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Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 Diameter Maintenance and D. Sun, Ed. 3 Extensions (DIME) Alcatel-Lucent 4 Internet-Draft P. McCann 5 Intended status: Standards Track Motorola Labs 6 Expires: November 8, 2009 H. Tschofenig 7 Nokia Siemens Networks 8 T. Tsou 9 Huawei 10 A. Doria 11 Lulea University of Technology 12 G. Zorn, Ed. 13 Aruba Networks 14 May 7, 2009 16 Diameter Quality of Service Application 17 draft-ietf-dime-diameter-qos-08.txt 19 Status of this Memo 21 This Internet-Draft is submitted to IETF in full conformance with the 22 provisions of BCP 78 and BCP 79. 24 Internet-Drafts are working documents of the Internet Engineering 25 Task Force (IETF), its areas, and its working groups. Note that 26 other groups may also distribute working documents as Internet- 27 Drafts. 29 Internet-Drafts are draft documents valid for a maximum of six months 30 and may be updated, replaced, or obsoleted by other documents at any 31 time. It is inappropriate to use Internet-Drafts as reference 32 material or to cite them other than as "work in progress." 34 The list of current Internet-Drafts can be accessed at 35 http://www.ietf.org/ietf/1id-abstracts.txt. 37 The list of Internet-Draft Shadow Directories can be accessed at 38 http://www.ietf.org/shadow.html. 40 This Internet-Draft will expire on November 8, 2009. 42 Copyright Notice 44 Copyright (c) 2009 IETF Trust and the persons identified as the 45 document authors. All rights reserved. 47 This document is subject to BCP 78 and the IETF Trust's Legal 48 Provisions Relating to IETF Documents in effect on the date of 49 publication of this document (http://trustee.ietf.org/license-info). 50 Please review these documents carefully, as they describe your rights 51 and restrictions with respect to this document. 53 Abstract 55 This document describes the framework, messages and procedures for 56 the Diameter Quality of Service (QoS) application. The Diameter QoS 57 application allows network elements to interact with Diameter servers 58 when allocating QoS resources in the network. In particular, two 59 modes of operation -- Pull and Push -- are defined. 61 Table of Contents 63 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 5 64 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 6 65 3. Framework . . . . . . . . . . . . . . . . . . . . . . . . . . 8 66 3.1. Network Element Functional Model . . . . . . . . . . . . . 9 67 3.2. Implications of Endpoint QoS Capabilities . . . . . . . . 11 68 3.2.1. Endpoint Categories . . . . . . . . . . . . . . . . . 11 69 3.2.2. Interaction Modes Between the Authorizing Entity 70 and Network Element . . . . . . . . . . . . . . . . . 11 71 3.3. Authorization Schemes . . . . . . . . . . . . . . . . . . 13 72 3.3.1. Pull Mode Schemes . . . . . . . . . . . . . . . . . . 13 73 3.3.2. Push Mode Schemes . . . . . . . . . . . . . . . . . . 16 74 3.4. QoS Application Requirements . . . . . . . . . . . . . . . 17 75 4. QoS Application Session Establishment and Management . . . . . 21 76 4.1. Parties Involved . . . . . . . . . . . . . . . . . . . . . 21 77 4.2. Session Establishment . . . . . . . . . . . . . . . . . . 21 78 4.2.1. Session Establishment for Pull Mode . . . . . . . . . 21 79 4.2.2. Session Establishment for Push Mode . . . . . . . . . 24 80 4.2.3. Discovery and Selection of Peer Diameter QoS 81 Application Node . . . . . . . . . . . . . . . . . . . 27 82 4.3. Session Re-authorization . . . . . . . . . . . . . . . . . 28 83 4.3.1. Client-Side Initiated Re-Authorization . . . . . . . . 29 84 4.3.2. Server-Side Initiated Re-Authorization . . . . . . . . 30 85 4.4. Session Termination . . . . . . . . . . . . . . . . . . . 31 86 4.4.1. Client-Side Initiated Session Termination . . . . . . 31 87 4.4.2. Server-Side Initiated Session Termination . . . . . . 32 88 5. QoS Application Messages . . . . . . . . . . . . . . . . . . . 34 89 5.1. QoS-Authorization Request (QAR) . . . . . . . . . . . . . 35 90 5.2. QoS-Authorization Answer (QAA) . . . . . . . . . . . . . . 35 91 5.3. QoS-Install Request (QIR) . . . . . . . . . . . . . . . . 36 92 5.4. QoS-Install Answer (QIA) . . . . . . . . . . . . . . . . . 37 93 5.5. Re-Auth-Request (RAR) . . . . . . . . . . . . . . . . . . 37 94 5.6. Re-Auth-Answer (RAA) . . . . . . . . . . . . . . . . . . . 38 95 6. QoS Application State Machine . . . . . . . . . . . . . . . . 39 96 6.1. Supplemented States for Push Mode . . . . . . . . . . . . 39 97 7. QoS Application AVPs . . . . . . . . . . . . . . . . . . . . . 41 98 7.1. Reused Base Protocol AVPs . . . . . . . . . . . . . . . . 41 99 7.2. QoS Application Defined AVPs . . . . . . . . . . . . . . . 41 101 8. Accounting . . . . . . . . . . . . . . . . . . . . . . . . . . 43 102 9. Examples . . . . . . . . . . . . . . . . . . . . . . . . . . . 44 103 9.1. Example Call Flow for Pull Mode . . . . . . . . . . . . . 44 104 9.2. Example Call Flow for Push Mode . . . . . . . . . . . . . 46 105 10. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 49 106 10.1. AVP Codes . . . . . . . . . . . . . . . . . . . . . . . . 49 107 10.2. AVP Specific Values . . . . . . . . . . . . . . . . . . . 49 108 10.3. AVP Flags . . . . . . . . . . . . . . . . . . . . . . . . 49 109 10.4. Application IDs . . . . . . . . . . . . . . . . . . . . . 49 110 10.5. Command Codes . . . . . . . . . . . . . . . . . . . . . . 50 111 11. Security Considerations . . . . . . . . . . . . . . . . . . . 51 112 12. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 53 113 13. Contributors . . . . . . . . . . . . . . . . . . . . . . . . . 54 114 14. References . . . . . . . . . . . . . . . . . . . . . . . . . . 55 115 14.1. Normative References . . . . . . . . . . . . . . . . . . . 55 116 14.2. Informative References . . . . . . . . . . . . . . . . . . 55 117 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 57 119 1. Introduction 121 This document describes the framework, messages and procedures for 122 the Diameter Quality of Service (QoS) Application. The Diameter QoS 123 Application allows Network Elements (NEs) to interact with Diameter 124 servers when allocating QoS resources in the network. 126 Two modes of operation are defined. In the first, called "Pull" 127 mode, the network element requests QoS authorization from the 128 Diameter server based on some trigger (such as a QoS signaling 129 protocol) that arrives along the data path. In the second, called 130 "Push" mode, the Diameter server pro-actively sends a command to the 131 network element(s) to install QoS authorization state. This could be 132 triggered, for instance, by off-path signaling such as Session 133 Initiation Protocol (SIP) [RFC3261] call control. 135 A set of command codes is specified that allows a single Diameter QoS 136 application server to support both Pull and Push modes based on the 137 requirements of network technologies, deployment scenarios and end- 138 host capabilities. In conjunction with parameters defined in the 139 documents "Quality of Service Attributes for Diameter" 140 [I-D.ietf-dime-qos-attributes] and "Quality of Service Parameters for 141 Usage with the AAA Framework" [I-D.ietf-dime-qos-parameters], this 142 note depicts the basic call flow procedures used to establish, modify 143 and terminate a Diameter QoS application session. 145 2. Terminology 147 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 148 "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this 149 document are to be interpreted as described in RFC 2119 [RFC2119]. 151 The following terms are used in this document: 153 AAA Cloud 154 An infrastructure of AAA entities (clients, agents, servers) 155 communicating via a AAA protocol over trusted, secure connections. 156 It offers authentication, authorization and accounting services to 157 applications in flexible local and roaming scenarios. Diameter 158 [RFC3588] and RADIUS [RFC2865] are both widely deployed AAA 159 protocols. 161 Application Endpoint (AppE) 162 An Application Endpoint is an entity in an end-user device that 163 exchanges signaling messages with Application Servers (see below) 164 or directly with other Application Endpoints. Based on the result 165 of this signaling, the Endpoint may make a request for QoS from 166 the network. For example, a SIP Agent is one kind of Application 167 Endpoint. 169 Application Server (AppS) 170 An Application Server is an entity that exchanges signaling 171 messages with an Application Endpoint (see above). It may be a 172 source of authorization for QoS-enhanced application flows. For 173 example, a SIP server is one kind of Application Server. 175 Authorizing Entity (AE) 176 The Authorizing Entity is a Diameter server that supports the QoS 177 application. It is responsible for authorizing QoS requests for a 178 particular application flow or aggregate. The Authorizing Entity 179 may be a standalone entity or may be integrated with an 180 Application Server and may be co-located with a subscriber 181 database. This entity corresponds to the Policy Decision Point 182 (PDP) [RFC2753]. 184 Network Element (NE) 185 A QoS aware router that acts as a Diameter client for the QoS 186 application. This entity triggers the protocol interaction for 187 the Pull mode, and it is the recipient of QoS information in the 188 Push mode. The Network Element corresponds to the Policy 189 Enforcement Point (PEP) [RFC2753]. 191 Pull Mode 192 In this mode, the QoS authorization process is invoked by the QoS 193 reservation request received from the Application Endpoint. The 194 Network Element then requests the QoS authorization decision from 195 the Authorizing Entity. 197 Push Mode 198 In this mode, the QoS authorization process is invoked by the 199 request from Application Server or local policies in the 200 Authorizing Entity. The Authorizing Entity then installs the QoS 201 authorization decision to the Network Element directly. 203 Resource Requesting Entity (RRE) 204 A Resource Requesting Entity is a logical entity that supports the 205 protocol interaction for QoS resources. The RRE resides in the 206 end-host and is able to communicate with peer logical entities in 207 an Authorizing Entity or a Network Element to trigger the QoS 208 authorization process. 210 3. Framework 212 The Diameter QoS application runs between a NE (acting as a Diameter 213 client) and the resource AE (acting as a Diameter server). A high- 214 level picture of the resulting architecture is shown in Figure 1. 216 +-------+---------+ 217 | Authorizing | 218 | Entity | 219 |(Diameter Server)| 220 +-------+---------+ 221 | 222 | 223 /\-----+-----/\ 224 //// \\\\ 225 || AAA Cloud || 226 | (Diameter application) | 227 || || 228 \\\\ //// 229 \-------+-----/ 230 | 231 +---+--+ +-----+----+ +---+--+ 232 | | | NE | | | Media 233 + NE +===+(Diameter +===+ NE +=============>> 234 | | | Client) | | | Flow 235 +------+ +----------+ +------+ 237 Figure 1: An Architecture Supporting QoS-AAA 239 Figure 1 depicts NEs through which media flows need to pass, a cloud 240 of AAA servers, and an AE. Note that there may be more than one 241 router that needs to interact with the AAA cloud along the path of a 242 given application flow, although the figure only depicts one for 243 clarity. 245 In some deployment scenarios, NEs may request authorization through 246 the AAA cloud based on an incoming QoS reservation request. The NE 247 will route the request to a designated AE. The AE will return the 248 result of the authorization decision. In other deployment scenarios, 249 the authorization will be initiated upon dynamic application state, 250 so that the request must be authenticated and authorized based on 251 information from one or more AppSs. After receiving the 252 authorization request from the AppS or the NE, the AE decides the 253 appropriate mode (i.e. Push or Pull). The usage Push or Pull mode 254 can be determined by the authorizing entity either statically or 255 dynamically. Static determination might be based on a configurable 256 defined policy in the authorizing entity, while dynamic determination 257 might be based on information received from an application server. 