idnits 2.17.1 draft-ietf-simple-pres-filter-reqs-01.txt: Checking boilerplate required by RFC 5378 and the IETF Trust (see https://trustee.ietf.org/license-info): ---------------------------------------------------------------------------- ** Looks like you're using RFC 2026 boilerplate. This must be updated to follow RFC 3978/3979, as updated by RFC 4748. Checking nits according to https://www.ietf.org/id-info/1id-guidelines.txt: ---------------------------------------------------------------------------- == No 'Intended status' indicated for this document; assuming Proposed Standard Checking nits according to https://www.ietf.org/id-info/checklist : ---------------------------------------------------------------------------- ** The document seems to lack an IANA Considerations section. (See Section 2.2 of https://www.ietf.org/id-info/checklist for how to handle the case when there are no actions for IANA.) ** The document seems to lack separate sections for Informative/Normative References. All references will be assumed normative when checking for downward references. Miscellaneous warnings: ---------------------------------------------------------------------------- == The copyright year in the RFC 3978 Section 5.4 Copyright Line does not match the current year == The document seems to lack the recommended RFC 2119 boilerplate, even if it appears to use RFC 2119 keywords. (The document does seem to have the reference to RFC 2119 which the ID-Checklist requires). -- The document seems to lack a disclaimer for pre-RFC5378 work, but may have content which was first submitted before 10 November 2008. If you have contacted all the original authors and they are all willing to grant the BCP78 rights to the IETF Trust, then this is fine, and you can ignore this comment. If not, you may need to add the pre-RFC5378 disclaimer. (See the Legal Provisions document at https://trustee.ietf.org/license-info for more information.) -- The document date (June 18, 2003) is 7616 days in the past. Is this intentional? Checking references for intended status: Proposed Standard ---------------------------------------------------------------------------- (See RFCs 3967 and 4897 for information about using normative references to lower-maturity documents in RFCs) -- Possible downref: Normative reference to a draft: ref. '3' == Outdated reference: A later version (-03) exists of draft-kiss-simple-presence-wireless-reqs-02 -- Possible downref: Normative reference to a draft: ref. '4' ** Obsolete normative reference: RFC 3265 (ref. '6') (Obsoleted by RFC 6665) == Outdated reference: A later version (-07) exists of draft-ietf-simple-event-list-03 == Outdated reference: A later version (-02) exists of draft-lonnfors-simple-partial-notify-01 -- Possible downref: Normative reference to a draft: ref. '9' Summary: 4 errors (**), 0 flaws (~~), 6 warnings (==), 5 comments (--). Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 SIMPLE WG T. Moran 3 Internet-Draft 4 Expires: December 17, 2003 S. Addagatla 5 E. Leppanen 6 Nokia 7 A. Allen 8 June 18, 2003 10 Requirements for Presence Specific Event Notification Filtering 11 draft-ietf-simple-pres-filter-reqs-01 13 Status of this Memo 15 This document is an Internet-Draft and is in full conformance with 16 all provisions of Section 10 of RFC2026. 18 Internet-Drafts are working documents of the Internet Engineering 19 Task Force (IETF), its areas, and its working groups. Note that other 20 groups may also distribute working documents as Internet-Drafts. 22 Internet-Drafts are draft documents valid for a maximum of six months 23 and may be updated, replaced, or obsoleted by other documents at any 24 time. It is inappropriate to use Internet-Drafts as reference 25 material or to cite them other than as "work in progress." 27 The list of current Internet-Drafts can be accessed at http:// 28 www.ietf.org/ietf/1id-abstracts.txt. 30 The list of Internet-Draft Shadow Directories can be accessed at 31 http://www.ietf.org/shadow.html. 33 This Internet-Draft will expire on December 17, 2003. 35 Copyright Notice 37 Copyright (C) The Internet Society (2003). All Rights Reserved. 39 Abstract 41 This document defines a set of structured requirements whereby a 42 presence information subscriber may select specific information to be 43 received in the presence infomation notification sent by the 44 notifier. The purpose is to limit the content and frequency of 45 notifications so that only essential information on a need basis is 46 delivered by the server. 48 Table of Contents 50 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3 51 2. Conventions . . . . . . . . . . . . . . . . . . . . . . . . 3 52 3. Overview of functionality . . . . . . . . . . . . . . . . . 4 53 4. Requirements for Specification of Filters . . . . . . . . . 4 54 4.1 Common Syntax . . . . . . . . . . . . . . . . . . . . . . . 