idnits 2.17.1 draft-ietf-siprec-architecture-06.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 (September 9, 2012) is 4239 days in the past. Is this intentional? Checking references for intended status: Informational ---------------------------------------------------------------------------- == Unused Reference: 'RFC3265' is defined on line 644, but no explicit reference was found in the text -- Obsolete informational reference (is this intentional?): RFC 4566 (Obsoleted by RFC 8866) == Outdated reference: A later version (-22) exists of draft-ietf-siprec-metadata-06 == Outdated reference: A later version (-18) exists of draft-ietf-siprec-protocol-04 -- Obsolete informational reference (is this intentional?): RFC 3265 (Obsoleted by RFC 6665) Summary: 0 errors (**), 0 flaws (~~), 4 warnings (==), 3 comments (--). Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 SIPREC A. Hutton, Ed. 3 Internet-Draft Siemens Enterprise 4 Intended status: Informational Communications 5 Expires: March 13, 2013 L. Portman, Ed. 6 NICE Systems 7 R. Jain 8 IPC Systems 9 K. Rehor 10 Cisco Systems, Inc. 11 September 9, 2012 13 An Architecture for Media Recording using the Session Initiation 14 Protocol 15 draft-ietf-siprec-architecture-06 17 Abstract 19 Session recording is a critical requirement in many communications 20 environments such as call centers and financial trading. In some of 21 these environments, all calls must be recorded for regulatory, 22 compliance, and consumer protection reasons. Recording of a session 23 is typically performed by sending a copy of a media stream to a 24 recording device. This document describes architectures for 25 deploying session recording solutions in an environment which is 26 based on the Session Initiation Protocol (SIP). 28 Status of this Memo 30 This Internet-Draft is submitted in full conformance with the 31 provisions of BCP 78 and BCP 79. 33 Internet-Drafts are working documents of the Internet Engineering 34 Task Force (IETF). Note that other groups may also distribute 35 working documents as Internet-Drafts. The list of current Internet- 36 Drafts is at http://datatracker.ietf.org/drafts/current/. 38 Internet-Drafts are draft documents valid for a maximum of six months 39 and may be updated, replaced, or obsoleted by other documents at any 40 time. It is inappropriate to use Internet-Drafts as reference 41 material or to cite them other than as "work in progress." 43 This Internet-Draft will expire on March 13, 2013. 45 Copyright Notice 47 Copyright (c) 2012 IETF Trust and the persons identified as the 48 document authors. All rights reserved. 50 This document is subject to BCP 78 and the IETF Trust's Legal 51 Provisions Relating to IETF Documents 52 (http://trustee.ietf.org/license-info) in effect on the date of 53 publication of this document. Please review these documents 54 carefully, as they describe your rights and restrictions with respect 55 to this document. Code Components extracted from this document must 56 include Simplified BSD License text as described in Section 4.e of 57 the Trust Legal Provisions and are provided without warranty as 58 described in the Simplified BSD License. 60 Table of Contents 62 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 63 2. Definitions . . . . . . . . . . . . . . . . . . . . . . . . . 4 64 3. Session Recording Architecture . . . . . . . . . . . . . . . . 5 65 3.1. Location of the Session Recording Client . . . . . . . . . 5 66 3.1.1. B2BUA acts as a Session Recording Client . . . . . . . 5 67 3.1.2. Endpoint acts as Session Recording Client . . . . . . 7 68 3.1.3. A SIP Proxy cannot be a Session Recording Client . . . 7 69 3.1.4. Interaction with MEDIACTRL . . . . . . . . . . . . . . 8 70 3.1.5. Interaction with Conference Focus . . . . . . . . . . 9 71 3.2. Establishing the Recording Session . . . . . . . . . . . . 10 72 3.2.1. Session Recording Client Initiated Recording . . . . . 11 73 3.2.2. Session Recording Server Initiated Recording . . . . . 11 74 3.2.3. Pause/Resume Recording Session . . . . . . . . . . . . 12 75 3.2.4. Media Stream Mixing . . . . . . . . . . . . . . . . . 12 76 3.2.5. Media Transcoding . . . . . . . . . . . . . . . . . . 12 77 3.3. Recording Metadata . . . . . . . . . . . . . . . . . . . . 