258 For Push mode, the authorizing entity needs to identify the 259 appropriate NE(s) to which QoS authorization information needs to be 260 pushed. It might determine this based on information received from 261 the AppS, such as the IP addresses of media flows. 263 In some deployment scenarios, there is a mapping between access 264 network type and the service logic (e.g. selection of the Push or 265 Pull mode, and other differentiated handling of the resource 266 admission and control). The access network type might be derived 267 from the authorization request from the AppS or the NE, and in this 268 case, the authorizing entity can identify the corresponding service 269 logic based on the mapping. 271 If defined properly, the interface between the NEs and AAA cloud 272 would be identical whether the AE communicates with an AppS or not. 273 Routers are therefore insulated from the details of particular 274 applications and need not know that Application Servers are involved 275 at all. Also, the AAA cloud would naturally encompass business 276 relationships such as those between network operators and third-party 277 application providers, enabling flexible intra- or inter-domain 278 authorization, accounting, and settlement. 280 3.1. Network Element Functional Model 282 Figure 2 depicts a logical operational model of resource management 283 in a router. 285 +-------------------------------------------------------+ 286 | DIAMETER Client | 287 | Functionality | 288 | +---------------++-----------------++---------------+ | 289 | | User || QoS Application || Accounting | | 290 | | Authentication|| Client || Client (e.g. | | 291 | | Client || (Authorization ||for QoS Traffic| | 292 | +---------------+| of QoS Requests)|+---------------+ | 293 | +-----------------+ | 294 +-------------------------------------------------------+ 295 ^ 296 v 297 +--------------+ +----------+ 298 |QoS Signaling | | Resource | 299 |Msg Processing|<<<<<>>>>>>>|Management| 300 +--------------+ +----------+ 301 . ^ | * ^ 302 | v . * ^ 303 +-------------+ * ^ 304 |Signaling msg| * ^ 305 | Processing | * V 306 +-------------+ * V 307 | | * V 308 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 309 . . * V 310 | | * ............................. 311 . . * . Traffic Control . 312 | | * . +---------+. 313 . . * . |Admission|. 314 | | * . | Control |. 315 +----------+ +------------+ . +---------+. 316 <-.-| Input | | Outgoing |-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-> 317 | Packet | | Interface | .+----------+ +---------+. 318 ===>|Processing|====| Selection |===.| Packet |====| Packet |.=> 319 | | |(Forwarding)| .|Classifier| Scheduler|. 320 +----------+ +------------+ .+----------+ +---------+. 321 ............................. 322 <.-.-> = signaling flow 323 =====> = data flow (sender --> receiver) 324 <<<>>> = control and configuration operations 325 ****** = routing table manipulation 327 Figure 2: Network Element Functional Model 329 Processing of incoming QoS reservation requests includes three 330 actions: admission control, authorization and resource reservation. 332 The admission control function provides information about available 333 resources and determines whether there are enough resources to 334 fulfill the request. Authorization is performed by the Diameter 335 client, which involves contacting an authorization entity through the 336 AAA cloud shown in Section 3. If both checks are successful, the 337 authorized QoS parameters are set in the packet classifier and the 338 packet scheduler. Note that the parameters passed to the Traffic 339 Control function may be different from requested QoS (depending on 340 the authorization decision). Once the requested resource is granted, 341 the Resource Management function provides accounting information to 342 the AE via the Diameter client. 344 3.2. Implications of Endpoint QoS Capabilities 346 3.2.1. Endpoint Categories 348 The QoS capabilities of Application Endpoints are varied, and can be 349 categorized as follows: 351 Category 1 352 A Category 1 Application Endpoint has no QoS capability at either 353 the application or the network level. This type of AppE may set 354 up a connection through application signaling, but it is incapable 355 of specifying resource/QoS requirements through either application 356 or network-level signaling. 358 Category 2 359 A Category 2 Application Endpoint only has QoS capability at the 360 application level. This type of AppE is able to set up a 361 connection through application signaling with certain resource/QoS 362 requirements (e.g., application attributes), but it is unable to 363 signal any resource/QoS requirements at the network level. 365 Category 3 366 A Category 3 Application Endpoint has QoS capability at the 367 network level. This type of AppE may set up a connection through 368 application signaling, translate service characteristics into 369 network resource/QoS requirements (e.g., network QoS class) 370 locally, and request the resources through network signaling, 371 e.g., Resource ReSerVation Protocol (RSVP) [RFC2205] or NSIS 372 [I-D.ietf-nsis-qos-nslp]. 374 3.2.2. Interaction Modes Between the Authorizing Entity and Network 375 Element 377 Different QoS mechanisms are employed in packet networks. Those QoS 378 mechanisms can be categorized into two schemes: IntServ [RFC2211], 379 [RFC2212] and DiffServ [RFC2474]. In the IntServ scheme, network 380 signaling (e.g., RSVP, NSIS, or link specific signaling) is commonly 381 used to initiate a request from an AppE for the desired QoS resource. 382 In the DiffServ scheme, QoS resources are provisioned based upon some 383 predefined QoS service classes rather than AppE-initiated, flow-based 384 QoS requests. 386 It is obvious that the eligible QoS scheme is correlated to the 387 AppE's capability in the context of QoS authorization. Since 388 Category 1 and 2 AppEs cannot initiate the QoS resource requests by 389 means of network signaling, using the current mechanism of IntServ 390 model to signal QoS information across the network is not applicable 391 to them in general. Depending on network technology and operator 392 requirements, a Category 3 AppE may either make use of network 393 signaling for resource requests or not. 395 The diversity of QoS capabilities of endpoints and QoS schemes of 396 network technology leads to the distinction on the interaction mode 397 between QoS authorization system and underlying NEs. When the 398 IntServ scheme is employed by a Category 3 endpoint, the 399 authorization process is typically initiated by a NE when a trigger 400 is received from the endpoint such as network QoS signaling. In the 401 DiffServ scheme, since the NE is unable to request the resource 402 authorization on its own initiative, the authorization process is 403 typically triggered by either the request of AppSs or policies 404 defined by the operator. 406 As a consequence, two interaction modes are needed in support of 407 different combinations of QoS schemes and endpoint's QoS 408 capabilities: Push mode and Pull mode. 410 Push mode 411 The QoS authorization process is triggered by AppSs or local 412 network conditions (e.g., time of day on resource usage and QoS 413 classes), and the authorization decisions are installed by the AE 414 to the network element on its own initiative without explicit 415 request. In order to support the push mode, the AE (i.e., 416 Diameter server) should be able to initiate a Diameter 417 authorization session to communicate with the NE (i.e., Diameter 418 client) without any pre-established connection from the network 419 element. 421 Pull mode 422 The QoS authorization process is triggered by the network 423 signaling received from end-user equipment or by a local event in 424 the NE according to pre-configured policies, and authorization 425 decisions are produced upon the request of the NE. In order to 426 support the pull mode, the NE (i.e., Diameter client) will 427 initiate a Diameter authorization session to communicate with the 428 authorizing entity (i.e., Diameter server). 430 For Category 1 and 2 Application Endpoints, Push mode is required. 431 For a Category 3 AppE, either Push mode or Pull mode may be used. 433 Push mode is applicable to certain networks, for example, Cable 434 network, DSL, Ethernet, and Diffserv-enabled IP/MPLS as defined by 435 other SDOs (e.g., ETSI TISPAN and ITU-T}. The Pull mode is more 436 appropriate to IntServ-enabled IP networks or certain wireless 437 networks such as the GPRS networks defined by 3GPP. Some networks 438 (for example, WiMAX) may require both Push and Pull modes. 440 3.3. Authorization Schemes 442 3.3.1. Pull Mode Schemes 444 Three types of basic authorization schemes for Pull mode exist: one 445 type of two-party scheme and two types of three-party schemes. The 446 notation adopted here is in respect to the entity that performs the 447 QoS authorization. The authentication of the QoS requesting entity 448 might be done at the NE as part of the QoS signaling protocol, or by 449 an off-path protocol run (on the application layer or for network 450 access authentication) or the AE might be contacted with request for 451 authentication and authorization of the QoS requesting entity. From 452 the Diameter QoS application's point of view these schemes differ in 453 type of information that need to be carried. Here we focus on the 454 'Basic Three Party Scheme' (see Figure 3) and the 'Token-based Three 455 Party Scheme' (see Figure 4). In the 'Two Party Scheme', the QoS RRE 456 is authenticated by the NE and the authorization decision is made 457 either locally at the NE itself or offloaded to a trusted entity 458 (most likely within the same administrative domain). In the two- 459 party case no Diameter QoS protocol interaction is required. 461 +--------------+ 462 | Entity | 463 | authorizing | <......+ 464 | resource | . 465 | request | . 466 +------------+-+ . 467 --^----------|-- . . 468 ///// | | \\\\\ . 469 // | | \\ . 470 | QoS | QoS AAA | QoS |. 471 | authz| protocol |authz |. 472 | req.| | res. |. 473 \\ | | // . 474 \\\\\ | | ///// . 475 QoS --|----------v-- . . 476 +-------------+ request +-+------------+ . 477 | Entity |----------------->| NE | . 478 | requesting | | performing | . 479 | resource |granted / rejected| QoS | <.....+ 480 | |<-----------------| reservation | financial 481 +-------------+ +--------------+ settlement 483 Figure 3: Three Party Scheme 485 In the 'Basic Three Party Scheme' a QoS reservation request that 486 arrives at the NE is forwarded to the Authorizing Entity (e.g., in 487 the user's home network), where the authorization decision is made. 488 A business relationship, such as a roaming agreement, between the 489 visited network and the home network ensures that the visited network 490 is compensated for the resources consumed by the user via the home 491 network. 493 financial settlement 494 ...........................+ 495 Authorization V ------- . 496 Token Request +--------------+ / QoS AAA \ . 497 +-------------->| | / protocol \ . 498 | | Authorizing +--------------+ \ . 499 | | Entity | | | | . 500 | +------+ |<--+----+ | | . 501 | | +--------------+ |QoS | |QoS |. 502 | | |authz| |authz|. 503 | |Authorization |req.+| |res. |. 504 | |Token |Token| | |. 505 | | | | | . | . 506 | | \ | | . / . 507 | | \ | | / . 508 | | QoS request |-----V . . 