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'I-D.ietf-nsis-qspec') ** Obsolete normative reference: RFC 2234 (Obsoleted by RFC 4234) ** Obsolete normative reference: RFC 3588 (Obsoleted by RFC 6733) ** Obsolete normative reference: RFC 4005 (Obsoleted by RFC 7155) ** Obsolete normative reference: RFC 4006 (Obsoleted by RFC 8506) == Outdated reference: A later version (-20) exists of draft-ietf-nsis-ntlp-09 == Outdated reference: A later version (-18) exists of draft-ietf-nsis-qos-nslp-09 == Outdated reference: A later version (-05) exists of draft-tschofenig-sip-saml-04 -- Obsolete informational reference (is this intentional?): RFC 2327 (Obsoleted by RFC 4566) -- Obsolete informational reference (is this intentional?): RFC 2486 (Obsoleted by RFC 4282) Summary: 9 errors (**), 0 flaws (~~), 15 warnings (==), 9 comments (--). Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 Diameter Maintanence and F. Alfano 3 Extensions (DIME) P. McCann 4 Internet-Draft Lucent Technologies 5 Expires: September 1, 2006 H. Tschofenig 6 Siemens 7 T. Tsenov 8 February 28, 2006 10 Diameter Quality of Service Application 11 draft-tschofenig-dime-diameter-qos-00.txt 13 Status of this Memo 15 By submitting this Internet-Draft, each author represents that any 16 applicable patent or other IPR claims of which he or she is aware 17 have been or will be disclosed, and any of which he or she becomes 18 aware will be disclosed, in accordance with Section 6 of BCP 79. 20 Internet-Drafts are working documents of the Internet Engineering 21 Task Force (IETF), its areas, and its working groups. Note that 22 other groups may also distribute working documents as Internet- 23 Drafts. 25 Internet-Drafts are draft documents valid for a maximum of six months 26 and may be updated, replaced, or obsoleted by other documents at any 27 time. It is inappropriate to use Internet-Drafts as reference 28 material or to cite them other than as "work in progress." 30 The list of current Internet-Drafts can be accessed at 31 http://www.ietf.org/ietf/1id-abstracts.txt. 33 The list of Internet-Draft Shadow Directories can be accessed at 34 http://www.ietf.org/shadow.html. 36 This Internet-Draft will expire on September 1, 2006. 38 Copyright Notice 40 Copyright (C) The Internet Society (2006). 42 Abstract 44 This document describes a Diameter application that performs 45 Authentication, Authorization, and Accounting for Quality of Service 46 (QoS) reservations. This protocol is used by elements along the path 47 of a given application flow to authenticate a reservation request, 48 ensure that the reservation is authorized, and to account for 49 resources consumed during the lifetime of the application flow. 50 Clients that implement the Diameter QoS application contact an 51 authorizing entity/application server that is located somewhere in 52 the network, allowing for a wide variety of flexible deployment 53 models. 55 Table of Contents 57 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 4 58 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 5 59 3. Framework . . . . . . . . . . . . . . . . . . . . . . . . . . 6 60 3.1. Network element functional model . . . . . . . . . . . . . 7 61 3.2. Authorization models . . . . . . . . . . . . . . . . . . . 9 62 3.3. QoS authorization considerations . . . . . . . . . . . . . 12 63 4. Diameter QoS Authorization session establishment and 64 management . . . . . . . . . . . . . . . . . . . . . . . . . . 16 65 4.1. Parties involved . . . . . . . . . . . . . . . . . . . . . 16 66 4.2. Initial QoS authorization (Diameter QoS authorization 67 session establishment) . . . . . . . . . . . . . . . . . . 16 68 4.3. QoS authorization session re-authorization . . . . . . . . 20 69 4.3.1. Client-side initiated Re-Authorization . . . . . . . . 20 70 4.3.2. Server-side initiated Re-Authorization . . . . . . . . 21 71 4.4. Server-side initiated QoS parameter provisioning . . . . . 22 72 4.5. Session Termination . . . . . . . . . . . . . . . . . . . 23 73 4.5.1. Client-side initiated session termination . . . . . . 23 74 4.5.2. Server-side initiated session termination . . . . . . 24 75 5. Accounting . . . . . . . . . . . . . . . . . . . . . . . . . . 26 76 6. Diameter QoS authorization application Messages . . . . . . . 28 77 6.1. QoS-Authorization Request (QAR) . . . . . . . . . . . . . 29 78 6.2. QoS-Authorization Answer (QAA) . . . . . . . . . . . . . . 29 79 6.3. QoS-Install Request (QIR) . . . . . . . . . . . . . . . . 30 80 6.4. QoS-Install Answer (QAA) . . . . . . . . . . . . . . . . . 31 81 6.5. Accounting Request (ACR) . . . . . . . . . . . . . . . . . 31 82 6.6. Accounting Answer (ACA) . . . . . . . . . . . . . . . . . 32 83 7. Diameter QoS Authorization Application AVPs . . . . . . . . . 33 84 7.1. Diameter Base Protocol AVPs . . . . . . . . . . . . . . . 33 85 7.2. Credit Control application AVPs . . . . . . . . . . . . . 33 86 7.3. Accounting AVPs . . . . . . . . . . . . . . . . . . . . . 34 87 7.4. Diameter QoS Application Defined AVPs . . . . . . . . . . 35 88 8. Examples . . . . . . . . . . . . . . . . . . . . . . . . . . . 39 89 9. Security Considerations . . . . . . . . . . . . . . . . . . . 42 90 10. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 43 91 11. Open Issues . . . . . . . . . . . . . . . . . . . . . . . . . 44 92 12. References . . . . . . . . . . . . . . . . . . . . . . . . . . 45 93 12.1. Normative References . . . . . . . . . . . . . . . . . . . 45 94 12.2. Informative References . . . . . . . . . . . . . . . . . . 45 95 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 48 96 Intellectual Property and Copyright Statements . . . . . . . . . . 49 98 1. Introduction 100 To meet the Quality of Service needs of applications such as Voice- 101 over-IP in a heavily loaded network, packets belonging to real-time 102 application flows must be identified and segregated from other 103 traffic to ensure that bandwidth, delay, and loss rate requirements 104 are met. In addition, new flows should not be added to the network 105 when it is at or near capacity, which would result in degradation of 106 quality for all flows carried by the network. 108 In some cases, these goals can be achieved with mechanisms such as 109 differentiated services and/or end-to-end congestion and admission 110 control. However, when bandwidth is scarce and must be carefully 111 managed, such as in cellular networks, or when applications and 112 transport protocols lack the capability to perform end-to-end 113 congestion control, explicit reservation techniques are required. In 114 these cases, the endpoints will send reservation requests to edge 115 and/or interior nodes along the communication path. In addition to 116 verifying whether resources are available, the recipient of a 117 reservation request must also authenticate and authorize the request, 118 especially in an environment where the endpoints are not trusted. In 119 addition, these nodes will generate accounting information about the 120 resources used and attribute usage to the requesting endpoints. This 121 will enable the owner of the network element to generate usage- 122 sensitive billing records and to understand how to allocate new 123 network capacity. 125 A variety of protocols could be used to make a QoS request, including 126 RSVP [RFC2210], NSIS [I-D.ietf-nsis-qos-nslp], link-specific 127 signaling or even SIP/SDP [RFC2327]. This document aims to be 128 agnostic to the QoS signaling protocol used and to the QoS model to 129 which the signaling is directed. 131 2. Terminology 133 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 134 "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this 135 document are to be interpreted as described in RFC 2119 [RFC2119]. 137 The following terms are used in this document: 139 Application Server 141 An application server is a network entity that exchanges signaling 142 messages with an application endpoint. It may be a source of 143 authorization for QoS-enhanced application flows. For example, a 144 SIP server is one kind of application server. 146 Application Endpoint 148 An application endpoint is an entity in an end user device that 149 exchanges signaling messages with application servers or directly 150 with other application endpoints. Based on the result of this 151 signaling, the endpoint will make a request for QoS from the 152 network. For example, a SIP User Agent is one kind of application 153 endpoint. 155 Authorizing Entity 157 The authorizing entity is that entity responsible for authorizing 158 QoS requests for a particular application flow or aggregate. This 159 may be a Diameter server (with a subscriber database) or an 160 application server acting as a Diameter server. 162 AAA Cloud 164 An infrastructure of AAA entities (clients, proxies, servers) 165 based on a AAA protocol, which provides trusted secure connections 166 between them. It offers authentication, authorization and 167 accounting services to applications in flexible local and roaming 168 scenarios. Diameter [RFC3588] and RADIUS [RFC2865] and both 169 widely deployed AAA protocols. 171 Network Element (NE) 173 QoS aware router that acts as Diameter client that implements the 174 Diameter QoS application in the context of this document. For 175 almost all scenarios this entity triggers the protocol interaction 176 described in this document. This entity corresponds to the Policy 177 Enforcement Point (PEP) (see [RFC2753]) from a functionality point 178 of view. 180 3. Framework 182 The Diameter QoS application runs between a network element receiving 183 QoS reservation requests (acting as a AAA client) and the resource 184 authorizing entity (acting as a AAA server). A high-level picture of 185 the resulting architecture is shown in Figure 1. 