12 78 3.3.1. Contents of recording metadata . . . . . . . . . . . . 13 79 3.3.2. Mechanisms for delivery of metadata to Session 80 Recording Server . . . . . . . . . . . . . . . . . . . 13 81 3.4. Notifications to the Recorded User Agents . . . . . . . . 13 82 3.5. Preventing the recording of a SIP session . . . . . . . . 13 83 4. IANA considerations . . . . . . . . . . . . . . . . . . . . . 13 84 5. Security considerations . . . . . . . . . . . . . . . . . . . 14 85 6. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 14 86 7. Informative References . . . . . . . . . . . . . . . . . . . . 15 87 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 16 89 1. Introduction 91 Session recording is a critical requirement in many communications 92 environments such as call centers and financial trading. In some of 93 these environments, all calls must be recorded for regulatory, 94 compliance, and consumer protection reasons. Recording of a session 95 is typically performed by sending a copy of a media stream to a 96 recording device. This document describes architectures for 97 deploying session recording solutions in an environment which is 98 based on the Session Initiation Protocol (SIP) the requirements for 99 which are described in [RFC6341]. 101 This document focuses on how sessions are established between a 102 Session Recording Client (SRC) and the Session Recording Server (SRS) 103 for the purpose of conveying the Replicated Media and Recording 104 Metadata (e.g. Identity of parties involved) relating to the 105 Communication Session. 107 Once the Replicated Media and Recording Metadata have been received 108 by the Session Recording Server they will typically be archived for 109 retrieval at a later time. The procedures relating to the archiving 110 and retrieval of this information is outside the scope of this 111 document. 113 This document only considers active recording, where the Session 114 Recording Client purposefully streams media to a Session Recording 115 Server. Passive recording, where a recording device detects media 116 directly from the network (E.g. using port mirroring techniques), is 117 outside the scope of this document. In addition, lawful intercept is 118 outside the scope of this document which takes account of the IETF 119 policy on wiretapping [RFC2804]. 121 The Recording Session that is established between the Session 122 Recording Client and the Session Recording Server uses the normal 123 procedures for establishing INVITE initiated dialogs as specified in 124 [RFC3261] and uses SDP for describing the media to be used during the 125 session as specified in [RFC4566]. However it is intended that some 126 extensions to SIP (E.g. Headers, Option Tags, Etc.) will be defined 127 to support the requirements for media recording. The Replicated 128 Media is required to be sent in real-time to the Session Recording 129 Server and is not buffered by the Session Recording Client to allow 130 for real-time analysis of the media by the Session Recording Server. 132 2. Definitions 134 Session Recording Server (SRS): A Session Recording Server (SRS) is 135 a SIP User Agent (UA) that is a specialized media server or collector 136 that acts as the sink of the recorded media. An SRS is typically 137 implemented as a multi-port device that is capable of receiving media 138 from multiple sources simultaneously. An SRS is the sink of the 139 recorded session metadata. 141 Session Recording Client (SRC): A Session Recording Client (SRC) is 142 a SIP User Agent (UA) that acts as the source of the recorded media, 143 sending it to the SRS. An SRC is a logical function. Its 144 capabilities may be implemented across one or more physical devices. 145 In practice, an SRC could be a personal device (such as a SIP phone), 146 a SIP Media Gateway (MG), a Session Border Controller (SBC) or a SIP 147 Media Server (MS) integrated with an Application Server (AS). This 148 specification defines the term SRC such that all such SIP entities 149 can be generically addressed under one definition. The SRC provides 150 metadata to the SRS. 152 Communication Session (CS): A session created between two or more 153 SIP User Agents (UAs) that is the subject of recording. 