509 +-------------+ + Authz. Token +--------+-----+ . 510 | Entity |----------------->| NE | . 511 | requesting | | performing | . 512 | resource |granted / rejected| QoS | <....+ 513 | |<-----------------| reservation | 514 +-------------+ +--------------+ 516 Figure 4: Token-based Three Party Scheme 518 The 'Token-based Three Party Scheme' is applicable to environments 519 where a previous protocol interaction is used to request 520 authorization tokens to assist the authorization process at the NE or 521 the AE [RFC3521]. 523 The QoS RRE may be involved in an application layer protocol 524 interaction, for example using SIP [RFC3313], with the AE. As part 525 of this interaction, authentication and authorization at the 526 application layer might take place. As a result of a successful 527 authorization decision, which might involve the user's home AAA 528 server, an authorization token is generated by the AE (e.g., the SIP 529 proxy and an entity trusted by the SIP proxy) and returned to the end 530 host for inclusion into the QoS signaling protocol. The 531 authorization token will be used by a NE that receives the QoS 532 signaling message to authorize the QoS request. Alternatively, the 533 Diameter QoS application will be used to forward the authorization 534 token to the user's home network. The authorization token allows the 535 authorization decision performed at the application layer protocol 536 run to be associated with a corresponding QoS signaling session. 537 Note that the authorization token might either refer to established 538 state concerning the authorization decision or the token might itself 539 carry the authorized parameters (protected by a digital signature or 540 a keyed message digest to prevent tampering). In the latter case the 541 authorization token may contain several pieces of information 542 pertaining to the authorized application session, but at minimum it 543 should contain: 544 o An identifier for the AE (for example, an AppS) that issued the 545 authorization token 546 o An identifier referring to a specific application protocol session 547 for which the token was issued and 548 o A keyed message digest or digital signature protecting the content 549 of the authorization token 551 A possible structure for the authorization token and the policy 552 element carrying it are proposed in context of RSVP [RFC3520]. 554 In the scenario mentioned above, where the QoS resource requesting 555 entity is involved in an application layer protocol interaction with 556 the AE, it may be worthwhile to consider a token-less binding 557 mechanism also. The application layer protocol interaction may have 558 indicated the transport port numbers at the QoS RRE where it might 559 receive media streams (for example in SIP/SDP [RFC4566] signalling, 560 these port numbers are advertised). The QoS RRE may also use these 561 port numbers in some IP filter indications to the NE performing QoS 562 reservation so that it may properly tunnel the inbound packets. The 563 NE performing QoS reservation will forward the QoS resource 564 requesting entity's IP address and the IP filter indications to the 565 AE in the QoS authorization request. The AE will use the QoS RRE's 566 IP address and the port numbers in the IP filter indication, which 567 will match the port numbers advertised in the earlier application 568 layer protocol interaction, to identify the right piece of policy 569 information to be sent to the NE performing the QoS reservation in 570 the QoS authz. response. 572 3.3.2. Push Mode Schemes 574 The push mode can be further divided into two types: endpoint- 575 initiated and network-initiated. In the former case, the 576 authorization process is triggered by AppS in response to an explicit 577 QoS request from an endpoint through application signaling, e.g. 578 SIP; in the latter case, the authorization process is triggered by 579 the AppS without an explicit QoS request from an endpoint. 581 In the endpoint-initiated scheme, the QoS RRE (i.e., the AppE) 582 determines the required application level QoS and sends a QoS request 583 through an application signaling message. The AppS will extract 584 application-level QoS information and trigger the authorization 585 process to the AE. In the network-initiated scheme, the AE and/or 586 AppS should derive and determine the QoS requirements according to 587 application attribute, subscription and endpoint's capability when 588 the endpoint does not explicitly indicate the QoS attributes. The AE 589 makes an authorization decision based on application level QoS 590 information, network policies, end-user subscription, network 591 resource availability, etc., and installs the decision to NE 592 directly. 594 A Category 1 AppE requires network-initiated Push mode and a Category 595 2 AppE may use either type of Push Mode. 597 financial settlement 598 ...........................+ 599 Application V ------- . 600 signaling msg +--------------+ / QoS AAA \ . 601 +-------------->| | / protocol \ . 602 | | Authorizing +--------------+ \ . 603 | | Entity | | | | . 604 | + |<--+----+ | | . 605 | +--------------+ |QoS | |QoS |. 606 | install| |install 607 | |rsp. | |req. |. 608 | | | | |. 609 | | | | . | . 610 | \ | | . / . 611 | \ | | / . 612 V |-----V . . 613 +-------------+ +--------+-----+ . 614 | Entity | | NE | . 615 | requesting | | performing | . 616 | resource |QoS rsrc granted | QoS | <....+ 617 | |<-----------------| reservation | 618 +-------------+ +--------------+ 620 Figure 5: Scheme for Push Mode 622 3.4. QoS Application Requirements 624 A QoS application must meet a number of requirements applicable to a 625 diverse set of networking environments and services. It should be 626 compatible with different deployment scenarios having specific QoS 627 signaling models and security issues. Satisfying the requirements 628 listed below while interworking with QoS signaling protocols, a 629 Diameter QoS application should accommodate the capabilities of the 630 QoS signaling protocols rather than introducing functional 631 requirements on them. A list of requirements for a QoS authorization 632 application is provided here: 634 Inter-domain support 635 In particular, users may roam outside their home network, leading 636 to a situation where the NE and AE are in different administrative 637 domains. 639 Identity-based Routing 640 The QoS AAA protocol MUST route AAA requests to the Authorizing 641 Entity, based on the provided identity of the QoS requesting 642 entity or the identity of the AE encoded in the provided 643 authorization token. 645 Flexible Authentication Support 646 The QoS AAA protocol MUST support a variety of different 647 authentication protocols for verification of authentication 648 information present in QoS signaling messages. The support for 649 these protocols MAY be provided indirectly by tying the signaling 650 communication for QoS to a previous authentication protocol 651 exchange (e.g., using network access authentication). 653 Making an Authorization Decision 654 The QoS AAA protocol MUST exchange sufficient information between 655 the AE and the enforcing entity (and vice versa) to compute an 656 authorization decision and to execute this decision. 658 Triggering an Authorization Process 659 The QoS AAA protocol MUST allow periodic and event triggered 660 execution of the authorization process, originated at the 661 enforcing entity or even at the AE. 663 Associating QoS Reservations and Application State 664 The QoS AAA protocol MUST carry information sufficient for an AppS 665 to identify the appropriate application session and associate it 666 with a particular QoS reservation. 668 Dynamic Authorization 669 It MUST be possible for the QoS AAA protocol to push updates 670 towards the NE(s) from authorizing entities. 672 Bearer Gating 673 The QoS AAA protocol MUST allow the AE to gate (i.e., enable/ 674 disable) authorized application flows based on, e.g., application 675 state transitions. 677 Accounting Records 678 The QoS AAA protocol may define QoS accounting records containing 679 duration, volume (byte count) usage information and description of 680 the QoS attributes (e.g., bandwidth, delay, loss rate) that were 681 supported for the flow. 683 Sending Accounting Records 684 The NE SHOULD be able to send accounting records for a particular 685 QoS reservation state to an accounting entity. 687 Failure Notification 688 The QoS AAA protocol MUST allow the NE to report failures, such as 689 loss of connectivity due to movement of a mobile node or other 690 reasons for packet loss, to the authorizing entity. 692 Accounting Correlation 693 The QoS AAA protocol may support the exchange of sufficient 694 information to allow for correlation between accounting records 695 generated by the NEs and accounting records generated by an AppS. 697 Interaction with other AAA Applications 698 Interaction with other AAA applications such as Diameter Network 699 Access (NASREQ) application [RFC4005] is required for exchange of 700 authorization, authentication and accounting information. 702 In deployment scenarios where authentication of the QoS reservation 703 requesting entity (e.g., the user) is done by means outside the 704 Diameter QoS application protocol interaction, the AE is contacted 705 only with a request for QoS authorization. Authentication might have 706 taken place already via the interaction with the Diameter NASREQ 707 application or as part of the QoS signaling protocol (e.g., Transport 708 Layer Security (TLS) [RFC4346] in the General Internet Signaling 709 Transport (GIST) protocol [I-D.ietf-nsis-ntlp]). 711 Authentication of the QoS reservation requesting entity to the AE is 712 necessary if a particular Diameter QoS application protocol run 713 cannot be related (or if there is no intention to relate it) to a 714 prior authentication. In this case the AE MUST authenticate the QoS 715 reservation requesting entity in order to authorize the QoS request 716 as part of the Diameter QoS protocol interaction. 718 The document refers to three types of sessions that need to be 719 properly correlated. 721 QoS Signaling Session 722 The time period during which a QoS signaling protocol establishes, 723 maintains and deletes a QoS reservation state at the QoS network 724 element is referred to as QoS signaling session. Different QoS 725 signaling protocols use different ways to identify QoS signaling 726 sessions. The same applies to different usage environments. 727 Currently, this document supports three types of QoS session 728 identifiers, namely a signaling session id (e.g., the Session 729 Identifier used by the NSIS protocol suite), a flow id (e.g., 730 identifier assigned by an application to a certain flow as used in 731 the 3GPP) and a flow description based on the IP parameters of the 732 flow's end points. 734 Diameter Authorization Session 735 The time period, for which a Diameter server authorizes a 736 requested service (i.e., QoS resource reservation) is referred to 737 as a Diameter authorization session. It is identified by a 738 Session-Id included in all Diameter messages used for management 739 of the authorized service (initial authorization, re- 740 authorization, termination), see [RFC3588]. 742 Application-layer Session 743 The application layer session identifies the duration of an 744 application layer service which requires provision of certain QoS. 745 An application layer session identifier is provided by the QoS 746 requesting entity in the QoS signaling messages, for example as 747 part of the authorization token. In general, the application 748 session identifier is opaque to the QoS aware NEs. It is included 749 in the authorization request message sent to the AE and helps it 750 to correlate the QoS authorization request to the application 751 session state information. 