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Checking references for intended status: Proposed Standard ---------------------------------------------------------------------------- (See RFCs 3967 and 4897 for information about using normative references to lower-maturity documents in RFCs) No issues found here. Summary: 0 errors (**), 0 flaws (~~), 1 warning (==), 1 comment (--). Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 Network Working Group G. Mirsky 3 Internet-Draft X. Min 4 Updates: 8762 (if approved) ZTE Corp. 5 Intended status: Standards Track H. Nydell 6 Expires: December 24, 2020 Accedian Networks 7 R. Foote 8 Nokia 9 A. Masputra 10 Apple Inc. 11 E. Ruffini 12 OutSys 13 June 22, 2020 15 Simple Two-way Active Measurement Protocol Optional Extensions 16 draft-ietf-ippm-stamp-option-tlv-06 18 Abstract 20 This document describes optional extensions to Simple Two-way Active 21 Measurement Protocol (STAMP) which enable measurement performance 22 metrics in addition to ones supported by the STAMP base 23 specification. The document also defines a STAMP Test Session 24 Identifier and thus updates RFC 8762. 26 Status of This Memo 28 This Internet-Draft is submitted in full conformance with the 29 provisions of BCP 78 and BCP 79. 31 Internet-Drafts are working documents of the Internet Engineering 32 Task Force (IETF). Note that other groups may also distribute 33 working documents as Internet-Drafts. The list of current Internet- 34 Drafts is at https://datatracker.ietf.org/drafts/current/. 36 Internet-Drafts are draft documents valid for a maximum of six months 37 and may be updated, replaced, or obsoleted by other documents at any 38 time. It is inappropriate to use Internet-Drafts as reference 39 material or to cite them other than as "work in progress." 41 This Internet-Draft will expire on December 24, 2020. 43 Copyright Notice 45 Copyright (c) 2020 IETF Trust and the persons identified as the 46 document authors. All rights reserved. 48 This document is subject to BCP 78 and the IETF Trust's Legal 49 Provisions Relating to IETF Documents 50 (https://trustee.ietf.org/license-info) in effect on the date of 51 publication of this document. Please review these documents 52 carefully, as they describe your rights and restrictions with respect 53 to this document. Code Components extracted from this document must 54 include Simplified BSD License text as described in Section 4.e of 55 the Trust Legal Provisions and are provided without warranty as 56 described in the Simplified BSD License. 58 Table of Contents 60 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 61 2. Conventions Used in This Document . . . . . . . . . . . . . . 3 62 2.1. Acronyms . . . . . . . . . . . . . . . . . . . . . . . . 3 63 2.2. Requirements Language . . . . . . . . . . . . . . . . . . 3 64 3. STAMP Test Session Identifier . . . . . . . . . . . . . . . . 4 65 4. TLV Extensions to STAMP . . . . . . . . . . . . . . . . . . . 8 66 4.1. Extra Padding TLV . . . . . . . . . . . . . . . . . . . . 9 67 4.2. Location TLV . . . . . . . . . . . . . . . . . . . . . . 10 68 4.3. Timestamp Information TLV . . . . . . . . . . . . . . . . 11 69 4.4. Class of Service TLV . . . . . . . . . . . . . . . . . . 12 70 4.5. Direct Measurement TLV . . . . . . . . . . . . . . . . . 14 71 4.6. Access Report TLV . . . . . . . . . . . . . . . . . . . . 15 72 4.7. Follow-up Telemetry TLV . . . . . . . . . . . . . . . . . 16 73 4.8. HMAC TLV . . . . . . . . . . . . . . . . . . . . . . . . 18 74 5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 19 75 5.1. STAMP TLV Registry . . . . . . . . . . . . . . . . . . . 19 76 5.2. Synchronization Source Sub-registry . . . . . . . . . . . 20 77 5.3. Timestamping Method Sub-registry . . . . . . . . . . . . 20 78 5.4. Return Code Sub-registry . . . . . . . . . . . . . . . . 21 79 6. Security Considerations . . . . . . . . . . . . . . . . . . . 22 80 7. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 22 81 8. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 22 82 9. References . . . . . . . . . . . . . . . . . . . . . . . . . 22 83 9.1. Normative References . . . . . . . . . . . . . . . . . . 22 84 9.2. Informative References . . . . . . . . . . . . . . . . . 23 85 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 24 87 1. Introduction 89 Simple Two-way Active Measurement Protocol (STAMP) [RFC8762] supports 90 the use of optional extensions that use Type-Length-Value (TLV) 91 encoding. Such extensions enhance the STAMP base functions, such as 92 measurement of one-way and round-trip delay, latency, packet loss, 93 and the ability to detect packet duplication and out-of- order 94 delivery of the test packets. This specification defines optional 95 STAMP extensions, their formats, and the theory of operation. Also, 96 a STAMP Test Session Identifier is defined as an update of the base 97 STAMP specification [RFC8762]. 