341 most recent measurement interval duration between successive 342 metrics reports. 343 I=11: Cumulative Duration - the reported value applies to the 344 accumulation period characteristic of cumulative measurements. 345 I=01: Sampled Value - the reported value is a sampled 346 instantaneous value. 348 In this document, the value I=00 is the reserved value and MUST 349 NOT be used. 351 Reserved: 6 bits 353 This field is reserved for future definition. In the absence of 354 such a definition, the bits in this field MUST be set to zero and 355 MUST be ignored by the receiver. 357 Block length: 16 bits 359 The constant 3, in accordance with the definition of this field in 360 Section 3 of RFC 3611 [RFC3611]. 362 SSRC of Source: 32 bits 364 The SSRC of the media source SHALL be set to the value of the SSRC 365 identifier of the reporting RTP stream to which the XR relates. 367 Synchronization Offset: 64 bits 369 The synchronization offset of two arbitrary RTP streams with the 370 common CNAME. The calculation of Synchronization Offset is 371 similar to Difference D calculation in the RFC3550. That is to 372 say, if Si is the NTP timestamp from the reporting RTP packet i, 373 and Ri is the time of arrival in NTP timestamp units for reporting 374 RTP packet i, Sj is the NTP timestamp from the reference RTP 375 packet j, and Rj is the time of arrival in NTP timestamp units for 376 reference RTP packet j, then the value of the synchronization 377 offset D may be expressed as 379 D(i,j) = (Rj - Ri) - (Sj - Si) = (Rj - Sj) - (Ri - Si) 381 If in-band delivery of NTP-format timestamps is supported 382 [RFC6051], Si and Sj should be obtained directly from the RTP 383 packets where NTP timestamps are available. If not, Si and Sj 384 should be calculated from their corresponding RTP timestamps. The 385 value of the synchronization offset is represented using a 64-bit 386 unsigned NTP-format timestamp as defined in [RFC5905], which is 387 64-bit unsigned fixed-point number with the integer part in the 388 first 32 bits and the fractional part in the last 32 bits. 390 If the measurement is unavailable, the value of this field with 391 all bits set to 1 MUST be reported. 393 5. SDP Signaling 395 [RFC3611] defines the use of SDP (Session Description Protocol) 396 [RFC4566] for signaling the use of XR blocks. XR blocks MAY be used 397 without prior signaling. 399 5.1. SDP rtcp-xr-attrib Attribute Extension 401 Two new parameters are defined for the two report blocks defined in 402 this document to be used with Session Description Protocol (SDP) 403 [RFC4566] using the Augmented Backus-Naur Form (ABNF) [RFC5234]. 405 They have the following syntax within the "rtcp-xr" attribute 406 [RFC3611]: 408 xr-format = xr-rfisd-block 409 / xr-rfso-block 411 xr-rfisd-block = " init-syn-delay" 412 xr-rfso-block = " syn-offset" 414 Refer to Section 5.1 of RFC 3611 [RFC3611] for a detailed description 415 and the full syntax of the "rtcp-xr" attribute. 417 5.2. Offer/Answer Usage 419 When SDP is used in offer-answer context, the SDP Offer/Answer usage 420 defined in [RFC3611] applies. 422 6. IANA Considerations 424 New report block types for RTCP XR are subject to IANA registration. 425 For general guidelines on IANA allocations for RTCP XR, refer to 426 Section 6.2 of [RFC3611]. 428 This document assigns two new block type values in the RTCP XR Block 429 Type Registry: 431 Name: RFISD 432 Long Name: RTP Flows Initial Synchronization Delay 433 Value 434 Reference: Section 3 436 Name: RFSO 437 Long Name: RTP Flows Synchronization Offset Metrics Block 438 Value 439 Reference: Section 4 441 This document also registers two new SDP [RFC4566] parameters for the 442 "rtcp-xr" attribute in the RTCP XR SDP Parameters Registry: 444 * "xr-rfisd " 445 * "xr-rfso" 447 The contact information for the registrations is: 449 Qin Wu 450 sunseawq@huawei.com 451 101 Software Avenue, Yuhua District 452 Nanjing, Jiangsu 210012, China 454 7. Security Considerations 456 The new RTCP XR report blocks proposed in this document introduces no 457 new security considerations beyond those described in [RFC3611]. 459 8. Acknowledgements 461 The authors would like to thank Bill Ver Steeg, David R Oran, Ali 462 Begen, Colin Perkins, Roni Even, Kevin Gross, Jing Zhao, Fernando 463 Boronat Segui, Mario Montagud Climent, Youqing Yang, Wenxiao Yu and 464 Yinliang Hu,Jonathan Lennox for their valuable comments and 465 suggestions on this document. 467 9. References 469 9.1. Normative References 471 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 472 Requirement Levels", BCP 14, RFC 2119, March 1997. 