753 Correlating these sessions is done at each of the three involved 754 entities: The QoS requesting entity correlates the application with 755 the QoS signaling sessions. The QoS NE correlates the QoS signaling 756 session with the Diameter authorization sessions. The AE SHOULD bind 757 the information about the three sessions together. Note that in 758 certain scenarios not all of the sessions are present. For example, 759 the application session might not be visible to QoS signaling 760 protocol directly if there is no binding between the application 761 session and the QoS requesting entity using the QoS signaling 762 protocol. 764 4. QoS Application Session Establishment and Management 766 4.1. Parties Involved 768 Authorization models supported by this application include three 769 parties: 770 o Resource Requesting Entity 771 o Network Elements (Diameter QoS application (DQA) client) 772 o Authorizing Entity (Diameter QoS application (DQA) server) 774 Note that the QoS RRE is only indirectly involved in the message 775 exchange. This entity provides the trigger to initiate the Diameter 776 QoS protocol interaction by transmitting QoS signaling messages. The 777 Diameter QoS application is only executed between the Network Element 778 (i.e., DQA client) and the Authorizing Entity (i.e., DQA server). 780 The QoS RRE may communicate with the AE using application layer 781 signaling for negotiation of service parameters. As part of this 782 application layer protocol interaction, for example using SIP, 783 authentication and authorization might take place. This message 784 exchange is, however, outside the scope of this document. The 785 protocol communication between the QoS resource requesting entity and 786 the QoS NE might be accomplished using the NSIS protocol suite, RSVP 787 or a link layer signaling protocol. A description of these protocols 788 is also outside the scope of this document. 790 4.2. Session Establishment 792 The Pull and Push modes use a different set of command codes for 793 session establishment. For other operations, such as session 794 modification and termination, they use the same set of command codes. 796 The selection of Pull mode or Push mode operation is based on the 797 trigger of the QoS Authorization session. When a QoS-Authz-Request 798 (QAR, see Section 5.1) message with a new session ID is received, the 799 AE operates in the Pull mode; when other triggers are received, the 800 AE operates in the Push mode. Similarly, when a QoS-Install-Request 801 (QIR, see Section 5.3} with a new session ID is received, the NE 802 operates in the Push mode; when other triggers are received, the NE 803 operation in the Pull mode. 805 4.2.1. Session Establishment for Pull Mode 807 A request for a QoS reservation or local events received by a NE can 808 trigger the initiation of a Diameter QoS authorization session. The 809 NE generates a QAR message in which the required objects from the QoS 810 signaling message that is converted to Diameter AVPs. 812 Figure 6 shows the protocol interaction between a Resource Requesting 813 Entity, a Network Element and the Authorizing Entity. 815 The AE's identity, information about the application session and/or 816 identity and credentials of the QoS RRE, requested QoS parameters, 817 signaling session identifier and/or QoS enabled data flows 818 identifiers MAY be encapsulated into respective Diameter AVPs and 819 included in the Diameter message sent to the AE. The QAR is sent to 820 a Diameter server that can either be the home server of the QoS 821 requesting entity or an AppS. 823 +-----------------------------------------------+-------------------+ 824 | QoS-specific Input Data | Diameter AVPs | 825 +-----------------------------------------------+-------------------+ 826 | Authorizing entity ID (e.g., Destination-Host | Destination-Host | 827 | taken from authorization token, | Destination-Realm | 828 | Destination-Realm or derived from the NAI of | | 829 | the QoS requesting entity) | | 830 | | | 831 | Authorization Token Credentials of the QoS | QoS-Authz-Data | 832 | requesting entity | User-Name | 833 | | | 834 | QoS parameters | QoS-Resources | 835 +-----------------------------------------------+-------------------+ 837 Table 1: Mapping Input Data to QoS AVPs--Pull Mode 839 Authorization processing starts at the Diameter QoS server when it 840 receives the QAR. Based on the information in the QoS- 841 Authentication-Data, User-Name and QoS-Resources AVPs the server 842 determines the authorized QoS resources and flow state (enabled/ 843 disabled) from locally available information (e.g., policy 844 information that may be previously established as part of an 845 application layer signaling exchange, or the user's subscription 846 profile). The QoS-Resources AVP is defined in 847 [I-D.ietf-dime-qos-attributes]. The authorization decision is then 848 reflected in the response returned to the Diameter client with the 849 QoS-Authorization-Answer message (QAA). 851 Authorizing 852 End-Host Network Element Entity 853 requesting QoS ( Diameter ( Diameter 854 QoS Client) QoS Server) 855 | | | 856 +---QoS-Reserve---->| | 857 | +- - - - - QAR - - - - - >| 858 | |(QoS-Resources, | 859 | | QoS-Auth-Data,User-ID)| 860 | | +--------+--------------+ 861 | | | Authorize request | 862 | | | Keep session data | 863 | | |/Authz-time,Session-Id/| 864 | | +--------+--------------+ 865 | |< - - - - QAA - - - - - -+ 866 | |(Result-Code, | 867 | |QoS-Resources,Authz-time)| 868 | +-------+---------+ 869 | |Install QoS state| 870 | | + | 871 | | Authz. session | 872 | | /Authz-time/ | QoS Responder 873 | | | Node 874 | +-------+---------+ | 875 | +----------QoS-Reserve---....--->| 876 | | | 877 | |<---------QoS-Response--....----| 878 |<--QoS-Response----+ | 879 | | | 880 |=====================Data Flow==============....===>| 881 | | 882 | +- - - - - QAR - - - - - >| 883 | |(START,QoS-Resources) | 884 | | | 885 | | +--------+--------------+ 886 | | | Report for successful | 887 | | | QoS reservation | 888 | | |Update of reserved QoS | 889 | | | resources | 890 | | +--------+--------------+ 891 | |< - - - - QAA - - - - - -+ 892 | | | 894 Figure 6: Initial QoS Request Authorization for Pull Mode 896 The Authorizing Entity keeps authorization session state and SHOULD 897 save additional information for management of the session (e.g., 898 Signaling-Session-Id, authentication data) as part of the session 899 state information. 901 The final result of the authorization request is provided in the 902 Result-Code AVP of the QAA message sent by the Authorizing Entity. 903 In case of successful authorization (i.e., Result-Code = 904 DIAMETER_LIMITED_SUCCESS, (see Section 7.1)), information about the 905 authorized QoS resources and the status of the authorized flow 906 (enabled/disabled) is provided in the QoS-Resources AVP of the QAA 907 message. The QoS information provided via the QAA is installed by 908 the QoS Traffic Control function of the NE. The value 909 DIAMETER_LIMITED_SUCCESS indicates that the AE expects confirmation 910 via another QAR message for successful QoS resource reservation and 911 for final reserved QoS resources (see below). 913 One important piece of information returned from the Authorizing 914 Entity is the authorization lifetime (carried inside the QAA). The 915 authorization lifetime allows the NE to determine how long the 916 authorization decision is valid for this particular QoS reservation. 917 A number of factors may influence the authorized session duration, 918 such as the user's subscription plan or currently available credits 919 at the user's account (see Section 8). The authorization duration is 920 time-based as specified in [RFC3588]. For an extension of the 921 authorization period, a new QoS-Authorization-Request/Answer message 922 exchange SHOULD be initiated. Further aspects of QoS authorization 923 session maintenance is discussed in Section 4.3, Section 4.4 and 924 Section 8. 926 The indication of a successful QoS reservation and activation of the 927 data flow is provided by the transmission of a QAR message, which 928 reports the parameters of the established QoS state: reserved 929 resources, duration of the reservation, and identification of the QoS 930 enabled flow/QoS signaling session. The Diameter QoS server 931 acknowledges the reserved QoS resources with the QA Answer (QAA) 932 message where the Result-Code is set to 'DIAMETER_SUCCESS'. Note 933 that the reserved QoS resources reported in this QAR message MAY be 934 different than those authorized with the initial QAA message, due to 935 the QoS signaling specific behavior (e.g., receiver-initiated 936 reservations with One-Path-With-Advertisements) or specific process 937 of QoS negotiation along the data path. 939 4.2.2. Session Establishment for Push Mode 941 The Diameter QoS server in the AE initiates a Diameter QoS 942 authorization session upon the request for QoS reservation triggered 943 by application layer signaling or by local events, and generates a 944 QoS-Install-Request (QIR) message to Diameter QoS client in the NE in 945 which it maps required objects to Diameter payload objects. 947 Figure 7 shows the protocol interaction between the AE, a Network 948 Element and a RRE. 950 The NE's identity, information about the application session and/or 951 identity and credentials of the QoS resource requesting entity, 952 requested QoS parameters, signaling session identifier and/or QoS 953 enabled data flows identifiers MAY be encapsulated into respective 954 Diameter AVPs and included into the Diameter message sent from a 955 Diameter QoS server in the Authorizing Entity to a Diameter QoS 956 client in the NE. This requires that the AE has knowledge of 957 specific information for allocating and identifying the NE that 958 should be contacted and the data flow for which the QoS reservation 959 should be established. This information can be statically configured 960 or dynamically discovered, see Section 4.2.3 for details. 962 +-----------------------------------------+-------------------------+ 963 | QoS-specific Input Data | Diameter AVPs | 964 +-----------------------------------------+-------------------------+ 965 | Network Element ID | Destination-Host | 966 | | Destination-Realm | 967 | | | 968 | Authorization Token Credentials of the | QoS-Authz-Data | 969 | QoS requesting entity | User-Name | 970 | | | 971 | QoS parameters | QoS-Resources | 972 +-----------------------------------------+-------------------------+ 974 Table 2: Mapping Input Data to QoS AVPs--Push Mode 976 Authorization processing starts at the Diameter QoS server when it 977 receives a request from a RRE through an AppS (e.g., SIP Invite) or 978 is triggered by a local event (e.g., pre-configured timer). Based on 979 the received information the server determines the authorized QoS 980 resources and flow state (enabled/disabled) from locally available 981 information (e.g., policy information that may be previously 982 established as part of an application layer signaling exchange, or 983 the user's subscription profile). The authorization decision is then 984 reflected in the QoS-Install-Request message (QIR) to the Diameter 985 QoS client. 987 Authorizing 988 End-Host Network Element Entity 989 requesting QoS ( Diameter ( Diameter 990 QoS Client) QoS Server) 991 | | | 992 | | |<-- Trigger -- 993 | | +--------+--------------+ 994 | | | Authorize request | 995 | | | Keep session data | 996 | | |/Authz-time,Session-Id/| 997 | | +--------+--------------+ 998 | | | 999 | |<-- - -- - QIR - - - - - -+ 1000 | |(Initial Request,Decision | 1001 | |(QoS-Resources,Authz-time)| 1002 | +-------+---------+ 1003 | |Install QoS state| 1004 | | + | 1005 | | Authz. session | 1006 | | /Authz-time/ | 1007 | | | 1008 | +-------+---------+ 1009 | + - - - - QIA - - - - - ->| 1010 | | (Result-Code, | 1011 | | QoS-Resources) | 1012 | | +--------+--------------+ 1013 | | | Report for successful | 1014 | | | QoS reservation | 1015 | | |Update of reserved QoS | 1016 | | | resources | 1017 | | +--------+--------------+ 1018 | | QoS Responder 1019 | | Node 1020 | | | 1021 |=====================Data Flow==============....