99 2. Conventions Used in This Document 101 2.1. Acronyms 103 STAMP Simple Two-way Active Measurement Protocol 105 DSCP Differentiated Services Code Point 107 ECN Explicit Congestion Notification 109 NTP Network Time Protocol 111 PTP Precision Time Protocol 113 HMAC Hashed Message Authentication Code 115 TLV Type-Length-Value 117 BITS Building Integrated Timing Supply 119 SSU Synchronization Supply Unit 121 GPS Global Positioning System 123 GLONASS Global Orbiting Navigation Satellite System 125 LORAN-C Long Range Navigation System Version C 127 MBZ Must Be Zero 129 CoS Class of Service 131 PMF Performance Measurement Function 133 SSID STAMP Session Identifier 135 2.2. Requirements Language 137 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 138 "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and 139 "OPTIONAL" in this document are to be interpreted as described in BCP 140 14 [RFC2119] [RFC8174] when, and only when, they appear in all 141 capitals, as shown here. 143 3. STAMP Test Session Identifier 145 STAMP Session-Sender transmits test packets to STAMP Session- 146 Reflector. STAMP Session-Reflector receives Session-Sender's packet 147 and acts according to the configuration and optional control 148 information communicated in the Session-Sender's test packet. STAMP 149 defines two different test packet formats, one for packets 150 transmitted by the STAMP-Session-Sender and one for packets 151 transmitted by the STAMP-Session-Reflector. STAMP supports two 152 modes: unauthenticated and authenticated. Unauthenticated STAMP test 153 packets are compatible on the wire with unauthenticated TWAMP-Test 154 [RFC5357] packet formats. 156 By default, STAMP uses symmetrical packets, i.e., the size of the 157 packet transmitted by Session-Reflector equals the size of the packet 158 received by the Session-Reflector. 160 A STAMP Session is identified using 4-tuple (source and destination 161 IP addresses, source and destination UDP port numbers). A STAMP 162 Session-Sender MAY generate a locally unique STAMP Session Identifier 163 (SSID). SSID is two octets long non-zero unsigned integer. A 164 Session-Sender MAY use SSID to identify a STAMP test session. If 165 SSID is used, it MUST be present in each test packet of the given 166 test session. In the unauthenticated mode, SSID is located, as 167 displayed in Figure 1. 169 0 1 2 3 170 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 1 171 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 172 | Sequence Number | 173 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 174 | Timestamp | 175 | | 176 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 177 | Error Estimate | SSID | 178 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 179 | | 180 | | 181 | MBZ (28 octets) | 182 | | 183 | | 184 | | 185 | | 186 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 187 | Type | Length | 188 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 189 ~ Value ~ 190 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 192 Figure 1: An example of an extended STAMP Session-Sender test packet 193 format in unauthenticated mode 195 An implementation of STAMP Session-Reflector that supports this 196 specification SHOULD identify a STAMP Session using the SSID in 197 combination with elements of the usual 4-tuple for the session. 198 Before a test session commences, a Session-Reflector MUST be 199 provisioned with all the elements that identify the STAMP Session. A 200 STAMP Session-Reflector MUST discard the non-matching STAMP test 201 packet(s). The means of provisioning the STAMP Session 202 identification is outside the scope of this specification. A 203 conforming implementation of STAMP Session-Reflector MUST copy the 204 SSID value from the received test packet and put it into the 205 reflected packet, as displayed in Figure 2. 207 0 1 2 3 208 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 1 209 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 210 | Sequence Number | 211 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 212 | Timestamp | 213 | | 214 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 215 | Error Estimate | SSID | 216 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 217 | Receive Timestamp | 218 | | 219 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 220 | Session-Sender Sequence Number | 221 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 222 | Session-Sender Timestamp | 223 | | 224 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 225 | Session-Sender Error Estimate | MBZ | 226 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 227 |Ses-Sender TTL | MBZ | 228 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 229 | Type | Length | 230 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 231 ~ Value ~ 232 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 234 Figure 2: An example of an extended STAMP Session-Reflector test 235 packet format in unauthenticated mode 237 A STAMP Session-Reflector that does not support this specification, 238 will return the zeroed SSID field in the reflected STAMP test packet. 239 The Session-Sender MAY stop the session if it receives a zeroed SSID 240 field. An implementation of a Session-Sender MUST support control of 241 its behavior in such a scenario. If the test session is not stopped, 242 the Session-Sender, can, for example, send a base STAMP packet 243 [RFC8762]. 245 In the authenticated mode, location of SSID field is shown in 246 Figure 3 and Figure 4. 