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Miscellaneous warnings: ---------------------------------------------------------------------------- == The copyright year in the IETF Trust and authors Copyright Line does not match the current year -- The document date (21 March 2022) is 766 days in the past. Is this intentional? Checking references for intended status: Proposed Standard ---------------------------------------------------------------------------- (See RFCs 3967 and 4897 for information about using normative references to lower-maturity documents in RFCs) -- Possible downref: Normative reference to a draft: ref. 'H1' -- Possible downref: Normative reference to a draft: ref. 'HTTP' Summary: 0 errors (**), 0 flaws (~~), 2 warnings (==), 3 comments (--). Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 MASQUE D. Schinazi 3 Internet-Draft Google LLC 4 Intended status: Standards Track L. Pardue 5 Expires: 22 September 2022 Cloudflare 6 21 March 2022 8 Using Datagrams with HTTP 9 draft-ietf-masque-h3-datagram-07 11 Abstract 13 The QUIC DATAGRAM extension provides application protocols running 14 over QUIC with a mechanism to send unreliable data while leveraging 15 the security and congestion-control properties of QUIC. However, 16 QUIC DATAGRAM frames do not provide a means to demultiplex 17 application contexts. This document describes how to use QUIC 18 DATAGRAM frames with HTTP/3 by association with HTTP requests. 19 Additionally, this document defines the Capsule Protocol that can 20 convey datagrams over prior versions of HTTP. 22 Discussion Venues 24 This note is to be removed before publishing as an RFC. 26 Discussion of this document takes place on the MASQUE WG mailing list 27 (masque@ietf.org), which is archived at 28 https://mailarchive.ietf.org/arch/browse/masque/. 30 Source for this draft and an issue tracker can be found at 31 https://github.com/ietf-wg-masque/draft-ietf-masque-h3-datagram. 33 Status of This Memo 35 This Internet-Draft is submitted in full conformance with the 36 provisions of BCP 78 and BCP 79. 38 Internet-Drafts are working documents of the Internet Engineering 39 Task Force (IETF). Note that other groups may also distribute 40 working documents as Internet-Drafts. The list of current Internet- 41 Drafts is at https://datatracker.ietf.org/drafts/current/. 43 Internet-Drafts are draft documents valid for a maximum of six months 44 and may be updated, replaced, or obsoleted by other documents at any 45 time. It is inappropriate to use Internet-Drafts as reference 46 material or to cite them other than as "work in progress." 48 This Internet-Draft will expire on 22 September 2022. 50 Copyright Notice 52 Copyright (c) 2022 IETF Trust and the persons identified as the 53 document authors. All rights reserved. 55 This document is subject to BCP 78 and the IETF Trust's Legal 56 Provisions Relating to IETF Documents (https://trustee.ietf.org/ 57 license-info) in effect on the date of publication of this document. 58 Please review these documents carefully, as they describe your rights 59 and restrictions with respect to this document. Code Components 60 extracted from this document must include Revised BSD License text as 61 described in Section 4.e of the Trust Legal Provisions and are 62 provided without warranty as described in the Revised BSD License. 64 Table of Contents 66 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 67 1.1. Conventions and Definitions . . . . . . . . . . . . . . . 3 68 2. Multiplexing . . . . . . . . . . . . . . . . . . . . . . . . 3 69 3. HTTP/3 Datagram Format . . . . . . . . . . . . . . . . . . . 3 70 3.1. The H3_DATAGRAM HTTP/3 SETTINGS Parameter . . . . . . . . 5 71 3.1.1. Note About Draft Versions . . . . . . . . . . . . . . 5 72 4. Capsules . . . . . . . . . . . . . . . . . . . . . . . . . . 6 73 4.1. Capsule Protocol . . . . . . . . . . . . . . . . . . . . 7 74 4.2. Error Handling . . . . . . . . . . . . . . . . . . . . . 8 75 4.3. The Capsule-Protocol Header Field . . . . . . . . . . . . 8 76 4.4. The DATAGRAM Capsule . . . . . . . . . . . . . . . . . . 