155 Recording Session (RS): The SIP session created between an SRC and 156 SRS for the purpose of recording a Communication Session. 158 Recording aware User Agent (UA): A SIP User Agent that is aware of 159 SIP extensions associated with the Communication Session. Such 160 extensions may be used to notify the Recording aware UA that a 161 session is being recorded, or by a Recording aware UA to express 162 preferences as to whether a recording should be started, paused, 163 resumed or stopped. 165 Recording unaware User Agent (UA): A SIP User Agent that is unaware 166 of SIP extensions associated with the Communication Session. Such 167 Recording unaware UA will be notified that a session is being 168 recorded or express preferences as to whether a recording should be 169 started, paused, resumed or stopped via some other means that is out 170 of scope of SIPREC. 172 Recording Metadata: The metadata describing the communication 173 session that is required by the Session Recording Server. This will 174 include for example the identity of users that participate in the 175 Communication Session and dialog state. Typically this metadata is 176 archived with the replicated media at the Session Recording Server. 177 The recording metadata is delivered in real-time to the Session 178 Recording Server. 180 Replicated Media: A copy of the media associated with the 181 Communication Session created by the Session Recording Client and 182 sent to the Session Recording Server. It may contain all the media 183 associated with the communication session (E.g. Audio and Video) or 184 just a subset (E.g. Audio). Replicated Media is part of Recording 185 Session. 187 3. Session Recording Architecture 189 3.1. Location of the Session Recording Client 191 This section contains some example session recording architectures 192 showing how the Session Recording Client is a logical function that 193 can be located in or split between various physical components. 195 3.1.1. B2BUA acts as a Session Recording Client 197 A SIP Back to Back User Agent (B2BUA) which has access to the media 198 that is to be recorded may act as a Session Recording Client. The 199 B2BUA may already be aware that a session needs to be recorded before 200 the initial establishment of the communication session or the 201 decision to record the session may occur after the session has been 202 established. 204 If the B2BUA/SRC makes the decision to initiate the Recording Session 205 (RS) then it will initiate the establishment of a SIP Session by 206 sending an INVITE to the Session Recording Server. 208 If the Session Recording Server makes the decision to initiate the 209 recording session then it will initiate the establishment of a SIP 210 Session by sending an INVITE to the B2BUA/Session Recording Client. 212 The RS INVITE contains information which identifies the session as 213 being established for the purposes of recording and prevents the 214 session from being accidentally rerouted to a UA which is not a SRS. 216 The B2BUA/SRC is responsible for notifying the UAs involved in the 217 communication session that the session is being recorded. 219 The B2BUA/SRC is responsible for complying with requests from 220 recording aware UAs or through some configured policies indicating 221 that the communication session should not be recorded. 223 +-----------+ 224 (Recording Session) | Session | 225 +------SIP------>| Recording | 226 | | Server | 227 | +--RTP/RTCP-->| (SRS) | 228 | | +-----------+ 229 V V ^ 230 +-------------+ | 231 | | | 232 | |-- MetaData -+ 233 | | 234 | B2BUA | 235 | | 236 | Session | 237 +--------+ | Recording | +---------+ 238 | |<- SIP ->| Client |<- SIP ->| | 239 | UA-A | | (SRC) | | UA-B | 240 | |<- RTP/->| |<- RTP/->| | 241 +--------+ RTCP | | RTCP +---------+ 242 +-------------+ 243 |____________________________________________________| 244 (Communication Session) 246 Figure 1: B2BUA Acts as the Session Recording Client. 248 3.1.2. Endpoint acts as Session Recording Client 250 A SIP Endpoint / UA may act as a Session Recording Client in which 251 case the endpoint sends the Replicated Media to the Session Recording 252 Server 254 If the endpoint makes the decision to initiate the Recording Session 255 then it will initiate the establishment of a SIP Session by sending 256 an INVITE to the Session Recording Server. 