248 0 1 2 3 249 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 1 250 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 251 | Sequence Number | 252 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 253 | | 254 | MBZ (12 octets) | 255 | | 256 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 257 | Timestamp | 258 | | 259 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 260 | Error Estimate | SSID | 261 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 262 ~ ~ 263 | MBZ (68 octets) | 264 ~ ~ 265 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 266 | | 267 | HMAC (16 octets) | 268 | | 269 | | 270 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 272 Figure 3: Base STAMP Session-Sender test packet format in 273 authenticated mode 275 0 1 2 3 276 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 1 277 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 278 | Sequence Number | 279 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 280 | MBZ (12 octets) | 281 | | 282 | | 283 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 284 | Timestamp | 285 | | 286 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 287 | Error Estimate | SSID | 288 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 289 | MBZ (4 octets) | 290 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 291 | Receive Timestamp | 292 | | 293 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 294 | MBZ (8 octets) | 295 | | 296 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 297 | Session-Sender Sequence Number | 298 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 299 | MBZ (12 octets) | 300 | | 301 | | 302 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 303 | Session-Sender Timestamp | 304 | | 305 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 306 | Session-Sender Error Estimate | | 307 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + 308 | MBZ (6 octets) | 309 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 310 |Ses-Sender TTL | | 311 +-+-+-+-+-+-+-+-+ + 312 | | 313 | MBZ (15 octets) | 314 | | 315 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 316 | HMAC (16 octets) | 317 | | 318 | | 319 | | 320 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 322 Figure 4: Base STAMP Session-Reflector test packet format in 323 authenticated mode 325 4. TLV Extensions to STAMP 327 Type-Length-Value (TLV) encoding scheme provides a flexible extension 328 mechanism for optional informational elements. TLV is an optional 329 field in the STAMP test packet. Multiple TLVs MAY be placed in the 330 STAMP test packet. A TLV MAY be enclosed in a TLV. TLVs have the 331 two octets long Type field, two octets long Length field that is 332 equal to the length of the Value field in octets. If a Type value 333 for TLV or sub-TLV is in the range for Vendor Private Use, the Length 334 MUST be at least 4, and the first four octets MUST be that vendor's 335 the Structure of Management Information (SMI) Private Enterprise 336 Codes, as recorded in IANA's SMI Private Enterprise Codes sub- 337 registry, in network octet order. The rest of the Value field is 338 private to the vendor. The following sections describe the use of 339 TLVs for STAMP that extend STAMP capability beyond its base 340 specification. 342 A STAMP node, whether Session-Sender or Session-Reflector, receiving 343 a test packet MUST determine whether the packet is a base STAMP 344 packet or includes one or more TLVs. The node MUST compare the value 345 in the Length field of the UDP header and the length of the base 346 STAMP test packet in the mode, unauthenticated or authenticated based 347 on the configuration of the particular STAMP test session. If the 348 difference between the two values is larger than the length of UDP 349 header, then the test packet includes one or more STAMP TLVs that 350 immediately follow the base STAMP test packet. 352 A system that has received a STAMP test packet with extension TLVs 353 MUST validate each TLV: 355 if an implementation does not recognize the value in the Type 356 field it MUST include the Extra Padding TLV into the reflected 357 STAMP packet. The Length field MUST be set equal to the value of 358 the Length field of that TLV. The size of the Value field MUST 359 equal the value of the Length field. Then proceed to process the 360 next TLV if any present; 362 fixed-size TLVs are verified that the Length field value equals 363 the value defined for the particular type. If the values are not 364 equal, the processing of extension TLVs MUST be stopped. Also, if 365 the system is the Session-Reflector, it MUST send the ICMP 366 Parameter Problem message with Code set to 0 and the Pointer 367 referring to the Length field of the TLV. 369 Detected error events MUST be logged. Note that transmission of ICMP 370 Error messages and logging SHOULD be throttled. 372 4.1. Extra Padding TLV 374 0 1 2 3 375 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 1 376 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 377 | Extra Padding Type | Length | 378 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 379 | | 380 ~ Extra Padding ~ 381 | | 382 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 384 Figure 5: Extra Padding TLV 386 where fields are defined as the following: 388 o Extra Padding Type - TBA1 allocated by IANA Section 5.1 389 o Length - two octets long field equals length on the Extra Padding 390 field in octets. 392 o Extra Padding - a pseudo-random sequence of numbers. The field 393 MAY be filled with all zeros. 395 The Extra Padding TLV is similar to the Packet Padding field in 396 TWAMP-Test packet [RFC5357]. The use of the Extra Padding TLV is 397 RECOMMENDED to perform STAMP test using test packets of larger size 398 than the base STAMP packet [RFC8762]. The length of the base STAMP 399 is 44 octets in the unauthenticated mode or 112 octets in the 400 authenticated mode. The Extra Padding TLV MAY be present more than 401 one time in an extended STAMP test packet. 