9 77 5. Prioritization . . . . . . . . . . . . . . . . . . . . . . . 10 78 6. Security Considerations . . . . . . . . . . . . . . . . . . . 10 79 7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 11 80 7.1. HTTP/3 SETTINGS Parameter . . . . . . . . . . . . . . . . 11 81 7.2. HTTP/3 Error Code . . . . . . . . . . . . . . . . . . . . 11 82 7.3. HTTP Header Field Name . . . . . . . . . . . . . . . . . 11 83 7.4. Capsule Types . . . . . . . . . . . . . . . . . . . . . . 12 84 8. References . . . . . . . . . . . . . . . . . . . . . . . . . 12 85 8.1. Normative References . . . . . . . . . . . . . . . . . . 12 86 8.2. Informative References . . . . . . . . . . . . . . . . . 14 87 Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . 14 88 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 14 90 1. Introduction 92 The QUIC DATAGRAM extension [DGRAM] provides application protocols 93 running over QUIC [QUIC] with a mechanism to send unreliable data 94 while leveraging the security and congestion-control properties of 95 QUIC. However, QUIC DATAGRAM frames do not provide a means to 96 demultiplex application contexts. This document describes how to use 97 QUIC DATAGRAM frames with HTTP/3 [H3] by association with HTTP 98 requests. Additionally, this document defines the Capsule Protocol 99 that can convey datagrams over prior versions of HTTP. 101 This document is structured as follows: 103 * Section 2 presents core concepts for multiplexing across HTTP 104 versions. 106 * Section 3 defines how QUIC DATAGRAM frames are used with HTTP/3. 108 - Section 3.1 defines an HTTP/3 setting that endpoints can use to 109 advertise support of the frame. 111 * Section 4 introduces the Capsule Protocol and the "data stream" 112 concept. Data streams are initiated using special-purpose HTTP 113 requests, after which Capsules, an end-to-end message, can be 114 sent. 116 - Section 4.4 defines Datagram Capsule types, along with guidance 117 for specifying new capsule types. 119 1.1. Conventions and Definitions 121 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 122 "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and 123 "OPTIONAL" in this document are to be interpreted as described in 124 BCP 14 [RFC2119] [RFC8174] when, and only when, they appear in all 125 capitals, as shown here. 127 2. Multiplexing 129 All HTTP Datagrams are associated with an HTTP request. 131 When running over HTTP/3, multiple exchanges of datagrams need the 132 ability to coexist on a given QUIC connection. To allow this, the 133 QUIC DATAGRAM frame payload starts with an encoded stream identifier 134 that associates the datagram with a request stream. 136 When running over HTTP/2, demultiplexing is provided by the HTTP/2 137 framing layer. When running over HTTP/1, requests are strictly 138 serialized in the connection, therefore demultiplexing is not needed. 140 3. HTTP/3 Datagram Format 142 When used with HTTP/3, the Datagram Data field of QUIC DATAGRAM 143 frames uses the following format (using the notation from the 144 "Notational Conventions" section of [QUIC]): 146 HTTP/3 Datagram { 147 Quarter Stream ID (i), 148 HTTP Datagram Payload (..), 149 } 151 Figure 1: HTTP/3 DATAGRAM Format 153 Quarter Stream ID: A variable-length integer that contains the value 154 of the client-initiated bidirectional stream that this datagram is 155 associated with, divided by four (the division by four stems from 156 the fact that HTTP requests are sent on client-initiated 157 bidirectional streams, and those have stream IDs that are 158 divisible by four). The largest legal QUIC stream ID value is 159 2^62-1, so the largest legal value of Quarter Stream ID is 2^60-1. 160 Receipt of a frame that includes a larger value MUST be treated as 161 an HTTP/3 connection error of type H3_DATAGRAM_ERROR. 163 HTTP Datagram Payload: The payload of the datagram, whose semantics 164 are defined by individual applications. Note that this field can 165 be empty. 167 Receipt of a QUIC DATAGRAM frame whose payload is too short to allow 168 parsing the Quarter Stream ID field MUST be treated as an HTTP/3 169 connection error of type H3_DATAGRAM_ERROR. 