187 +-----------------+ 188 | Authorizing | 189 | Entity | 190 |(Diameter Server)| 191 +-------+---------+ 192 | 193 | 194 /\-----+-----/\ 195 //// \\\\ 196 || AAA Cloud || 197 | (Diameter application) | 198 || || 199 \\\\ //// 200 \-------+-----/ 201 | 202 +---+--+ +-----+----+ +---+--+ 203 | | | NE | | | Application 204 + NE +===+(Diameter +===+ NE +=============>> 205 | | | Client) | | | Flow 206 +------+ +----------+ +------+ 208 Figure 1: An Architecture supporting QoS-AAA 210 Figure 1 depicts network elements through which application flows 211 need to pass, a cloud of AAA servers, and an authorizing entity. 212 Note that there may be more than one router that needs to interact 213 with the AAA cloud along the path of a given application flow, 214 although the figure only depicts one for clarity. QoS aware network 215 elements will request authorization from the AAA cloud based on an 216 incoming QoS reservation request. The AAA entities will route the 217 request to a designated AAA authorizing entity, for example in the 218 home domain. The home authorizing entity will return the result of 219 the authorization decision. 221 In more complex deployment models, the authorization will be based on 222 dynamic application state, so that the request must be authenticated 223 and authorized based on information from one or more application 224 servers. If defined properly, the interface between the routers and 225 AAA cloud would be identical in both cases. Routers are therefore 226 insulated from the details of particular applications and need not 227 know that application servers are involved at all. Also, the AAA 228 cloud would naturally encompass business relationships such as those 229 between network operators and third-party application providers, 230 enabling flexible intra- or inter-domain authorization, accounting, 231 and settlement. 233 3.1. Network element functional model 235 Figure 2 depicts a logical operational model of resource management 236 in a router. 238 +-----------------------------------------------------+ 239 | DIAMETER Client | 240 | Functionality | 241 | +---------------++---------------++---------------+ | 242 | | User || Authorization || Accounting | | 243 | | Authentication|| of QoS || for QoS | | 244 | +---------------+| Requests || Traffic | | 245 | +---------------++---------------+ | 246 +-----------------------------------------------------+ 247 ^ 248 v 249 +--------------+ +----------+ 250 |QoS Signaling | | Resource | 251 |Msg Processing|<<<<<>>>>>>>|Management| 252 +--------------+ +----------+ 253 . ^ | * ^ 254 | v . * ^ 255 +-------------+ * ^ 256 |Signaling msg| * ^ 257 | Processing | * V 258 +-------------+ * V 259 | | * V 260 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 261 . . * V 262 | | * ............................. 263 . . * . Traffic Control . 264 | | * . +---------+. 265 . . * . |Admission|. 266 | | * . | Control |. 267 +----------+ +------------+ . +---------+. 268 <-.-| Input | | Outgoing |-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-> 269 | Packet | | Interface | .+----------+ +---------+. 270 ===>|Processing|====| Selection |===.| Packet |====| Packet |.=> 271 | | |(Forwarding)| .|Classifier| Scheduler|. 272 +----------+ +------------+ .+----------+ +---------+. 273 ............................. 274 <.-.-> = signaling flow 275 =====> = data flow (sender --> receiver) 276 <<<>>> = control and configuration operations 277 ****** = routing table manipulation 279 Figure 2: Network element functional model 281 Processing of incoming QoS reservation requests includes three 282 actions: admission control, authorization and resource reservation. 284 The admission control function provides information for available 285 resources and determines whether there are enough resources to 286 fulfill the request. Authorization is performed by the Diameter 287 client function which involves contacting an authorization entity 288 through the AAA cloud shown in Section 3. If both checks are 289 successful, the authorized QoS parameters are set in the packet 290 classifier and the packet scheduler. Note that the parameters passed 291 to the Traffic Control function may be different from requested QoS 292 (depending on the authorization decision). Once the requested 293 resource is granted, the Resource Management function provides 294 accounting information to the Authorizing entity using the Diameter 295 client function. 297 3.2. Authorization models 299 Three fundamental models for authorizing QoS reservations exist: one 300 two-party and two three party models. See [I-D.tschofenig-nsis-aaa- 301 issues] and in [I-D.tschofenig-nsis-qos-authz-issues] for a more 302 detailed discussion of authorization models and the impact for QoS 303 reservations. The notation adopted here is in respect to the entity 304 that performs the QoS authorization. The authentication of the QoS 305 requesting entity might be done at the network element as part of the 306 QoS signaling protocol, or by an off-path protocol run (on the 307 application layer or for network access authentication) or the 308 authorizing entity might be contacted with request for authentication 309 and authorization of the QoS requesting entity. From the Diameter 310 QoS application's point of view these models differ in type of 311 information that need to be carried. Here we focus on the 'Three 312 party model' (Figure 3) and the Token-based three party model' 313 (Figure 4). With the 'Two party model' the QoS resource requesting 314 entity is authenticated by the Network Element and the authorization 315 decision is made either locally at the Network Element itself or 316 offloaded to a trusted entity (most likely within the same 317 administrative domain). In the former case no Diameter QoS protocol 318 interaction is required. 320 +--------------+ 321 | Entity | 322 | authorizing | <......+ 323 | resource | . 324 | request | . 325 +------------+-+ . 326 --^----------|-- . . 327 ///// | | \\\\\ . 328 // | | \\ . 329 | QoS | QoS AAA | QoS |. 330 | authz| protocol |authz |. 331 | req.| | res. |. 332 \\ | | // . 333 \\\\\ | | ///// . 334 QoS --|----------v-- . . 335 +-------------+ request +-+------------+ . 336 | Entity |----------------->| NE | . 337 | requesting | | performing | . 338 | resource |granted / rejected| QoS | <.....+ 339 | |<-----------------| reservation | financial 340 +-------------+ +--------------+ settlement 342 Figure 3: Three Party Model 344 With the 'Three party model' a QoS reservation request that arrives 345 at the Network Element is forwarded to the Authorizing Entity (e.g., 346 in the user's home network), where the authorization decision is 347 made. A business relationship, such as a roaming agreement, between 348 the visited network and the home network ensures that the visited 349 network is compensated for the resources consumed by the user via the 350 home network. 352 financial settlement 353 ...........................+ 354 Authorization V ------- . 355 Token Request +--------------+ / QoS AAA \ . 356 +-------------->| | / protocol \ . 357 | | Authorizing +--------------+ \ . 358 | | Entity | | | | . 359 | +------+ |<--+----+ | | . 360 | | +--------------+ |QoS | |QoS |. 361 | | |authz| |authz|. 362 | |Authorization |req.+| |res. |. 363 | |Token |Token| | |. 364 | | | | | . | . 365 | | \ | | . / . 366 | | \ | | / . 367 | | QoS request |-----V . . 368 +-------------+ + Authz. Token +--------+-----+ . 369 | Entity |----------------->| NE | . 370 | requesting | | performing | . 371 | resource |granted / rejected| QoS | <....+ 372 | |<-----------------| reservation | 373 +-------------+ +--------------+ 375 Figure 4: Token-based Three Party Model 377 The 'Token-based Three Party model' is applicable to environments 378 where a previous protocol interaction is used to request 379 authorization tokens to assist the authorization process at the 380 Network Element or the Authorizing Entity. 382 The QoS resource requesting entity may be involved in an application 383 layer protocol interaction, for example using SIP, with the 384 Authorizing Entity. As part of this interaction, authentication and 385 authorization at the application layer might take place. As a result 386 of a successful authorization decision, which might involve the 387 user's home AAA server, an authorization token is generated by the 388 Authorizing Entity (e.g., the SIP proxy and an entity trusted by the 389 SIP proxy) and returned to the end host for inclusion into the QoS 390 signaling protocol. The authorization token will be used by a 391 Network Element that receives the QoS signaling message to authorize 392 the QoS request. Alternatively, the Diameter QoS application will be 393 used to forward the authorization token to the user's home network. 394 The authorization token allows the authorization decision performed 395 at the application layer protocol run to be associated with a 396 corresponding QoS signaling session. Note that the authorization 397 token might either refer to established state concerning the 398 authorization decision or the token might itself carry the authorized 399 parameters (protected by a digital signature or a keyed message 400 digest to prevent tampering). In the latter case the authorization 401 token may contain several pieces of information pertaining to the 402 authorized application session, but at minimum it should contain: 403 o An identifier of the Authorizing Entity (for example, of an 404 application server) that issued the authorization token, 405 o An identifier referring to a specific application protocol session 406 for which the token was issued and 407 o A keyed message digest or digital signature protecting the content 408 of the authorization token. 410 A possible structure for the authorization token and the policy 411 element carrying it are proposed in context of RSVP [RFC3520], with 412 the OSP [ETSI-OSP] or as outlined in [I-D.ietf-sipping-trait-authz] 413 and [I-D.tschofenig-sip-saml]. 