===>| 1022 | | 1023 | (+- - - - - QAR - - - - - >|) 1024 | (|(START,QoS-Resources) |) 1025 | (|< - - - - QAA - - - - - -+) 1026 | | | 1028 Figure 7: Initial QoS Request Authorization for Push Mode 1030 The AE keeps authorization session state and SHOULD save additional 1031 information for management of the session (e.g., 1032 Signaling-Session-Id, authentication data) as part of the session 1033 state information. 1035 The final result of the authorization decision is provided in the 1036 QoS-Resources AVP of the QIR message sent by the AE. The QoS 1037 information provided via the QIR is installed by the QoS Traffic 1038 Control function of the NE. 1040 One important piece of information from the AE is the authorization 1041 lifetime (carried inside the QIR). The authorization lifetime allows 1042 the NE to determine how long the authorization decision is valid for 1043 this particular QoS reservation. A number of factors may influence 1044 the authorized session duration, such as the user's subscription plan 1045 or currently available credits at the user's account (see Section 8). 1046 The authorization duration is time-based as specified in [RFC3588]. 1047 For an extension of the authorization period, a new QoS-Install- 1048 Request/Answer message or QoS-Authorization-Request/Answer message 1049 exchange SHOULD be initiated. Further aspects of QoS authorization 1050 session maintenance is discussed in Section 4.3, Section 4.4 and 1051 Section 8. 1053 The indication of QoS reservation and activation of the data flow can 1054 be provided by the QoS-Install-Answer message immediately. In the 1055 case of successful enforcement, the Result-Code (= DIAMETER_SUCCESS, 1056 (see Section 7.1)) information is provided in the QIA message. Note 1057 that the reserved QoS resources reported in the QIA message MAY be 1058 different than those initially authorized with the QIR message, due 1059 to the QoS signaling specific behavior (e.g., receiver-initiated 1060 reservations with One-Path-With-Advertisements) or specific process 1061 of QoS negotiation along the data path. When path coupled signaling 1062 is used for QoS reservation along the data path, QAR/QAA may be used 1063 to update the results of QoS reservation and enforcement following 1064 the establishment of data flows. 1066 4.2.3. Discovery and Selection of Peer Diameter QoS Application Node 1068 Discovery of Diameter QoS application nodes 1070 The Diameter QoS application node may obtain information of its peer 1071 nodes (e.g., FQDN, IP address) through static configuration or 1072 dynamic discovery as described in [RFC3588]. In particular, the NE 1073 shall perform the relevant operation for Pull mode; the AE shall 1074 perform the relevant operations for Push mode. 1076 Selection of peer Diameter QoS application node 1078 Upon receipt of a trigger to initiate a new Diameter QoS 1079 authorization session, the Diameter QoS application node selects and 1080 retrieves the location information of the peer node and based on some 1081 index information provided by the RRE. For instance, it can be the 1082 Authorization Entity's ID stored in the authorization token, the end- 1083 user's identity (e.g., NAI [RFC4282]) or globally routable IP 1084 address. 1086 4.3. Session Re-authorization 1088 Client and server-side initiated re-authorizations are considered in 1089 the design of the Diameter QoS application. Whether the re- 1090 authorization events are transparent for the resource requesting 1091 entity or result in specific actions in the QoS signaling protocol is 1092 outside the scope of the Diameter QoS application. It is directly 1093 dependent on the capabilities of the QoS signaling protocol. 1095 There are a number of options for policy rules according to which the 1096 NE (AAA client) contacts the AE for re-authorization. These rules 1097 depend on the semantics and contents of the QAA message sent by the 1098 AE: 1100 a. The QAA message contains the authorized parameters of the flow 1101 and its QoS and sets their limits (presumably upper). With these 1102 parameters the AE specifies the services that the NE can provide 1103 and will be financially compensated for. Therefore, any change 1104 or request for change of the parameters of the flow and its QoS 1105 that do not conform to the authorized limits requires contacting 1106 the AE for authorization. 1107 b. The QAA message contains authorized parameters of the flow and 1108 its QoS. The rules that determine whether parameters' changes 1109 require re-authorization are agreed out of band, based on a 1110 Service Level Agreement (SLA) between the domains of the NE and 1111 the AE. 1112 c. The QAA message contains the authorized parameters of the flow 1113 and its QoS. Any change or request for change of these 1114 parameters requires contacting the AE for re-authorization. 1115 d. In addition to the authorized parameters of the flow and its QoS, 1116 the QAA message contains policy rules that determine the NEs 1117 actions in case of change or request for change in authorized 1118 parameters. 1120 Provided options are not exhaustive. Elaborating on any of the 1121 listed approaches is deployment /solution specific and is not 1122 considered in the current document. 1124 In addition, the AE may use a RAR to perform re-authorization with 1125 the authorized parameters directly when the re-authorization is 1126 triggered by service request or local events/policy rules. 1128 4.3.1. Client-Side Initiated Re-Authorization 1130 The AE provides the duration of the authorization session as part of 1131 the QoS-Authorization-Answer message (QAA). At any time before 1132 expiration of this period, a new QoS-Authorization-Request message 1133 (QAR) MAY be sent to the AE. The transmission of the QAR MAY be 1134 triggered when the NE receives a QoS signaling message that requires 1135 modification of the authorized parameters of an ongoing QoS session, 1136 or authorization lifetime expires. 1138 Authorizing 1139 End-Host Network Element Entity 1140 requesting QoS ( Diameter ( Diameter 1141 QoS Client) QoS Server) 1142 | | | 1143 |=====================Data Flow==========================> 1144 | | | 1145 | +-------+----------+ | 1146 | |Authz-time/CC-Time| | 1147 | | expires | | 1148 | +-------+----------+ | 1149 | +- - - - - QAR - - - - - >| 1150 | |(QoS-Resources, | 1151 | | QoS-Authz-Data,User-ID) | 1152 | +--------+--------------+ 1153 NOTE: | | Authorize request | 1154 Re-authorization | | Update session data | 1155 is transparent to | |/Authz-time,Session-Id/| 1156 the End-Host | +--------+--------------+ 1157 |< - - - - QAA - - - - - -+ 1158 | |(Result-Code, | 1159 | |QoS-Resources,Authz-time)| 1160 | +-------+---------+ | 1161 | |Update QoS state | | 1162 | | + | | 1163 | | Authz. session | | 1164 | | /Authz-time/ | | 1165 | | | | 1166 | +-------+---------+ | 1167 | | | 1168 |=====================Data Flow==========================> 1169 | | 1171 Figure 8: Client-side Initiated QoS Re-Authorization 1173 4.3.2. Server-Side Initiated Re-Authorization 1175 The AE MAY initiate a QoS re-authorization by issuing a Re-Auth- 1176 Request message (RAR) as defined in the Diameter base protocol 1177 [RFC3588], which may include the parameters of the re-authorized QoS 1178 state: reserved resources, duration of the reservation, 1179 identification of the QoS enabled flow/QoS signaling session for re- 1180 installation of the resource state by the QoS Traffic Control 1181 function of the NE. 1183 A NE that receives such a RAR message with Session-Id matching a 1184 currently active QoS session acknowledges the request by sending the 1185 Re-Auth-Answer (RAA) message towards the AE. 1187 If RAR does not include any parameters of the re-authorized QoS 1188 state, the NE MUST initiate a QoS re-authorization by sending a QoS- 1189 Authorization-Request (QAR) message towards the AE. 1191 Authorizing 1192 End-Host Network Element Entity 1193 requesting QoS ( Diameter ( Diameter 1194 QoS Client) QoS Server) 1195 | | | 1196 | | |<-- Trigger -- 1197 | | +--------+--------------+ 1198 | | | Authorize request | 1199 | | | Keep session data | 1200 | | |/Authz-time,Session-Id/| 1201 | | +--------+--------------+ 1202 | | | 1203 | |<-- - -- - RAR - - - - - -+ 1204 | |(Request,Decision | 1205 | |(QoS-Resources,Authz-time)| 1206 | +-------+---------+ 1207 | |Install QoS state| 1208 | | + | 1209 | | Authz. session | 1210 | | /Authz-time/ | 1211 | | | 1212 | +-------+---------+ 1213 | + - - - - RAA - - - - - ->| 1214 | | (Result-Code, | 1215 | | QoS-Resources) | 1216 | | +--------+--------------+ 1217 | | | Report for successful | 1218 | | | QoS reservation | 1219 | | |Update of reserved QoS | 1220 | | | resources | 1221 | | +--------+--------------+ 1222 | | | 1224 Figure 9: Server-side Initiated QoS Re-Authorization 1226 4.4. Session Termination 1228 4.4.1. Client-Side Initiated Session Termination 1230 The authorization session for an installed QoS reservation state MAY 1231 be terminated by the Diameter client by sending a Session- 1232 Termination-Request message (STR) to the Diameter server. This is a 1233 Diameter base protocol function and it is defined in [RFC3588]. 1234 Session termination can be caused by a QoS signaling messaging 1235 requesting deletion of the existing QoS reservation state or it can 1236 be caused as a result of a soft-state expiration of the QoS 1237 reservation state. 1239 Authorizing 1240 End-Host Network Element Entity 1241 requesting QoS ( Diameter ( Diameter 1242 QoS Client) QoS Server) 1243 | | | 1244 |==Data Flow==>X /Stop of the data flow/ | 1245 | | | 1246 +---QoS-Reserve---->| | 1247 | (Delete QoS +- - - - - STR - - - - - >| 1248 | reservation) | +--------+--------------+ 1249 | | | Remove authorization | 1250 |<--QoS-Response----+ | session state | 1251 | | +--------+--------------+ 1252 |< - - - - STA - - - - - -+ 1253 +-------+--------+ | 1254 |Delete QoS state| 1255 +-------+--------+ QoS Responder 1256 | Node 1257 +----------QoS-Reserve-----....--->| 1258 | (Delete QoS | 1259 | reservation) | 1260 |<---------QoS-Response----....----+ 1261 | | 1263 Figure 10: Client-Side Initiated Session Termination 1265 4.4.2. Server-Side Initiated Session Termination 1267 At anytime during a session the AE MAY send an Abort-Session-Request 1268 message (ASR) to the NE. This is a Diameter base protocol function 1269 and it is defined in [RFC3588]. Possible reasons for initiating the 1270 ASR message to the NE are insufficient credits or session termination 1271 at the application layer. The ASR message results in termination of 1272 the authorized session, release of the reserved resources at the NE 1273 and transmission of an appropriate QoS signaling message indicating a 1274 notification to other Network Elements aware of the signaling 1275 session. 1277 Authorizing 1278 End-Host Network Element Entity 1279 requesting QoS ( Diameter ( Diameter 1280 QoS Client) QoS Server) 1281 | | | 1282 |=====================Data Flow==========================> 1283 | | 1284 | |< - - - - ASR - - - - - -+ 1285 | | | 1286 |====Data Flow=====>X | QoS Responder 1287 | | | Node 1288 |<--QoS-Notify------+----------QoS-Reserve-----....