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'I-D.sinnreich-sipdev-req') ** Obsolete normative reference: RFC 822 (Obsoleted by RFC 2822) ** Obsolete normative reference: RFC 2246 (Obsoleted by RFC 4346) ** Obsolete normative reference: RFC 2616 (Obsoleted by RFC 7230, RFC 7231, RFC 7232, RFC 7233, RFC 7234, RFC 7235) ** Obsolete normative reference: RFC 2617 (Obsoleted by RFC 7235, RFC 7615, RFC 7616, RFC 7617) ** Obsolete normative reference: RFC 2818 (Obsoleted by RFC 9110) ** Obsolete normative reference: RFC 3265 (Obsoleted by RFC 6665) ** Obsolete normative reference: RFC 3377 (Obsoleted by RFC 4510) ** Downref: Normative reference to an Informational RFC: RFC 3617 Summary: 11 errors (**), 0 flaws (~~), 12 warnings (==), 5 comments (--). Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 SIPPING D. Petrie 3 Internet-Draft Pingtel Corp. 4 Expires: November 15, 2004 May 17, 2004 6 A Framework for Session Initiation Protocol User Agent Profile 7 Delivery 8 draft-ietf-sipping-config-framework-03.txt 10 Status of this Memo 12 This document is an Internet-Draft and is in full conformance with 13 all provisions of Section 10 of RFC2026. 15 Internet-Drafts are working documents of the Internet Engineering 16 Task Force (IETF), its areas, and its working groups. Note that 17 other groups may also distribute working documents as 18 Internet-Drafts. 20 Internet-Drafts are draft documents valid for a maximum of six months 21 and may be updated, replaced, or obsoleted by other documents at any 22 time. It is inappropriate to use Internet-Drafts as reference 23 material or to cite them other than as "work in progress." 25 The list of current Internet-Drafts can be accessed at 26 http://www.ietf.org/ietf/1id-abstracts.txt. 28 The list of Internet-Draft Shadow Directories can be accessed at 29 http://www.ietf.org/shadow.html. 31 This Internet-Draft will expire on November 15, 2004. 33 Copyright Notice 35 Copyright (C) The Internet Society (2004). All Rights Reserved. 37 Abstract 39 This document defines the application of a set of protocols for 40 providing profile data to SIP user agents. The objective is to 41 define a means for automatically providing profile data a user agent 42 needs to be functional without user or administrative intervention. 43 The framework for discovery, delivery, notification and updates of 44 user agent profile data is defined here. As part of this framework a 45 new SIP event package is defined here for the notification of profile 46 changes. This framework is also intended to ease ongoing 47 administration and upgrading of large scale deployments of SIP user 48 agents. The contents and format of the profile data to be defined is 49 outside the scope of this document. 51 Table of Contents 53 1. Motivation . . . . . . . . . . . . . . . . . . . . . . . . . 3 54 2. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3 55 2.1 Requirements Terminology . . . . . . . . . . . . . . . . . 3 56 2.2 Profile Delivery Framework Terminology . . . . . . . . . . 4 57 2.3 Overview . . . . . . . . . . . . . . . . . . . . . . . . . 4 58 3. Profile Change Event Notification Package . . . . . . . . . 6 59 3.1 Event Package Name . . . . . . . . . . . . . . . . . . . . 6 60 3.2 Event Package Parameters . . . . . . . . . . . . . . . . . 6 61 3.3 SUBSCRIBE Bodies . . . . . . . . . . . . . . . . . . . . . 9 62 3.4 Subscription Duration . . . . . . . . . . . . . . . . . . 9 63 3.5 NOTIFY Bodies . . . . . . . . . . . . . . . . . . . . . . 9 64 3.6 Notifier processing of SUBSCRIBE requests . . . . . . . . 10 65 3.7 Notifier generation of NOTIFY requests . . . . . . . . . . 10 66 3.8 Subscriber processing of NOTIFY requests . . . . . . . . . 11 67 3.9 Handling of forked requests . . . . . . . . . . . . . . . 11 68 3.10 Rate of notifications . . . . . . . . . . . . . . . . . 11 69 3.11 State Agents . . . . . . . . . . . . . . . . . . . . . . 12 70 3.12 Examples . . . . . . . . . . . . . . . . . . . . . . . . 12 71 3.13 Use of URIs to Retrieve State . . . . . . . . . . . . . 13 72 4. Profile Delivery Framework Details . . . . . . . . . . . . . 13 73 4.1 Discovery of Subscription URI . . . . . . . . . . . . . . 13 74 4.2 Enrollment with Profile Server . . . . . . . . . . . . . . 15 75 4.3 Notification of Profile Changes . . . . . . . . . . . . . 15 76 4.4 Retrieval of Profile Data . . . . . . . . . . . . . . . . 15 77 4.5 Upload of Profile Changes . . . . . . . . . . . . . . . . 16 78 5. IANA Considerations . . . . . . . . . . . . . . . . . . . . 16 79 5.1 SIP Event Package . . . . . . . . . . . . . . . . . . . . 16 80 6. Security Considerations . . . . . . . . . . . . . . . . . . 16 81 6.1 Symmetric Encryption of Profile Data . . . . . . . . . . . 16 82 7. Differences from Simple XCAP Package . . . . . . . . . . . . 17 83 8. Open Issues . . . . . . . . . . . . . . . . . . . . . . . . 17 84 9. Change History . . . . . . . . . . . . . . . . . . . . . . . 17 85 9.1 Changes from draft-ietf-sipping-config-framework-02.txt . 18 86 9.2 Changes from draft-ietf-sipping-config-framework-01.txt . 18 87 9.3 Changes from draft-ietf-sipping-config-framework-00.txt . 18 88 9.4 Changes from 89 draft-petrie-sipping-config-framework-00.txt . . . . . . . 18 90 9.5 Changes from draft-petrie-sip-config-framework-01.txt . . 19 91 9.6 Changes from draft-petrie-sip-config-framework-00.txt . . 19 92 10. References . . . . . . . . . . . . . . . . . . . . . . . . . 19 93 Author's Address . . . . . . . . . . . . . . . . . . . . . . 21 94 A. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . 21 95 Intellectual Property and Copyright Statements . . . . . . . 22 97 1. Motivation 99 Today all SIP user agent implementers use proprietary means of 100 delivering user or device profiles to the user agent. The profile 101 delivery framework defined in this document is intended to enable a 102 first phase migration to a standard means of providing profiles to 103 SIP user agents. It is expected that UA implementers will be able to 104 use this framework as a means of delivering their existing 105 proprietary user and device data profiles (i.e. using their existing 106 proprietary binary or text formats). This in itself is a tremendous 107 advantage in that a SIP environment can use a single profile delivery 108 server for profile data to user agents from multiple implementers. 