4 55 4.2 Package Identification . . . . . . . . . . . . . . . . . . . 4 56 4.3 Target URI . . . . . . . . . . . . . . . . . . . . . . . . . 4 57 4.4 Notification Triggering . . . . . . . . . . . . . . . . . . 4 58 4.5 Notification Content Limiting . . . . . . . . . . . . . . . 5 59 4.6 Discovery of Items . . . . . . . . . . . . . . . . . . . . . 5 60 5. Requirements for Uploading Filter Criteria (Operational 61 Rules) . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 62 5.1 SUBSCRIBE Method . . . . . . . . . . . . . . . . . . . . . . 6 63 5.1.1 Retention of Filter Criteria . . . . . . . . . . . . . . . . 6 64 5.1.2 Changing Filter Criteria . . . . . . . . . . . . . . . . . . 6 65 5.2 Server does not Support Filters . . . . . . . . . . . . . . 6 66 5.3 Server does not Support Filter Criteria . . . . . . . . . . 6 67 5.4 Server can no Longer Support Filter Criteria . . . . . . . . 7 68 6. Interaction with Other Features . . . . . . . . . . . . . . 7 69 6.1 Resource Lists . . . . . . . . . . . . . . . . . . . . . . . 7 70 6.2 Partial Notifications . . . . . . . . . . . . . . . . . . . 7 71 6.3 Authorization . . . . . . . . . . . . . . . . . . . . . . . 7 72 7. Security Considerations . . . . . . . . . . . . . . . . . . 7 73 8. Example Applications for Notification Filtering . . . . . . 8 74 9. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 9 75 10. Main changes from version 00 . . . . . . . . . . . . . . . . 9 76 References . . . . . . . . . . . . . . . . . . . . . . . . . 9 77 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . 10 78 Intellectual Property and Copyright Statements . . . . . . . 12 80 1. Introduction 82 SIP event notification is described in [6]. It defines a general 83 framework for subscriptions and notifications for SIP event packages. 84 Concrete applications of the general event framework to a specific 85 group of events are described in [5] (user presence) and [7] (watcher 86 information). 88 The presence information refers to a set of presence attributes 89 describing the availability and willingness of the user (presentity) 90 for communication. The user makes his presence information available 91 for other users (watchers). 93 As the inherent usage of event packages grows, the client needs some 94 mechanisms for controlling the event notifications at the source. 95 Evidence of this need is found in [4]. 97 The Internet Draft describing the Presence event package [5] mentions 98 the possibility for a filtering. Accordingly, the SUBSCRIBE request 99 may contain a body for filtering the presence information 100 subscription. However, the definition of the filtering has been left 101 out of the scope of the Internet Draft. As an example, the body of 102 the SUBSCRIBE request may include a restriction on the set of data 103 returned in NOTIFY requests. 105 These mechanisms are expected to be particularly valuable to users of 106 wireless devices. The characteristics of these devices typically 107 include low bandwidth, low data processing capabilities, small 108 display and limited battery power. Such devices can benefit from the 109 ability to filter the amount of information generated at the source 110 of the event notification. 112 However, it is expected that the control mechanisms for event 113 notifications add value for all users irrespectively of their device 114 or network access characteristics. 116 Section 4 and Section 5 of this draft propose a set of requirements 117 whereby a client may specify which notifications it is interested in. 118 That is, a means to specify filtering rules to be executed by the 119 server. Section 8 provides a few example applications of notification 120 filtering. 122 2. Conventions 124 In this document, the key words 'MUST', 'MUST NOT', 'REQUIRED', 125 'SHALL', 'SHALL NOT', 'SHOULD', 'SHOULD NOT', 'RECOMMENDED', 'MAY', 126 and 'OPTIONAL' are to be interpreted as described in RFC 2119 [1] 127 and indicate requirement levels for compliant implementations. 129 3. Overview of functionality 131 Filter Criteria set by a watcher may be set based on some 132 predetermined knowledge of the structure of the presence information, 133 or the filtering mechanism may itself be used to first discover the 134 structure of the presence information thus enabling the setting new 135 filter criteria to deliver the values of interest. 137 The filtering may be performed either by the presence server of the 138 presentity (the notifier) or by some intermediate server between the 139 notifier and the watcher. The filtering should be considered as a 140 post processing operation on the presence document after it has been 141 modified due the rules of the authorization. As a result the 142 authorization policy always overides any of the data or notifications 143 requested by any of the filter criteria. 