474 [RFC3550] Schulzrinne, H., Casner, S., Frederick, R., and V. 475 Jacobson, "RTP: A Transport Protocol for Real-Time 476 Applications", STD 64, RFC 3550, July 2003. 478 [RFC3611] Friedman, T., Caceres, R., and A. Clark, "RTP Control 479 Protocol Extended Reports (RTCP XR)", RFC 3611, 480 November 2003. 482 [RFC4566] Handley, M., Jacobson, V., and C. Perkins, "SDP: Session 483 Description Protocol", RFC 4566, July 2006. 485 [RFC5234] Crocker, D. and P. Overell, "Augmented BNF for Syntax 486 Specifications: ABNF", STD 68, RFC 5234, January 2008. 488 [RFC5905] Mills, D., Martin, J., Burbank, J., and W. Kasch, "Network 489 Time Protocol Version 4: Protocol and Algorithms 490 Specification", RFC 5905, June 2010. 492 [RFC6051] Perkins, C. and T. Schierl, "Rapid Synchronisation of RTP 493 Flows", RFC 6051, November 2010. 495 [RFC6190] Wenger, S., Wang, Y., Schierl, T., and A. Eleftheriadis, 496 "RTP Payload Format for Scalable Video Coding", RFC 6190, 497 May 2011. 499 [RFC6776] Wu, Q., "Measurement Identity and information Reporting 500 using SDES item and XR Block", RFC 6776, August 2012. 502 9.2. Informative References 504 [RFC6390] Clark, A. and B. Claise, "Guidelines for Considering New 505 Performance Metric Development", RFC 6390, October 2011. 507 [RFC6792] Wu, Q., "Guidelines for Use of the RTP Monitoring 508 Framework", RFC 6792, November 2012. 510 [TR-126] BBF Forum, "Triple-play Services Quality of Experience 511 (QoE) Requirements", December 2006. 513 [Y.1540] ITU-T, "ITU-T Rec. Y.1540, IP packet transfer and 514 availability performance parameters", November 2007. 516 Appendix A. Metrics represented using RFC6390 Template 518 RFC EDITOR NOTE: please change XXXX in [RFCXXXX] by the new RFC 519 number, when assigned. 521 a. Initial Synchronization Delay Metric 523 * Metric Name: RTP Initial Synchronization Delay 525 * Metric Description: See Section 2.1,Initial Synchronization 526 Delay term [RFCXXXX]. 528 * Method of Measurement or Calculation: See section 3.2, Initial 529 Synchronization Delay definition [RFCXXXX]. 531 * Units of Measurement: See section 3.2, Initial Synchronization 532 Delay definition [RFCXXXX]. 534 * Measurement Point(s) with Potential Measurement Domain: See 535 section 3, 1st paragraph [RFCXXXX]. 537 * Measurement Timing: See section 3, 2nd paragraph [RFCXXXX] for 538 measurement timing and section 3.2 [RFCXXXX] for Interval 539 Metric flag. 541 * Use and applications: See section 1.4 [RFCXXXX]. 543 * Reporting model: See RFC3611. 545 b. Synchronization Offset Metric 547 * Metric Name: RTP Synchronization Offset Delay 549 * Metric Description: See Section 2.1, Synchronization Offset 550 term [RFCXXXX]. 552 * Method of Measurement or Calculation: See section 4.2, Initial 553 Synchronization Delay definition definition [RFCXXXX]. 555 * Units of Measurement: See section 4.2, Initial Synchronization 556 Delay definition definition [RFCXXXX]. 558 * Measurement Point(s) with Potential Measurement Domain: See 559 section 4, 2nd paragraph [RFCXXXX]. 561 * Measurement Timing: See section 4, 3rd paragraph [RFCXXXX] for 562 measurement timing and section 4.2 [RFCXXXX] for Interval 563 Metric flag. 565 * Use and applications: See section 1.4 [RFCXXXX]. 567 * Reporting model: See RFC3611. 569 Appendix B. Change Log 571 Note to the RFC-Editor: please remove this section prior to 572 publication as an RFC. 574 B.1. draft-ietf-xrblock-rtcp-xr-syncronization-03 576 The following are the major changes compared to previous version: 578 Remove the need to signal the reference source in the 579 synchronisation offset metrics RTCP XR report. 580 Apply RFC6390 template to metrics in the appendix. 581 Other editorial changes to get inline with other XRBLOCK drafts. 583 B.2. draft-ietf-xrblock-rtcp-xr-syncronization-02 585 The following are the major changes compared to previous version: 587 Editorial change based on comments raised on the list and in the 588 IETF85 meeting 590 Authors' Addresses 592 Hitoshi Asaeda 593 National Institute of Information and Communications Technology 594 4-2-1 Nukui-Kitamachi 595 Koganei, Tokyo 184-8795 596 Japan 598 Email: asaeda@nict.go.jp 600 Rachel Huang 601 Huawei Technologies Co., Ltd. 602 101 Software Avenue, Yuhua District 603 Nanjing, Jiangsu 210012 604 China 606 Email: Rachel@huawei.com 608 Qin Wu 609 Huawei Technologies Co., Ltd. 610 101 Software Avenue, Yuhua District 611 Nanjing, Jiangsu 210012 612 China 614 Email: sunseawq@huawei.com