--->| 1289 | | (Delete QoS | | 1290 | reservation) | 1291 +-------+--------+ | 1292 |Delete QoS state| | 1293 +-------+--------+ | 1294 +- - - - - ASA - - - - - >| 1295 | +--------+--------------+ 1296 | | Remove authorization | 1297 | | session state | 1298 | +--------+--------------+ 1299 | QoS Responder 1300 | Node 1301 |<---------QoS-Response----....----+ 1302 | | 1304 Figure 11: Server-Side Initiated Session Termination 1306 5. QoS Application Messages 1308 The Diameter QoS Application requires the definition of new mandatory 1309 AVPs and Command-codes (see Section 3 of [RFC3588]). Four new 1310 Diameter messages are defined along with Command-Codes whose values 1311 MUST be supported by all Diameter implementations that conform to 1312 this specification. 1314 +---------------------+---------+--------+-------------+ 1315 | Command Name | Abbrev. | Code | Reference | 1316 +---------------------+---------+--------+-------------+ 1317 | QoS-Authz-Request | QAR | [TBD1] | Section 5.1 | 1318 | | | | | 1319 | QoS-Authz-Answer | QAA | [TBD2] | Section 5.2 | 1320 | | | | | 1321 | QoS-Install-Request | QIR | [TBD3] | Section 5.3 | 1322 | | | | | 1323 | QoS-Install-Answer | QIA | [TBD4] | Section 5.4 | 1324 +---------------------+---------+--------+-------------+ 1326 Table 3: Diameter QoS Commands 1328 In addition, the following Diameter Base protocol messages are used 1329 in the Diameter QoS application: 1331 +-----------------------+---------+------+-----------+ 1332 | Command-Name | Abbrev. | Code | Reference | 1333 +-----------------------+---------+------+-----------+ 1334 | Re-Auth-Request | RAR | 258 | [RFC3588] | 1335 | | | | | 1336 | Re-Auth-Answer | RAA | 258 | [RFC3588] | 1337 | | | | | 1338 | Abort-Session-Request | ASR | 274 | [RFC3588] | 1339 | | | | | 1340 | Abort-Session-Answer | ASA | 274 | [RFC3588] | 1341 | | | | | 1342 | Session-Term-Request | STR | 275 | [RFC3588] | 1343 | | | | | 1344 | Session-Term-Answer | STA | 275 | [RFC3588] | 1345 +-----------------------+---------+------+-----------+ 1347 Table 4: Diameter Base Commands 1349 Diameter nodes conforming to this specification MAY advertise support 1350 by including the value of [TBD5] in the Auth-Application-Id or the 1351 Acct-Application-Id AVP of the Capabilities-Exchange-Request and 1352 Capabilities-Exchange-Answer commands, see [RFC3588]. 1354 The value of {TBD5] MUST be used as the Application-Id in all QAR/QAA 1355 and QIR/QIA commands. 1357 The value of zero (0) SHOULD be used as the Application-Id in all 1358 STR/STA, ASR/ASA, and RAR/RAA commands, because these commands are 1359 defined in the Diameter base protocol and no additional mandatory 1360 AVPs for those commands are defined in this document. 1362 5.1. QoS-Authorization Request (QAR) 1364 The QoS-Authorization-Request message (QAR) indicated by the Command- 1365 Code field (see Section 3 of [RFC3588]) set to [TBD1] and 'R' bit set 1366 in the Command Flags field is used by NEs to request quality of 1367 service related resource authorization for a given flow. 1369 The QAR message MUST carry information for signaling session 1370 identification, AE identification, information about the requested 1371 QoS, and the identity of the QoS requesting entity. In addition, 1372 depending on the deployment scenario, an authorization token and 1373 credentials of the QoS requesting entity SHOULD be included. 1375 The message format, presented in ABNF form [RFC4234], is defined as 1376 follows: 1378 ::= < Diameter Header: [TBD1], REQ, PXY > 1379 < Session-Id > 1380 { Auth-Application-Id } 1381 { Origin-Host } 1382 { Origin-Realm } 1383 { Destination-Realm } 1384 { Auth-Request-Type } 1385 [ Destination-Host ] 1386 [ User-Name ] 1387 * [ QoS-Resources ] 1388 [ QoS-Authz-Data ] 1389 [ Bound-Auth-Session-Id ] 1390 * [ AVP ] 1392 5.2. QoS-Authorization Answer (QAA) 1394 The QoS-Authorization-Answer message (QAA), indicated by the Command- 1395 Code field set to [TBD2] and 'R' bit cleared in the Command Flags 1396 field is sent in response to the QoS-Authorization-Request message 1397 (QAR). If the QoS authorization request is successfully authorized, 1398 the response will include the AVPs to allow authorization of the QoS 1399 resources and transport plane gating information. 1401 The message format is defined as follows: 1403 ::= < Diameter Header: [TBD2], PXY > 1404 < Session-Id > 1405 { Auth-Application-Id } 1406 { Auth-Request-Type } 1407 { Result-Code } 1408 { Origin-Host } 1409 { Origin-Realm } 1410 * [ QoS-Resources ] 1411 [ Acct-Multisession-Id ] 1412 [ Session-Timeout ] 1413 [ Authorization-Session-Lifetime ] 1414 [ Authorization-Grace-Period ] 1415 * [ AVP ] 1417 5.3. QoS-Install Request (QIR) 1419 The QoS-Install Request message (QIR), indicated by the Command-Code 1420 field set to [TBD3] and 'R' bit set in the Command Flags field is 1421 used by AE to install or update the QoS parameters and the flow state 1422 of an authorized flow at the transport plane element. 1424 The message MUST carry information for signaling session 1425 identification or identification of the flow to which the provided 1426 QoS rules apply, identity of the transport plane element, description 1427 of provided QoS parameters, flow state and duration of the provided 1428 authorization. 1430 The message format is defined as follows: 1432 ::= < Diameter Header: [TBD3], REQ, PXY > 1433 < Session-Id > 1434 { Auth-Application-Id } 1435 { Origin-Host } 1436 { Origin-Realm } 1437 { Destination-Realm } 1438 { Auth-Request-Type } 1439 [ Destination-Host ] 1440 * [ QoS-Resources ] 1441 [ Session-Timeout ] 1442 [ Authorization-Session-Lifetime ] 1443 [ Authorization-Grace-Period ] 1444 [ Authorization-Session-Volume ] 1445 * [ AVP ] 1447 5.4. QoS-Install Answer (QIA) 1449 The QoS-Install Answer message (QIA), indicated by the Command-Code 1450 field set to [TBD4] and 'R' bit cleared in the Command Flags field is 1451 sent in response to the QoS-Install Request message (QIR) for 1452 confirmation of the result of the installation of the provided QoS 1453 reservation instructions. 1455 The message format is defined as follows: 1457 ::= < Diameter Header: [TBD4], PXY > 1458 < Session-Id > 1459 { Auth-Application-Id } 1460 { Origin-Host } 1461 { Origin-Realm } 1462 { Result-Code } 1463 * [ QoS-Resources ] 1464 * [ AVP ] 1466 5.5. Re-Auth-Request (RAR) 1468 The Re-Auth-Request message (RAR), indicated by the Command-Code 1469 field set to 258 and the 'R' bit set in the Command Flags field, is 1470 sent by the AE to the NE in order to initiate the QoS re- 1471 authorization from DQA server side. 1473 If the RAR command is received by the NE without any parameters of 1474 the re-authorized QoS state, the NE MUST initiate a QoS re- 1475 authorization by sending a QoS-Authorization-Request (QAR) message 1476 towards the AE. 1478 The message format is defined as follows: 1480 ::= < Diameter Header: 258, REQ, PXY > 1481 < Session-Id > 1482 { Auth-Application-Id } 1483 { Origin-Host } 1484 { Origin-Realm } 1485 { Destination-Realm } 1486 { Auth-Request-Type } 1487 [ Destination-Host ] 1488 * [ QoS-Resources ] 1489 [ Session-Timeout ] 1490 [ Authorization-Session-Lifetime ] 1491 [ Authorization-Grace-Period ] 1492 [ Authorization-Session-Volume ] 1494 * [ AVP ] 1496 5.6. Re-Auth-Answer (RAA) 1498 The Re-Auth-Answer message (RAA), indicated by the Command-Code field 1499 set to 258 and the 'R' bit cleared in the Command Flags field, is 1500 sent by the NE to the AE in response to the RAR command. 1502 The message format is defined as follows: 1504 ::= < Diameter Header: 258, PXY > 1505 < Session-Id > 1506 { Auth-Application-Id } 1507 { Origin-Host } 1508 { Origin-Realm } 1509 { Result-Code } 1510 * [ QoS-Resources ] 1511 * [ AVP ] 1513 6. QoS Application State Machine 1515 The QoS application defines its own state machine that is based on 1516 the authorization state machine defined in Section 8.1 of the Base 1517 Protocol ([RFC3588]). The Qos state machine uses own messages as 1518 defined in Section 5 and QoS AVPs as defined in Section 7. 1520 6.1. Supplemented States for Push Mode 1522 Using the Base Protocol state machine as a basis, the following 1523 states are supplemented to first 2 state machines in which the 1524 session state is maintained on the Server. This MUST be supported in 1525 any QoS application implementations in support of server initiated 1526 push mode (see (Section 4.2.2)). 1528 The following states are supplemented to the state machine on the 1529 client when state is maintained on the client as defined in Section 1530 8.1 of the Base Protocol [RFC3588]: 1532 SERVER, STATEFUL 1533 State Event Action New State 1534 ------------------------------------------------------------- 1535 Idle An application or local Send Pending 1536 event triggers an initial QIR initial 1537 QoS request to the server request 1539 Pending Received QIA with a failed Cleanup Idle 1540 Result-Code 1542 Pending Received QIA with Result-Code Update Open 1543 = SUCCESS session 1544 Pending Error in processing received Send Discon 1545 QIA with Result-Code = SUCCESS ASR 1547 The following states are supplemented to the state machine on the 1548 client when state is maintained on the server as defined in Section 1549 8.1 of the Base Protocol [RFC3588]: 1551 CLIENT, STATEFUL 1552 State Event Action New State 1553 ------------------------------------------------------------- 1554 Idle QIR initial request Send Open 1555 received and successfully QIA initial 1556 processed answer, 1557 reserve resources 1559 Idle QIR initial request Send Idle 1560 received but not QIA initial 1561 successfully processed answer with 1562 Result-Code 1563 != SUCCESS 1565 7. QoS Application AVPs 1567 Each of the AVPs identified in the QoS-Authorization-Request/Answer 1568 and QoS-Install-Request/Answer messages and the assignment of their 1569 value(s) is given in this section. 1571 7.1. Reused Base Protocol AVPs 1573 The QoS application uses a number of session management AVPs, defined 1574 in the Base Protocol ([RFC3588]). 1576 Attribute Name AVP Code Reference [RFC3588] 1577 Origin-Host 264 Section 6.3 1578 Origin-Realm 296 Section 6.4 1579 Destination-Host 293 Section 6.5 1580 Destination-Realm 283 Section 6.6 1581 Auth-Application-Id 258 Section 6.8 1582 Result-Code 268 Section 7.1 1583 Auth-Request-Type 274 Section 8.7 1584 Session-Id 263 Section 8.8 1585 Authorization-Lifetime 291 Section 8.9 1586 Authorization-Grace-Period 276 Section 8.10 1587 Session-Timeout 27 Section 8.13 1588 User-Name 1 Section 8.14 1590 The Auth-Application-Id AVP (AVP Code 258) is assigned by IANA to 1591 Diameter applications. The value of the Auth-Application-Id for the 1592 Diameter QoS application is TBD. 1594 7.2. QoS Application Defined AVPs 1596 This document reuses the AVPs defined in Section 4 of 1597 [I-D.ietf-dime-qos-attributes]. 1599 This section lists the AVPs that are introduced specifically for the 1600 QoS application. The following new AVPs are defined: Bound-Auth- 1601 Session-Id and the QoS-Authorization-Data AVP. 1603 The following table describes the Diameter AVPs newly defined in this 1604 document for usage with the QoS Application, their AVP code values, 1605 types, possible flag values, and whether the AVP may be encrypted. 1607 +-------------------+ 1608 | AVP Flag rules | 1609 +----------------------------------------------|----+--------+-----+ 1610 | AVP Section | | SHLD| MUST| 1611 | Attribute Name Code Defined Data Type |MUST| NOT| NOT| 1612 +----------------------------------------------+----+--------+-----+ 1613 |QoS-Authorization-Data TBD 7.2 Grouped | M | | V | 1614 |Bound-Auth-Session-Id TBD 7.2 UTF8String | M | | V | 1615 +----------------------------------------------+----+--------+-----+ 1616 |M - Mandatory bit. An AVP with "M" bit set and its value MUST be | 1617 | supported and recognized by a Diameter entity in order the | 1618 | message, which carries this AVP, to be accepted. | 1619 |V - Vendor specific bit that indicates whether the AVP belongs to | 1620 | a address space. | 1621 +------------------------------------------------------------------+ 1623 QoS-Authz-Data 1624 The QoS-Authorization-Data AVP (AVP Code TBD) is of type 1625 OctetString. It is a container that carries application session 1626 or user specific data that has to be supplied to the AE as input 1627 to the computation of the authorization decision. 