171 Endpoints MUST NOT send HTTP/3 datagrams unless the corresponding 172 stream's send side is open. On a given endpoint, once the receive 173 side of a stream is closed, incoming datagrams for this stream are no 174 longer expected so the endpoint can release related state. Endpoints 175 MAY keep state for a short time to account for reordering. Once the 176 state is released, the endpoint MUST silently drop received 177 associated datagrams. 179 If an HTTP/3 datagram is received and its Quarter Stream ID maps to a 180 stream that has not yet been created, the receiver SHALL either drop 181 that datagram silently or buffer it temporarily (on the order of a 182 round trip) while awaiting the creation of the corresponding stream. 184 If an HTTP/3 datagram is received and its Quarter Stream ID maps to a 185 stream that cannot be created due to client-initiated bidirectional 186 stream limits, it SHOULD be treated as an HTTP/3 connection error of 187 type H3_ID_ERROR. Generating an error is not mandatory in this case 188 because HTTP/3 implementations might have practical barriers to 189 determining the active stream concurrency limit that is applied by 190 the QUIC layer. 192 HTTP/3 datagrams MUST only be sent with an association to a stream 193 that supports semantics for HTTP Datagrams. For example, existing 194 HTTP methods GET and POST do not define semantics for associated HTTP 195 Datagrams; therefore, HTTP/3 datagrams cannot be sent associated with 196 GET or POST request streams. If an endpoint receives an HTTP/3 197 datagram associated with a method that has no known semantics for 198 HTTP Datagrams, it MUST abort the corresponding stream with 199 H3_DATAGRAM_ERROR. Future extensions MAY remove these requirements 200 if they define semantics for such HTTP Datagrams and negotiate mutual 201 support. 203 3.1. The H3_DATAGRAM HTTP/3 SETTINGS Parameter 205 Implementations of HTTP/3 that support HTTP Datagrams can indicate 206 that to their peer by sending the H3_DATAGRAM SETTINGS parameter with 207 a value of 1. The value of the H3_DATAGRAM SETTINGS parameter MUST 208 be either 0 or 1. A value of 0 indicates that HTTP Datagrams are not 209 supported. An endpoint that receives the H3_DATAGRAM SETTINGS 210 parameter with a value that is neither 0 or 1 MUST terminate the 211 connection with error H3_SETTINGS_ERROR. 213 Endpoints MUST NOT send QUIC DATAGRAM frames until they have both 214 sent and received the H3_DATAGRAM SETTINGS parameter with a value of 215 1. 217 When clients use 0-RTT, they MAY store the value of the server's 218 H3_DATAGRAM SETTINGS parameter. Doing so allows the client to send 219 QUIC DATAGRAM frames in 0-RTT packets. When servers decide to accept 220 0-RTT data, they MUST send a H3_DATAGRAM SETTINGS parameter greater 221 than or equal to the value they sent to the client in the connection 222 where they sent them the NewSessionTicket message. If a client 223 stores the value of the H3_DATAGRAM SETTINGS parameter with their 224 0-RTT state, they MUST validate that the new value of the H3_DATAGRAM 225 SETTINGS parameter sent by the server in the handshake is greater 226 than or equal to the stored value; if not, the client MUST terminate 227 the connection with error H3_SETTINGS_ERROR. In all cases, the 228 maximum permitted value of the H3_DATAGRAM SETTINGS parameter is 1. 230 It is RECOMMENDED that implementations that support receiving HTTP 231 Datagrams using QUIC always send the H3_DATAGRAM SETTINGS parameter 232 with a value of 1, even if the application does not intend to use 233 HTTP Datagrams. This helps to avoid "sticking out"; see Section 6. 235 3.1.1. Note About Draft Versions 237 [[RFC editor: please remove this section before publication.]] 