109 Follow-on standardization activities can: 110 1. define a standard profile content format framework (e.g. XML 111 with name spaces [??] or name-value pairs [RFC0822]). 112 2. specify the content (i.e. name the profile data parameters, xml 113 schema, name spaces) of the data profiles. 115 One of the objectives of the framework described in this document is 116 to provide a start up experience similar to that of users of an 117 analog telephone. When you plug in an analog telephone it just works 118 (assuming the line is live and the switch has been provisioned). 119 There is no end user configuration required to make analog phone 120 work, at least in a basic sense. So the objective here is to be able 121 to take a new SIP user agent out of the box, plug it in or install 122 the software and have it get its profiles without human intervention 123 other than security measures. This is necessary for cost effective 124 deployment of large numbers of user agents. 126 Another objective is to provide a scalable means for ongoing 127 administration of profiles. Administrators and users are likely to 128 want to make changes to user and device profiles. 130 Additional requirements for the framework defined in this document 131 are described in: [I-D.ietf-sipping-ua-prof-framewk-reqs], 132 [I-D.sinnreich-sipdev-req] 134 2. Introduction 136 2.1 Requirements Terminology 138 Keywords "MUST", "MUST NOT", "REQUIRED", "SHOULD", "SHOULD NOT" and 139 "MAY" that appear in this document are to be interpreted as described 140 in RFC 2119[RFC2119]. 142 2.2 Profile Delivery Framework Terminology 144 profile - data set specific to a user or device. 145 device - SIP user agent, either software or hardware appliance. 146 profile content server - The server that provides the content of the 147 profiles using the protocol specified by the URL scheme. 148 notifier - The SIP user agent server which processes SUBSCRIBE 149 requests for events and sends NOTIFY requests with profile data or 150 URI(s) point to the data. 151 profile delivery server - The logical collection of the SIP notifier 152 and the server which provides the contents of the profile URI(s). 154 2.3 Overview 156 The profile life cycle can be described by five functional steps. 157 These steps are not necessarily discrete. However it is useful to 158 describe these steps as logically distinct. These steps are named as 159 follows: 161 Discovery - discover a profile delivery server 162 Enrollment - enroll with the profile delivery server 163 Profile Retrieval - retrieve profile data 164 Profile Change Notification - receive notification of profile changes 165 Profile Change Upload - upload profile data changes back to the 166 profile delivery server 168 Discovery is the process by which a UA finds the address and port at 169 which it enrolls with the profile delivery server. As there is no 170 single discovery mechanism which will work in all network 171 environments, a number of discovery mechanisms are defined with a 172 prescribed order in which the UA tries them until one succeeds. 174 Enrollment is the process by which a UA makes itself known to the 175 profile delivery server. In enrolling the UA provides identity 176 information, name requested profile type(s) and supported protocols 177 for profile retrieval. It also subscribes to a mechanism for 178 notification of profile changes. As a result of enrollment, the UA 179 receives the data or the URI for each of the profiles that the 180 profile delivery server is able to provide. Each profile type (set) 181 requires a separate enrollment or SUBSCRIBE session. 183 Profile Retrieval is the process of retrieving the content for each 184 of the profiles the UA requested. 186 Profile Change Notification is the process by which the profile 187 delivery server notifies the UA that the content of one or more of 188 the profiles has changed. If the content is provided indirectly the 189 UA SHOULD retrieve the profile from the specified URI upon receipt of 190 the change notification. 192 Profile Upload is the process by which a UA or other entity (e.g. 193 OSS, corporate directory or configuration management server) pushes a 194 change to the profile data back up to the profile delivery server. 196 This framework defines a new SIP event package [RFC3265] to solve 197 enrollment and profile change notification steps. 199 The question arises as to why SIP should be used for the profile 200 delivery framework. In this document SIP is used for only a small 201 portion of the framework. Other existing protocols are more 202 appropriate for transport of the profile contents (to and from the 203 user agent) and are suggested in this document. The discovery step 204 is simply a specified order and application of existing protocols. 205 SIP is only needed for the enrollment and change notification 206 functionality of the profile delivery framework. In many SIP 207 environments (e.g. carrier/subscriber and multi-site enterprise) 208 firewall, NAT and IP addressing issues make it difficult to get 209 messages between the profile delivery server and the user agent 210 requiring the profiles. 212 With SIP the users and devices already are assigned globally routable 213 addresses. In addition the firewall and NAT problems are already 214 presumably solved in the environments in which SIP user agents are to 215 be used. Therefore SIP is the best solution for allowing the user 216 agent to enroll with the profile delivery server which may require 217 traversal of multiple firewalls and NATs. For the same reason the 218 notification of profile changes is best solved by SIP. 220 It is assumed that the content delivery server will be either in the 221 public network or accessible through a DMZ. The user agents 222 requiring profiles may be behind firewalls and NATs and many 223 protocols, such as HTTP, may be used for profile content retrieval 224 without special consideration in the firewalls and NATs. 226 A conscious separation of user, device and local network profiles is 227 made in this document. This is useful to provide features such as 228 hoteling as well as securing or restricting user agent functionality. 