415 3.3. QoS authorization considerations 417 A QoS authorization application must meet a number of requirements 418 applicable to a diverse set of networking environments and services. 419 It should be compliant with different deployment scenarios with 420 specific QoS signaling models and security issues. Satisfying the 421 requirements listed below while interworking with QoS signaling 422 protocols, a Diameter QoS application should accommodate the 423 capabilities of the QoS signaling protocols rather than introducing 424 functional requirements on them. A list of requirements for a QoS 425 authorization application is provided here: 426 Inter-domain support 428 In particular, users may roam outside their home network, leading 429 to a situation where the network element and authorizing entity 430 are in different administrative domains. 432 Identity-based Routing 434 The QoS AAA protocol MUST route AAA requests to the Authorizing 435 Entity, based on the provided identity of the QoS requesting 436 entity or the identity of the Authorizing entity encoded in the 437 provided authorization token. 439 Flexible Authentication Support 441 The QoS AAA protocol MUST support a variety of different 442 authentication protocols for verification of authentication 443 information present in QoS signaling messages. The support for 444 these protocols MAY be provided indirectly by tying the signaling 445 communication for QoS to a previous authentication protocol 446 exchange (e.g., using network access authentication). 448 Making an Authorization Decision 450 The QoS AAA protocol MUST exchange sufficient information between 451 the authorizing entity and the enforcing entity (and vice versa) 452 to compute an authorization decision and to execute this decision. 454 Triggering an Authorization Process 456 The QoS AAA protocol MUST allow periodic and event triggered 457 execution of the authorization process, originated at the 458 enforcing entity or even at the authorizing entity. 460 Associating QoS Reservations and Application State 462 The QoS AAA protocol MUST carry information sufficient for an 463 application server to identify the appropriate application session 464 and associate it with a particular QoS reservation. 466 Dynamic Authorization 468 It MUST be possible for the QoS AAA protocol to push updates 469 towards the network element(s) from authorizing entities. 471 Bearer Gating 473 The QoS AAA protocol MUST allow the authorizing entity to gate 474 (i.e., enable/disable) authorized application flows based on e.g., 475 application state transitions. 477 Accounting Records 479 The QoS AAA protocol MUST define QoS accounting records containing 480 duration, volume (byte count) usage information and description of 481 the QoS attributes (e.g., bandwidth, delay, loss rate) that were 482 supported for the flow. 484 Sending Accounting Records 486 The network element SHOULD send accounting records for a 487 particular QoS reservation state to the authorizing entity, which 488 plays the role of an accounting entity. 490 Failure Notification 492 The QoS AAA protocol MUST allow the network element to report 493 failures(such as loss of connectivity due to movement of a mobile 494 node or other reasons for packet loss) to the authorizing entity. 496 Accounting Correlation 498 The QoS AAA protocol MUST support the exchange of sufficient 499 information to allow for correlation between accounting records 500 generated by the network elements and accounting records generated 501 by an application server. 503 Interaction with other AAA Applications 504 Interaction with other AAA applications such as Diameter Network 505 Access (NASREQ) application [RFC4005] is required for exchange of 506 authorization, authentication and accounting information. 508 In deployment scenarios, where authentication of the QoS reservation 509 requesting entity (e.g., the user) is done by means outside the 510 Diameter QoS application protocol interaction the Authorizing Entity 511 is contacted only with a request for QoS authorization. 512 Authentication might have taken place already via the interaction 513 with the Diameter NASREQ application or as part of the QoS signaling 514 protocol (e.g., Transport Layer Security (TLS) handshake in General 515 Internet Signaling Transport (GIST) [I-D.ietf-nsis-ntlp]). 517 Authentication of the QoS reservation requesting entity to the 518 Authorizing Entity is necessary if a particular Diameter QoS 519 application protocol run cannot be related (of if there is no 520 intention to relate it) to a prior authentication. In this case the 521 Authorizing Entity MUST authenticate the QoS reservation requesting 522 entity in order to authorize the QoS request as part of the Diameter 523 QoS protocol interaction. 525 The document refers to three types of sessions that need to be 526 properly correlated. 527 QoS signaling session 529 The time period during which a QoS signaling protocol establishes, 530 maintains and deletes a QoS reservation state at the QoS network 531 element is referred as QoS signaling session. Different QoS 532 signaling protocols use different ways to identify QoS signaling 533 sessions. The same applies to different usage environments. 534 Currently, this document supports three types of QoS session 535 identifiers, namely a signaling session id (e.g., the Session 536 Identifier used by the NSIS protocol suite), a flow id (e.g., 537 identifier assigned by an application to a certain flow as used in 538 the 3GPP) and a flow description based on the IP parameters of the 539 flow's end points). The details can be found in Section 7.4. 541 Diameter authorization session 543 The time period, for which a Diameter server authorizes a 544 requested service (i.e., QoS resource reservation). It is 545 identified by a Session-Id included in all Diameter messages used 546 for management of the authorized service (initial authorization, 547 re-authorization, termination)[RFC3588]. 549 Application layer session 551 The application layer session identifies the duration of an 552 application layer service which requires provision of certain QoS. 553 An application layer session identifier is provided by the QoS 554 requesting entity in the QoS signaling messages, for example as 555 part of the authorization token. In general, the application 556 session identifier is opaque to the QoS aware network elements. 557 It is included in the authorization request message sent to the 558 Authorizing entity and helps it to correlate the QoS authorization 559 request to the application session state information. (see 560 Figure 4). 562 Correlation of these sessions is done at each of the three involved 563 entities: The QoS requesting entity correlates the application with 564 the QoS signaling sessions. The QoS network element correlates the 565 QoS signaling session with the Diameter authorization sessions. The 566 Authorizing entity SHOULD bind the information about the three 567 sessions together. Note that in certain scenarios not all of the 568 sessions are present. For example, the application session might not 569 be visible to QoS signaling protocol directly if there is no binding 570 between the application session and the QoS requesting entity using 571 the QoS signaling protocol. 573 4. Diameter QoS Authorization session establishment and management 575 4.1. Parties involved 577 Authorization models supported by this application include three 578 parties: 579 o Resource requesting entity 580 o Network Elements (Diameter QoS clients) 581 o Authorizing Entity (Diameter QoS server) 582 Note that the QoS resource requesting entity is only indirectly 583 involved in the message exchange. This entity provides the trigger 584 to initiate the Diameter QoS protocol interaction by transmitting QoS 585 signaling messages. The Diameter QoS application is only executed 586 between the Network Element (i.e., Diameter QoS client) and the 587 Authorizing Entity (i.e., Diameter QoS server). 589 The QoS resource requesting entity may communicate with the 590 Authorizing Entity using application layer signaling for negotiation 591 of service parameters. As part of this application layer protocol 592 interaction, for example using SIP, authentication and authorization 593 might take place (see Figure 4). This message exchange is, however, 594 outside the scope of this document. The protocol communication 595 between the the QoS resource requesting entity and the QoS Network 596 Element might be accomplished using the NSIS protocol suite, RSVP or 597 a link layer signaling protocol. A description of these protocols is 598 also outside the scope of this document and a tight coupling with 599 these protocols is not desirable since this applications aims to be 600 generic. 602 4.2. Initial QoS authorization (Diameter QoS authorization session 603 establishment) 605 Figure 6 shows the protocol interaction between a resource requesting 606 entity, a Network Element and the Authorizing Entity. 608 A request for a QoS reservation received by a Network Element 609 initiates a Diameter QoS authorization session. The Network Element 610 generates a QoS-Authorization-Request (QAR) message in which it maps 611 required objects from the QoS signaling message to Diameter payload 612 objects - Attribute Value Parts (AVPs, [RFC3588]). 