1629 Bound-Authentication-Session-Id 1630 The Bound-Authentication-Session AVP (AVP Code TBD) is of type 1631 UTF8String. It carries the id of the Diameter authentication 1632 session that is used for the network access authentication (NASREQ 1633 authentication session). It is used to tie the QoS authorization 1634 request to a prior authentication of the end host done by a co- 1635 located application for network access authentication (Diameter 1636 NASREQ) at the QoS NE. 1638 8. Accounting 1640 A NE may start an accounting session by sending an Accounting-Request 1641 message (ACR) after successful QoS reservation and activation of the 1642 data flow (see Figure 6 and Figure 7). After every successful re- 1643 authorization procedure (see Figure 8 and Figure 9), the NE may 1644 initiate an interim accounting message exchange. After successful 1645 session termination (see Figure 10 and Figure 11), the NE may 1646 initiate a final exchange of accounting messages for terminating of 1647 the accounting session and reporting final records for the usage of 1648 the QoS resources reserved. It should be noted that the two sessions 1649 (authorization and accounting) have independent management by the 1650 Diameter base protocol, which allows for finalizing the accounting 1651 session after the end of the authorization session. 1653 The detailed QoS accounting procedures are out of scope in this 1654 document. 1656 9. Examples 1658 9.1. Example Call Flow for Pull Mode 1660 This section presents an example of the interaction between the end 1661 host and Diameter QoS application entities using Pull mode. The 1662 application layer signaling is, in this example, provided using SIP. 1663 Signaling for a QoS resource reservation is done using the QoS NSLP. 1664 The authorization of the QoS reservation request is done by the 1665 Diameter QoS application (DQA). 1667 End-Host SIP Server Correspondent 1668 requesting QoS (DQA Server) Node 1670 | | | 1671 ..|....Application layer SIP signaling.......|..............|.. 1672 . | Invite (SDP) | | . 1673 . +.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-> | . 1674 . | 100 Trying | | . 1675 . <.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-+ Invite (SDP)| . 1676 . | +-.-.-.....-.-.> . 1677 . | | 180 SDP' | . 1678 . | <-.-.-.....-.-.+ . 1679 . | +--------+--------+ | . 1680 . | |Authorize session| | . 1681 . | | parameters | | . 1682 . | 180 (Session parameters) +--------+--------+ | . 1683 . <.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-+ | . 1684 ..|..........................................|... ..........|.. 1685 | | | 1686 | +------------+ | | 1687 | | NE | | | 1688 | |(DQA Client)| | | 1689 | +------+-----+ | | 1690 | | | | 1691 |QoS NSLP Reserve | | | 1692 +------------------> QAR | | 1693 | (POLICY_DATA>v +- - - - -<>- - - -> | 1694 | QSPEC) v >===>(Destination-Host, | | 1695 | v >=======>QoS-Authorization-Data ++------------+ | 1696 | >===========>QoS-Resources) |Authorize | | 1697 | | |QoS resources| | 1698 | | ++------------+ | 1699 | | QAA | | 1700 | <- - - - -<>- - - -+ | 1701 | |(Result-Code, | | 1702 | |QoS-Resources, | | 1703 | |Authorization-Lifetime) | | 1704 | +---------+--------+ | | 1705 | |Install QoS state1| | | 1706 | |+ Authorization. session | | | 1707 | +---------+--------+ | | 1708 | |QoS NSLP Reserve | 1709 | +---------------..............---------> 1710 | | | 1711 | | QoS NSLP Response| 1712 |QoS NSLP Response <---------------..............---------+ 1713 <------------------+ | 1714 | | QoS NSLP Query| 1715 |QoS NSLP Query <---------------..............---------+ 1716 <------------------+ | 1717 |QoS NSLP Reserve | | 1718 +------------------> QAR | | 1719 | +- - - - -<>- - - -> | 1720 | | +---+---------+ | 1721 | | |Authorize | | 1722 | | |QoS resources| | 1723 | | QAA +---+---------+ | 1724 | <- - - - -<>- - - -+ | 1725 | +---------+--------+ | | 1726 | |Install QoS state2| | 1727 | |+ Authorization. session | | 1728 | +---------+--------+ | 1729 | | QoS NSLP Reserve | 1730 | +---------------..............---------> 1731 | | QoS NSLP Response| 1732 |QoS NSLP Response <---------------..............---------+ 1733 <------------------+ | 1734 | | | 1735 /------------------+--Data Flow---------------------------\ 1736 \------------------+--------------------------------------/ 1737 | | | 1739 .-.-.-.-. SIP signaling 1740 --------- QoS NSLP signaling 1741 - - - - - Diameter QoS Application messages 1742 ========= Mapping of objects between QoS and AAA protocol 1744 Figure 12: QoS Authorization Example - Pull Mode 1746 The communication starts with SIP signaling between the two end 1747 points and the SIP server for negotiation and authorization of the 1748 requested service and its parameters (see Figure 12). As a part of 1749 the process, the SIP server verifies whether the user at Host A is 1750 authorized to use the requested service (and potentially the ability 1751 to be charged for the service usage). Negotiated session parameters 1752 are provided to the end host. 1754 Subsequently, Host A initiates a QoS signaling message towards Host 1755 B. It sends a QoS NSLP Reserve message, in which it includes 1756 description of the required QoS (QSPEC object) and authorization data 1757 for negotiated service session (part of the POLICY_DATA object). 1758 Authorization data includes, as a minimum, the identity of the AE 1759 (e.g., the SIP server) and an identifier of the application service 1760 session for which QoS resources are requested. 1762 A QoS NSLP Reserve message is intercepted and processed by the first 1763 QoS aware Network Element. The NE uses the Diameter QoS application 1764 to request authorization for the received QoS reservation request. 1765 The identity of the AE (in this case the SIP server that is co- 1766 located with a Diameter server) is put into the Destination-Host AVP, 1767 any additional session authorization data is encapsulated into the 1768 QoS-Authorization-Data AVP and the description of the QoS resources 1769 is included into QoS-Resources AVP. These AVPs are included into a 1770 QoS Authorization Request message, which is sent to the AE. 1772 A QAR message will be routed through the AAA network to the AE. The 1773 AE verifies the requested QoS against the QoS resources negotiated 1774 for the service session and replies with QoS-Authorization answer 1775 (QAA) message. It carries the authorization result (Result-Code AVP) 1776 and the description of the authorized QoS parameters (QoS-Resources 1777 AVP), as well as duration of the authorization session 1778 (Authorization-Lifetime AVP). 1780 The NE interacts with the traffic control function and installs the 1781 authorized QoS resources and forwards the QoS NSLP Reserve message 1782 further along the data path. Moreover, the NE may serve as a 1783 signaling proxy and process the QoS signaling (e.g. initiation or 1784 termination of QoS signaling) based on the QoS decision received from 1785 the authorizing entity. 1787 9.2. Example Call Flow for Push Mode 1789 This section presents an example of the interaction between the end- 1790 host and Diameter QoS application entities using Push mode. The 1791 application layer signaling is, in this example, provided using SIP. 1792 Signaling for a QoS resource reservation is done using the QoS NSLP. 1793 The authorization of the QoS reservation request is done by the 1794 Diameter QoS application (DQA). 1796 End-Host NE SIP Server Correspondent 1797 requesting QoS (DQA Client) (DQA Server) Node 1798 | | | | 1799 ..|....Application layer SIP signaling..........|..............|.. 1800 . | Invite(SDP offer)| | | . 1801 . +.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.> | . 1802 . | 100 Trying | | | . 1803 . <.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.+ | . 1804 . |.............................................|..............| . 1805 | | +---------+-------------+| 1806 | | | Authorize request || 1807 | | | Keep session data || 1808 | | |/Authorization-time,Session-Id/|| 1809 | | +---------+-------------+| 1810 | | | | 1811 | |<-- - -- - QIR - -- - -- -+ | 1812 | |(Initial Request,Decision | | 1813 | |(QoS-Resources,Authorization-time)| | 1814 | +-------+---------+ | | 1815 | |Install QoS state| | | 1816 | | + | | | 1817 | | Authorization. session | | | 1818 | | /Authorization-time/ | | | 1819 | +-------+---------+ | | 1820 | + - - -- - QIA - - - - - ->| | 1821 | | (Result-Code, | | 1822 | | QoS-Resources) | | 1823 | | +----------+------------+ | 1824 | | | Report for successful | | 1825 | | | QoS reservation | | 1826 | | |Update of reserved QoS | | 1827 | | | resources | | 1828 | | +----------+------------+ | 1829 . | | | Invite (SDP) | . 1830 . | | +-.-.-.....-.-.> . 1831 . | 180 (Ringing) | | . 1832 . <.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.<.-.-.-.-.-.-.-+ . 1833 . | | | 200 OK (SDP)| . 1834 . | | <-.-.-.....-.-.+ . 1835 | | +--------+-----------+ | 1836 | | |re-Authorize session| | 1837 | | | parameters | | 1838 | | +--------+-----------+ | 1839 | <- - - - - - RAR - - - - - + | 1840 | +---------+--------+ | | 1841 | |Activate QoS state| | | 1842 | +---------+--------+ | | 1843 | +- - - - - - RAA - - - - - > | 1844 . | 200 (SDP answer) | | | . 1845 . <.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.+ | . 1847 | | | 1848 /------------------+-----Data Flow---------------------------\ 1849 \------------------+-----------------------------------------/ 1850 | | | 1852 .-.-.-.-. SIP signaling 1853 - - - - - Diameter QoS Application messages 1855 Figure 13: QoS Authorization Example - Push Mode 1857 The communication starts with SIP signaling between the two end 1858 points and the SIP server for negotiation and authorization of the 1859 requested service and its parameters (see Figure 13). As a part of 1860 the process, the SIP server verifies whether the user at Host A is 1861 authorized to use the requested service (and potentially the ability 1862 to be charged for the service usage). The DQA server is triggered to 1863 authorize the QoS request based on session parameters (i.e., SDP 1864 offer), initiate a Diameter QoS authorization session and install 1865 authorized QoS state to the Network Element via QIR message. 1867 The DQA server may obtain the info of peer DQA client from pre- 1868 configured information or query the DNS based on Host A's identity or 1869 IP address (In this case a DQA server is co-located with a SIP server 1870 and a DQA client is co-located with a NE). The identity of Network 1871 Element is put into the Destination-Host AVP, the description of the 1872 QoS resources is included into QoS-Resources AVP, as well as duration 1873 of the authorization session (Authorization-Lifetime AVP). The NE 1874 interacts with the traffic control function and reserves the 1875 authorized QoS resources accordingly, for instance, the NE may serve 1876 as a signaling proxy and process the QoS signaling (e.g. initiation 1877 or termination of QoS signaling) based on the QoS decision received 1878 from the authorizing entity. 1880 With successful QoS authorization, the SDP offer in SIP Invite is 1881 forwarded to Host B. Host B sends back a 18x (ringing) message 1882 towards Host A and processes the SDP. Once Host B accepts the call, 1883 it sends back a 200 OK, in which it includes description of the 1884 accepted session parameters (i.e. SDP answer). 