idnits 2.17.1 draft-ietf-bfcpbis-rfc4583bis-10.txt: Checking boilerplate required by RFC 5378 and the IETF Trust (see https://trustee.ietf.org/license-info): ---------------------------------------------------------------------------- No issues found here. Checking nits according to https://www.ietf.org/id-info/1id-guidelines.txt: ---------------------------------------------------------------------------- No issues found here. Checking nits according to https://www.ietf.org/id-info/checklist : ---------------------------------------------------------------------------- No issues found here. Miscellaneous warnings: ---------------------------------------------------------------------------- == The copyright year in the IETF Trust and authors Copyright Line does not match the current year -- The document date (October 27, 2014) is 3440 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) -- Looks like a reference, but probably isn't: 'RFC XXXX' on line 514 ** Obsolete normative reference: RFC 5750 (ref. '6') (Obsoleted by RFC 8550) == Outdated reference: A later version (-16) exists of draft-ietf-bfcpbis-rfc4582bis-12 ** Obsolete normative reference: RFC 4572 (ref. '10') (Obsoleted by RFC 8122) ** Obsolete normative reference: RFC 4566 (ref. '11') (Obsoleted by RFC 8866) ** Obsolete normative reference: RFC 6347 (ref. '12') (Obsoleted by RFC 9147) ** Obsolete normative reference: RFC 4582 (ref. '14') (Obsoleted by RFC 8855) ** Obsolete normative reference: RFC 4583 (ref. '15') (Obsoleted by RFC 8856) Summary: 6 errors (**), 0 flaws (~~), 2 warnings (==), 2 comments (--). Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 BFCPbis Working Group G. Camarillo 3 Internet-Draft Ericsson 4 Obsoletes: 4583 (if approved) T. Kristensen 5 Intended status: Standards Track Cisco 6 Expires: April 30, 2015 October 27, 2014 8 Session Description Protocol (SDP) Format for Binary Floor Control 9 Protocol (BFCP) Streams 10 draft-ietf-bfcpbis-rfc4583bis-10 12 Abstract 14 This document specifies how to describe Binary Floor Control Protocol 15 (BFCP) streams in Session Description Protocol (SDP) descriptions. 16 User agents using the offer/answer model to establish BFCP streams 17 use this format in their offers and answers. 19 This document obsoletes RFC 4583. Changes from RFC 4583 are 20 summarized in Section 13. 22 Status of this Memo 24 This Internet-Draft is submitted in full conformance with the 25 provisions of BCP 78 and BCP 79. 27 Internet-Drafts are working documents of the Internet Engineering 28 Task Force (IETF). Note that other groups may also distribute 29 working documents as Internet-Drafts. The list of current Internet- 30 Drafts is at http://datatracker.ietf.org/drafts/current/. 32 Internet-Drafts are draft documents valid for a maximum of six months 33 and may be updated, replaced, or obsoleted by other documents at any 34 time. It is inappropriate to use Internet-Drafts as reference 35 material or to cite them other than as "work in progress." 37 This Internet-Draft will expire on April 30, 2015. 39 Copyright Notice 41 Copyright (c) 2014 IETF Trust and the persons identified as the 42 document authors. All rights reserved. 44 This document is subject to BCP 78 and the IETF Trust's Legal 45 Provisions Relating to IETF Documents 46 (http://trustee.ietf.org/license-info) in effect on the date of 47 publication of this document. Please review these documents 48 carefully, as they describe your rights and restrictions with respect 49 to this document. Code Components extracted from this document must 50 include Simplified BSD License text as described in Section 4.e of 51 the Trust Legal Provisions and are provided without warranty as 52 described in the Simplified BSD License. 54 Table of Contents 56 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 57 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3 58 3. Fields in the 'm' Line . . . . . . . . . . . . . . . . . . . . 