614 +----------------------------------+-------------------------------+ 615 | QoS authorization data | Diameter QoS AVPs (Section 7) | 616 +----------------------------------+-------------------------------+ 617 | Authorizing entity ID (e.g., | Destination-Host | 618 |taken from authorization token or | Destination-Realm | 619 |from Network Access ID(NAI), | | 620 |[RFC2486] of the QoS requesting | | 621 |entity) | | 622 +----------------------------------+-------------------------------+ 623 | Application session Id (authori- | QoS-Authorization-Data | 624 | zation token) / credentials of | User-Name | 625 | the QoS requesting entity | | 626 +----------------------------------+-------------------------------+ 627 | QoS parameters | QSPEC | 628 +----------------------------------+-------------------------------+ 629 | Signaling session Id / Flow(s) Id| Signaling-session | 630 | | Flows | 631 +----------------------------------+-------------------------------+ 633 The Authorizing Entity's identity, information about the application 634 session and/or identity and credentials of the QoS resource 635 requesting entity, requested QoS parameters, signaling session 636 identifier and/or QoS enabled data flows identifiers MAY be 637 encapsulated into respective Diameter AVPs and included into the 638 Diameter message sent to the Authorizing Entity. The QAR is sent to 639 a Diameter server that can either be the home server of the QoS 640 requesting entity or an application server. 642 Authorization processing starts at the Diameter QoS server when it 643 receives the QAR authorization processing starts. Based on the 644 information in the QoS-Authentication-Data, User-Name-ID and QoS- 645 Authorized-Resources AVPs the server determines the authorized QoS 646 resources and flow state (enabled/disabled) from locally available 647 information (e.g., policy information that may be previously 648 established as part of an application layer signaling exchange, or 649 the user's subscription profile). The authorization decision is then 650 reflected in the response returned to the Diameter client with the 651 QoS-Authorization-Answer message (QAA). 653 Authorizing 654 End-Host Network Element Entity 655 requesting QoS ( Diameter ( Diameter 656 QoS Client) QoS Server) 657 | | | 658 +---QoS-Reserve---->| | 659 | +- - - - - QAR - - - - - >| 660 | |(QoS-Resources,Cost, | 661 | | QoS-Auth-Data,User-ID)| 662 | | +--------+--------------+ 663 | | | Authorize request | 664 | | | Keep session data | 665 | | |/Authz-time,Session-Id/| 666 | | +--------+--------------+ 667 | |< - - - - QAA - - - - - -+ 668 | |(Result-Code,CC-Time,Cost| 669 | |QoS-Resources,Authz-time)| 670 | +-------+---------+ 671 | |Install QoS state| 672 | | + | 673 | | Authz. session | 674 | | /Authz-time, | QoS Responder 675 | | CC-Time,Cost/ | Node 676 | +-------+---------+ | 677 | +----------QoS-Reserve---....--->| 678 | | | 679 | |<---------QoS-Response--....----| 680 |<--QoS-Response----+ | 681 | | | 682 |=====================Data Flow==============....===>| 683 | | 684 | +- - - - - ACR - - - - - >| 685 | |(START,QoS-Resources,Cost| 686 | |CC-Time,Acc-Multisess-id)| 687 | | +--------+--------------+ 688 | | | Report for successful | 689 | | | QoS reservation | 690 | | |Update of reserved QoS | 691 | | | resources | 692 | | +--------+--------------+ 693 | |< - - - - ACA - - - - - -+ 694 | | | 696 Figure 6: Initial QoS request authorization 698 The Authorizing Entity keeps authorization session state and SHOULD 699 save additional information for management of the session (e.g., Acc- 700 Multi-Session-Id, Signaling-Session-Id, authentication data) as part 701 of the session state information. A Signaling-session-Id (if 702 present) SHOULD be used together with the generated Acc-Multi- 703 Session-Id AVP (see Section 7.3) for binding the authorization and 704 the accounting session information in case of end host mobility 705 (i.e., to correlate the Diameter sessions that are initiated for the 706 same signaling session from different QoS NE). 708 The final result of the authorization request is provided in the 709 Result-Code AVP of the QAA message sent by the Authorizing Entity. 710 In case of successful authorization (i.e., Result-Code = 711 DIAMETER_LIMITED_SUCCESS, (see Section 7.1)), information about the 712 authorized QoS resources and the status of the authorized flow 713 (enabled/disabled) is provided in the QoS-Authorization-Resources AVP 714 of the QAA message. The QoS information provided via the QAA is 715 installed by the QoS Traffic Control function of the Network Element 716 (see Figure 2). The value DIAMETER_LIMITED_SUCCESS indicates that 717 the Authorizing entity expects confirmation via an accounting message 718 for successful QoS resource reservation and for final reserved QoS 719 resources (see bellow). 721 One important piece of information returned from the Authorizing 722 Entity is the authorization lifetime (carried inside the QAA). The 723 authorization lifetime allows the Network Element to determine how 724 long the authorization decision is valid for this particular QoS 725 reservation. A number of factors may influence the authorized 726 session duration, such as the user's subscription plan or currently 727 available credits at the user's account (see Section 5). The 728 authorization duration is time-based as specified in [RFC3588]. For 729 an extension of the authorization period, a new QoS-Authorization- 730 Request/Answer message exchange SHOULD be initiated. Further aspects 731 of QoS authorization session maintenance is discussed in Section 4.3, 732 Section 4.5 and Section 5. 734 The indication of a successful QoS reservation and activation of the 735 data flow, is provided by the transmission of an Accounting Request 736 (ACR) message, which reports the parameters of the established QoS 737 state: reserved resources, duration of the reservation, 738 identification of the QoS enabled flow/QoS signaling session and 739 accounting parameters. The Diameter QoS server acknowledges the 740 reserved QoS resources with the Accounting Answer (ACA) message where 741 the Result-Code is set to 'DIAMETER_SUCCESS'. Note that the reserved 742 QoS resources reported in the ACR message MAY be different than those 743 initially authorized with QAA message, due to the QoS signaling 744 specific behavior (e.g., receiver-initiated reservations with One- 745 Path-With-Advertisements) specific process of QoS negotiation along 746 the data path. 748 4.3. QoS authorization session re-authorization 750 Client and server-side initiated re-authorizations are considered in 751 the design of the Diameter QoS application. Whether the re- 752 authorization events are transparent for the resource requesting 753 entity or result in specific actions in the QoS signaling protocol is 754 outside the scope of the Diameter QoS application. It is directly 755 dependent on the capabilities of the QoS signaling protocol. 757 In addition, there are number of options for policy rules according 758 to which the NE (AAA client) contacts the Authorizing Entity for re- 759 authorization. These rules depend on the semantics and contents of 760 the QAA message sent by the Authorizing Entity: 761 a. The QAA message contains the authorized parameters of the flow 762 and its QoS and sets their limits (presumably upper). With these 763 parameters the Authorizing Entity specifies the services that the 764 NE can provide and will be financially compensated for. 765 Therefore, any change or request for change of the parameters of 766 the flow and its QoS that do not conform to the authorized limits 767 requires contacting the Authorizing Entity for authorization. 768 b. The QAA message contains authorized parameters of the flow and 769 its QoS. The rules that determine whether parameters' changes 770 require re-authorization are agreed out of band, based on a 771 Service Level Agreement (SLA) between the domains of the NE and 772 the Authorizing Entity. 773 c. The QAA message contains the authorized parameters of the flow 774 and its QoS. Any change or request for change of these 775 parameters requires contacting the Authorizing entity for re- 776 authorization. 777 d. In addition to the authorized parameters of the flow and its QoS, 778 the QAA message contains policy rules that determine the NEs 779 actions in case of change or request for change in authorized 780 parameters. 782 Provided options are not exhaustive. Elaborating on any of the 783 listed approaches is deployment /solution specific and is not 784 considered in the current document. 786 4.3.1. Client-side initiated Re-Authorization 788 The Authorizing Entity provides the duration of the authorization 789 session as part of the QoS-Authorization-Answer message (QAA). At 790 any time before expiration of this period, a new QoS-Authorization- 791 Request message (QAR) MAY be sent to the Authorizing Entity. The 792 transmission of the QAR MAY be triggered when the Network Element 793 receives a QoS signaling message that requires modification of the 794 authorized parameters of an ongoing QoS session, when authorization 795 lifetime expires or by an accounting event. (see Section 5)(Figure 7) 796 Authorizing 797 End-Host Network Element Entity 798 requesting QoS ( Diameter ( Diameter 799 QoS Client) QoS Server) 800 | | | 801 |=====================Data Flow==========================> 802 | | | 803 | +-------+----------+ | 804 | |Authz-time/CC-Time| | 805 | | expires | | 806 | +-------+----------+ | 807 | +- - - - - QAR - - - - - >| 808 | |(QoS-Resources,Cost, | 809 | | QoS-Auth-Data,User-ID)| 810 | +--------+--------------+ 811 NOTE: | | Authorize request | 812 Re-authorization | | Update session data | 813 is transparent to | |/Authz-time,Session-Id/| 814 the End-Host | +--------+--------------+ 815 |< - - - - QAA - - - - - -+ 816 | |(Result-Code,CC-Time,Cost| 817 | |QoS-Resources,Authz-time)| 818 | +-------+---------+ | 819 | |Update QoS state | | 820 | | + | | 821 | | Authz. session | | 822 | | /Authz-time, | | 823 | | CC-Time,Cost/ | | 824 | +-------+---------+ | 825 | | | 826 | +- - - - - ACR - - - - - >| 827 | |(INTRM,QoS-Resources,Cost| 828 | |CC-Time,Acc-Multisess-id)| 829 | | +--------+--------------+ 830 | | |Update of QoS resources| 831 | | |/CC-Time,Cost/ used | 832 | | +--------+--------------+ 833 | |< - - - - ACA - - - - - -+ 834 | | | 835 |=====================Data Flow==========================> 836 | | 838 Figure 7: QoS request re-authorization 840 4.3.2. Server-side initiated Re-Authorization 842 The Authorizing Entity MAY optionally initiate a QoS re-authorization 843 by issuing a Re-Auth-Request message (RAR) as defined in the Diameter 844 base protocol [RFC3588]. A Network Element client that receives such 845 a RAR message with Session-Id matching a currently active QoS session 846 acknowledges the request by sending the Re-Auth-Answer (RAA) message 847 and MUST initiate a QoS reservation re-authorization by sending a 848 QoS-Authorization-Request (QAR) message towards the Authorizing 849 entity. 