403 4.2. Location TLV 405 STAMP Session-Sender MAY include the Location TLV to request 406 information from the Session-Reflector. The Session-Sender SHOULD 407 NOT fill any information fields except for Type and Length. The 408 Session-Reflector MUST validate the Length value against the address 409 family of the transport encapsulating the STAMP test packet. If the 410 Length field's value is invalid, the Session-Reflector MUST zero all 411 fields and MUST NOT return any information to the Session-Sender. 412 The Session-Reflector MUST ignore all other fields of the received 413 Location TLV. 415 0 1 2 3 416 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 1 417 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 418 | Location Type | Length | 419 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 420 | Source MAC | 421 + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 422 | | Reserved | 423 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 424 ~ Destination IP Address ~ 425 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 426 ~ Source IP Address ~ 427 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 428 | Destination Port | Source Port | 429 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 431 Figure 6: Session-Reflector Location TLV 433 where fields are defined as the following: 435 o Location Type - TBA2 allocated by IANA Section 5.1 436 o Length - two octets long field equals the length of the Value 437 field in octets. The Length field value MUST equal 20 octets for 438 the IPv4 address family. For the IPv6 address family, the value 439 of the Length field MUST equal 44 octets. All other values are 440 invalid. 442 o Source MAC - 6 octets 48 bits long field. The Session-Reflector 443 MUST copy Source MAC of received STAMP packet into this field. 445 o Reserved - two octets long field. MUST be zeroed on transmission 446 and ignored on reception. 448 o Destination IP Address - IPv4 or IPv6 destination address of the 449 packet received by the STAMP Session-Reflector. 451 o Source IP Address - IPv4 or IPv6 source address of the packet 452 received by the STAMP Session-Reflector. 454 o Destination Port - two octets long UDP destination port number of 455 the received STAMP packet. 457 o Source Port - two octets long UDP source port number of the 458 received STAMP packet. 460 The Location TLV MAY be used to determine the last-hop IP addresses, 461 ports, and last-hop MAC address for STAMP packets. The MAC address 462 can indicate a path switch on the last hop The IP addresses and UDP 463 port will indicate if there is a NAT router on the path, and allows 464 the Session-Sender to identify the IP address of the Session- 465 Reflector behind the NAT, detect changes in the NAT mapping that 466 could cause sending the STAMP packets to the wrong Session-Reflector. 468 4.3. Timestamp Information TLV 470 STAMP Session-Sender MAY include the Timestamp Information TLV to 471 request information from the Session-Reflector. The Session-Sender 472 SHOULD NOT fill any information fields except for Type and Length. 473 The Session-Reflector MUST validate the Length value of the STAMP 474 test packet. If the value of the Length field is invalid, the 475 Session-Reflector MUST zero all fields and MUST NOT return any 476 information to the Session-Sender. 478 0 1 2 3 479 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 1 480 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 481 | Timestamp Information Type | Length | 482 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 483 | Sync. Src In | Timestamp In | Sync. Src Out | Timestamp Out | 484 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 486 Figure 7: Timestamp Information TLV 488 where fields are defined as the following: 490 o Timestamp Information Type - TBA3 allocated by IANA Section 5.1 492 o Length - two octets long field, set equal to the value 4. 494 o Sync Src In - one octet long field that characterizes the source 495 of clock synchronization at the ingress of Session-Reflector. 496 There are several methods to synchronize the clock, e.g., Network 497 Time Protocol (NTP) [RFC5905]. The value is one of those listed 498 in Table 4. 500 o Timestamp In - one octet long field that characterizes the method 501 by which the ingress of Session-Reflector obtained the timestamp 502 T2. A timestamp may be obtained with hardware assistance, via 503 software API from a local wall clock, or from a remote clock (the 504 latter is referred to as "control plane"). The value is one of 505 those listed in Table 6. 507 o Sync Src Out - one octet long field that characterizes the source 508 of clock synchronization at the egress of Session-Reflector. The 509 value is one of those listed in Table 4. 511 o Timestamp Out - one octet long field that characterizes the method 512 by which the egress of Session-Reflector obtained the timestamp 513 T3. The value is one of those listed in Table 6. 515 4.4. Class of Service TLV 517 The STAMP Session-Sender MAY include Class of Service (CoS) TLV in 518 the STAMP test packet. The format of the CoS TLV is presented in 519 Figure 8. 521 0 1 2 3 522 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 1 523 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 524 | Class of Service Type | Length | 525 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 526 | DSCP1 | DSCP2 |ECN| Reserved | 527 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 529 Figure 8: Class of Service TLV 531 where fields are defined as the following: 533 o Class of Service Type - TBA4 allocated by IANA Section 5.1 535 o Length - two octets long field, set equal to the value 4. 