258 If the Session Recording Server makes the decision to initiate the 259 Recording Session then it will initiate the establishment of a SIP 260 Session by sending an INVITE to the endpoint. The actual decision 261 mechanism is out of scope of SIPREC. 263 (Recording Session) +-----------+ 264 +----------SIP------>| | 265 | +----RTP/RTCP---->| Session | 266 | | | Recording | 267 | | | Server | 268 | | +-- Metadata -->| (SRS) | 269 | | | | | 270 | | | +-----------+ 271 | | | 272 | | | 273 | | | 274 | | | 275 V V | (Communication Session) 276 +--+------+ +---------+ 277 | |<-------SIP--------->| | 278 | UA-A | | UA-B | 279 | (SRC) |<-----RTP/RTCP------>| | 280 +---------+ +---------+ 282 Figure 2: SIP Endpoint acts as the Session Recording Client 284 3.1.3. A SIP Proxy cannot be a Session Recording Client 286 A SIP Proxy is unable to act as an SRC because it does not have 287 access to the media and therefore has no way of enabling the delivery 288 of the replicated media to the SRS 290 3.1.4. Interaction with MEDIACTRL 292 The mediactrl architecture [RFC5567] describes an architecure in 293 which an Application Server (AS) controls a Media Server (MS) which 294 may be used for purposes such as conferencing and recording media 295 streams. In the [RFC5567] architecure the AS typically uses SIP 296 Third Party Call Control (3PCC) to instruct the SIP UAs to direct 297 their media to the Media Server. 299 The Session Recording Client and Session Recording Server described 300 in this document may act as an application server as described in 301 [RFC5567]; and therefore, when further decomposed, may be made up of 302 an application server which uses a mediactrl interface to control a 303 media server for the purpose of recording the media streams. 304 However, this interface is considered outside the scope of this 305 document. 307 Session Recording Server (SRS) 308 +----------------------------------------+ 309 | | 310 (Recording Session) | +-----------+ +------------+ | 311 +------------SIP----|->| | | | | 312 | | | MediaCtrl |MEDIACTRL | Media | | 313 | | |Application|<-------->| Server | | 314 | +-----Metadata--->| Server | | (Recorder)| | 315 | | | | | | | | 316 | | | +-----------+ +------------+ | 317 | | | ^ | 318 | | +------------------------------|---------+ 319 | | +--------------- RTP/RTCP -----------------+ 320 | | | 321 V | V 322 +---+------+ +---------+ 323 | |<-------SIP-------------->| | 324 | UA-A | (Communication Session) | UA-B | 325 | (SRC) |<-------RTP/RTCP--------->| | 326 +----------+ +---------+ 328 Figure 3: Example of Session Recording Server using MEDIACTRL 329 +----------+ 330 (Recording Session) | Session | 331 +-----------SIP------------------------->|Recording | 332 | | Server | 333 | | (SRS) | 334 | UA-A Session Recording Client (SRC) +----------+ 335 +----------------------------------------+ ^ 336 | | | 337 | +-----------+ +------------+ | | 338 | | | Control | |<-RTP/RTCP-+ +---------+ 339 | | UA | Protocol | Media | | | | 340 | |Application|<-------->| Server | |<----SIP----->| UA-B | 341 | | Server | | |<-----RTP------>| | 342 | | | | | | +---------+ 343 | +-----------+ +------------+ | 344 | | 345 +----------------------------------------+ 346 Figure 4: Example of Session Recording Client decomposition 348 3.1.5. Interaction with Conference Focus 350 In the case of a centralised conference a combination of the 351 conference focus and mixer [RFC4353] may act as a SRC and therefore 352 provide the SRS with the replicated media and associated recording 353 metadata. In this arrangement the SRC is able to provide media and 354 metadata relating to each of the participants, including, for 355 example, any side conversations where the media passes through the 356 mixer. 358 Conference Focus can either provide mixed replicated media or 359 separate streams per conference participant (as depicted in the 360 Figure 5). 362 The conference focus may also act as a Recording Aware UA in the case 363 when one of the participants acts as a SRC. 365 In an alternative arrangement a SIP endpoint which is a conference 366 participant can act as an SRC. The SRC will in this case have access 367 to the media and metadata relating to that particular participant and 368 may be able to obtain additional metadata from the conference focus. 