851 4.4. Server-side initiated QoS parameter provisioning 853 In certain deployment scenarios (mostly applicable for local QoS 854 provision) an active control over the QoS resource and QoS enabled 855 data flows from the network side is required. Therefore, the 856 Authorizing Entity is enabled to update installed QoS parameters and 857 flow state at the Network Element by sending a QoS-Install Request 858 message (QIR). Network Elements MUST apply the updates and respond 859 with an QoS-Install Answer message (QIA). This functionality, for 860 example, allows the update of already authorized flow status of an 861 established QoS reservation due to a change at the application layer 862 session (Figure 8). 864 Authorizing 865 End-Host Network Element Entity 866 requesting QoS ( Diameter ( Diameter 867 QoS Client) QoS Server) 868 | | | 869 +===================+=Data Flow==========================> 870 | | +--------+--------------+ 871 | | |Data flow preemption | 872 | | +--------+--------------+ 873 | |< - - - - QIR - - - - - -+ 874 | |(QoS-Resources[QoS-Flow- | 875 | | -State=CLOSE]) | 876 | +-------+---------+ | 877 | |Update QoS state | | 878 | | + | | 879 | | Authz. session | | 880 | |/QoS-Flow-State= | | 881 | | CLOSE/ | | 882 | +-------+---------+ | 883 +====Data Flow=====>X | 884 | +- - - - - QIA - - - - - >| 885 | | (Result-Code) | 887 Figure 8: Server-side initiated QoS parameter provisioning 889 The Authorizing Entity MAY initiate a QoS authorization session 890 establishment and QoS reservation state installation (prior to a 891 request from a Network Element). This function requires that the 892 Authorizing Entity has knowledge of specific information identifying 893 the Network Element that should be contacted and the data flow for 894 which the QoS reservation should be established.(mostly applicable 895 for local scenarios) 897 4.5. Session Termination 899 4.5.1. Client-side initiated session termination 901 The authorization session for an installed QoS reservation state MAY 902 be terminated by the Diameter client by sending a Session- 903 Termination-Request message (STR) to the Diameter server. This is a 904 Diameter base protocol function and it is defined in [RFC3588]. 905 Session termination can be caused by a QoS signaling messaging 906 requesting deletion of the existing QoS reservation state or it can 907 be caused as a result of a soft-state expiration of the QoS 908 reservation state. After a successful termination of the 909 authorization session, final accounting messages MUST be exchanged 910 (Figure 9). It should be noted that the two sessions (authorization 911 and accounting) have independent management by the Diameter base 912 protocol, which allows for finalizing the accounting session after 913 the end of the authorization session. 915 Authorizing 916 End-Host Network Element Entity 917 requesting QoS ( Diameter ( Diameter 918 QoS Client) QoS Server) 919 | | | 920 |==Data Flow==>X /Stop of the data flow/ | 921 | | | 922 +---QoS-Reserve---->| | 923 | (Delete QoS +- - - - - STR - - - - - >| 924 | reservation) | +--------+--------------+ 925 | | | Remove authorization | 926 |<--QoS-Response----+ | session state | 927 | | +--------+--------------+ 928 |< - - - - STA - - - - - -+ 929 +-------+--------+ | 930 |Delete QoS state| 931 | Report final | 932 | accounting data| QoS Responder 933 +-------+--------+ Node 934 +----------QoS-Reserve-----....--->| 935 | (Delete QoS | 936 | reservation) 937 | 938 +- - - - - ACR - - - - - >| 939 |(FINAL,QoS-Resources,Cost| 940 |CC-Time,Acc-Multisess-id)| 941 | +--------+--------------+ 942 | | Report for successful | 943 | | end of QoS session | 944 | +--------+--------------+ 945 |< - - - - ACA - - - - - -+ 946 | 947 | QoS Responder 948 | Node 949 |<---------QoS-Response----....----+ 950 | | 952 Figure 9: Client-side initiated session termination 954 4.5.2. Server-side initiated session termination 956 At anytime during a session the Authorizing Entity MAY send an Abort- 957 Session-Request message (ASR) to the Network Element. This is a 958 Diameter base protocol function and it is defined in [RFC3588]. 959 Possible reasons for initiating the ASR message to the Network 960 Element are insufficient credits or session termination at the 961 application layer. The ASR message results in termination of the 962 authorized session, release of the reserved resources at the Network 963 Element and transmission of an appropriate QoS signaling message 964 indicating a notification to other Network Elements aware of the 965 signaling session. A final accounting message exchange MUST be 966 triggered as a result of this ASR message exchange (Figure 10). 968 Authorizing 969 End-Host Network Element Entity 970 requesting QoS ( Diameter ( Diameter 971 QoS Client) QoS Server) 972 | | | 973 |=====================Data Flow==========================> 974 | | 975 | |< - - - - ASR - - - - - -+ 976 | | | 977 |====Data Flow=====>X | QoS Responder 978 | | | Node 979 |<--QoS-Notify------+----------QoS-Reserve-----....--->| 980 | | (Delete QoS | | 981 | reservation) | 982 +-------+--------+ | 983 |Delete QoS state| | 984 | Report final | | 985 | accounting data| | 986 +-------+--------+ | 987 +- - - - - ASA - - - - - >| 988 | +--------+--------------+ 989 | | Remove authorization | 990 | | session state | 991 | +--------+--------------+ 992 +- - - - - ACR - - - - - >| 993 |(FINAL,QoS-Resources,Cost| 994 |CC-Time,Acc-Multisess-id)| 995 | +--------+--------------+ 996 | | Report for successful | 997 | | end of QoS session | 998 | +--------+--------------+ 999 |< - - - - ACA - - - - - -+ 1000 | QoS Responder 1001 | Node 1002 |<---------QoS-Response----....----+ 1003 | | 1005 Figure 10: Server-side initiated session termination 1007 5. Accounting 1009 The Diameter QoS application provides accounting for usage of 1010 reserved QoS resources. Diameter QoS accounting has built-in support 1011 for online, duration based accounting. This accounting is based on 1012 the notion that the routers making the QoS Authorization Request 1013 (Diameter QoS clients) are in the best position to determine the cost 1014 of those resources. This cost represents the financial settlement 1015 that will be ultimately demanded by the owner of the router if the 1016 Resource Authorizing Entity authorizes the reservation. 1018 In the Diameter QoS application, the router MAY send a Cost- 1019 Information AVP ([RFC4006]) in the QAR. If the Cost-Information AVP 1020 includes a Cost-Unit AVP ([RFC4006]) then the Cost-Unit SHOULD be 1021 "minute". The Cost-Information AVPs represent the cost to allocate 1022 the resources requested in the QoS-Authorization-Resources AVP 1023 included in the same QAR message. The QAR MAY optionally contain a 1024 Tariff-Time-Change AVP ([RFC4006]) which is the time at which the 1025 cost will change, a second Cost-Information AVP, which is the cost of 1026 the reserved resources after the tariff time change, and a second 1027 Tariff-Time-Change, which is the time at which the tariff would 1028 change again. Either all three or none of these AVPs MUST be present 1029 in the QAR. 1031 The Resource Authorizing Entity returns a CC-Time AVP ([RFC4006]) in 1032 the QAA message which is the total authorized gate-on time for the 1033 service. If the QAR included two Tariff-Time-Change AVPs, the 1034 current time plus the CC-Time AVP returned in the QAA MUST NOT exceed 1035 the second Tariff-Time-Change AVP from the QAR. Based on information 1036 in the Cost-Information AVPs, the Resource Authorizing Entity can use 1037 the CC-Time AVP to guarantee that the total cost of the session will 1038 not exceed a certain threshold, which allows, for example, support of 1039 prepaid users. 1041 Each ACR message contains a triplet of QoS-Authorization-Resources 1042 AVP, Cost-Information AVP, and CC-Time AVP. This represents the 1043 total time consumed at the given cost for the given resources. Note 1044 that an ACR message MUST be sent separately for each interval defined 1045 by the Tariff-Time-Change AVPs and the expiration of the CC-Time 1046 returned in the QAA (Figure 7). 1048 The Network Element starts an accounting session by sending an 1049 Accounting-Request message (ACR) after successful QoS reservation and 1050 activation of the data flow (Figure 6). After every successful re- 1051 authorization procedure the Network element MUST initiate an interim 1052 accounting message exchange (Figure 7). After successful session 1053 termination the Network element MUST initiate a final exchange of 1054 accounting messages for terminating of the accounting session and 1055 reporting final records for the usage of the QoS resources reserved. 1056 (Figure 9). 1058 6. Diameter QoS authorization application Messages 1060 The Diameter QoS Application requires the definition of new mandatory 1061 AVPs and Command-codes (Section 3 of [RFC3588]). Four new Diameter 1062 messages are defined along with Command-Codes whose values MUST be 1063 supported by all Diameter implementations that conform to this 1064 specification. 