238 Some revisions of this draft specification use a different value (the 239 Identifier field of a Setting in the HTTP/3 SETTINGS frame) for the 240 H3_DATAGRAM Settings Parameter. This allows new draft revisions to 241 make incompatible changes. Multiple draft versions MAY be supported 242 by either endpoint in a connection. Such endpoints MUST send 243 multiple values for H3_DATAGRAM. Once an endpoint has sent and 244 received SETTINGS, it MUST compute the intersection of the values it 245 has sent and received, and then it MUST select and use the most 246 recent draft version from the intersection set. This ensures that 247 both endpoints negotiate the same draft version. 249 4. Capsules 251 This specification introduces the Capsule Protocol. The Capsule 252 Protocol is a sequence of type-length-value tuples that new HTTP 253 Upgrade Tokens (see Section 16.7 of [HTTP]) can choose to use. It 254 allows endpoints to reliably communicate request-related information 255 end-to-end on HTTP request streams, even in the presence of HTTP 256 intermediaries. The Capsule Protocol can be used to exchange HTTP 257 Datagrams when HTTP is running over a transport that does not support 258 the QUIC DATAGRAM frame. 260 This specification defines the "data stream" of an HTTP request as 261 the bidirectional stream of bytes that follow the headers in both 262 directions. In HTTP/1.x, the data stream consists of all bytes on 263 the connection that follow the blank line that concludes either the 264 request header section, or the 2xx (Successful) response header 265 section. (Note that only a single HTTP request starting the capsule 266 protocol can be sent on HTTP/1.x connections.) In HTTP/2 and HTTP/3, 267 the data stream of a given HTTP request consists of all bytes sent in 268 DATA frames with the corresponding stream ID. The concept of a data 269 stream is particularly relevant for methods such as CONNECT where 270 there is no HTTP message content after the headers. 272 Note that use of the Capsule Protocol is not required to use HTTP 273 Datagrams. If a new HTTP Upgrade Token is only defined over 274 transports that support QUIC DATAGRAM frames, they might not need a 275 stream encoding. Additionally, definitions of new HTTP Upgrade 276 Tokens can use HTTP Datagrams with their own data stream protocol. 277 However, new HTTP Upgrade Tokens that wish to use HTTP Datagrams 278 SHOULD use the Capsule Protocol unless they have a good reason not 279 to. 281 4.1. Capsule Protocol 283 Definitions of new HTTP Upgrade Tokens can state that their data 284 stream uses the Capsule Protocol. If they do so, that means that the 285 contents of their data stream uses the following format (using the 286 notation from the "Notational Conventions" section of [QUIC]): 288 Capsule Protocol { 289 Capsule (..) ..., 290 } 292 Figure 2: Capsule Protocol Stream Format 294 Capsule { 295 Capsule Type (i), 296 Capsule Length (i), 297 Capsule Value (..), 298 } 300 Figure 3: Capsule Format 302 Capsule Type: A variable-length integer indicating the Type of the 303 capsule. Endpoints that receive a capsule with an unknown Capsule 304 Type MUST silently skip over that capsule. 306 Capsule Length: The length of the Capsule Value field following this 307 field, encoded as a variable-length integer. Note that this field 308 can have a value of zero. 310 Capsule Value: The payload of this capsule. Its semantics are 311 determined by the value of the Capsule Type field. 313 Because new protocols or extensions may involve defining new capsule 314 types, intermediaries that wish to allow for future extensibility 315 SHOULD forward capsules unmodified. One exception to this rule is 316 the DATAGRAM capsule; see Section 4.4. An intermediary can identify 317 the use of the capsule protocol either through the presence of the 318 Capsule-Protocol header field (Section 4.3) or by understanding the 319 chosen HTTP Upgrade token. An intermediary that identifies the use 320 of the capsule protocol MAY convert between DATAGRAM capsules and 321 QUIC DATAGRAM frames when forwarding. Definitions of new Capsule 322 Types MAY specify optional custom intermediary processing. 324 Endpoints which receive a Capsule with an unknown Capsule Type MUST 325 silently drop that Capsule. 