145 Subscriptions containing filter criteria may either be accepted or 146 rejected by the notifier based on the presence of filter criteria. 148 4. Requirements for Specification of Filters 150 The following requirements relate to the creation of filter criteria. 152 4.1 Common Syntax 154 A common set of constructs MUST be defined for the creation of rules. 155 There MUST be a common set of operations that follow a common syntax. 156 The user MUST be possible to define different rules for different 157 purposes using a common filtering mechanism. 159 4.2 Package Identification 161 A means is REQUIRED whereby the user may specify the package the 162 rules apply to. 164 4.3 Target URI 166 It MUST be possible for the watcher in the filter criteria to 167 indicate the target presentity, resource list or sub list of the 168 resource list to which a certain filter criteria is applied if this 169 is different from the Request-URI in the subscription. 171 4.4 Notification Triggering 173 This chapter presents requirements for specifying the desired 174 conditions for when notifications are to be sent to the client. 176 The scope of the 'when' part is to allow a possibility for the user 177 to specify such rules for the notification triggering where the 178 criteria is based on the presence information, e.g., the value of the 179 status element. 181 The notification triggering criteria would override the default 182 trigger conditions of the server/service as defined in the package 183 when they are within the server's local policy constraints. 185 It MUST be possible to specify logical expressions based on the value 186 of elements defined in the package for the purpose of when to send 187 notifications. This covers expressions (tests) related to the change 188 of an element's value, and reaching a certain value of an element. 190 It MUST be possible to construct expressions that combine multiple 191 tests. 193 4.5 Notification Content Limiting 195 This chapter presents requirements for specifying the content to be 196 sent in the notifications. 198 It MUST be possible for the watcher to specify the presence 199 information elements [2] (XML elements and/or attributes) to be 200 delivered in the notification. The specified elements MUST be 201 possible to cover also extensions to PIDF formated presence 202 information, see for example [3]. 204 E.g. the following two cases must be possible: 206 o It MUST be possible for the watcher to define a criteria which 207 allows the complete tuple and all information within a tuple to be 208 transmitted. 210 o It MUST be possible for the watcher to define a criteria which 211 result notifies to contain values only for defined attributes. 213 It MUST be possible to specify logical expressions based on the value 214 of elements defined in the package for the purpose of determining 215 what to send in the notification. The existence of an element SHOULD 216 be considered as a criterion. 218 It MUST be possible to construct expressions that combine multiple 219 tests. 221 4.6 Discovery of Items 223 It MUST be possible for the watcher to request to learn new items of 224 the presence information that the notifier may make available to the 225 watcher. E.g., to discover additions of new tuples and/or other new 226 presence information items. 228 It MUST be possible for the watcher using the filter criteria to 229 determine what presence information is available before subscribing 230 to presence information with the actual values. 232 5. Requirements for Uploading Filter Criteria (Operational Rules) 234 It MUST be possible for the watcher to upload filter criteria to the 235 server (notifier) and know the status - accepted or rejected. 237 5.1 SUBSCRIBE Method 239 Placing filter criteria in the body of the subscription MUST be 240 supported. Other means of delivering the filter criteria to the 241 server MAY be supported. E.g. it should be possible for the rules to 242 be (permanently) stored in the server, as in a resource list case. 244 5.1.1 Retention of Filter Criteria 246 The server MUST retain the filter criteria through the lifetime of 247 the subscription dialog until there is a modification to the filter 248 settings. 250 5.1.2 Changing Filter Criteria 252 It MUST be possible to change the filter settings during a 253 subscription. 255 It MUST be possible for the watcher to reset the filter settings to 256 the service (server) defined default. 258 Changing filter criteria SHOULD be bandwidth efficient. 260 5.2 Server does not Support Filters 262 If the server does not support filters (the content type) then it 263 MUST be possible to indicate so in a response. 265 5.3 Server does not Support Filter Criteria 267 It MUST be possible for the server to explicitly indicate that it 268 does not support or understand the filter criteria. This indication 269 MAY include a reason about the refusal of the subscription. 