3 59 4. Floor Control Server Determination . . . . . . . . . . . . . . 4 60 5. The 'confid' and 'userid' SDP Attributes . . . . . . . . . . . 6 61 6. Association between Streams and Floors . . . . . . . . . . . . 6 62 7. BFCP Version Negotiation . . . . . . . . . . . . . . . . . . . 7 63 8. BFCP Connection Management . . . . . . . . . . . . . . . . . . 8 64 8.1. TCP Connection Management . . . . . . . . . . . . . . . . 8 65 9. Authentication . . . . . . . . . . . . . . . . . . . . . . . . 8 66 10. Examples . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 67 11. Security Considerations . . . . . . . . . . . . . . . . . . . 11 68 12. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 12 69 12.1. Registration of SDP 'proto' Values . . . . . . . . . . . . 12 70 12.2. Registration of the SDP 'floorctrl' Attribute . . . . . . 12 71 12.3. Registration of the SDP 'confid' Attribute . . . . . . . . 13 72 12.4. Registration of the SDP 'userid' Attribute . . . . . . . . 13 73 12.5. Registration of the SDP 'floorid' Attribute . . . . . . . 13 74 12.6. Registration of the SDP 'bfcpver' Attribute . . . . . . . 14 75 13. Changes from RFC 4583 . . . . . . . . . . . . . . . . . . . . 14 76 14. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 15 77 15. Normative References . . . . . . . . . . . . . . . . . . . . . 15 78 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 17 80 1. Introduction 82 As discussed in the BFCP (Binary Floor Control Protocol) 83 specification [8], a given BFCP client needs a set of data in order 84 to establish a BFCP connection to a floor control server. This data 85 includes the transport address of the server, the conference 86 identifier, and the user identifier. 88 One way for clients to obtain this information is to use an offer/ 89 answer [4] exchange. This document specifies how to encode this 90 information in the SDP session descriptions that are part of such an 91 offer/answer exchange. 93 User agents typically use the offer/answer model to establish a 94 number of media streams of different types. Following this model, a 95 BFCP connection is described as any other media stream by using an 96 SDP 'm' line, possibly followed by a number of attributes encoded in 97 'a' lines. 99 2. Terminology 101 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 102 "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and 103 "OPTIONAL" in this document are to be interpreted as described in BCP 104 14, RFC 2119 [1] and indicate requirement levels for compliant 105 implementations. 107 3. Fields in the 'm' Line 109 This section describes how to generate an 'm' line for a BFCP stream. 111 According to the SDP specification [11], the 'm' line format is the 112 following: 114 m= ... 116 The media field MUST have a value of "application". 118 The port field is set depending on the value of the proto field, as 119 explained below. A port field value of zero has the standard SDP 120 meaning (i.e., rejection of the media stream) regardless of the proto 121 field. 123 When TCP is used as the transport, the port field is set following 124 the rules in [7]. Depending on the value of the 'setup' attribute 125 (discussed in Section 8.1), the port field contains the port to 126 which the remote endpoint will direct BFCP messages or is 127 irrelevant (i.e., the endpoint will initiate the connection 128 towards the remote endpoint) and should be set to a value of 9, 129 which is the discard port. 131 When UDP is used as the transport, the port field contains the 132 port to which the remote endpoint will direct BFCP messages 133 regardless of the value of the 'setup' attribute. 