327 By virtue of the definition of the data stream, the Capsule Protocol 328 is not in use on responses unless the response includes a 2xx 329 (Successful) status code. 331 The Capsule Protocol MUST NOT be used with messages that contain 332 Content-Length, Content-Type, or Transfer-Encoding header fields. 333 Additionally, HTTP status codes 204 (No Content), 205 (Reset 334 Content), and 206 (Partial Content) MUST NOT be sent on responses 335 that use the Capsule Protocol. 337 4.2. Error Handling 339 When an error occurs processing the capsule protocol, the receiver 340 MUST treat the message as malformed or incomplete, according to the 341 underlying transport protocol. For HTTP/3, the handling of malformed 342 messages is described in Section 4.1.3 of [H3]. For HTTP/2, the 343 handling of malformed messages is described in Section 8.1.1 of [H2]. 344 For HTTP/1.1, the handling of incomplete messages is described in 345 Section 8 of [H1]. 347 Each capsule's payload MUST contain exactly the fields identified in 348 its description. A capsule payload that contains additional bytes 349 after the identified fields or a capsule payload that terminates 350 before the end of the identified fields MUST be treated as a 351 malformed or incomplete message. In particular, redundant length 352 encodings MUST be verified to be self-consistent. 354 When a stream carrying capsules terminates cleanly, if the last 355 capsule on the stream was truncated, this MUST be treated as a 356 malformed or incomplete message. 358 4.3. The Capsule-Protocol Header Field 360 This document defines the "Capsule-Protocol" header field. It is an 361 Item Structured Field, see Section 3.3 of [STRUCT-FIELD]; its value 362 MUST be a Boolean. Its ABNF is: 364 Capsule-Protocol = sf-item 366 Endpoints indicate that the Capsule Protocol is in use on the data 367 stream by sending the Capsule-Protocol header field with a value of 368 ?1. A Capsule-Protocol header field with a value of ?0 has the same 369 semantics as when the header is not present. Intermediaries MAY use 370 this header field to allow processing of HTTP Datagrams for unknown 371 HTTP Upgrade Tokens; note that this is only possible for HTTP Upgrade 372 or Extended CONNECT. 374 The Capsule-Protocol header field MUST NOT be sent multiple times on 375 a message. The Capsule-Protocol header field MUST NOT be used on 376 HTTP responses with a status code different from 2xx (Successful). 377 This specification does not define any parameters for the Capsule- 378 Protocol header field value, but future documents MAY define 379 parameters. Receivers MUST ignore unknown parameters. 381 Definitions of new HTTP Upgrade Tokens that use the Capsule Protocol 382 MAY use the Capsule-Protocol header field to simplify intermediary 383 processing. 385 4.4. The DATAGRAM Capsule 387 This document defines the DATAGRAM capsule type (see Section 7.4 for 388 the value of the capsule type). This capsule allows an endpoint to 389 send an HTTP Datagram on a stream using the Capsule Protocol. This 390 is particularly useful when HTTP is running over a transport that 391 does not support the QUIC DATAGRAM frame. 393 Datagram Capsule { 394 Type (i) = DATAGRAM, 395 Length (i), 396 HTTP Datagram Payload (..), 397 } 399 Figure 4: DATAGRAM Capsule Format 401 HTTP Datagram Payload: The payload of the datagram, whose semantics 402 are defined by individual applications. Note that this field can 403 be empty. 405 Datagrams sent using the DATAGRAM capsule have the same semantics as 406 datagrams sent in QUIC DATAGRAM frames. In particular, the 407 restrictions on when it is allowed to send an HTTP Datagram and how 408 to process them from Section 3 also apply to HTTP Datagrams sent and 409 received using the DATAGRAM capsule. 411 An intermediary can reencode HTTP Datagrams as it forwards them. In 412 other words, an intermediary MAY send a DATAGRAM capsule to forward 413 an HTTP Datagram which was received in a QUIC DATAGRAM frame, and 414 vice versa. 416 Note that while DATAGRAM capsules that are sent on a stream are 417 reliably delivered in order, intermediaries can reencode DATAGRAM 418 capsules into QUIC DATAGRAM frames when forwarding messages, which 419 could result in loss or reordering. 