537 o DSCP1 - The Differentiated Services Code Point (DSCP) intended by 538 the Session-Sender to be used as the DSCP value of the reflected 539 by the Session-Reflector test packet. 541 o DSCP2 - The received value in the DSCP field at the Session- 542 Reflector in the forward direction. 544 o ECN - The received value in the ECN field at the Session-Reflector 545 in the forward direction. 547 o Reserved - 18 bits long field, must be zeroed in transmission and 548 ignored on receipt. 550 A STAMP Session-Reflector that received the test packet with the CoS 551 TLV MUST include the CoS TLV in the reflected test packet. Also, the 552 Session-Reflector MUST copy the value of the DSCP and ECN fields of 553 the IP header of the received STAMP test packet into the DSCP2 field 554 in the reflected test packet. Finally, the Session-Reflector MUST 555 set the DSCP field's value in the IP header of the reflected test 556 packet equal to the value of the DSCP1 field of the received test 557 packet. Upon receiving the reflected packet, the Session-Sender will 558 save the DSCP and ECN values for analysis of the CoS in the reverse 559 direction. 561 Re-mapping of CoS can be used to provide multiple services (e,g., 2G, 562 3G, LTE in mobile backhaul networks) over the same network. But if 563 it is misconfigured, then it is often difficult to diagnose the root 564 cause of excessive packet drops of higher-level service while packet 565 drops for lower service packets are at a normal level. Using CoS TLV 566 in STAMP testing helps to troubleshoot the existing problem and also 567 verify whether DiffServ policies are processing CoS as required by 568 the configuration. 570 4.5. Direct Measurement TLV 572 The Direct Measurement TLV enables collection of "in profile" packets 573 that had been transmitted and received by the Session-Sender and 574 Session-Reflector respectfully. The definition of "in-profile 575 packet" is outside the scope of this document and is left to the test 576 operators to determine. 578 0 1 2 3 579 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 1 580 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 581 | Direct Measurement Type | Length | 582 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 583 | Session-Sender Tx counter (S_TxC) | 584 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 585 | Session-Reflector Rx counter (R_RxC) | 586 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 587 | Session-Reflector Tx counter (R_TxC) | 588 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 590 Figure 9: Direct Measurement TLV 592 where fields are defined as the following: 594 o Direct Measurement Type - TBA5 allocated by IANA Section 5.1 596 o Length - two octets long field equals length on the Value field in 597 octets. Length field value MUST equal 12 octets. 599 o Session-Sender Tx counter (S_TxC) is four octets long field. 601 o Session-Reflector Rx counter (R_RxC) is four octets long field. 602 MUST be zeroed by the Session-Sender and filled by the Session- 603 Reflector. 605 o Session-Reflector Tx counter (R_TxC) is four octets long field. 606 MUST be zeroed by the Session-Sender and filled by the Session- 607 Reflector. 609 A Session-Sender MAY include the Direct Measurement TLV in a STAMP 610 test packet. The Session-Sender MUST zero R_RxC and R_TxC fields 611 before the transmission of the STAMP test packet. If the received 612 STAMP test packet includes the Direct Measurement TLV, the Session- 613 Reflector MUST include it in the reflected test packet. The Session- 614 Reflector MUST copy the value from the S_TxC field of the received 615 test packet into the same field of the reflected packet before its 616 transmission. 618 4.6. Access Report TLV 620 A STAMP Session-Sender MAY include Access Report TLV (Figure 10) to 621 indicate changes to the access network status to the Session- 622 Reflector. The definition of an access network is outside the scope 623 of this document. 625 0 1 2 3 626 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 1 627 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 628 | Access Report Type | Length | 629 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 630 | ID | Resv | Return Code | Reserved | 631 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 633 Figure 10: Access Report TLV 635 where fields are defined as follows: 637 o Access Report Type - TBA6 allocated by IANA Section 5.1. 639 o Length - two octets long field, set equal to the value 4. 641 o ID (Access ID) - four bits long field that identifies the access 642 network, e.g., 3GPP (Radio Access Technologies specified by 3GPP) 643 or Non-3GPP (accesses that are not specified by 3GPP) [TS23501]. 644 The value is one of those listed below: 646 * 1 - 3GPP Network 648 * 2 - Non-3GPP Network 650 All other values are invalid and the TLV that contains it MUST be 651 discarded. 653 o Resv - four bits long field, must be zeroed on transmission and 654 ignored on receipt. 656 o Return Code - one octet long field that identifies the report 657 signal, e.g., available, unavailable. The value is passed, 658 supplied to the STAMP end-point through some mechanism that is 659 outside the scope of this document. The value is one of those 660 listed in Section 5.4. 662 o Reserved - two octets long field, must be zeroed on transmission 663 and ignored on receipt. 665 The STAMP Session-Sender that includes the Access Report TLV sets the 666 value of the Access ID field according to the type of access network 667 it reports on. Also, the Session-Sender sets the value of the Return 668 Code field to reflect the operational state of the access network. 