369 The SRC may for example use the conference event package as described 370 in [RFC4575] to obtain information about other participants which it 371 provides to the SRS within the recording metadata. 373 The SRC may be involved in the conference from the very beginning or 374 may join at some later point of time. 376 User 1 377 +-----------+ 378 | | 379 | | 380 |Participant| 381 | 1 | 382 | | 383 +-----------+ 384 ^ ^SIP 385 RTP | |Dialog 386 | |1 387 User 2 V V Recording 388 +-----------+ +-----------+ Session ************* 389 | | | |<------------>* * 390 | |<-- RTP -->| |<-RTP/RTCP 1->* * 391 |Participant|<--------->| Focus/SRC |<-RTP/RTCP 2->* SRS * 392 | 2 | SIP | |<-RTP/RTCP 3->* * 393 | | Dialog | | * * 394 +-----------+ 2 +-----------+ ************* 395 ^ ^ 396 | |SIP 397 RTP | |Dialog 398 | |3 399 V V 400 +-----------+ 401 | | 402 | | 403 |Participant| 404 | 3 | 405 | | 406 +-----------+ 407 User 3 409 Figure 5: Conference Focus acting as an SRC. 411 3.2. Establishing the Recording Session 413 The Session Recording Client or the Session Recording Server may 414 initiate the Recording Session. 416 It should be noted that the Recording Session is independent from the 417 Communication Session that is being recorded at both the SIP dialog 418 level and at the session level. 420 Concerning media negotiation, regular SIP/SDP capabilities should be 421 used, and existing transcoding capabilities and media encryption 422 should not be precluded. 424 3.2.1. Session Recording Client Initiated Recording 426 When the Session Recording Client initiates the Recording Session for 427 the purpose of conveying media to the Session Recording Server it 428 performs the following actions. 430 o The SRC is provisioned with a Unified Resource Identifier (URI) 431 for the SRS, which is resolved through normal [RFC3263] 432 procedures. 434 o Initiates the dialog by sending an INVITE request to the Session 435 Recording Server. The dialog is established according to the 436 normal procedures for establishing an INVITE initiated dialog as 437 specified in [RFC3261]. 439 o Include in the INVITE an indication that the session is 440 established for the purpose of recording the associated media. 442 o If the Replicated Media is to be started immediately then the 443 Session Recording Client will include an SDP attribute of 444 "a=sendonly" for each media line or "a=inactive" if it is not 445 ready to transmit the media. 447 o The Recording Session may replicate all media associated with the 448 Communication Session or only a subset. 450 o Replicate the media streams that are to be recorded and transmit 451 the media to the Session Recording Server. 453 3.2.2. Session Recording Server Initiated Recording 455 When the Session Recording Server initiates the media recording 456 session with the Session Recording Client it performs the following 457 actions. 459 o The SRS is provisioned with a Unified Resource Identifier (URI) 460 for the SRC, which is resolved through normal [RFC3263] 461 procedures. 463 o Send an INVITE request to the Session Recording Client 465 o Include in the INVITE an indication that the session is 466 established for the purpose of recording the associated media. 467 Possible mechanisms for this include using the Require header or a 468 media feature tag as defined in [RFC3840]. 470 o Identify the sessions that is to be recorded. The actual 471 mechanism of the identification depends on SRC policy. 473 o If the Recording Session is to be started immediately then the 474 Session Recording Client will include an SDP attribute of 475 "a=recvonly" for each media line or "a=inactive" if it is not 476 ready to receive the media 478 If the Session Recording Server does not have prior knowledge of what 479 media streams are available to be recorded it can make use of an 480 offerless INVITE which allows the Session Recording Client to make 481 the initial Session Description Protocol (SDP) offer. 483 3.2.3. Pause/Resume Recording Session 485 The Session Recording Server or the Session Recording Client may 486 pause the recording by changing the SDP direction attribute to 487 "inactive" and resume the recording by changing the direction back to 488 "recvonly" or "sendonly". 