421 If an intermediary receives an HTTP Datagram in a QUIC DATAGRAM frame 422 and is forwarding it on a connection that supports QUIC DATAGRAM 423 frames, the intermediary SHOULD NOT convert that HTTP Datagram to a 424 DATAGRAM capsule. If the HTTP Datagram is too large to fit in a 425 DATAGRAM frame (for example because the path MTU of that QUIC 426 connection is too low or if the maximum UDP payload size advertised 427 on that connection is too low), the intermediary SHOULD drop the HTTP 428 Datagram instead of converting it to a DATAGRAM capsule. This 429 preserves the end-to-end unreliability characteristic that methods 430 such as Datagram Packetization Layer Path MTU Discovery (DPLPMTUD) 431 depend on [DPLPMTUD]. An intermediary that converts QUIC DATAGRAM 432 frames to DATAGRAM capsules allows HTTP Datagrams to be arbitrarily 433 large without suffering any loss; this can misrepresent the true path 434 properties, defeating methods such as DPLPMTUD. 436 While DATAGRAM capsules can theoretically carry a payload of length 437 2^62-1, most applications will have their own limits on what datagram 438 payload sizes are practical. Implementations SHOULD take those 439 limits into account when parsing DATAGRAM capsules: if an incoming 440 DATAGRAM capsule has a length that is known to be so large as to not 441 be usable, the implementation SHOULD discard the capsule without 442 buffering its contents into memory. 444 5. Prioritization 446 Data streams (see Section 4.1) can be prioritized using any means 447 suited to stream or request prioritization. For example, see 448 Section 11 of [PRIORITY]. 450 Prioritization of HTTP/3 datagrams is not defined in this document. 451 Future extensions MAY define how to prioritize datagrams, and MAY 452 define signaling to allow endpoints to communicate their 453 prioritization preferences. 455 6. Security Considerations 457 Since transmitting HTTP Datagrams using QUIC DATAGRAM frames requires 458 sending an HTTP/3 Settings parameter, it "sticks out". In other 459 words, probing clients can learn whether a server supports HTTP 460 Datagrams over QUIC DATAGRAM frames. As some servers might wish to 461 obfuscate the fact that they offer application services that use HTTP 462 datagrams, it's best for all implementations that support this 463 feature to always send this Settings parameter, see Section 3.1. 465 Since use of the Capsule Protocol is restricted to new HTTP Upgrade 466 Tokens, it is not accessible from Web Platform APIs (such as those 467 commonly accessed via JavaScript in web browsers). 469 7. IANA Considerations 471 7.1. HTTP/3 SETTINGS Parameter 473 This document will request IANA to register the following entry in 474 the "HTTP/3 Settings" registry: 476 Value: 0xffd277 (note that this will switch to a lower value before 477 publication) 479 Setting Name: H3_DATAGRAM 481 Default: 0 483 Status: provisional (permanent if this document is approved) 485 Specification: This Document 487 Change Controller: IETF 489 Contact: HTTP_WG; HTTP working group; ietf-http-wg@w3.org 491 7.2. HTTP/3 Error Code 493 This document will request IANA to register the following entry in 494 the "HTTP/3 Error Codes" registry: 496 Value: 0x4A1268 (note that this will switch to a lower value before 497 publication) 499 Name: H3_DATAGRAM_ERROR 501 Description: Datagram or capsule protocol parse error 503 Status: provisional (permanent if this document is approved) 505 Specification: This Document 507 Change Controller: IETF 509 Contact: HTTP_WG; HTTP working group; ietf-http-wg@w3.org 511 7.3. HTTP Header Field Name 513 This document will request IANA to register the following entry in 514 the "HTTP Field Name" registry: 516 Field Name: Capsule-Protocol 517 Template: None 519 Status: provisional (permanent if this document is approved) 521 Reference: This document 523 Comments: None 525 7.4. Capsule Types 527 This document establishes a registry for HTTP capsule type codes. 528 The "HTTP Capsule Types" registry governs a 62-bit space. 