135 This document defines four values for the proto field: TCP/BFCP, TCP/ 136 TLS/BFCP, UDP/BFCP, and UDP/TLS/BFCP. TCP/BFCP is used when BFCP 137 runs directly on top of TCP, TCP/TLS/BFCP is used when BFCP runs on 138 top of TLS, which in turn runs on top of TCP. Similarly, UDP/BFCP is 139 used when BFCP runs directly on top of UDP, and UDP/TLS/BFCP is used 140 when BFCP runs on top of DTLS [12], which in turn runs on top of UDP. 142 The fmt (format) list is not applicable to BFCP. The fmt list of 'm' 143 lines in the case of any proto field value related to BFCP SHOULD 144 contain a single "*" character. If the the fmt list contains any 145 other value it is ignored. 147 The following is an example of an 'm' line for a BFCP connection: 149 m=application 50000 TCP/TLS/BFCP * 151 4. Floor Control Server Determination 153 When two endpoints establish a BFCP stream, they need to determine 154 which of them acts as a floor control server. In the most common 155 scenario, a client establishes a BFCP stream with a conference server 156 that acts as the floor control server. Floor control server 157 determination is straight forward because one endpoint can only act 158 as a client and the other can only act as a floor control server. 160 However, there are scenarios where both endpoints could act as a 161 floor control server. For example, in a two-party session that 162 involves an audio stream and a shared whiteboard, the endpoints need 163 to decide which party will be acting as the floor control server. 165 Furthermore, there are situations where both the offerer and the 166 answerer act as both clients and floor control servers in the same 167 session. For example, in a two-party session that involves an audio 168 stream and a shared whiteboard, one party acts as the floor control 169 server for the audio stream and the other acts as the floor control 170 server for the shared whiteboard. 172 This document defines the 'floorctrl' SDP media-level attribute to 173 perform floor control determination. Its Augmented BNF syntax [2] 174 is: 176 floor-control-attribute = "a=floorctrl:" role *(SP role) 177 role = "c-only" / "s-only" / "c-s" 179 The offerer includes this attribute to state all the roles it would 180 be willing to perform: 182 c-only: The offerer would be willing to act as a floor control 183 client only. 185 s-only: The offerer would be willing to act as a floor control 186 server only. 188 c-s: The offerer would be willing to act both as a floor control 189 client and as a floor control server. 191 If an SDP media description in an offer contains a 'floorctrl' 192 attribute, the answerer accepting that media MUST include a 193 'floorctrl' attribute in the corresponding media description of the 194 answer. The answerer includes this attribute to state which role the 195 answerer will perform. That is, the answerer chooses one of the 196 roles the offerer is willing to perform and generates an answer with 197 the corresponding role for the answerer. Table 1 shows the 198 corresponding roles for an answerer, depending on the offerer's role. 200 +---------+----------+ 201 | Offerer | Answerer | 202 +---------+----------+ 203 | c-only | s-only | 204 | s-only | c-only | 205 | c-s | c-s | 206 +---------+----------+ 208 Table 1: Roles 210 The following are the descriptions of the roles when they are chosen 211 by an answerer: 213 c-only: The answerer will act as a floor control client. 214 Consequently, the offerer will act as a floor control server. 216 s-only: The answerer will act as a floor control server. 217 Consequently, the offerer will act as a floor control client. 219 c-s: The answerer will act both as a floor control client and as a 220 floor control server. Consequently, the offerer will also act 221 both as a floor control client and as a floor control server. 223 Endpoints that use the offer/answer model to establish BFCP 224 connections MUST support the 'floorctrl' attribute. A floor control 225 server acting as an offerer or as an answerer SHOULD include this 226 attribute in its session descriptions. 228 If the 'floorctrl' attribute is not used in an offer/answer exchange, 229 by default the offerer and the answerer will act as a floor control 230 client and as a floor control server, respectively. 