490 3.2.4. Media Stream Mixing 492 In a basic session involving only audio there are typically two 493 audio/RTP streams between the two UAs involved transporting media in 494 each direction. When recording this media the two streams may be 495 mixed at the SRC before being transmitted to the SRS or it may be a 496 requirement of the recording server that the media streams are not 497 mixed and are sent to the SRS as two separate streams. The case when 498 media is mixed at the SRC is simple as only a single media stream is 499 required to be sent to the SRS. However in the case when the media 500 streams are not mixed then the SDP offer sent to the SRS must 501 describe two separate media streams. 503 3.2.5. Media Transcoding 505 The communication session (CS) and the recording session (RS) are 506 negotiated separately using a standard SDP offer/answer exchange 507 which may result in the SRC having to perform media transcoding 508 between the two sessions. If the SRC is not capable of performing 509 media transcoding it may limit the media formats in the offer to the 510 SRS depending on what media is negotiated on the CS or may limit what 511 it includes in the offer on the CS if it has prior knowledge of the 512 media formats supported by the SRS. However typically the SRS will 513 be a more capable device which can provide a wide range of media 514 format options to the SRC and may also be able to make use of a media 515 transcoder as detailed in [RFC5369]. 517 3.3. Recording Metadata 518 3.3.1. Contents of recording metadata 520 The metadata model is defined in [I-D.ietf-siprec-metadata]. 522 3.3.2. Mechanisms for delivery of metadata to Session Recording Server 524 The SRS obtains session recording metadata from the SRC. The 525 metadata is transported via SIP based mechanisms as specified in 526 [I-D.ietf-siprec-protocol] 528 It is also possible that metadata is transported via non SIP based 529 mechanisms but these are considered out of scope. 531 It is also possible to have RS session without the metadata, in such 532 case SRS will be receiving it by some other means or not at all. 534 3.4. Notifications to the Recorded User Agents 536 Typically a user that is involved in a session that is to be recorded 537 is notified by an announcement at the beginning of the session or may 538 receive some warning tones within the media. However the 539 standardization of media recording protocols when using SIP enable an 540 indication that the call is being recorded to be included in the SIP 541 requests and responses associated with that communication session. 543 It is the Session Recording Client that provides the notification to 544 all SIP UAs for which it is replicating received media for the 545 purpose of recording including the local user if the Session 546 Recording Client is a SIP endpoint. 548 3.5. Preventing the recording of a SIP session 550 A Recording Aware UA may during the initial session establishment or 551 during an established session provide an indication of their 552 preference with regard to recording the media in the communication 553 session. The mechanism for this are specified in 554 [I-D.ietf-siprec-protocol] 556 4. IANA considerations 558 This draft mentions SIP/SDP extensions. The associated IANA 559 considerations are addressed in [I-D.ietf-siprec-protocol] that 560 defines them. 562 5. Security considerations 564 The Recording Session is fundamentally a standard SIP dialog and 565 media session and therefore makes use of existing SIP security 566 mechanisms for securing the Recording Session and Recording Metadata. 568 The intended use of this architecture is only for the case where the 569 users are aware that they are being recorded, and the architecture 570 provides the means for the Session Recording Client to notify users 571 that they are being recorded. 573 This architectural solution is not intended to support lawful 574 intercept which in contrast requires that users are not informed. 