229 By maintaining this separation, a user may walk up to someone else's 230 user agent and direct that user agent to get their profile data. In 231 doing so the user agent can replace the previous user's profile data 232 while still keeping the devices profile data that may be necessary 233 for core functionality and communication described in this document. 234 The local network profiles are relevant to a visiting device which 235 gets plugged in to a foreign network. The concept of the local 236 network providing profile data is useful to provide hoteling 237 (described above) as well as local policy data that may constrain the 238 user or device behavior relative to the local network. For example 239 media types and codecs may be constrained to reflect the networks 240 capabilities. 242 3. Profile Change Event Notification Package 244 This section defines a new SIP event package [RFC3265]. The purpose 245 of this event package is to send to subscribers notification of 246 content changes to the profile(s) of interest and to provide the 247 location of the profile(s) via content indirection 248 [I-D.ietf-sip-content-indirect-mech] or directly in the body of the 249 NOTIFY. Frequently the profiles delivered to the user agent are much 250 larger (e.g. several KB or even several MB) than the MTU of the 251 network. These larger profiles will cause larger than normal SIP 252 messages and consequently higher impact on the SIP servers and 253 infrastructure. To avoid the higher impact and load on the SIP 254 infrastructure, content indirection SHOULD be used if the profile is 255 large enough to cause packet fragmentation over the transport 256 protocol. The user agent SHOULD specify the profile delivery means 257 and format via the MIME type in the Accepts header. 259 The MIME types or formats of profile to be delivered via this 260 framework are to be defined in other documents. These profile MIME 261 types specified in the Accepts header along with the profile types 262 specified in the Event header parameter "profile-name" MAY be used to 263 specify which profiles get delivered either directly or indirectly in 264 the NOTIFY requests. When content indirection is not used, it is 265 more important to specify the minimum set of profiles, as the entire 266 content for all of the profiles is included in the NOTIFY request. 268 3.1 Event Package Name 270 The name of this package is "sip-profile". This value appears in the 271 Event header field present in SUBSCRIBE and NOTIFY requests for this 272 package as defined in [RFC3265]. 274 3.2 Event Package Parameters 276 This package defines the following new parameters for the event 277 header: profile-name, vendor, model, version, effective-by. The 278 effective-by parameter is for use in NOTIFY requests only. The 279 others are for use in the SUBSCRIBE request, but may be used in 280 NOTIFY requests as well. 282 The profile-name parameter is used to indicate the token name of the 283 profile type the user agent wishes to obtain URIs for or to 284 explicitly specify the URI to which it is to be notified of change. 285 Using a token in this parameter allows the URL semantics for 286 retrieving the profiles to be opaque to the subscribing user agent. 287 All it needs to know is the token value for this parameter. However 288 in some cases the user agent may know the URI of the profile and only 289 wishes to know about changes to the profile. The user agent MAY 290 supply the URI for the profile as the value of the profile-name 291 parameter. This document defines three type categories of profiles 292 and their token names. The contents or format of the profiles is 293 outside the scope of this document. The three types of profiles 294 define here are "user", "device" and "local". Specifying device type 295 profile(s) indicates the desire for the profile(s) (URIs when content 296 indirection is used) and change notification of all profiles that are 297 specific to the device or user agent. Specifying user type 298 profile(s) indicates the desire for the profiles(s) or URI(s) and 299 change notification of all profile(s) that are specific to the user. 300 Specifying local type profiles indicates the desire for profile(s) or 301 URI(s) specific to the local network. The user, device or local 302 network is identified in the URI of the SUBSCRIBE request. The 303 Accept header of the SUBSCRIBE request MUST include the MIME types 304 for all profile content types that the subscribing user agent wishes 305 to retrieve profiles or receive change notifications. 307 The user, device or local token in the profile-name parameter may 308 represent a class or set of profiles as opposed to a single 309 profile. As standards are defined for specific profile contents 310 related to the user device or local network, it may be desirable 311 to define additional tokens for the profile-name header. This is 312 to allow a user agent to subscribe to that specific profile as 313 opposed to the entire class or set of user or device profiles. 315 The rational for the separation of user, device and local network 316 type profiles is provided in Section 2.3. It should be noted that 317 any of the types may indicate that zero or more profiles or URIs are 318 provided in the NOTIFY request. As discussed, a default user may be 319 assigned to a device. In this scenario the profile delivery server 320 may provide the URI(s) in the NOTIFY request for the default user 321 when subscribing to the device profile type. Effectively the device 322 profile type becomes a superset of the user profile type 323 subscription. That is the list of profile URIs (or MIME parts if 324 multiple profiles are provided directly in the NOTIFY) provided when 325 requesting profile type "device" includes the profiles provided when 326 subscribing for profile type "user" for the default user of that 327 device. The user type is still useful in this scenario to allow the 328 user agent to obtain profile data or URIs for a user other than the 329 default user. This provides the ability to support a hoteling 330 function where a user may "login" to any user agent and have it use a 331 user's profile(s). 333 The data provided in the three types of profiles may overlap. As an 334 example the codecs that a user prefers to use, the codecs that the 335 device supports (and the enterprise wishes to use), the codecs that 336 the local network can support (and the management wishes to allow) 337 all may overlap in how they are specified in the three corresponding 338 profiles. Typically these should be applied in the order of the 339 least to most constraint (i.e. user, device then local network). 