232 The following is an example of a 'floorctrl' attribute in an offer. 233 When this attribute appears in an answer, it only carries one role: 235 a=floorctrl:c-only s-only c-s 237 5. The 'confid' and 'userid' SDP Attributes 239 This document defines the 'confid' and the 'userid' SDP media-level 240 attributes. These attributes are used by a floor control server to 241 provide a client with a conference ID and a user ID, respectively. 242 Their Augmented BNF syntax [2] is: 244 confid-attribute = "a=confid:" conference-id 245 conference-id = token 246 userid-attribute = "a=userid:" user-id 247 user-id = token 249 The 'confid' and the 'userid' attributes carry the decimal integer 250 representation of a conference ID and a user ID, respectively. 252 Endpoints that use the offer/answer model to establish BFCP 253 connections MUST support the 'confid' and the 'userid' attributes. A 254 floor control server acting as an offerer or as an answerer MUST 255 include these attributes in its session descriptions. 257 6. Association between Streams and Floors 259 This document defines the 'floorid' SDP media-level attribute. Its 260 Augmented BNF syntax [2] is: 262 floor-id-attribute = "a=floorid:" token [" mstrm:" token *(SP token)] 264 The 'floorid' attribute is used in the SDP media description for BFCP 265 media. It defines a floor identifier and, possibly, associates it 266 with one or more media streams. The token representing the floor ID 267 is the integer representation of the Floor ID to be used in BFCP. 268 The token representing the media stream is a pointer to the media 269 stream, which is identified by an SDP label attribute [9]. 271 Endpoints that use the offer/answer model to establish BFCP 272 connections MUST support the 'floorid' and the 'label' attributes. A 273 floor control server acting as an offerer or as an answerer MUST 274 include these attributes in its session descriptions. 276 Note: In [15] 'm-stream' was erroneously used in Section 10. 277 Although the example was non-normative, it is implemented by some 278 vendors and occurs in cases where the endpoint is willing to act as 279 an server. Therefore, it is RECOMMENDED to support parsing and 280 interpreting 'm-stream' the same way as 'mstrm' when receiving. 282 7. BFCP Version Negotiation 284 This document defines the 'bfcpver' SDP media-level attribute. Its 285 Augmented BNF syntax [2] is: 287 bfcp-version-attribute = "a=bfcpver:" bfcp-version *(SP bfcp-version) 288 bfcp-version = token 290 The 'bfcpver' attribute defines the list of the versions of BFCP 291 supported by the endpoint. Tokens representing versions MUST be 292 integers matching the "Version" field that would be presented in the 293 BFCP COMMON-HEADER [8]. The version of BFCP to be used will then be 294 confirmed with a BFCP-level Hello/HelloAck. 296 Endpoints that use the offer/answer model to establish BFCP 297 connections SHOULD support the 'bfcpver' attribute. A floor control 298 server acting as an offerer or as an answerer SHOULD include this 299 attribute in its session descriptions. However, endpoints that 300 support RFCXXXX, and not only the RFC 4583 subset, are REQUIRED to 301 support and, when acting as a floor control server, to use the 302 'bfcpver' attribute. 304 If a 'bfcpver' attribute is not present, default values are inferred 305 from the transport specified in the m-line (Section 3). In 306 accordance with definition of the Version field in [8], when used 307 over a reliable transport the default value is "1", and when used 308 over an unreliable transport the default value is "2". 310 8. BFCP Connection Management 312 BFCP connections can use TCP or UDP as the underlying transport. 313 BFCP entities exchanging BFCP messages over UDP direct the BFCP 314 messages to the peer side connection address and port provided in the 315 SDP 'm' line. TCP connection management is more complicated and is 316 described below. 