669 The mechanism to determine the state of the access network is outside 670 the scope of this specification. A STAMP Session-Reflector that 671 received the test packet with the Access Report TLV MUST include the 672 Access Report TLV in the reflected test packet. The Session- 673 Reflector MUST set the value of the Access ID and Return Code fields 674 equal to the values of the corresponding fields from the test packet 675 it has received. 677 The Session-Sender MUST also arm a retransmission timer after sending 678 a test packet that includes the Access Report TLV. This timer MUST 679 be disarmed upon the reception of the reflected STAMP test packet 680 that includes Access Report TLV. In the event the timer expires 681 before such a packet is received, the Session-Sender MUST retransmit 682 the STAMP test packet that contains the Access Report TLV. This 683 retransmission SHOULD be repeated up to four times before the 684 procedure is aborted. Setting the value for the retransmission timer 685 is based on local policies, network environment. The default value 686 of the retransmission timer for Access Report TLV SHOULD be three 687 seconds. An implementation MUST provide control of the 688 retransmission timer value and the number of retransmissions. 690 The Access Report TLV is used by the Performance Measurement Function 691 (PMF) components of the Access Steering, Switching and Splitting 692 feature for 5G networks [TS23501]. The PMF component in the User 693 Equipment acts as the STAMP Session-Sender, and the PMF component in 694 the User Plane Function acts as the STAMP Session-Reflector. 696 4.7. Follow-up Telemetry TLV 698 A Session-Reflector might be able to put in the Timestamp field only 699 an "SW Local" (see Table 6) timestamp. But the hosting system might 700 provide the timestamp closer to the start of the actual packet 701 transmission even though when it is not possible to deliver the 702 information to the Session-Sender in the packet itself. This 703 timestamp might nevertheless be important for the Session-Sender, as 704 it improves the accuracy of measuring network delay by minimizing the 705 impact of egress queuing delays on the measurement. 707 A STAMP Session-Sender MAY include the Follow-up Telemetry TLV to 708 request information from the Session-Reflector. The Session-Sender 709 MUST set the Follow-up Telemetry Type and Length fields to their 710 appropriate values. Sequence Number and Timestamp fields MUST be 711 zeroed on transmission by the Session-Sender and ignored by the 712 Session-Reflector upon receipt of the STAMP test packet that includes 713 the Follow-up Telemetry TLV. The Session-Reflector MUST validate the 714 Length value of the STAMP test packet. If the value of the Length 715 field is invalid, the Session-Reflector MUST zero Sequence Number and 716 Timestamp fields. If the Session-Reflector is in stateless mode 717 (defined in Section 4.2 [RFC8762]), it MUST zero Sequence Number and 718 Timestamp fields. 720 0 1 2 3 721 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 1 722 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 723 | Follow-up Telemetry Type | Length | 724 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 725 | Sequence Number | 726 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 727 | Follow-up Timestamp | 728 | | 729 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 730 | Timestamp M | Reserved | 731 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 733 Figure 11: Follow-up Telemetry TLV 735 where fields are defined as follows: 737 o Follow-up Telemetry Type - TBA7 allocated by IANA Section 5.1. 739 o Length - two octets long field, set equal to the value 16 octets. 741 o Sequence Number - four octets long field indicating the sequence 742 number of the last packet reflected in the same STAMP-test 743 session. Since the Session-Reflector runs in the stateful mode 744 (defined in Section 4.2 [RFC8762]), it is the Session-Reflector's 745 Sequence Number of the previous reflected packet. 747 o Follow-up Timestamp - eight octets long field, with the format 748 indicated by the Z flag of the Error Estimate field of the packet 749 transmitted by a Session-Reflector, as described in Section 4.1 750 [RFC8762]. It carries the timestamp when the reflected packet 751 with the specified sequence number was sent. 753 o Timestamp M(ode) - one octet long field that characterizes the 754 method by which the entity that transmits a reflected STAMP packet 755 obtained the Follow-up Timestamp. The value is one of those 756 listed in Table 6. 758 o Reserved - the three octets-long field. Its value MUST be zeroed 759 on transmission and ignored on receipt. 761 4.8. HMAC TLV 763 The STAMP authenticated mode protects the integrity of data collected 764 in the STAMP base packet. STAMP extensions are designed to provide 765 valuable information about the condition of a network, and protecting 766 the integrity of that data is also essential. The keyed Hashed 767 Message Authentication Code (HMAC) TLV MUST be included in a STAMP 768 test packet in the authenticated mode, excluding when the only TLV 769 present is Extra Padding TLV. The HMAC TLV MUST follow all TLVs 770 included in a STAMP test packet, except for the Extra Padding TLV. 771 The HMAC TLV MAY be used to protect the integrity of STAMP extensions 772 in STAMP unauthenticated mode. 774 0 1 2 3 775 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 1 776 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 777 | HMAC Type | Length | 778 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 779 | | 780 | HMAC | 781 | | 782 | | 783 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 785 Figure 12: HMAC TLV 787 where fields are defined as follows: 789 o HMAC Type - is two octets long field, value TBA8 allocated by IANA 790 Section 5.1. 