1066 Command-Name Abbrev. Code Reference 1067 QoS-Authz-Request QAR [TBD] Section 6.1 1068 QoS-Authz-Answer QAA [TBD] Section 6.2 1069 QoS-Install-Request QIR [TBD] Section 6.3 1070 QoS-Install-Answer QIA [TBD] Section 6.4 1072 In addition, the following Diameter Base protocol messages are used 1073 in the Diameter QoS application: 1075 Command-Name Abbrev. Code Reference 1076 Accounting-Request ACR 271 RFC 3588 1077 Accounting-Request ACR 271 RFC 3588 1078 Accounting-Answer ACA 271 RFC 3588 1079 Re-Auth-Request RAR 258 RFC 3588 1080 Re-Auth-Answer RAA 258 RFC 3588 1081 Abort-Session-Request ASR 274 RFC 3588 1082 Abort-Session-Answer ASA 274 RFC 3588 1083 Session-Term-Request STR 275 RFC 3588 1084 Session-Term-Answer STA 275 RFC 3588 1086 Diameter nodes conforming to this specification MAY advertise support 1087 by including the value of TBD in the Auth-Application-Id or the Acct- 1088 Application-Id AVP of the Capabilities-Exchange-Request and 1089 Capabilities-Exchange-Answer commands [RFC3588]. 1091 The value of TBD MUST be used as the Application-Id in all QAR/QAA 1092 and QIR/QIA commands. 1094 The value of TBD MUST be used as the Application-Id in all ACR/ACA 1095 commands, because this application defines new, mandatory AVPs for 1096 accounting. 1098 The value of zero (0) SHOULD be used as the Application-Id in all 1099 STR/STA, ASR/ASA, and RAR/RAA commands, because these commands are 1100 defined in the Diameter base protocol and no additional mandatory 1101 AVPs for those commands are defined in this document. 1103 6.1. QoS-Authorization Request (QAR) 1105 The QoS-Authorization-Request message (QAR) indicated by the Command- 1106 Code field (Section 3 of [RFC3588]) set to TBD and 'R' bit set in the 1107 Command Flags field is used by Network elements to request quality of 1108 service related resource authorization for a given flow. 1110 The QAR message MUST carry information for signaling session 1111 identification, Authorizing Entity identification, information about 1112 the requested QoS, and the identity of the QoS requesting entity. In 1113 addition, depending on the deployment scenario, an authorization 1114 token and credentials of the QoS requesting entity SHOULD be 1115 included. 1117 The message format, presented in ABNF form [RFC2234], is defined as 1118 follows: 1120 ::= < Diameter Header: XXX, REQ, PXY > 1121 < Session-Id > 1122 { Auth-Application-Id } 1123 { Origin-Host } 1124 { Origin-Realm } 1125 { Destination-Realm } 1126 { Auth-Request-Type } 1127 [ Destination-Host ] 1128 [ User-Name ] 1129 * [ QoS-Authorization-Resources ] 1130 [ QoS-Authentication-Data ] 1131 [ Cost-Information ] 1132 [ Acc-Multisession-Id ] 1133 [ Bound-Auth-Session-Id ] 1134 * [ AVP ] 1136 6.2. QoS-Authorization Answer (QAA) 1138 The QoS-Authorization-Answer message (QAA), indicated by the Command- 1139 Code field set to TBD and 'R' bit cleared in the Command Flags field 1140 is sent in response to the QoS-Authorization-Request message (QAR). 1141 If the QoS authorization request is successfully authorized, the 1142 response will include the AVPs to allow authorization of the QoS 1143 resources as well as accounting and transport plane gating 1144 information. 1146 The message format is defined as follows: 1148 ::= < Diameter Header: XXX, PXY > 1149 < Session-Id > 1150 { Auth-Application-Id } 1151 { Auth-Request-Type } 1152 { Result-Code } 1153 { Origin-Host } 1154 { Origin-Realm } 1155 * [ QoS-Authorization-Resources ] 1156 [ CC-Time ] 1157 [ Acc-Multisession-Id ] 1158 [ Session-Timeout ] 1159 [ Authz-Session-Lifetime ] 1160 [ Authz-Grace-Period ] 1161 * [ AVP ] 1163 6.3. QoS-Install Request (QIR) 1165 The QoS-Install Request message (QIR), indicated by the Command-Code 1166 field set to TDB and 'R' bit set in the Command Flags field is used 1167 by Authorizing entity to install or update the QoS parameters and the 1168 flow state of an authorized flow at the transport plane element. 1170 The message MUST carry information for signaling session 1171 identification or identification of the flow to which the provided 1172 QoS rules apply, identity of the transport plane element, description 1173 of provided QoS parameters, flow state and duration of the provided 1174 authorization. 1176 The message format is defined as follows: 1178 ::= < Diameter Header: XXX, REQ, PXY > 1179 < Session-Id > 1180 { Auth-Application-Id } 1181 { Origin-Host } 1182 { Origin-Realm } 1183 { Destination-Realm } 1184 { Auth-Request-Type } 1185 [ Destination-Host ] 1186 * [ QoS-Authorization-Resources ] 1187 [ Session-Timeout ] 1188 [ Authz-Session-Lifetime ] 1189 [ Authz-Grace-Period ] 1190 [ Authz-Session-Volume ] 1191 * [ AVP ] 1193 6.4. QoS-Install Answer (QAA) 1195 The QoS-Install Answer message (QAA), indicated by the Command-Code 1196 field set to TBD and 'R' bit cleared in the Command Flags field is 1197 sent in response to the QoS-Install Request message (QIR) for 1198 confirmation of the result of the installation of the provided QoS 1199 reservation instructions. 1201 The message format is defined as follows: 1203 ::= < Diameter Header: XXX, PXY > 1204 < Session-Id > 1205 { Auth-Application-Id } 1206 { Origin-Host } 1207 { Origin-Realm } 1208 { Result-Code } 1209 * [ QoS-Authorization-Resources ] 1210 * [ AVP ] 1212 6.5. Accounting Request (ACR) 1214 The Accounting Request message (ACR), indicated by the Command-Code 1215 field set to 271 and 'R' bit set in the Command Flags field is used 1216 by Network Element to report parameters of the authorized and 1217 established QoS reservation. 1219 The message MUST carry accounting information authorized QoS 1220 resources and its usage, e.g., QoS-Authorized-Resources, CC-Time, CC- 1221 Cost, Acc-Multi-Session-Id. 1223 The message format is defined as follows: 1225 ::= < Diameter Header: XXX, REQ, PXY > 1226 < Session-Id > 1227 { Acct-Application-Id } 1228 { Destination-Realm } 1229 [ Destination-Host ] 1230 [ Accounting-Record-Type ] 1231 [ Accounting-Record-Number ] 1232 * [ QoS-Authorization-Resources ] 1233 [ Cost-Information ] 1234 [ CC-Time ] 1235 [ Acc-Multi-Session-Id ] 1236 * [ AVP ] 1238 6.6. Accounting Answer (ACA) 1240 The Accounting Answer message (ACA), indicated by the Command-Code 1241 field set to 271 and 'R' bit cleared in the Command Flags field is 1242 sent in response to the Accounting Request message (ACR) as an 1243 acknowledgment of the ACR message and MAY carry additional management 1244 information for the accounting session, e.g. Acc-Interim-Interval 1245 AVP. 1247 The message format is defined as follows: 1249 ::= < Diameter Header: XXX, PXY > 1250 < Session-Id > 1251 { Acct-Application-Id } 1252 [ Result-Code ] 1253 [ Accounting-Record-Type ] 1254 [ Accounting-Record-Number ] 1255 [ Acc-Multi-Session-Id ] 1256 * [ AVP ] 1258 7. Diameter QoS Authorization Application AVPs 1260 Each of the AVPs identified in the QoS-Authorization-Request/Answer 1261 and QoS-Install-Request/Answer messages and the assignment of their 1262 value(s) is given in this section. 1264 7.1. Diameter Base Protocol AVPs 1266 The Diameter QoS application uses a number of session management 1267 AVPs, defined in the Base Protocol ([RFC3588]). 1269 Attribute Name AVP Code Reference [RFC3588] 1270 Origin-Host 264 Section 6.3 1271 Origin-Realm 296 Section 6.4 1272 Destination-Host 293 Section 6.5 1273 Destination-Realm 283 Section 6.6 1274 Auth-Application-Id 258 Section 6.8 1275 Result-Code 268 Section 7.1 1276 Auth-Request-Type 274 Section 8.7 1277 Session-Id 263 Section 8.8 1278 Authz-Lifetime 291 Section 8.9 1279 Authz-Grace-Period 276 Section 8.10 1280 Session-Timeout 27 Section 8.13 1281 User-Name 1 Section 8.14 1282 QoS-Filter-Rule 407 Section 6.9 [RFC4005] 1284 The Auth-Application-Id AVP (AVP Code 258) is assigned by IANA to 1285 Diameter applications. The value of the Auth-Application-Id for the 1286 Diameter QoS application is TBD. 1288 7.2. Credit Control application AVPs 1290 The Diameter QoS application provides accounting for usage of 1291 reserved QoS resources. Diameter QoS accounting has built-in support 1292 for online, duration based accounting. For this purpose it re-uses a 1293 number of AVPs defined in Diameter Credit Control application. 1294 [RFC4006]. 1296 Attribute Name AVP Code Reference [RFC4006] 1297 Cost-Information AVP 423 Section 8.7 1298 Unit-Value AVP 445 Section 8.8 1299 Currency-Code AVP 425 Section 8.11 1300 Cost-Unit AVP 424 Section 8.12 1301 CC-Time AVP 420 Section 8.21 1302 Tariff-Time-Change AVP 451 Section 6.20 1303 Usage of the listed AVPs is described in Section 5 1305 Diameter QoS application is designed to independently provide credit 1306 control over the controlled QoS resources. However, deployment 1307 scenarios, where Diameter QoS application is collocated with Diameter 1308 Credit Control application, are not excluded. In such scenarios the 1309 credit control over the QoS resources might be managed by the Credit 1310 control application. Possible interworking approach might be a usage 1311 of Credit-Control AVP (AVP Code 426) with a newly defined value. It 1312 will indicate to the Diameter QoS entities that the credit control 1313 over the QoS resources would be handled in separate session by Credit 1314 Control application. An active cooperation of both applications 1315 would be required but it is not elaborated further in this document. 1317 7.3. Accounting AVPs 1319 The Diameter QoS application uses Diameter Accounting and accounting 1320 AVPs as defined in Section 9 of [RFC3588]. Additional description of 1321 the usage of some of them in the QoS authorization context is 1322 provided: 1324 Attribute Name AVP Code Reference [RFC3588] 1325 Acct-Application-Id 259 Section 6.9 1326 Accounting-Record-Type 480 Section 9.8.1 1327 Accounting-Interim-Interval 85 Section 9.8.2 1328 Accounting-Record-Number 485 Section 9.8.3 1329 Accounting-Realtime-Required 483 Section 9.8.7 1330 Acc-Multi-Session-ID 50 Section 9.8.5 1332 The following AVP needs further explanation: 1334 Acct-Application-Id AVP 1336 The Acct-Application-Id AVP (AVP Code 259)is assigned by IANA to 1337 Diameter applications. The value of the Acct-Application-Id for 1338 the Diameter QoS application is TBD (TBD). 