271 5.4 Server can no Longer Support Filter Criteria 273 The server MUST be able to terminate the subscription if the any of 274 the active filters are no longer applicable due to a policy in the 275 server. 277 6. Interaction with Other Features 279 6.1 Resource Lists 281 It MUST be possible to support filtering for subscriptions to 282 resource lists [8]. 284 It MUST be possible for a watcher to specify filter criteria for a 285 resource list and/or any nested sub list of the resource list. 287 It MUST be possible for a watcher to specify different filter for any 288 individual member of a resource list in a resource list subscription. 290 It MUST be possible for a watcher to specify different filter 291 criteria for individual members of any of nested sub lists of a 292 resource list in a resource list subscription. Any of the nested sub 293 lists may be located in a different domain from the parent list. 295 It MUST be possible for each watcher to define own filter criteria 296 within resource list subscription if there are several simultaneous 297 watchers using the same list. 299 6.2 Partial Notifications 301 It MUST be possible to use filtering along with the partial 302 notification [9] within the same subscription. 304 6.3 Authorization 306 Authorization SHOULD occur irrespective of the filtering. 308 7. Security Considerations 310 Security requirements specified for [5] also applies to the presence 311 filtering. Additional security considerations related to the presence 312 filtering are described as follows. 314 The filter criteria should not be rejected based on the authorization 315 policy since this would enable the watcher by experimentation with 316 the use of filter criteria to determine the authorization policy the 317 presentity has set for him and thus discover what the presentity 318 wants to hide from him. 320 The presence of filter criteria in the body in a SIP message has a 321 significant effect on the way in which the request is handled at a 322 server. As a result, it is especially important that messages 323 containing filter criteria are authenticated and authorized. 325 Modification to the Filter Criteria by an intermediary could also 326 result in the watcher either not receiving notifications of presence 327 information they are interested in or receiving a very large presence 328 document. Therefore the filter criteria should be integrity protected 329 between those nodes that are authorised to modify it (e.g., the 330 resource list servers). 332 Processing of requests and looking up filter criteria requires some 333 amount of computation. This enables a DoS attack whereby a user can 334 send requests with substantial numbers messages with large contents, 335 in the hopes of overloading the server. To prevent this the number of 336 filter criteria allowed in a request should be limited. 338 Requests containing filter criteria can reveal sensitive information 339 about a UA's capabilities. If this information is sensitive, it 340 SHOULD be encrypted using methods that allow it to be read by those 341 nodes that need to do so (e.g., the resource list servers). 343 The resource list servers should convey only those parts of filter 344 information targetted to the same destination as the fanned out 345 individual subscriptions, if the filter information is conveyed 346 further within the subscription. 348 8. Example Applications for Notification Filtering 350 1. A watcher wishes to get to know presentity's availability and 351 willingness for messaging (e.g. IM and MMS). 353 2. A watcher is interested in getting information about the 354 communication means and contact addresses the presentity is 355 currently available for communication. 357 3. A watcher requires a notification if the state of a buddy has 358 changed to 'open'. 360 4. A Subscriber only wants to be notified when the presentity's 361 location is Dallas or Fort Worth. The notification should include 362 the vehicle license, driver name, and city. 364 5. A Basic location tracking service requires notification when the 365 presentity's cell id changes. The notification should include the 366 cell id. 368 6. A watcher is intrested in being notified when a presentity gains 369 a new communication capability such as a new networked 370 multi-player game. 372 9. Acknowledgements 374 The authors would like to thank Hisham Khartabil, Mikko Lonnfors, 375 Juha Kalliokulju, Aki Niemi, Jose Costa-Requena and Markus Isomaki 376 for their valuable input. 378 10. Main changes from version 00 380 o Overview of functionality chapter added. 382 o More specific requirements for supporting filtering with the 383 resource lists, and nested lists. 385 o Interaction with other features chapter added. 387 o More specific requirements to support getting information about 388 the structure of presence document, and changes in it. 390 o Several filter specific additions to security considerations. 