529 Registrations in this registry MUST include the following fields: 531 Type: A name or label for the capsule type. 533 Value: The value of the Capsule Type field (see Section 4.1) is a 534 62-bit integer. 536 Reference: An optional reference to a specification for the type. 537 This field MAY be empty. 539 Registrations follow the "First Come First Served" policy (see 540 Section 4.4 of [IANA-POLICY]) where two registrations MUST NOT have 541 the same Type. 543 This registry initially contains the following entry: 545 Capsule Type: DATAGRAM 547 Value: 0xff37a5 (note that this will switch to a lower value before 548 publication) 550 Reference: This document 552 Capsule types with a value of the form 41 * N + 23 for integer values 553 of N are reserved to exercise the requirement that unknown capsule 554 types be ignored. These capsules have no semantics and can carry 555 arbitrary values. These values MUST NOT be assigned by IANA and MUST 556 NOT appear in the listing of assigned values. 558 8. References 560 8.1. Normative References 562 [DGRAM] Pauly, T., Kinnear, E., and D. Schinazi, "An Unreliable 563 Datagram Extension to QUIC", Work in Progress, Internet- 564 Draft, draft-ietf-quic-datagram-10, 4 February 2022, 565 . 568 [H1] Fielding, R. T., Nottingham, M., and J. Reschke, 569 "HTTP/1.1", Work in Progress, Internet-Draft, draft-ietf- 570 httpbis-messaging-19, 12 September 2021, 571 . 574 [H2] Thomson, M. and C. Benfield, "HTTP/2", Work in Progress, 575 Internet-Draft, draft-ietf-httpbis-http2bis-07, 24 January 576 2022, . 579 [H3] Bishop, M., "Hypertext Transfer Protocol Version 3 580 (HTTP/3)", Work in Progress, Internet-Draft, draft-ietf- 581 quic-http-34, 2 February 2021, 582 . 585 [HTTP] Fielding, R. T., Nottingham, M., and J. Reschke, "HTTP 586 Semantics", Work in Progress, Internet-Draft, draft-ietf- 587 httpbis-semantics-19, 12 September 2021, 588 . 591 [IANA-POLICY] 592 Cotton, M., Leiba, B., and T. Narten, "Guidelines for 593 Writing an IANA Considerations Section in RFCs", BCP 26, 594 RFC 8126, DOI 10.17487/RFC8126, June 2017, 595 . 597 [QUIC] Iyengar, J., Ed. and M. Thomson, Ed., "QUIC: A UDP-Based 598 Multiplexed and Secure Transport", RFC 9000, 599 DOI 10.17487/RFC9000, May 2021, 600 . 602 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 603 Requirement Levels", BCP 14, RFC 2119, 604 DOI 10.17487/RFC2119, March 1997, 605 . 607 [RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 608 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, 609 May 2017, . 611 [STRUCT-FIELD] 612 Nottingham, M. and P-H. Kamp, "Structured Field Values for 613 HTTP", RFC 8941, DOI 10.17487/RFC8941, February 2021, 614 . 616 8.2. Informative References 618 [DPLPMTUD] Fairhurst, G., Jones, T., Tüxen, M., Rüngeler, I., and T. 619 Völker, "Packetization Layer Path MTU Discovery for 620 Datagram Transports", RFC 8899, DOI 10.17487/RFC8899, 621 September 2020, . 623 [PRIORITY] Oku, K. and L. Pardue, "Extensible Prioritization Scheme 624 for HTTP", Work in Progress, Internet-Draft, draft-ietf- 625 httpbis-priority-12, 17 January 2022, 626 . 629 Acknowledgments 631 Portions of this document were previously part of the QUIC DATAGRAM 632 frame definition itself, the authors would like to acknowledge the 633 authors of that document and the members of the IETF MASQUE working 634 group for their suggestions. Additionally, the authors would like to 635 thank Martin Thomson for suggesting the use of an HTTP/3 SETTINGS 636 parameter. Furthermore, the authors would like to thank Ben Schwartz 637 for writing the first proposal that used two layers of indirection. 638 The final design in this document came out of the HTTP Datagrams 639 Design Team, whose members were Alan Frindell, Alex Chernyakhovsky, 640 Ben Schwartz, Eric Rescorla, Marcus Ihlar, Martin Thomson, Mike 641 Bishop, Tommy Pauly, Victor Vasiliev, and the authors of this 642 document. 644 Authors' Addresses 646 David Schinazi 647 Google LLC 648 1600 Amphitheatre Parkway 649 Mountain View, California 94043, 650 United States of America 651 Email: dschinazi.ietf@gmail.com 653 Lucas Pardue 654 Cloudflare 655 Email: lucaspardue.24.7@gmail.com