1340 Acc-Multisession-ID 1342 Acc-Multi-Session-ID AVP (AVP Code 50) SHOULD be used to link 1343 multiple accounting sessions together, allowing the correlation of 1344 accounting information. This AVP MAY be returned by the Diameter 1345 server in a QoS-Authorization-Answer message (QAA), and MUST be 1346 used in all accounting messages for the given session. 1348 7.4. Diameter QoS Application Defined AVPs 1350 This section defines the Quality of Service AVPs that are specific to 1351 the Diameter QoS application and MAY be included in the Diameter QoS 1352 application messages. Unlike the approach followed with RSVP (see 1353 [RFC2749]), where the entire RSVP message is encapsulated into a COPS 1354 message, only the relevant fields SHOULD be included. This approach 1355 avoids a certain overhead of transmitting fields which are irrelevant 1356 for the AAA infrastructure. It keeps implementations simpler and it 1357 allows the reuse of other Diameter AVPs. 1359 The following table describes the Diameter AVPs in the QoS 1360 Application, their AVP code values, types, possible flag values, and 1361 whether the AVP MAY be encrypted. 1363 | AVP Flag rules | 1364 +----------------------------------------------|----+---+----+-----+ 1365 | AVP Section | | |SHLD| MUST| 1366 | Attribute Name Code Defined Data Type |MUST|MAY| NOT| NOT| 1367 +----------------------------------------------+----+---+----+-----+ 1368 |Signaling-Session-Id TBD 7.4 Unsigned32 | M | P | | V | 1369 |Flow-ID TBD 7.4 Unsigned32 | M | P | | V | 1370 |SPI TBD 7.4 Unsigned32 | M | P | | V | 1371 |QoS-Flow-State TBD 7.4 Enumerated | M | P | | V | 1372 |IND-Flow TBD 7.4 Grouped | M | P | | V | 1373 |Flows TBD 7.4 Grouped | M | P | | V | 1374 |QSPEC TBD 7.4 OctetString| M | P | | V | 1375 |QoS-Auth-Resources TBD 7.4 Grouped | M | P | | V | 1376 |QoS-Auth-Data TBD 7.4 Grouped | M | P | | V | 1377 |Bound-Auth-Session-Id TBD 7.4 UTF8String | M | P | | V | 1378 +----------------------------------------------+----+---+----+-----+ 1379 |M - Mandatory bit. An AVP with "M" bit set and its value MUST be | 1380 | supported and recognized by a Diameter entity in order the | 1381 | message, which carries this AVP, to be accepted. | 1382 |P - Indicates the need for encryption for end-to-end security. | 1383 |V - Vendor specific bit that indicates whether the AVP belongs to | 1384 | a address space. | 1385 +------------------------------------------------------------------+ 1387 Signaling-Session-ID 1389 Signaling-Session-ID AVP (AVP Code TBD) is of type Unsigned32 and 1390 is derived from the QoS signaling session identifier, which is a 1391 unique identifier of the QoS signaling session that in the NSIS 1392 case remains unchanged for the duration of the session. 1394 Flow-ID 1396 The Flow-ID AVP (AVP Code TBD) is of type Unsigned32 and contains 1397 identifier of an IP flow. 1399 SPI 1401 The SPI AVP (AVP Code TBD) is of type Unsigned32 and extends the 1402 QoS-Filter-Rule AVP to support IPsec protected traffic. 1404 QoS-Flow-State 1406 The QoS-Flow-State AVP (AVP Code TBD) is of type Enumerated. It 1407 gives an indication by the Authorizing entity as to how the flow 1408 MUST be treated. When included in a QAA message, it contains an 1409 action to be performed on the state of the flow to which the 1410 message applies. The values supported are: 1412 0 Open - Enable the transport plane service, for which 1413 the signaling has been performed. 1414 1 Close - Disable the transport plane service 1415 2 Maintain - Do not alter the current state (enabled/disabled) 1416 of the transport plane service. 1418 The QoS-Flow-State is an optional AVP. When not included in a QAA 1419 response, the default behavior is to immediately allow the flow of 1420 packets (Open). 1422 The behavior of Close (0) for the QoS-Flow-State refers to the 1423 case where a QoS reservation exists but it is not activated and 1424 therefore not charged. For time-based charging the time interval 1425 where the gate is closed will not be included of the chargeable 1426 time interval. The QoS model might give some indication whether 1427 an established QoS reservation needs to be freed or needs to be 1428 removed only if not enough resources are available. 1430 IND-Flows 1432 The IND-Flows AVP (AVP Code TBD) is of type Grouped and specifies 1433 an IP flow via its flow identifier and/or filter-rule. Note that 1434 more than one IP flow may be described if only QoS-Filter-Rule is 1435 used. 1437 IND-Flows ::= 1438 [Flow-Id] 1439 [QoS-Filter-Rule] 1440 [SPI] 1442 Flows 1444 The Flows AVP (AVP Code TBD) is of type Grouped and contains all 1445 the individual flows that receive the same QoS specified in the 1446 QPSEC AVP included in the QoS-Authorization-Resources AVP. 1448 Flows ::= < AVP Header: XXX > 1449 1* [ IND-Flows ] 1451 QSPEC 1453 The QSPEC AVP (AVP Code TBD) is of type OctetString and contains 1454 QoS parameter information. The description format is taken from 1455 QoS NSLP Qspec template, which is expected to cover all present 1456 QoS description methods [I-D.ietf-nsis-qspec]. 1458 QoS-Authorization-Resources 1460 The QoS-Auth-Resources AVP (AVP Code TBD) is of type Grouped and 1461 includes description of the resources that have been requested by 1462 the user or authorized by the application server for a particular 1463 QoS request. More than one MAY be included into a message. 1465 QoS-Auth-Resources ::= < AVP Header: XXX > 1466 [ Signaling-Session-ID ] 1467 [ Flows ] 1468 [ QSPEC ] 1469 [ QoS-Flow-State ] 1471 The three types of identifiers for the QoS signaling session (i.e, 1472 Signaling-Session-ID, Flow-ID and OoSFilter-Rule with SPI) SHOULD 1473 be used separately when included in the QoS-Authorization-Request 1474 (QAR) messages. 1476 QoS-Authentication-Data 1478 The QoS-Authentication-Data AVP (AVP Code TBD) is of type 1479 OctetString. It is a container that carries application session 1480 or user specific data that has to be supplied to the Authorizing 1481 entity as input to the computation of the authorization decision. 1483 Bound-Authentication-Session-Id 1485 The Bound-Authentication-Session AVP (AVP Code TBD) is of type 1486 UTF8String. It carries the id of the Diameter authentication 1487 session that is used for the network access authentication (NASREQ 1488 authentication session). It is used to tie the QoS authorization 1489 request to a prior authentication of the end host done by a co- 1490 located application for network access authentication (Diameter 1491 NASREQ) at the QoS NE. 1493 8. Examples 1495 This section presents an example of the interaction between the 1496 application layer signaling and the QoS signaling along the data 1497 path. The application layer signaling is, in this example, provided 1498 using SIP. Signaling for a QoS resource reservation is done using 1499 the QoS NSLP. The authorization of the QoS reservation request is 1500 done by the Diameter QoS application (DQA). 1502 End-Host SIP Server Correspondent 1503 requesting QoS (DQA Server) Node 1505 | | | 1506 ..|....Application layer SIP signaling.......|..............|.. 1507 . | Invite (SDP) | | . 1508 . +.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-> | . 1509 . | 100 Trying | | . 1510 . <.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-+ Invite (SDP)| . 1511 . | +-.-.-.....-.-.> . 1512 . | | 180 SDP' | . 1513 . | <-.-.-.....-.-.+ . 1514 . | +--------+--------+ | . 1515 . | |Authorize session| | . 1516 . | | parameters | | . 1517 . | 180 (Session parameters) +--------+--------+ | . 1518 . <.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-+ | . 1519 ..|..........................................|... ..........|.. 1520 | | | 1521 | +------------+ | | 1522 | | NE | | | 1523 | |(DQA Client)| | | 1524 | +------+-----+ | | 1525 | | | | 1526 |QoS NSLP Reserve | | | 1527 +------------------> QAR | | 1528 | (POLICY_DATA>v +- - - - -<>- - - -> | 1529 | QSPEC) v >===>(Destination-Host, | | 1530 | v >=======>QoS-Auth-Data, ++------------+ | 1531 | >===========>QoS-Authz-Resources, |Authorize | | 1532 | |Cost-Info) |QoS resources| | 1533 | | ++------------+ | 1534 | | QAA | | 1535 | <- - - - -<>- - - -+ | 1536 | |(Result-Code, | | 1537 | |QoS-Authz-Resources, | | 1538 | |CC-Time, | | 1539 | |Authz-Lifetime) | | 1540 | +---------+--------+ | | 1541 | |Install QoS state1| | | 1542 | |+ Authz. session | | | 1543 | +---------+--------+ | | 1544 | |QoS NSLP Reserve | 1545 | +---------------..............---------> 1546 | | | 1547 | | QoS NSLP Response| 1548 |QoS NSLP Response <---------------..............---------+ 1549 <------------------+ | 1550 | | QoS NSLP Query| 1551 |QoS NSLP Query <---------------..............---------+ 1552 <------------------+ | 1553 |QoS NSLP Reserve | | 1554 +------------------> QAR | | 1555 | +- - - - -<>- - - -> | 1556 | | +---+---------+ | 1557 | | |Authorize | | 1558 | | |QoS resources| | 1559 | | QAA +---+---------+ | 1560 | <- - - - -<>- - - -+ | 1561 | +---------+--------+ | | 1562 | |Install QoS state2| | 1563 | |+ Authz. session | | 1564 | +---------+--------+ | 1565 | | QoS NSLP Reserve | 1566 | +---------------..............---------> 1567 | | QoS NSLP Response| 1568 |QoS NSLP Response <---------------..............---------+ 1569 <------------------+ | 1570 | | | 1571 /------------------+--Data Flow---------------------------\ 1572 \------------------+--------------------------------------/ 1573 | | | 1575 .-.-.-.