318 8.1. TCP Connection Management 320 The management of the TCP connection used to transport BFCP is 321 performed using the 'setup' and 'connection' attributes, as defined 322 in [7]. 324 The 'setup' attribute indicates which of the endpoints (client or 325 floor control server) initiates the TCP connection. The 'connection' 326 attribute handles TCP connection reestablishment. 328 The BFCP specification [8] describes a number of situations when the 329 TCP connection between a client and the floor control server needs to 330 be reestablished. However, that specification does not describe the 331 reestablishment process because this process depends on how the 332 connection was established in the first place. BFCP entities using 333 the offer/answer model follow the following rules. 335 When the existing TCP connection is closed and reestablished 336 following the rules in [8], the client MUST generate an offer towards 337 the floor control server in order to reestablish the connection. If 338 a TCP connection cannot deliver a BFCP message and times out, the 339 entity that attempted to send the message (i.e., the one that 340 detected the TCP timeout) MUST generate an offer in order to 341 reestablish the TCP connection. 343 Endpoints that use the offer/answer model to establish TCP 344 connections MUST support the 'setup' and 'connection' attributes. 346 9. Authentication 348 When a BFCP connection is established using the offer/answer model, 349 it is assumed that the offerer and the answerer authenticate each 350 other using some mechanism. TLS/DTLS is the preferred mechanism, but 351 other mechanisms are possible and outside the scope of this document. 352 Once this mutual authentication takes place, all the offerer and the 353 answerer need to ensure is that the entity they are receiving BFCP 354 messages from is the same as the one that generated the previous 355 offer or answer. 357 When SIP is used to perform an offer/answer exchange, the initial 358 mutual authentication takes place at the SIP level. Additionally, 359 SIP uses S/MIME [6] to provide an integrity-protected channel with 360 optional confidentiality for the offer/answer exchange. BFCP takes 361 advantage of this integrity-protected offer/answer exchange to 362 perform authentication. Within the offer/answer exchange, the 363 offerer and answerer exchange the fingerprints of their self-signed 364 certificates. These self-signed certificates are then used to 365 establish the TLS/DTLS connection that will carry BFCP traffic 366 between the offerer and the answerer. 368 BFCP clients and floor control servers follow the rules in [10] 369 regarding certificate choice and presentation. This implies that 370 unless a 'fingerprint' attribute is included in the session 371 description, the certificate provided at the TLS-/DTLS-level MUST 372 either be directly signed by one of the other party's trust anchors 373 or be validated using a certification path that terminates at one of 374 the other party's trust anchors [5]. Endpoints that use the offer/ 375 answer model to establish BFCP connections MUST support the 376 'fingerprint' attribute and MUST include it in their session 377 descriptions. 379 When TLS is used with TCP, once the underlying connection is 380 established, the answerer which may be the client or the floor 381 control server acts as the TLS server regardless of its role (passive 382 or active) in the TCP establishment procedure. If the TCP connection 383 is lost, the active endpoint is responsible for re-establishing the 384 TCP connection. Unless a new TLS session is negotiated, subsequent 385 SDP offers and answers will not impact the previously negotiated TLS 386 roles. 388 Endpoints that use the offer/answer model to establish a DTLS 389 association MUST support the 'setup' attribute, as defined in [7]. 