792 o Length - two octets long field, set equal to the value 16 octets. 794 o HMAC - is 16 octets long field that carries HMAC digest of the 795 text of all preceding TLVs. 797 As defined in [RFC8762], STAMP uses HMAC-SHA-256 truncated to 128 798 bits ([RFC4868]). All considerations regarding using the key and key 799 distribution and management listed in Section 4.4 of [RFC8762] are 800 fully applicable to the use of the HMAC TLV. HMAC is calculated as 801 defined in [RFC2104] over text as the concatenation of all preceding 802 TLVs. The digest then MUST be truncated to 128 bits and written into 803 the HMAC field. In the authenticated mode, HMAC MUST be verified 804 before using any data in the included STAMP TLVs. If HMAC 805 verification by the Session-Reflector fails, then an ICMP Parameter 806 Problem message MUST be generated (with consideration of limiting the 807 rate of error messages). The Code value MUST be set to 0 and the 808 Pointer identifying HMAC Type. Also, both Session-Sender and 809 Session-Reflector SHOULD log the notification that HMAC verification 810 of STAMP TLVs failed. The packet that failed HMAC verification MUST 811 be dropped. 813 5. IANA Considerations 815 5.1. STAMP TLV Registry 817 IANA is requested to create the STAMP TLV Type registry. All code 818 points in the range 1 through 32759 in this registry shall be 819 allocated according to the "IETF Review" procedure as specified in 820 [RFC8126]. Code points in the range 32760 through 65279 in this 821 registry shall be allocated according to the "First Come First 822 Served" procedure as specified in [RFC8126]. Remaining code points 823 are allocated according to Table 1: 825 +---------------+---------------------------------+---------------+ 826 | Value | Description | Reference | 827 +---------------+---------------------------------+---------------+ 828 | 0 | Reserved | This document | 829 | 1- 65279 | STAMP extension TLV, unassigned | IETF Review | 830 | 65280 - 65519 | Experimental | This document | 831 | 65520 - 65534 | Private Use | This document | 832 | 65535 | Reserved | This document | 833 +---------------+---------------------------------+---------------+ 835 Table 1: STAMP TLV Type Registry 837 This document defines the following new values in the STAMP Extension 838 TLV range of the STAMP TLV Type registry: 840 +-------+-----------------------+---------------+ 841 | Value | Description | Reference | 842 +-------+-----------------------+---------------+ 843 | TBA1 | Extra Padding | This document | 844 | TBA2 | Location | This document | 845 | TBA3 | Timestamp Information | This document | 846 | TBA4 | Class of Service | This document | 847 | TBA5 | Direct Measurement | This document | 848 | TBA6 | Access Report | This document | 849 | TBA7 | Follow-up Telemetry | This document | 850 | TBA8 | HMAC | This document | 851 +-------+-----------------------+---------------+ 853 Table 2: STAMP Types 855 5.2. Synchronization Source Sub-registry 857 IANA is requested to create Synchronization Source sub-registry as 858 part of the STAMP TLV Type registry. All code points in the range 1 859 through 127 in this registry shall be allocated according to the 860 "IETF Review" procedure as specified in [RFC8126]. Code points in 861 the range 128 through 239 in this registry shall be allocated 862 according to the "First Come First Served" procedure as specified in 863 [RFC8126]. Remaining code points are allocated according to Table 1: 865 +-----------+--------------+-------------------------+ 866 | Value | Description | Reference | 867 +-----------+--------------+-------------------------+ 868 | 0 | Reserved | This document | 869 | 1- 127 | Unassigned | IETF Review | 870 | 128 - 239 | Unassigned | First Come First Served | 871 | 240 - 249 | Experimental | This document | 872 | 250 - 254 | Private Use | This document | 873 | 255 | Reserved | This document | 874 +-----------+--------------+-------------------------+ 876 Table 3: Synchronization Source Sub-registry 878 This document defines the following new values in the Synchronization 879 Source sub-registry: 881 +-------+---------------------+---------------+ 882 | Value | Description | Reference | 883 +-------+---------------------+---------------+ 884 | 1 | NTP | This document | 885 | 2 | PTP | This document | 886 | 3 | SSU/BITS | This document | 887 | 4 | GPS/GLONASS/LORAN-C | This document | 888 | 5 | Local free-running | This document | 889 +-------+---------------------+---------------+ 891 Table 4: Synchronization Sources 893 5.3. Timestamping Method Sub-registry 895 IANA is requested to create Timestamping Method sub-registry as part 896 of the STAMP TLV Type registry. All code points in the range 1 897 through 127 in this registry shall be allocated according to the 898 "IETF Review" procedure as specified in [RFC8126]. Code points in 899 the range 128 through 239 in this registry shall be allocated 900 according to the "First Come First Served" procedure as specified in 901 [RFC8126]. Remaining code points are allocated according to Table 1: 903 +-----------+--------------+-------------------------+ 904 | Value | Description | Reference | 905 +-----------+--------------+-------------------------+ 906 | 0 | Reserved | This document | 907 | 1- 127 | Unassigned | IETF Review | 908 | 128 - 239 | Unassigned | First Come First Served | 909 | 240 - 249 | Experimental | This document | 910 | 250 - 254 | Private Use | This document | 911 | 255 | Reserved | This document | 912 +-----------+--------------+-------------------------+ 914 Table 5: Timestamping Method Sub-registry 916 This document defines the following new values in the Timestamping 917 Methods sub-registry: 919 +-------+---------------+---------------+ 920 | Value | Description | Reference | 921 +-------+---------------+---------------+ 922 | 1 | HW Assist | This document | 923 | 2 | SW local | This document | 924 | 3 | Control plane | This document | 925 +-------+---------------+---------------+ 927 Table 6: Timestamping Methods 929 5.4. Return Code Sub-registry 931 IANA is requested to create Return Code sub-registry as part of STAMP 932 TLV Type registry. All code points in the range 1 through 127 in 933 this registry shall be allocated according to the "IETF Review" 934 procedure as specified in [RFC8126]. Code points in the range 128 935 through 239 in this registry shall be allocated according to the 936 "First Come First Served" procedure as specified in [RFC8126]. 937 Remaining code points are allocated according to Table 7: 939 +-----------+--------------+-------------------------+ 940 | Value | Description | Reference | 941 +-----------+--------------+-------------------------+ 942 | 0 | Reserved | This document | 943 | 1- 127 | Unassigned | IETF Review | 944 | 128 - 239 | Unassigned | First Come First Served | 945 | 240 - 249 | Experimental | This document | 946 | 250 - 254 | Private Use | This document | 947 | 255 | Reserved | This document | 948 +-----------+--------------+-------------------------+ 950 Table 7: Return Code Sub-registry 952 This document defines the following new values in the Return Code 953 sub-registry: 955 +-------+---------------------+---------------+ 956 | Value | Description | Reference | 957 +-------+---------------------+---------------+ 958 | 1 | Network available | This document | 959 | 2 | Network unavailable | This document | 960 +-------+---------------------+---------------+ 962 Table 8: Return Codes 964 6. Security Considerations 966 This document defines extensions to STAMP [RFC8762] and inherits all 967 the security considerations applicable to the base protocol. 968 Additionally, the HMAC TLV is defined in this document to protect the 969 integrity of optional STAMP extensions. The use of HMAC TLV is 970 discussed in detail in Section 4.8. 972 7. Acknowledgments 974 Authors much appreciate the thorough review and thoughtful comments 975 received from Tianran Zhou, Rakesh Gandhi, Yuezhong Song and Yali 976 Wang. Authors express their gratitude to Al Morton for his comments 977 and the most valuable suggestions. Authors greatly appreciate 978 comments and thoughtful suggestions received from Martin Duke. 980 8. Contributors 982 The following people contributed text to this document: 984 Guo Jun 985 ZTE Corporation 986 68# Zijinghua Road 987 Nanjing, Jiangsu 210012 988 P.R.China 990 Phone: +86 18105183663 991 Email: guo.jun2@zte.com.cn 993 9. References 995 9.1. Normative References 997 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 998 Requirement Levels", BCP 14, RFC 2119, 999 DOI 10.17487/RFC2119, March 1997, 1000 . 1002 [RFC5357] Hedayat, K., Krzanowski, R., Morton, A., Yum, K., and J. 1003 Babiarz, "A Two-Way Active Measurement Protocol (TWAMP)", 1004 RFC 5357, DOI 10.17487/RFC5357, October 2008, 1005 . 1007 [RFC8126] Cotton, M., Leiba, B., and T. Narten, "Guidelines for 1008 Writing an IANA Considerations Section in RFCs", BCP 26, 1009 RFC 8126, DOI 10.17487/RFC8126, June 2017, 1010 . 1012 [RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 1013 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, 1014 May 2017, . 1016 [RFC8762] Mirsky, G., Jun, G., Nydell, H., and R. Foote, "Simple 1017 Two-Way Active Measurement Protocol", RFC 8762, 1018 DOI 10.17487/RFC8762, March 2020, 1019 . 1021 9.2. Informative References 1023 [RFC2104] Krawczyk, H., Bellare, M., and R. Canetti, "HMAC: Keyed- 1024 Hashing for Message Authentication", RFC 2104, 1025 DOI 10.17487/RFC2104, February 1997, 1026 . 1028 [RFC4868] Kelly, S. and S. Frankel, "Using HMAC-SHA-256, HMAC-SHA- 1029 384, and HMAC-SHA-512 with IPsec", RFC 4868, 1030 DOI 10.17487/RFC4868, May 2007, 1031 . 1033 [RFC5905] Mills, D., Martin, J., Ed., Burbank, J., and W. Kasch, 1034 "Network Time Protocol Version 4: Protocol and Algorithms 1035 Specification", RFC 5905, DOI 10.17487/RFC5905, June 2010, 1036 . 1038 [TS23501] 3GPP (3rd Generation Partnership Project), "Technical 1039 Specification Group Services and System Aspects; System 1040 Architecture for the 5G System; Stage 2 (Release 16)", 1041 3GPP TS23501, 2019. 1043 Authors' Addresses 1045 Greg Mirsky 1046 ZTE Corp. 1048 Email: gregimirsky@gmail.com 1050 Xiao Min 1051 ZTE Corp. 1053 Email: xiao.min2@zte.com.cn 1055 Henrik Nydell 1056 Accedian Networks 1058 Email: hnydell@accedian.com 1060 Richard Foote 1061 Nokia 1063 Email: footer.foote@nokia.com 1065 Adi Masputra 1066 Apple Inc. 1067 One Apple Park Way 1068 Cupertino, CA 95014 1069 USA 1071 Email: adi@apple.com 1073 Ernesto Ruffini 1074 OutSys 1075 via Caracciolo, 65 1076 Milano 20155 1077 Italy 1079 Email: eruffini@outsys.org