576 It is the responsibility of the Session Recording Server to protect 577 the Replicated Media and Recording Metadata once it has been received 578 and archived. The mechanism for protecting the storage and retrieval 579 from the SRS is out of scope of this work. 581 Protection of the RS should be not weaker than protection of the CS, 582 and may need to be stronger because the media is retransmitted 583 (allowing more possibility for interception). This applies to both 584 the signaling and media paths. 586 It is essential that the SRC will authenticate the SRS because the 587 client must be certain that it is recording on the right recording 588 system. It is less important that the SRS authenticate the SRC, but 589 implementations must have the ability to perform mutual 590 authentication. 592 In some environments, it is desirable to not decrypt and re-encrypt 593 the media. This means the same key is used on the CS and RS. This 594 only works when the media is encrypted, not the transport. When the 595 media must be decrypted on the CS, and is re-encrypted on the RS, a 596 new key must be used. 598 The retrieval mechanism for media recorded by this protocol is out of 599 scope. Implementations of retrieval mechanisms should consider the 600 security implications carefully as the retriever is not usually a 601 party to the call that was recorded. Retrievers should be 602 authenticated carefully. The crypto suites on the retrieval should 603 be no less strong than used on the RS, and may need to be stronger. 605 6. Acknowledgements 607 Thanks to John Elwell, Brian Rosen, Alan Johnson, Cullen Jennings, 608 Hadriel Kaplan, Henry Lum, Paul Kyzivat, Parthasarathi R, Ram Mohan 609 R, Charles Eckel and Friso Feenstra for their significant 610 contributions and assistance with this document and Working Group, 611 and to all the members of SIPREC WG mailing list for providing 612 valuable input to this work. 614 7. Informative References 616 [RFC3261] Rosenberg, J., Schulzrinne, H., Camarillo, G., Johnston, 617 A., Peterson, J., Sparks, R., Handley, M., and E. 618 Schooler, "SIP: Session Initiation Protocol", RFC 3261, 619 June 2002. 621 [RFC3263] Rosenberg, J. and H. Schulzrinne, "Session Initiation 622 Protocol (SIP): Locating SIP Servers", RFC 3263, 623 June 2002. 625 [RFC4566] Handley, M., Jacobson, V., and C. Perkins, "SDP: Session 626 Description Protocol", RFC 4566, July 2006. 628 [RFC6341] Rehor, K., Portman, L., Hutton, A., and R. Jain, "Use 629 Cases and Requirements for SIP-Based Media Recording 630 (SIPREC)", RFC 6341, August 2011. 632 [I-D.ietf-siprec-metadata] 633 R, R., Ravindran, P., and P. Kyzivat, "Session Initiation 634 Protocol (SIP) Recording Metadata", 635 draft-ietf-siprec-metadata-06 (work in progress), 636 March 2012. 638 [I-D.ietf-siprec-protocol] 639 Portman, L., Lum, H., Eckel, C., Johnston, A., and A. 640 Hutton, "Session Recording Protocol", 641 draft-ietf-siprec-protocol-04 (work in progress), 642 May 2012. 644 [RFC3265] Roach, A., "Session Initiation Protocol (SIP)-Specific 645 Event Notification", RFC 3265, June 2002. 647 [RFC3840] Rosenberg, J., Schulzrinne, H., and P. Kyzivat, 648 "Indicating User Agent Capabilities in the Session 649 Initiation Protocol (SIP)", RFC 3840, August 2004. 651 [RFC4353] Rosenberg, J., "A Framework for Conferencing with the 652 Session Initiation Protocol (SIP)", RFC 4353, 653 February 2006. 655 [RFC4575] Rosenberg, J., Schulzrinne, H., and O. Levin, "A Session 656 Initiation Protocol (SIP) Event Package for Conference 657 State", RFC 4575, August 2006. 659 [RFC5567] Melanchuk, T., "An Architectural Framework for Media 660 Server Control", RFC 5567, June 2009. 662 [RFC5369] Camarillo, G., "Framework for Transcoding with the Session 663 Initiation Protocol (SIP)", RFC 5369, October 2008. 665 [RFC2804] IAB and IESG, "IETF Policy on Wiretapping", RFC 2804, 666 May 2000. 668 Authors' Addresses 670 Andrew Hutton (editor) 671 Siemens Enterprise Communications 672 Hofmannstrasse 51 673 Munich D-81379 674 Germany 676 Email: andrew.hutton@siemens-enterprise.com 678 Leon Portman (editor) 679 NICE Systems 680 8 Hapnina 681 Ra'anana 43017 682 Israel 684 Email: leon.portman@nice.com 686 Rajnish Jain 687 IPC Systems 688 777 Commerce Drive 689 Fairfield, CT 06825 690 USA 692 Email: rajnish.jain@ipc.com 693 Ken Rehor 694 Cisco Systems, Inc. 695 170 West Tasman Drive 696 San Jose, CA 95134-1706 697 USA 699 Email: krehor@cisco.com