390 When DTLS is used with UDP, the 'setup' attribute indicates which of 391 the endpoints (client or floor control server) initiates the DTLS 392 association setup. The requirements for the offer/answer exchange 393 specified in [13], Section 5 MUST be followed when using DTLS. 395 Informational note: How to determine which endpoint initiates the 396 TLS/DTLS association depends on the selected underlying transport. 397 It was decided to keep the original semantics in [15] for TCP to 398 retain backwards compatibility. When using UDP, the procedure 399 above was preferred since it adheres to [13] as used for DTLS- 400 SRTP, it does not overload offer/answer semantics, and it works 401 for offerless INVITE in scenarios with B2BUAs. 403 10. Examples 405 For the purpose of brevity, the main portion of the session 406 description is omitted in the examples, which only show 'm' lines and 407 their attributes. 409 The following is an example of an offer sent by a conference server 410 to a client. 412 m=application 50000 TCP/TLS/BFCP * 413 a=setup:passive 414 a=connection:new 415 a=fingerprint:SHA-1 \ 416 4A:AD:B9:B1:3F:82:18:3B:54:02:12:DF:3E:5D:49:6B:19:E5:7C:AB 417 a=floorctrl:s-only 418 a=confid:4321 419 a=userid:1234 420 a=floorid:1 mstrm:10 421 a=floorid:2 mstrm:11 422 a=bfcpver:1 423 m=audio 50002 RTP/AVP 0 424 a=label:10 425 m=video 50004 RTP/AVP 31 426 a=label:11 428 Note that due to RFC formatting conventions, this document splits SDP 429 across lines whose content would exceed 72 characters. A backslash 430 character marks where this line folding has taken place. This 431 backslash and its trailing CRLF and whitespace would not appear in 432 actual SDP content. 434 The following is the answer returned by the client. 436 m=application 9 TCP/TLS/BFCP * 437 a=setup:active 438 a=connection:new 439 a=fingerprint:SHA-1 \ 440 3D:B4:7B:E3:CC:FC:0D:1B:5D:31:33:9E:48:9B:67:FE:68:40:E8:21 441 a=floorctrl:c-only 442 a=bfcpver:1 443 m=audio 55000 RTP/AVP 0 444 m=video 55002 RTP/AVP 31 446 A similar example using unreliable transport and DTLS is shown below, 447 where the offer is sent from a client. 449 m=application 50000 UDP/TLS/BFCP * 450 a=setup:actpass 451 a=fingerprint:SHA-1 \ 452 4A:AD:B9:B1:3F:82:18:3B:54:02:12:DF:3E:5D:49:6B:19:E5:7C:AB 453 a=floorctrl:c-only s-only 454 a=confid:4321 455 a=userid:1234 456 a=floorid:1 mstrm:10 457 a=floorid:2 mstrm:11 458 a=bfcpver:2 459 m=audio 50002 RTP/AVP 0 460 a=label:10 461 m=video 50004 RTP/AVP 31 462 a=label:11 464 The following is the answer returned by the server. 466 m=application 55000 UDP/TLS/BFCP * 467 a=setup:active 468 a=fingerprint:SHA-1 \ 469 3D:B4:7B:E3:CC:FC:0D:1B:5D:31:33:9E:48:9B:67:FE:68:40:E8:21 470 a=floorctrl:s-only 471 a=confid:4321 472 a=userid:1234 473 a=floorid:1 mstrm:10 474 a=floorid:2 mstrm:11 475 a=bfcpver:2 476 m=audio 55002 RTP/AVP 0 477 m=video 55004 RTP/AVP 31 479 11. Security Considerations 481 The BFCP [8], SDP [11], and offer/answer [4] specifications discuss 482 security issues related to BFCP, SDP, and offer/answer, respectively. 483 In addition, [7] and [10] discuss security issues related to the 484 establishment of TCP and TLS connections using an offer/answer model. 485 Furthermore, when using DTLS over UDP, considerations for its use 486 with RTP and RTCP are presented in [13]. The requirements for the 487 offer/answer exchange, as listed in Section 5 of that document, MUST 488 be followed. 490 An initial integrity-protected channel is REQUIRED for BFCP to 491 exchange self-signed certificates between a client and the floor 492 control server. For session descriptions carried in SIP [3], S/MIME 493 [6] is the natural choice to provide such a channel. 495 12. IANA Considerations 497 [Editorial note: The changes in Section 12.1 instruct the IANA to 498 register the two new values UDP/BFCP and UDP/TLS/BFCP for the SDP 499 'proto' field. The new section Section 12.6 registers a new SDP 500 "bfcpver" attribute. The rest is unchanged from [14].] 