-. SIP signaling 1576 --------- QoS NSLP signaling 1577 - - - - - Diameter QoS Application messages 1578 ========= Mapping of objects between QoS and AAA protocol 1580 Figure 27: Example for a token-based QoS authorization 1582 The communication starts with SIP signaling between the two end 1583 points and the SIP server for negotiation and authorization of the 1584 requested service and its parameters (Figure 27). As a part of the 1585 process, the SIP server verifies whether the user at Host A is 1586 authorized to use the requested service (and potentially the ability 1587 to be charged for the service usage). Negotiated session parameters 1588 are provided to the end host. 1590 Subsequently, Host A initiates a QoS signaling message towards Host 1591 B. It sends a QoS NSLP Reserve message, in which it includes 1592 description of the required QoS (QSPEC object) and authorization data 1593 for negotiated service session (part of the POLICY_DATA object). 1594 Authorization data includes, as a minimum, the identity of the 1595 authorizing entity (e.g., the SIP server) and an identifier of the 1596 application service session for which QoS resources are requested. 1598 A QoS NSLP Reserve message is intercepted and processed by the first 1599 QoS aware Network Element. The NE uses the Diameter QoS application 1600 to request authorization for the received QoS reservation request. 1601 The identity of the Authorizing Entity (in this case the SIP server 1602 that is co-located with a Diameter server) is put into the 1603 Destination-Host AVP, any additional session authorization data is 1604 encapsulated into the QoS-Authentication AVP and the description of 1605 the QoS resources is included into QoS-Authorized-Resources AVP. In 1606 addition, the NE rates the requested QoS resources and announces the 1607 charging rate into the Cost-Information AVP. These AVPs are included 1608 into a QoS Authorization Request message, which is sent to the 1609 Authorizing entity. 1611 A Diameter QAR message will be routed through the AAA network to the 1612 Authorizing Entity. The Authorizing Entity verifies the requested 1613 QoS against the QoS resources negotiated for the service session and 1614 replies with QoS-Authorization answer (QAA) message. It carries the 1615 authorization result (Result-Code AVP) and the description of the 1616 authorized QoS parameters (QoS-Authorized-Resources AVP), as well as 1617 duration of the authorization session (Authorization-Lifetime AVP) 1618 and duration of the time (CC-Time) for which the end-user should be 1619 charged with the rate announced in the QAR message. The NE interacts 1620 with the traffic control function and installs the authorized QoS 1621 resources and forwards the QoS NSLP Reserve message further along the 1622 data path. 1624 Note that the example above shows a sender-initiated reservation from 1625 the End-Host towards the corresponding node and a receiver-initiated 1626 reservation from the correspondent node towards the End-Host. 1628 9. Security Considerations 1630 This document describes a mechanism for performing authorization of a 1631 QoS reservation at a third party entity. Therefore, it is necessary 1632 the QoS signaling application to carry sufficient information that 1633 should be forwarded to the backend AAA server. This functionality is 1634 particularly useful in roaming environments where the authorization 1635 decision is most likely provided at an entity where the user can be 1636 authorized, such as in the home realm. 1638 QoS signaling application MAY re-use the authenticated identities 1639 used for the establishment of the secured transport channel for the 1640 signaling messages, e.g., TLS or IPsec between the end host and the 1641 policy aware QoS NE. In addition, a collocation of the QoS NE with, 1642 for example, the Diameter NASREQ application ([RFC4005]) may allow 1643 the QoS authorization to be based on the authenticated identity used 1644 during the network access authentication protocol run. If a co- 1645 located deployment is not desired then special security protection is 1646 required to ensure that arbitrary nodes cannot reuse a previous 1647 authentication exchange to perform an authorization decision. 1649 Additionally, QoS authorization might be based on the usage of 1650 authorization tokens that are generated by the Authorizing Entity and 1651 provided to the end host via application layer signaling. 1653 The impact of the existence of different authorization models is 1654 (with respect to this Diameter QoS application) the ability to carry 1655 different authentication and authorization information. Further 1656 discussions on the authorization handling for QoS signaling protocols 1657 is available with [I-D.tschofenig-nsis-aaa-issues] and 1658 [I-D.tschofenig-nsis-qos-authz-issues]. 1660 10. Acknowledgements 1662 The authors would like to thank John Loughney and Allison Mankin for 1663 their input to this document. In September 2005 Robert Hancock, 1664 Jukka Manner, Cornelia Kappler, Xiaoming Fu, Georgios Karagiannis and 1665 Elwyn Davies provided a detailed review. Robert also provided us 1666 with good feedback earlier in 2005. Jerry Ash provided us review 1667 comments late 2005/early 2006. 1669 11. Open Issues 1671 Open issues related to this draft are listed at the issue tracker 1672 available at: http://www.tschofenig.com:8080/diameter-qos/ 1674 12. References 1676 12.1. Normative References 1678 [I-D.ietf-nsis-qspec] 1679 Ash, J., "QoS-NSLP QSPEC Template", 1680 draft-ietf-nsis-qspec-08 (work in progress), 1681 December 2005. 1683 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 1684 Requirement Levels", BCP 14, RFC 2119, March 1997. 1686 [RFC2234] Crocker, D., Ed. and P. Overell, "Augmented BNF for Syntax 1687 Specifications: ABNF", RFC 2234, November 1997. 1689 [RFC3588] Calhoun, P., Loughney, J., Guttman, E., Zorn, G., and J. 1690 Arkko, "Diameter Base Protocol", RFC 3588, September 2003. 1692 [RFC4005] Calhoun, P., Zorn, G., Spence, D., and D. Mitton, 1693 "Diameter Network Access Server Application", RFC 4005, 1694 August 2005. 1696 [RFC4006] Hakala, H., Mattila, L., Koskinen, J-P., Stura, M., and J. 1697 Loughney, "Diameter Credit-Control Application", RFC 4006, 1698 August 2005. 1700 12.2. Informative References 1702 [ETSI-OSP] 1703 European Telecommunications Standards Institute, 1704 "Telecommunications and Internet Protocol Harmonization 1705 Over Networks (TIPHON); Open Settlement Protocol (OSP) 1706 for Inter-domain pricing, authorization, and usage 1707 exchange", TS 101 321. 1709 [I-D.ietf-nsis-ntlp] 1710 Schulzrinne, H. and R. Hancock, "GIST: General Internet 1711 Signaling Transport", draft-ietf-nsis-ntlp-09 (work in 1712 progress), February 2006. 1714 [I-D.ietf-nsis-qos-nslp] 1715 Manner, J., "NSLP for Quality-of-Service signalling", 1716 draft-ietf-nsis-qos-nslp-09 (work in progress), 1717 February 2006. 1719 [I-D.ietf-sipping-trait-authz] 1720 Peterson, J., "Trait-based Authorization Requirements for 1721 the Session Initiation Protocol (SIP)", 1722 draft-ietf-sipping-trait-authz-02 (work in progress), 1723 January 2006. 1725 [I-D.tschofenig-nsis-aaa-issues] 1726 Tschofenig, H., "NSIS Authentication, Authorization and 1727 Accounting Issues", draft-tschofenig-nsis-aaa-issues-01 1728 (work in progress), March 2003. 1730 [I-D.tschofenig-nsis-qos-authz-issues] 1731 Tschofenig, H., "QoS NSLP Authorization Issues", 1732 draft-tschofenig-nsis-qos-authz-issues-00 (work in 1733 progress), June 2003. 1735 [I-D.tschofenig-sip-saml] 1736 Tschofenig, H., "Using SAML for SIP", 1737 draft-tschofenig-sip-saml-04 (work in progress), 1738 July 2005. 1740 [RFC2210] Wroclawski, J., "The Use of RSVP with IETF Integrated 1741 Services", RFC 2210, September 1997. 1743 [RFC2327] Handley, M. and V. Jacobson, "SDP: Session Description 1744 Protocol", RFC 2327, April 1998. 1746 [RFC2486] Aboba, B. and M. Beadles, "The Network Access Identifier", 1747 RFC 2486, January 1999. 1749 [RFC2749] Herzog, S., Boyle, J., Cohen, R., Durham, D., Rajan, R., 1750 and A. Sastry, "COPS usage for RSVP", RFC 2749, 1751 January 2000. 1753 [RFC2753] Yavatkar, R., Pendarakis, D., and R. Guerin, "A Framework 1754 for Policy-based Admission Control", RFC 2753, 1755 January 2000. 1757 [RFC2865] Rigney, C., Willens, S., Rubens, A., and W. Simpson, 1758 "Remote Authentication Dial In User Service (RADIUS)", 1759 RFC 2865, June 2000. 1761 [RFC3313] Marshall, W., "Private Session Initiation Protocol (SIP) 1762 Extensions for Media Authorization", RFC 3313, 1763 January 2003. 1765 [RFC3520] Hamer, L-N., Gage, B., Kosinski, B., and H. Shieh, 1766 "Session Authorization Policy Element", RFC 3520, 1767 April 2003. 1769 [RFC3521] Hamer, L-N., Gage, B., and H. Shieh, "Framework for 1770 Session Set-up with Media Authorization", RFC 3521, 1771 April 2003. 1773 [RFC4027] Josefsson, S., "Domain Name System Media Types", RFC 4027, 1774 April 2005. 1776 Authors' Addresses 1778 Frank M. Alfano 1779 Lucent Technologies 1780 1960 Lucent Lane 1781 Naperville, IL 60563 1782 USA 1784 Phone: +1 630 979 7209 1785 Email: falfano@lucent.com 1787 Peter J. McCann 1788 Lucent Technologies 1789 1960 Lucent Lane 1790 Naperville, IL 60563 1791 USA 1793 Phone: +1 630 713 9359 1794 Email: mccap@lucent.com 1796 Hannes Tschofenig 1797 Siemens 1798 Otto-Hahn-Ring 6 1799 Munich, Bavaria 81739 1800 Germany 1802 Email: Hannes.Tschofenig@siemens.com 1803 URI: http://www.tschofenig.com 1805 Tseno Tsenov 1806 Sofia, 1807 Bulgaria 1809 Email: tseno.tsenov@mytum.de 1811 Intellectual Property Statement 1813 The IETF takes no position regarding the validity or scope of any 1814 Intellectual Property Rights or other rights that might be claimed to 1815 pertain to the implementation or use of the technology described in 1816 this document or the extent to which any license under such rights 1817 might or might not be available; nor does it represent that it has 1818 made any independent effort to identify any such rights. 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