340 However this policy of merging the constraints across the multiple 341 profile types can only unambiguously be defined along with the 342 profile format and syntax. This is out of scope for this document. 344 The "vendor", "model" and "version" parameter values are tokens 345 specified by the vendor of the user agent. These parameters are 346 useful to the profile delivery server to affect the profiles 347 provided. In some scenarios it is desirable to provide different 348 profiles based upon these parameters. For example feature parameter 349 X in a profile may work differently on two versions of user agent. 350 This gives the profile deliver server the ability to compensate for 351 or take advantage of the differences. 353 The "network-user" parameter is used when subscribing for local 354 network profiles. If the value of the profile-name parameter is not 355 "local", the "network-user" parameter has no defined meaning. If the 356 user has special privileges beyond that of an anonymous user in the 357 local network, the "network-user" parameter identifies the user to 358 the local network. The value of this parameter is the user's address 359 of record. The SUBSCRIBE server may authenticate the subscriber to 360 verify this AOR. 362 The "effective-by" parameter in the Event header of the NOTIFY 363 specifies the maximum number of seconds before the user agent MUST 364 make the new profile effective. A value of 0 (zero) indicates that 365 the user agent MUST make the profiles effective immediately (despite 366 possible service interruptions). This gives the profile delivery 367 server the power to control when the profile is effective. This may 368 be important to resolve an emergency problem or disable a user agent 369 immediately. 371 SUBSCRIBE request example: 372 Event: sip-profile;profile-name=device; 373 vendor=acme;model=Z100;version=1.2.3 375 Event: sip-profile;profile-name= 376 "http://example.com/services/user-profiles/users/freds.xml"; 377 vendor=premier;model=trs8000;version=5.5 379 NOTIFY request examples: 380 Event:sip-profile;effective-by=0 381 Event:sip-profile;effective-by=3600 383 3.3 SUBSCRIBE Bodies 385 This package defines no new use of the SUBSCRIBE request body. 387 3.4 Subscription Duration 389 As the presence (or lack of) a device or user agent it not very time 390 critical to the functionality of the profile delivery server, it is 391 recommended that default subscription duration be 86400 seconds (one 392 day). 394 3.5 NOTIFY Bodies 396 The size of profile content is likely to be hundreds to several 397 thousand bytes in size. Frequently even with very modest sized SDP 398 bodies, SIP messages get fragmented causing problems for many user 399 agents. For this reason the profile delivery server MUST use content 400 indirection [I-D.ietf-sip-content-indirect-mech] in the NOTIFY body 401 for providing the profiles if the Accept header of the SUBSCRIBE 402 included the MIME type: message/external-body indicating support for 403 content indirection. 405 When delivering profiles via content indirection the profile delivery 406 server MUST include the Content-ID defined in 407 [I-D.ietf-sip-content-indirect-mech] for each profile URL. This is 408 to avoid unnecessary download of the profiles. Some user agents are 409 not able to make a profile effective without rebooting or restarting. 410 Rebooting is probably something to be avoided on a user agent 411 performing services such as telephony. In this way the Content-ID 412 allows the user agent to avoid unnecessary interruption of service as 413 well. The Content-Type MUST be specified for each URI. 415 Initially it is expected that most user agent implementers will 416 use a proprietary content type for the profiles retrieved from the 417 URIs(s). It is hoped that over time a standard content type will 418 be specified that will be adopted by implementers of user agents. 419 One direction that appears to be promising for this content is to 420 use XML with name spaces [??] to segment the data into sets that 421 the user agent implementer may choose to support based upon 422 desired feature set. The specification of the content is out of 423 the scope of this document. 425 Likewise the URL scheme used in the content indirection is outside 426 the scope of this document. This document is agnostic to the URL 427 schemes as the profile content may dictate what is required. It is 428 expected that TFTP [RFC3617], FTP [??], HTTP [RFC2616], HTTPS 429 [RFC2818], LDAP [RFC3377], XCAP [I-D.rosenberg-simple-xcap] and other 430 URL schemes are supported by this package and framework. 432 3.6 Notifier processing of SUBSCRIBE requests 434 The general rules for processing SUBSCRIBE requests [RFC3265] apply 435 to this package. If content indirection is used for delivering the 436 profiles, the notifier does not need to authenticate the subscription 437 as the profile content is not transported in the SUBSCRIBE or NOTIFY 438 transaction messages. With content indirection only URLs are 439 transported in the NOTIFY request which may be secured using the 440 techniques in Section 6. If content indirection is not used, SIPS 441 and SIP authentication SHOULD be used. 443 The behavior of the profile delivery server is left to the 444 implementer. The profile delivery server may be as simple as a SIP 445 SUBSCRIBE UAS and NOTIFY UAC front end to a simple HTTP server 446 delivering static files that are hand edited. At the other extreme 447 the profile delivery server can be part of a configuration management 448 system that integrates with a corporate directory and IT system or 449 carrier OSS, where the profiles are automatically generated. The 450 design of this framework intentionally provides the flexibility of 451 implementation from simple/cheap to complex/expensive. 