392 o Several editorial changes, e.g., reference and terminology 393 updates. 395 References 397 [1] Bradner, S., "Key words for use in RFCs to Indicate Requirement 398 Levels", BCP 14, RFC 2119, March 1997. 400 [2] Sugano, H., "CPIM Presence Information Data Format", 401 draft-ietf-impp-cpim-pidf-08.txt, May 2003. 403 [3] Schulzrinne, H., "RPIDS -- Rich Presence Information Data Format 404 for Presence Based on the Session Initiation Protocol (SIP)", 405 draft-schulzrinne-simple-rpids-01.txt, February 2003. 407 [4] Kiss, K., "Requirements for Presence Service based on 3GPP 408 specifications and wireless environment characteristics", 409 draft-kiss-simple-presence-wireless-reqs-02, February 2003. 411 [5] Rosenberg, J., "Session Initiation Protocol (SIP) Extensions for 412 Presence", draft-ietf-simple-presence-10.txt, January 2003. 414 [6] Roach, A., "Session Initiation Protocol (SIP)-Specific Event 415 Notification", RFC 3265, June 2002. 417 [7] Rosenberg, J., "A Watcher Information Event Template-Package for 418 the Session Initiation Protocol (SIP)", 419 draft-ietf-simple-winfo-package-05.txt, January 2003. 421 [8] Rosenberg, J., "A Session Initiation Protocol (SIP) Event 422 Notification Extension for Resource Lists", 423 draft-ietf-simple-event-list-03.txt, May 2003. 425 [9] Lonnfors, M., "Partial Notification of Presence Information", 426 draft-lonnfors-simple-partial-notify-01.txt, May 2003. 428 Authors' Addresses 430 Tim Moran 431 2800 Britt Drive 432 Argyle, Texas 76226 433 USA 435 Phone: +1 972 849 8821 436 EMail: tl_moran@att.net 438 Sreenivas Addagatla 439 Nokia 440 6000 Connection Drive 441 Irving, Texas 75039 442 USA 444 Phone: +1 972 374 1917 445 EMail: sreenivas.addagatla@nokia.com 447 Eva Leppanen 448 Nokia 449 P.O BOX 785 450 Tampere 451 Finland 453 Phone: +358 7180 77066 454 EMail: eva-maria.leppanen@nokia.com 455 Andrew Allen 456 1937 McRae Lane 457 Mundelein, Illinois 60060 458 USA 460 EMail: AndrewAllen007@aol.com 462 Intellectual Property Statement 464 The IETF takes no position regarding the validity or scope of any 465 intellectual property or other rights that might be claimed to 466 pertain to the implementation or use of the technology described in 467 this document or the extent to which any license under such rights 468 might or might not be available; neither does it represent that it 469 has made any effort to identify any such rights. Information on the 470 IETF's procedures with respect to rights in standards-track and 471 standards-related documentation can be found in BCP-11. Copies of 472 claims of rights made available for publication and any assurances of 473 licenses to be made available, or the result of an attempt made to 474 obtain a general license or permission for the use of such 475 proprietary rights by implementors or users of this specification can 476 be obtained from the IETF Secretariat. 478 The IETF invites any interested party to bring to its attention any 479 copyrights, patents or patent applications, or other proprietary 480 rights which may cover technology that may be required to practice 481 this standard. Please address the information to the IETF Executive 482 Director. 484 Full Copyright Statement 486 Copyright (C) The Internet Society (2003). All Rights Reserved. 488 This document and translations of it may be copied and furnished to 489 others, and derivative works that comment on or otherwise explain it 490 or assist in its implementation may be prepared, copied, published 491 and distributed, in whole or in part, without restriction of any 492 kind, provided that the above copyright notice and this paragraph are 493 included on all such copies and derivative works. However, this 494 document itself may not be modified in any way, such as by removing 495 the copyright notice or references to the Internet Society or other 496 Internet organizations, except as needed for the purpose of 497 developing Internet standards in which case the procedures for 498 copyrights defined in the Internet Standards process must be 499 followed, or as required to translate it into languages other than 500 English. 502 The limited permissions granted above are perpetual and will not be 503 revoked by the Internet Society or its successors or assignees. 505 This document and the information contained herein is provided on an 506 "AS IS" basis and THE INTERNET SOCIETY AND THE INTERNET ENGINEERING 507 TASK FORCE DISCLAIMS ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING 508 BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION 509 HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF 510 MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. 512 Acknowledgment 514 Funding for the RFC Editor function is currently provided by the 515 Internet Society.