502 12.1. Registration of SDP 'proto' Values 504 The IANA has registered the following values for the SDP 'proto' 505 field under the Session Description Protocol (SDP) Parameters 506 registry: 508 +--------------+------------+ 509 | Value | Reference | 510 +--------------+------------+ 511 | TCP/BFCP | [RFC XXXX] | 512 | TCP/TLS/BFCP | [RFC XXXX] | 513 | UDP/BFCP | [RFC XXXX] | 514 | UDP/TLS/BFCP | [RFC XXXX] | 515 +--------------+------------+ 517 Table 2: Values for the SDP 'proto' field 519 12.2. Registration of the SDP 'floorctrl' Attribute 521 The IANA has registered the following SDP att-field under the Session 522 Description Protocol (SDP) Parameters registry: 524 Contact name: Gonzalo.Camarillo@ericsson.com 526 Attribute name: floorctrl 528 Long-form attribute name: Floor Control 530 Type of attribute: Media level 532 Subject to charset: No 534 Purpose of attribute: The 'floorctrl' attribute is used to perform 535 floor control server determination. 537 Allowed attribute values: 1*("c-only" / "s-only" / "c-s") 539 12.3. Registration of the SDP 'confid' Attribute 541 The IANA has registered the following SDP att-field under the Session 542 Description Protocol (SDP) Parameters registry: 544 Contact name: Gonzalo.Camarillo@ericsson.com 546 Attribute name: confid 548 Long-form attribute name: Conference Identifier 550 Type of attribute: Media level 552 Subject to charset: No 554 Purpose of attribute: The 'confid' attribute carries the integer 555 representation of a Conference ID. 557 Allowed attribute values: A token 559 12.4. Registration of the SDP 'userid' Attribute 561 The IANA has registered the following SDP att-field under the Session 562 Description Protocol (SDP) Parameters registry: 564 Contact name: Gonzalo.Camarillo@ericsson.com 566 Attribute name: userid 568 Long-form attribute name: User Identifier 570 Type of attribute: Media level 572 Subject to charset: No 574 Purpose of attribute: The 'userid' attribute carries the integer 575 representation of a User ID. 577 Allowed attribute values: A token 579 12.5. Registration of the SDP 'floorid' Attribute 581 The IANA has registered the following SDP att-field under the Session 582 Description Protocol (SDP) Parameters registry: 584 Contact name: Gonzalo.Camarillo@ericsson.com 586 Attribute name: floorid 588 Long-form attribute name: Floor Identifier 590 Type of attribute: Media level 592 Subject to charset: No 594 Purpose of attribute: The 'floorid' attribute associates a floor 595 with one or more media streams. 597 Allowed attribute values: Tokens 599 12.6. Registration of the SDP 'bfcpver' Attribute 601 The IANA has registered the following SDP att-field under the Session 602 Description Protocol (SDP) Parameters registry: 604 Contact name: Gonzalo.Camarillo@ericsson.com 606 Attribute name: bfcpver 608 Long-form attribute name: BFCP Version 610 Type of attribute: Media level 612 Subject to charset: No 614 Purpose of attribute: The 'bfcpver' attribute lists supported BFCP 615 versions. 617 Allowed attribute values: Tokens 619 13. Changes from RFC 4583 621 Following is the list of technical changes and other fixes from [15]. 623 Main purpose of this work was to add signaling support necessary to 624 support BFCP over unreliable transport, as described in [8], 625 resulting in the following changes: 627 1. Fields in the 'm' Line (Section 3): 628 The section is re-written to remove reference to the exclusivity 629 of TCP as a transport for BFCP streams. The proto field values 630 UDP/BFCP and UDP/TLS/BFCP added. 632 2. Authentication (Section 9): 633 In last paragraph, made clear that a TCP connection was 634 described. 636 3. Security Considerations (Section 11): 637 For the DTLS over UDP case, mention existing considerations and 638 requirements for the offer/answer exchange in [13]. 640 4. Registration of SDP 'proto' Values (Section 12.1): 641 Register the two new values UDP/BFCP and UDP/TLS/BFCP in the SDP 642 parameters registry. 