453 If the user or device is not known to the profile delivery server, 454 the implementer MAY accept the subscription or reject it. It is 455 recommended that the implementer accept the subscription. It is 456 useful for the profile delivery server to maintain the subscription 457 as an administrator may add the user or device to the system, 458 defining the profile contents. This allows the profile delivery 459 server to immediately send a NOTIFY request with the profile URIs. 460 If the profile delivery server does not accept the subscription from 461 an unknown user or device, the administer or user must manually 462 provoke the user agent to reSUBSCRIBE. This may be difficult if the 463 user agent and administrator are at different sites. 465 3.7 Notifier generation of NOTIFY requests 467 As in [RFC3265], the profile delivery server MUST always send a 468 NOTIFY request upon accepting a subscription. If the device or user 469 is unknown to the profile delivery server and it chooses to accept 470 the subscription, the implementer has two choices. A NOTIFY MAY be 471 sent with no body or content indirection containing the profile 472 URI(s). Alternatively a NOTIFY MAY be sent with URI(s) pointing to a 473 default data set. Typically this data set allows for only limited 474 functionality of the user agent (e.g. a phone user agent with data 475 to call help desk and emergency services.). This is an 476 implementation and business policy decision. 478 A user or device known and fully provisioned on the profile delivery 479 server SHOULD send a NOTIFY with profile data or content indirection 480 containing URIs for all of the profiles associated with the user or 481 device (i.e. whichever specified in the profile-name parameter). 482 The device may be associated with a default user. The URI(s) for 483 this default user profiles MAY be included with the URI(s) of the 484 device if the profile type specified is device. 486 A user agent can provide Hoteling by collecting a user�s AOR and 487 credentials needed to SUBSCRIBE and retrieve the user profiles from 488 the URI(s). Hoteling functionality is achieved by subscribing to the 489 AOR and specifying the "user" profile type. This same mechanism can 490 be used to secure a user agent, requiring a user to login to enable 491 functionality beyond the default user�s restricted functionality. 493 The profile delivery server MAY specify when the new profiles MUST be 494 made effective by the user agent. By default the user agent makes 495 the profiles effective as soon as it thinks that it is non-obtrusive. 496 Profile changes SHOULD effect behavior all new sessions which are 497 created after the notification, but may not be able to effect 498 existing sessions. However the profile delivery server MAY specify a 499 maximum time in seconds (zero or more), in the effective-by event 500 header parameter, by which the user agent MUST make the new profiles 501 effective for all sessions. 503 3.8 Subscriber processing of NOTIFY requests 505 The user agent subscribing to this event package MUST adhere to the 506 NOTIFY request processing behavior specified in [RFC3265]. The user 507 agent MUST make the profiles effective as specified in the NOTIFY 508 request (see Section 3.7). The user agent SHOULD use one of the 509 techniques specified in [RFC3265] to securely retrieve the profiles. 511 3.9 Handling of forked requests 513 This event package allows the creation of only one dialog as a result 514 of an initial SUBSCRIBE request. The techniques to achieve this are 515 described in section 4.4.9 of [RFC3265]. 517 3.10 Rate of notifications 519 It is anticipated that the rate of change for user and device 520 profiles will be very infrequent (i.e. days or weeks apart). For 521 this reason no throttling or minimum period between NOTIFY requests 522 is specified for this package. 524 3.11 State Agents 526 State agents are not applicable to this event package. 528 3.12 Examples 530 SUBSCRIBE sip:00df1e004cd0@example.com SIP/2.0 531 Event: sip-profile;profile-name=device;vendor=acme; 532 model=Z100;version=1.2.3 533 From: sip:00df1e004cd0@acme.com;tag=1234 534 To: sip:00df1e004cd0@acme.com;tag=abcd 535 Call-ID: 3573853342923422@10.1.1.44 536 CSeq: 2131 SUBSCRIBE 537 Contact: sip:00df1e004cd0@10.1.1.44 538 Content-Length: 0 540 NOTIFY sip:00df1e004cd0@10.1.1.44 SIP/2.0 541 Event: sip-profile;effective-by=3600 542 From: sip:00df1e004cd0@acme.com;tag=abcd 543 To: sip:00df1e004cd0@acme.com;tag=1234 544 Call-ID: 3573853342923422@10.1.1.44 545 CSeq: 321 NOTIFY 546 MIME-Version: 1.0 547 Content-Type: multipart/mixed; boundary=boundary42 548 Content-Length: ... 550 --boundary42 551 Content-Type: message/external-body; 552 access-type="URL"; 553 expiration="Mon, 24 June 2002 09:00:00 GMT"; 554 URL="http://www.example.com/devices/fsmith"; 555 size=2222 557 Content-Type: application/z100-user-profile 558 Content-ID: <69ADF2E92@example.com> 560 --boundary42 561 Content-Type: message/external-body; 562 access-type="URL"; 563 expiration="Mon, 24 June 2002 09:00:00 GMT"; 564 URL="http://www.example.com/devices/ff00000036c5"; 565 size=1234 567 Content-Type: application/z100-device-profile 568 Content-ID: <39EHF78SA@example.com> 569 --boundary42-- 571 3.13 Use of URIs to Retrieve State 573 The profile type specified determines what goes in the user part of 574 the SUBSRIBE URI. If the profile type requested is "device", the 575 user part of the URI is an identity that MUST be unique across all 576 user agents from all implementers. This identity must be static over 577 time so that the profile delivery server can keep a specific device 578 and its identity associated with its profiles. For Ethernet hardware 579 type user agents supporting only a single user at a time this is most 580 easily accomplished using its MAC address. Software based user 581 agents running on general purpose hardware may also be able to use 582 the MAC address for identity. However in situations where multiple 583 instances of user agents are running on the same hardware it may be 584 necessary to use another scheme, such as using a unique serial number 585 for each software user agent instance. 586 For example a device having a MAC address of 00df1e004cd0 might 587 subscribe to the device profile URI: 588 sip:00df1e004cd0@sipuaconfig.example.com. When subscribing to a 589 user profile for user Fred S. the user agent would subscribe to 590 the URI: sip:freds@sipuaconfig.example.com 592 If the profile type requested is "user", the URI in the SUBSCRIBE 593 request is the address of record for the user. This allows the user 594 to specify (e.g. login) to the user agent by simply entering their 595 known identity. 597 If the profile type specified in the profile-name parameter is 598 "local", the URI in the SUBSCRIBE request has the user ID: anonymous. 599 The host part of the URI is the local network name. This typically 600 is discovered as part of the DHCP request/response or provisioned as 601 part of the static IP configuration for the device. When subscribing 602 to the local network profile type the device should provide the 603 user's address of record in the "network-user" parameter, if the AOR 604 is known to the device. Example URI: sip:ananymous@example.com 606 4. Profile Delivery Framework Details 608 The following describes how different functional steps of the profile 609 delivery framework work. Also described here is how the event 610 package defined in this document provides the enrollment and 611 notification functions within the framework. 613 4.1 Discovery of Subscription URI 615 The discovery function is needed to bootstrap user agents to the 616 point of knowing where to enroll with the profile delivery server. 617 Section 3.13 describes how to form the URI used to send the SUBSCRIBE 618 request for enrollment. However the bootstrapping problem for the 619 user agent (out of the box) is what to use for the host and port in 620 the URI. Due to the wide variation of environments in which the 621 enrolling user agent may reside (e.g. behind residential router, 622 enterprise LAN, ISP, dialup modem) and the limited control that the 623 administrator of the profile delivery server (e.g. enterprise, 624 service provider) may have over that environment, no single discovery 625 mechanism works everywhere. Therefore a number of mechanisms SHOULD 626 be tried in the specified order: SIP DHCP option [RFC3361], SIP DNS 627 SRV [RFC3263], DNS A record and manual. 629 1. The first discovery mechanism that SHOULD be tried is to 630 construct the SUBSCRIBE URI as described in Section 3.13 using 631 the host and port of out bound proxy discovered by the SIP DHCP 632 option as described in [RFC3361]. If the SIP DHCP option is not 633 provided in the DHCP response, no SIP response or a SIP failure 634 response other than for authorization is received for the 635 SUBSCRIBE request to the sip-profile event, the next discovery 636 mechanism SHOULD be tried. 637 2. The local IP network domain for the user agent, either configured 638 or discovered via DHCP, should be used with the technique in 639 [RFC3263] to obtain a host and port to use in the SUBSCRIBE URI. 640 If no SIP response or a SIP failure response other than for 641 authorization is received for the SUBSCRIBE request to the 642 sip-profile event, the next discovery mechanism SHOULD be tried. 643 3. The fully qualified host name constructed using the host name 644 "sipuaconfig" and concatenated with the local IP network domain 645 should be tried next using the technique in [RFC3263] to obtain a 646 host and port to use in the SUBSCRIBE URI. If no SIP response or 647 a SIP failure response other than for authorization is received 648 for the SUBSCRIBE request to the sip-profile event, the next 649 discovery mechanism SHOULD be tried. 650 4. If all other discovery techniques fail, the user agent MUST 651 provide a manual means for the user to enter the host and port 652 used to construct the SUBSCRIBE URI. 654 Once a user agent has successfully discovered, enrolled, received a 655 NOTIFY response with profile data or URI(s), the user agent SHOULD 656 cache the SUBCRIBE URI to avoid having to rediscover the profile 657 delivery server again in the future. The user agent SHOULD NOT cache 658 the SUBSCRIBE URI until it receives a NOTIFY with profile data or 659 URI(s). The reason for this is that a profile delivery server may 660 send 202 responses to SUBSCRIBE requests and NOTIFY responses to 661 unknown user agent (see Section 3.6) with no URIs. Until the profile 662 delivery server has sent a NOTIFY request with profile data or 663 URI(s), it has not agreed to provide profiles. 665 To illustrate why the user agent should not cache the SUBSCRIBE 666 URI until profile URI(s) are provided in the NOTIFY, consider the 667 following example: a user agent running on a laptop plugged into 668 a visited LAN in which a foreign profile delivery server is 669 discovered. The profile delivery server never provides profile 670 URIs in the NOTIFY request as it is not provisioned to accept the 671 user agent. The user then takes the laptop to their enterprise 672 LAN. If the user agent cached the SUBSCRIBE URI from the visited 673 LAN (which did not provide profiles), when subsequently placed in 674 the enterprise LAN which is provisioned to provide profiles to the 675 user agent, the user agent would not attempt to discover the 676 profile delivery server. 678 4.2 Enrollment with Profile Server 680 Enrollment is accomplished by subscribing to the event package 681 described in Section 3. The enrollment process is useful to the 682 profile delivery server as it makes the server aware of user agent to 683 which it may delivery profiles (those user agents the profile 684 delivery server is provisioned to provide profiles to; those present 685 that the server may be provide profiles in the future; and those that 686 the server can automatically provide default profiles). It is an 687 implementation choice and business policy as to whether the profile 688 delivery server provides profiles to user agents that it is not 689 provisioned to do so. However the profile server SHOULD accept (with 690 2xx response) SUBSCRIBE requests from any user agent. 692 4.3 Notification of Profile Changes 694 The NOTIFY request in the sip-profile event package serves two 695 purposes. First it provides the user agent with a means to obtain 696 the profile data or URI(s) for desired profiles without requiring the 697 end user to manually enter them. It also provides the means for the 698 profile delivery server to notify the user agent that the content of 699 the profiles have changed and should be made effective. 701 4.4 Retrieval of Profile Data 703 The user agent retrieves its needed profile(s) via the URI(s) 704 provided in the NOTIFY request as specified in Section 3.5. The 705 profile delivery server SHOULD secure the content of the profiles 706 using one of the techniques described in Section 6. The user agent 707 SHOULD make the new profiles effective in the timeframe described in 708 Section 3.2. 