644 5. BFCP Version Negotiation (Section 7): 645 A new 'bfcpver' SDP media-level attribute is added in order to 646 signal supported version number. 648 Clarification and bug fixes: 650 1. Errata ID: 712 (Section 4 and Section 6): 651 Language clarification. Don't use terms like an SDP attribute is 652 "used in an 'm' line", instead make clear that the attribute is a 653 media-level attribute. 655 2. Fix typo in example (Section 10): 656 Do not use 'm-stream' in the SDP example, use the correct 'mstrm' 657 as specified in Section 10. Recommend interpreting 'm-stream' if 658 it is received, since it is present in some implementations. 660 3. Assorted clarifications (Across the document): 661 Language clarifications as a result of reviews. Also, the 662 normative language where tightened where appropriate, i.e. 663 changed from SHOULD strength to MUST in a number of places. 665 14. Acknowledgements 667 Joerg Ott, Keith Drage, Alan Johnston, Eric Rescorla, Roni Even, and 668 Oscar Novo provided useful ideas for the original [15]. The authors 669 also acknowledge contributions to the revision of BFCP for use over 670 an unreliable transport from Geir Arne Sandbakken, Charles Eckel, 671 Alan Ford, Eoin McLeod and Mark Thompson. Useful and important final 672 reviews were done by Ali C. Begen, Mary Barnes and Charles Eckel. 674 15. Normative References 676 [1] Bradner, S., "Key words for use in RFCs to Indicate Requirement 677 Levels", BCP 14, RFC 2119, March 1997. 679 [2] Crocker, D. and P. Overell, "Augmented BNF for Syntax 680 Specifications: ABNF", STD 68, RFC 5234, January 2008. 682 [3] Rosenberg, J., Schulzrinne, H., Camarillo, G., Johnston, A., 683 Peterson, J., Sparks, R., Handley, M., and E. Schooler, "SIP: 684 Session Initiation Protocol", RFC 3261, June 2002. 686 [4] Rosenberg, J. and H. Schulzrinne, "An Offer/Answer Model with 687 Session Description Protocol (SDP)", RFC 3264, June 2002. 689 [5] Cooper, D., Santesson, S., Farrell, S., Boeyen, S., Housley, 690 R., and W. Polk, "Internet X.509 Public Key Infrastructure 691 Certificate and Certificate Revocation List (CRL) Profile", 692 RFC 5280, May 2008. 694 [6] Ramsdell, B. and S. Turner, "Secure/Multipurpose Internet Mail 695 Extensions (S/MIME) Version 3.2 Certificate Handling", 696 RFC 5750, January 2010. 698 [7] Yon, D. and G. Camarillo, "TCP-Based Media Transport in the 699 Session Description Protocol (SDP)", RFC 4145, September 2005. 701 [8] Camarillo, G., Drage, K., Kristensen, T., Ott, J., and C. 702 Eckel, "The Binary Floor Control Protocol (BFCP)", 703 draft-ietf-bfcpbis-rfc4582bis-12 (work in progress), 704 October 2014. 706 [9] Levin, O. and G. Camarillo, "The Session Description Protocol 707 (SDP) Label Attribute", RFC 4574, August 2006. 709 [10] Lennox, J., "Connection-Oriented Media Transport over the 710 Transport Layer Security (TLS) Protocol in the Session 711 Description Protocol (SDP)", RFC 4572, July 2006. 713 [11] Handley, M., Jacobson, V., and C. Perkins, "SDP: Session 714 Description Protocol", RFC 4566, July 2006. 716 [12] Rescorla, E. and N. Modadugu, "Datagram Transport Layer 717 Security Version 1.2", RFC 6347, January 2012. 719 [13] Fischl, J., Tschofenig, H., and E. Rescorla, "Framework for 720 Establishing a Secure Real-time Transport Protocol (SRTP) 721 Security Context Using Datagram Transport Layer Security 722 (DTLS)", RFC 5763, May 2010. 724 [14] Camarillo, G., Ott, J., and K. Drage, "The Binary Floor Control 725 Protocol (BFCP)", RFC 4582, November 2006. 727 [15] Camarillo, G., "Session Description Protocol (SDP) Format for 728 Binary Floor Control Protocol (BFCP) Streams", RFC 4583, 729 November 2006. 731 Authors' Addresses 733 Gonzalo Camarillo 734 Ericsson 735 Hirsalantie 11 736 Jorvas 02420 737 Finland 739 Email: Gonzalo.Camarillo@ericsson.com 741 Tom Kristensen 742 Cisco 743 Philip Pedersens vei 1 744 N-1366 Lysaker 745 Norway 747 Email: tomkrist@cisco.com, tomkri@ifi.uio.no