710 The contents of the profiles SHOULD be cached by the user agent. 711 This it to avoid the situation where the content delivery server is 712 not available, leaving the user agent non-functional. 714 4.5 Upload of Profile Changes 716 The user agent or other service MAY push changes up to the profile 717 delivery server using the technique appropriate to the profile's URL 718 scheme (e.g. HTTP PUT method, FTP put command). The technique for 719 pushing incremental or atomic changes MUST be described by the 720 specific profile data framework. 722 5. IANA Considerations 724 There are several IANA considerations associated with this 725 specification. 727 5.1 SIP Event Package 729 This specification registers a new event package as defined in 730 [RFC3265]. The following information required for this registration: 731 Package Name: sip-profile 732 Package or Template-Package: This is a package 733 Published Document: RFC XXXX (Note to RFC Editor: Please fill in 734 XXXX with the RFC number of this specification). 735 Person to Contact: Daniel Petrie dpetrie@pingtel.com 736 New event header parameters: profile-name, vendor, model, version, 737 effective-by 739 6. Security Considerations 741 Profiles may contain sensitive data such as user credentials. The 742 protection of this data depends upon how the data is delivered. If 743 the data is delivered in the NOTIFY body, SIP authentication MUST be 744 used for SUBSCRIPTION and SIPS and/or S/MIME MAY be use to encrypt 745 the data. If the data is provided via content indirection, SIP 746 authentication is not necessary for the SUBSCRIBE request. With 747 content indirection the data is protected via the authentication, 748 authorization and encryption mechanisms provided by the profile URL 749 scheme. Use of the URL scheme security mechanisms via content 750 indirection simplifies the security solution as the SIP event package 751 does not need to authenticate, authorize or protect the contents of 752 the SIP messages. Effectively the profile delivery server will 753 provide profile URI(s) to anyone. The URLs themselves are protected 754 via authentication, authorization and snooping (e.g. via HTTPS). 756 6.1 Symmetric Encryption of Profile Data 758 If the URL scheme used for content indirection does not provide 759 authentication, authorization or encryption, a technique to provide 760 this is to encrypt the profiles on the content delivery server using 761 a symmetric encryption algorithm using a shared key. The encrypted 762 profiles are delivered by the content delivery server via the URIs 763 provided in the NOTIFY requests. Using this technique the profile 764 delivery server does not need to provide authentication or 765 authorization for the retrieval as the profiles are obscured. The 766 user agent must obtain the username and password from the user or 767 other out of band means to generate the key and decrypt the profiles. 769 7. Differences from Simple XCAP Package 771 The author of this document had an action item from the July 2003 772 IETF SIPPING WG meeting to consider resolving the differences of the 773 sip-profile and simple XCAP package [I-D.ietf-simple-xcap-package]. 774 It is the author's opinion that XCAP [I-D.rosenberg-simple-xcap] can 775 be supported by the framework and event package defined in this 776 document and that this package provides a superset of the 777 functionality in the XCAP package. The following lists the 778 differences between the event packaged defined in this document vs. 779 the one defined in [I-D.ietf-simple-xcap-package]. 781 The simple XCAP package requires that the relative path be known and 782 specified by the user agent when subscribing for change notification. 783 The event package in this document requires a token or complete URI 784 be known and specified when subscribing. The advantage of the token 785 is that bootstrapping is easier and well defined. It also leaves the 786 freedom of specifying and changing the entire path of the profile URL 787 up to the profile delivery server. 789 The event package defined in this document allows multiple URIs to be 790 provided in the NOTIFY request body as a result of a single token 791 specified in the SUBSCRIBE event parameter: profile-name. This 792 allows the profile delivery server to provide sets of profiles that 793 the user agent may not have enough information to specify in the 794 SUBSCRIBE URI (e.g. at boot strapping time the user agent may not 795 know the user's identity, but the profile delivery server may know 796 the default user for the device's identity) or the doc-component of 797 the simple XCAP package. 799 All other functional differences between 800 draft-ietf-sipping-config-framework-00 and 801 draft-ietf-simple-xcap-package-00 are believed to be resolved in this 802 version of this document. 804 8. Open Issues 806 9. Change History 808 Many thanks to those who contributed and commented on the many 809 iterations of this document. Detailed input was provided by Jonathan 810 Rosenberg from Dynamicsoft, Henning Schulzrinne from Columbia U., 811 Cullen Jennings from Cisco, Rohan Mahy from Cisco, Rich Schaaf from 812 Pingtel, Volker Hilt from Bell Labs. 814 9.1 Changes from draft-ietf-sipping-config-framework-02.txt 816 Added the concept of the local network as a source of profile data. 817 There are now three separate logical sources for profile data: user, 818 device and local network. Each of these requires a separate 819 subscription to obtain. 821 9.2 Changes from draft-ietf-sipping-config-framework-01.txt 823 Changed the name of the profile-type event parameter to profile-name. 824 Also allow the profile-name parameter to be either a token or an 825 explicit URI. 827 Allow content indirection to be optional. Clarified the use of the 828 Accept header to indicate how the profile is to be delivered. 830 Added some content to the Iana section. 832 9.3 Changes from draft-ietf-sipping-config-framework-00.txt 834 This version of the document was entirely restructured and re-written 835 from the previous version as it had been micro edited too much. 837 All of the aspects of defining the event package are now organized in 838 one section and is believed to be complete and up to date with 839 [RFC3265]. 841 The URI used to subscribe to the event package is now either the user 842 or device address or record. 844 The user agent information (vendor, model, MAC and serial number) are 845 now provided as event header parameters. 847 Added a mechanism to force profile changes to be make effective by 848 the user agent in a specified maximum period of time. 850 Changed the name of the event package from sip-config to sip-profile 852 Three high level securityapproaches are now specified. 854 9.4 Changes from draft-petrie-sipping-config-framework-00.txt 856 Changed name to reflect SIPPING work group item 857 Synchronized with changes to SIP DHCP [RFC3361], SIP [RFC3261] and 858 [RFC3263], SIP Events [RFC3265] and content indirection 859 [I-D.ietf-sip-content-indirect-mech] 861 Moved the device identity parameters from the From field parameters 862 to User-Agent header parameters. 864 Many thanks to Rich Schaaf of Pingtel, Cullen Jennings of Cisco and 865 Adam Roach of Dyamicsoft for the great comments and input. 867 9.5 Changes from draft-petrie-sip-config-framework-01.txt 869 Changed the name as this belongs in the SIPPING work group. 871 Minor edits 873 9.6 Changes from draft-petrie-sip-config-framework-00.txt 875 Split the enrollment into a single SUBSCRIBE dialog for each profile. 876 The 00 draft sent a single SUBSCRIBE listing all of the desired. 877 These have been split so that each enrollment can be routed 878 differently. As there is a concept of device specific and user 879 specific profiles, these may also be managed on separate servers. 880 For instance in a roaming situation the device might get its profile 881 data from a local server which knows the LAN specific profile data. 882 At the same time the user specific profiles might come from the 883 user's home environment profile delivery server. 885 Removed the Config-Expires header as it is largely superfluous with 886 the SUBSCRIBE Expires header. 888 Eliminated some of the complexity in the discovery mechanism. 890 Suggest caching information discovered about a profile delivery 891 server to avoid an avalanche problem when a whole building full of 892 devices powers up. 894 Added the User-Profile From header field parameter so that the device 895 can request a user specific profile for a user that is different from 896 the device's default user. 898 10 References 900 [I-D.ietf-simple-xcap-package] 901 Rosenberg, J., "A Session Initiation Protocol (SIP) Event 902 Package for Modification Events for the Extensible Markup 903 Language (XML) Configuration Access Protocol (XCAP) 904 Managed Documents", draft-ietf-simple-xcap-package-01 905 (work in progress), February 2004. 907 [I-D.ietf-sip-content-indirect-mech] 908 Olson, S., "A Mechanism for Content Indirection in Session 909 Initiation Protocol (SIP) Messages", 910 draft-ietf-sip-content-indirect-mech-03 (work in 911 progress), June 2003. 913 [I-D.ietf-sipping-ua-prof-framewk-reqs] 914 Petrie, D. and C. Jennings, "Requirements for SIP User 915 Agent Profile Delivery Framework", 916 draft-ietf-sipping-ua-prof-framewk-reqs-00 (work in 917 progress), March 2003. 919 [I-D.rosenberg-simple-xcap] 920 Rosenberg, J., "The Extensible Markup Language (XML) 921 Configuration Access Protocol (XCAP)", 922 draft-rosenberg-simple-xcap-00 (work in progress), May 923 2003. 925 [I-D.sinnreich-sipdev-req] 926 Butcher, I., Lass, S., Petrie, D., Sinnreich, H. and C. 927 Stredicke, "SIP Telephony Device Requirements, 928 Configuration and Data", draft-sinnreich-sipdev-req-03 929 (work in progress), February 2004. 931 [RFC0822] Crocker, D., "Standard for the format of ARPA Internet 932 text messages", STD 11, RFC 822, August 1982. 934 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 935 Requirement Levels", BCP 14, RFC 2119, March 1997. 937 [RFC2131] Droms, R., "Dynamic Host Configuration Protocol", RFC 938 2131, March 1997. 940 [RFC2132] Alexander, S. and R. Droms, "DHCP Options and BOOTP Vendor 941 Extensions", RFC 2132, March 1997. 943 [RFC2246] Dierks, T. and C. Allen, "The TLS Protocol Version 1.0", 944 RFC 2246, January 1999. 946 [RFC2616] Fielding, R., Gettys, J., Mogul, J., Frystyk, H., 947 Masinter, L., Leach, P. and T. Berners-Lee, "Hypertext 948 Transfer Protocol -- HTTP/1.1", RFC 2616, June 1999. 950 [RFC2617] Franks, J., Hallam-Baker, P., Hostetler, J., Lawrence, S., 951 Leach, P., Luotonen, A. and L. Stewart, "HTTP 952 Authentication: Basic and Digest Access Authentication", 953 RFC 2617, June 1999. 955 [RFC2818] Rescorla, E., "HTTP Over TLS", RFC 2818, May 2000. 957 [RFC3261] Rosenberg, J., Schulzrinne, H., Camarillo, G., Johnston, 958 A., Peterson, J., Sparks, R., Handley, M. and E. Schooler, 959 "SIP: Session Initiation Protocol", RFC 3261, June 2002. 961 [RFC3263] Rosenberg, J. and H. Schulzrinne, "Session Initiation 962 Protocol (SIP): Locating SIP Servers", RFC 3263, June 963 2002. 965 [RFC3265] Roach, A., "Session Initiation Protocol (SIP)-Specific 966 Event Notification", RFC 3265, June 2002. 968 [RFC3361] Schulzrinne, H., "Dynamic Host Configuration Protocol 969 (DHCP-for-IPv4) Option for Session Initiation Protocol 970 (SIP) Servers", RFC 3361, August 2002. 972 [RFC3377] Hodges, J. and R. Morgan, "Lightweight Directory Access 973 Protocol (v3): Technical Specification", RFC 3377, 974 September 2002. 976 [RFC3617] Lear, E., "Uniform Resource Identifier (URI) Scheme and 977 Applicability Statement for the Trivial File Transfer 978 Protocol (TFTP)", RFC 3617, October 2003. 980 Author's Address 982 Daniel Petrie 983 Pingtel Corp. 984 400 W. Cummings Park 985 Suite 2200 986 Woburn, MA 01801 987 US 989 Phone: "Dan Petrie (+1 781 938 5306)" 990 EMail: dpetrie@pingtel.com 991 URI: http://www.pingtel.com/ 993 Appendix A. Acknowledgments 994 Intellectual Property Statement 996 The IETF takes no position regarding the validity or scope of any 997 intellectual property or other rights that might be claimed to 998 pertain to the implementation or use of the technology described in 999 this document or the extent to which any license under such rights 1000 might or might not be available; neither does it represent that it 1001 has made any effort to identify any such rights. Information on the 1002 IETF's procedures with respect to rights in standards-track and 1003 standards-related documentation can be found in BCP-11. 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