1886 The DQA server may verify the accepted QoS against the pre-authorized 1887 QoS resources, and sends a Diameter RAR message to the DQA client in 1888 the NE for activating the installed policies and commit the resource 1889 allocation. With successful QoS enforcement, the 200 OK is forwarded 1890 towards Host A. 1892 Note that the examples above show a sender-initiated reservation from 1893 the end host towards the corresponding node and a receiver-initiated 1894 reservation from the correspondent node towards the end host. 1896 10. IANA Considerations 1898 This section contains the namespaces that have either been created in 1899 this specification or had their values assigned to existing 1900 namespaces managed by IANA. 1902 10.1. AVP Codes 1904 IANA is requested to allocate two AVP codes to the following: 1906 Registry: 1907 AVP Code Attribute Name Reference 1908 ----------------------------------------------------------- 1909 to be assigned QoS-Authorization-Data Section 7.2 1910 to be assigned Bound-Auth-Session-Id Section 7.2 1912 10.2. AVP Specific Values 1914 IANA is requested to allocate the following sub-registry values. 1916 Sub-registry: Auth-Application-Id AVP Values (code 258) 1917 Registry: 1918 AVP Values Attribute Name Reference 1919 ------------- ------------------------------------------- 1920 to be assigned DIAMETER-QOS-NOSUPPORT Section 5 1921 to be assigned DIAMETER-QOS-SUPPORT Section 5 1923 Sub-registry: Acct-Application-Id AVP Values (code 259) 1924 Registry: 1925 AVP Values Attribute Name Reference 1926 ------------- ------------------------------------------- 1927 to be assigned DIAMETER-QOS-NOSUPPORT Section 5 1928 to be assigned DIAMETER-QOS-SUPPORT Section 5 1930 10.3. AVP Flags 1932 There are no new AVP flags defined for either the QoS-Authorization- 1933 Data AVP or the Bound-Ath-Session-ID AVP. 1935 10.4. Application IDs 1937 IANA is requested to allocate the following application ID using the 1938 next value from the 7-16777215 range. 1940 Registry: 1941 ID values Name Reference 1942 ----------------------------------------------------------- 1943 to be assigned Diameter QoS application Section 5 1945 10.5. Command Codes 1947 IANA is requested to allocate command code values for the following 1948 from the range 289-299. 1950 Registry: 1951 Code Value Name Reference 1952 ----------------------------------------------------------- 1953 to be assigned QoS-Authorization-Request (QAR) Section 5.1 1954 to be assigned QoS-Authorization-Answer (QAA) Section 5.2 1955 to be assigned QoS-Install-Request (QIR) Section 5.3 1956 to be assigned QoS-Install-Answer (QIA) Section 5.4 1958 11. Security Considerations 1960 This document describes a mechanism for performing authorization of a 1961 QoS reservation at a third party entity. Therefore, sufficient 1962 information needs to be made available to the Authorizing Entity to 1963 can make such an authorization decision. Information may come from 1964 various sources, including the application layer signaling, the 1965 Diameter protocol (with its security mechanisms), from policy 1966 information stored available with a AAA server and from a QoS 1967 signaling protocol. 1969 Below there is a discussion about considerations for the Diameter QoS 1970 interaction between an Authorizing Entity and a Network Element. 1971 Security between the Authorizing Entity and the Network Element has a 1972 number of components: authentication, authorization, integrity and 1973 confidentiality. 1975 Authentication refers to confirming the identity of an originator for 1976 all datagrams received from the originator. Lack of authentication 1977 of Diameter messages between the Authorizing Entity and the Network 1978 Element can seriously jeopardize the fundamental service rendered by 1979 the Network Element. A consequence of not authenticating the message 1980 sender by the Network Element would be that an attacker could spoof 1981 the identity of a "legitimate" Authorizing Entity in order to 1982 allocate resources, change resource assignments or free resources. 1983 The adversary can also manipulate the state at the Network Element in 1984 such a way that it leads to a denial of service attack by, for 1985 example, setting the allowed bandwidth to zero or allocating the 1986 entire bandwidth available to a single flow. 1988 A consequence of not authenticating the Network Element to an 1989 Authorizing Entity is that an attacker could impact the policy based 1990 admission control procedure run by the Authorizing Entity to provide 1991 a wrong view of the resources used in the network. Failing to 1992 provide the required credentials should be subject to logging. 1994 Authorization refers to whether a particular Authorizing Entity is 1995 authorized to signal a Network Element with requests for one or more 1996 applications, adhering to a certain policy profile. Failing the 1997 authorization process might indicate a resource theft attempt or 1998 failure due to administrative and/or credential deficiencies. In 1999 either case, the Network Element should take the proper measures to 2000 log such attempts. 2002 Integrity is required to ensure that a Diameter message has not been 2003 maliciously altered. The result of a lack of data integrity 2004 enforcement in an untrusted environment could be that an imposter 2005 will alter the messages exchanged between a Network Entity and an 2006 Authorizing Entity potentially causing a denial of service. 2008 Confidentiality protection of Diameter messages ensures that the 2009 signaling data is accessible only to the authorized entities. When 2010 signaling messages from the Application Server, via the Authorizing 2011 Entity towards the Network Element traverse untrusted networks, lack 2012 of confidentiality will allow eavesdropping and traffic analysis. 2013 Additionally, Diamater QoS messages may carry authorization tokens 2014 that require confidentiality protection. 2016 Lastly, there can be security vulnerability to the applications 2017 traversing a Network Element when a resource on a Network Element is 2018 controlled by multiple Authorizing Entities. The operation of a 2019 Network Element may be disrupted due to conflicting directives from 2020 multiple Authorizing Entities. Care must be taken in deployment to 2021 ensure that Network Elements are impacted by misconfiguration. 2023 Diameter offers security mechanisms to deal with the functionality 2024 demanded in the paragraphs above. In particular, Diameter offers 2025 communication security between neighboring Diameter peers using 2026 Transport Layer Security (TLS) or IPsec. Authorization capabilities 2027 are application specific and part of the overal implementation. 2029 12. Acknowledgements 2031 The authors would like to thank John Loughney and Allison Mankin for 2032 their input to this document. In September 2005 Robert Hancock, 2033 Jukka Manner, Cornelia Kappler, Xiaoming Fu, Georgios Karagiannis and 2034 Elwyn Davies provided a detailed review. Robert also provided us 2035 with good feedback earlier in 2005. Jerry Ash provided us review 2036 comments late 2005/early 2006. Rajith R provided some inputs to the 2037 document early 2007 2039 13. Contributors 2041 The authors would like to thank Tseno Tsenov and Frank Alfano for 2042 starting the Diameter Quality of Service work within the IETF, for 2043 your significant draft contributions and for being the driving force 2044 for the first few draft versions. 2046 14. References 2048 14.1. Normative References 2050 [I-D.ietf-dime-qos-attributes] 2051 Korhonen, J., Tschofenig, H., Arumaithurai, M., Jones, M., 2052 and A. Lior, "Quality of Service Attributes for Diameter", 2053 draft-ietf-dime-qos-attributes-11 (work in progress), 2054 February 2009. 2056 [I-D.ietf-dime-qos-parameters] 2057 Korhonen, J., Tschofenig, H., and E. Davies, "Quality of 2058 Service Parameters for Usage with Diameter", 2059 draft-ietf-dime-qos-parameters-10 (work in progress), 2060 March 2009. 2062 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 2063 Requirement Levels", BCP 14, RFC 2119, March 1997. 2065 [RFC3588] Calhoun, P., Loughney, J., Guttman, E., Zorn, G., and J. 2066 Arkko, "Diameter Base Protocol", RFC 3588, September 2003. 2068 [RFC4005] Calhoun, P., Zorn, G., Spence, D., and D. Mitton, 2069 "Diameter Network Access Server Application", RFC 4005, 2070 August 2005. 2072 [RFC4234] Crocker, D., Ed. and P. Overell, "Augmented BNF for Syntax 2073 Specifications: ABNF", RFC 4234, October 2005. 2075 14.2. Informative References 2077 [I-D.ietf-nsis-ntlp] 2078 Schulzrinne, H. and M. Stiemerling, "GIST: General 2079 Internet Signalling Transport", draft-ietf-nsis-ntlp-19 2080 (work in progress), March 2009. 2082 [I-D.ietf-nsis-qos-nslp] 2083 Manner, J., Karagiannis, G., and A. McDonald, "NSLP for 2084 Quality-of-Service Signaling", draft-ietf-nsis-qos-nslp-16 2085 (work in progress), February 2008. 2087 [RFC2205] Braden, B., Zhang, L., Berson, S., Herzog, S., and S. 2088 Jamin, "Resource ReSerVation Protocol (RSVP) -- Version 1 2089 Functional Specification", RFC 2205, September 1997. 2091 [RFC2211] Wroclawski, J., "Specification of the Controlled-Load 2092 Network Element Service", RFC 2211, September 1997. 2094 [RFC2212] Shenker, S., Partridge, C., and R. Guerin, "Specification 2095 of Guaranteed Quality of Service", RFC 2212, 2096 September 1997. 2098 [RFC2474] Nichols, K., Blake, S., Baker, F., and D. Black, 2099 "Definition of the Differentiated Services Field (DS 2100 Field) in the IPv4 and IPv6 Headers", RFC 2474, 2101 December 1998. 2103 [RFC2753] Yavatkar, R., Pendarakis, D., and R. Guerin, "A Framework 2104 for Policy-based Admission Control", RFC 2753, 2105 January 2000. 2107 [RFC2865] Rigney, C., Willens, S., Rubens, A., and W. Simpson, 2108 "Remote Authentication Dial In User Service (RADIUS)", 2109 RFC 2865, June 2000. 2111 [RFC3261] Rosenberg, J., Schulzrinne, H., Camarillo, G., Johnston, 2112 A., Peterson, J., Sparks, R., Handley, M., and E. 2113 Schooler, "SIP: Session Initiation Protocol", RFC 3261, 2114 June 2002. 2116 [RFC3313] Marshall, W., "Private Session Initiation Protocol (SIP) 2117 Extensions for Media Authorization", RFC 3313, 2118 January 2003. 2120 [RFC3520] Hamer, L-N., Gage, B., Kosinski, B., and H. Shieh, 2121 "Session Authorization Policy Element", RFC 3520, 2122 April 2003. 2124 [RFC3521] Hamer, L-N., Gage, B., and H. Shieh, "Framework for 2125 Session Set-up with Media Authorization", RFC 3521, 2126 April 2003. 2128 [RFC4282] Aboba, B., Beadles, M., Arkko, J., and P. Eronen, "The 2129 Network Access Identifier", RFC 4282, December 2005. 2131 [RFC4346] Dierks, T. and E. Rescorla, "The Transport Layer Security 2132 (TLS) Protocol Version 1.1", RFC 4346, April 2006. 2134 [RFC4566] Handley, M., Jacobson, V., and C. Perkins, "SDP: Session 2135 Description Protocol", RFC 4566, July 2006. 2137 Authors' Addresses 2139 Dong Sun (editor) 2140 Alcatel-Lucent 2141 600 Mountain Ave 2142 Murray Hill, NJ 07974 2143 USA 2145 Phone: +1 908 582 2617 2146 Email: dongsun@alcatel-lucent.com 2148 Peter J. McCann 2149 Motorola Labs 2150 1301 E. Algonquin Rd 2151 Schaumburg, IL 60196 2152 USA 2154 Phone: +1 847 576 3440 2155 Email: pete.mccann@motorola.com 2157 Hannes Tschofenig 2158 Nokia Siemens Networks 2159 Linnoitustie 6 2160 Espoo 02600 2161 Finland 2163 Phone: +358 (50) 4871445 2164 Email: Hannes.Tschofenig@gmx.net 2165 URI: http://www.tschofenig.priv.at 2167 Tina Tsou 2168 Huawei 2169 Shenzhen, 2170 P.R.C 2172 Email: tena@huawei.com 2173 Avri Doria 2174 Lulea University of Technology 2175 Arbetsvetenskap 2176 Lulea, SE-97187 2177 Sweden 2179 Email: avri@ltu.se 2181 Glen Zorn (editor) 2182 Aruba Networks 2183 1322 Crossman Avenue 2184 Sunnyvale, CA 94089-1113 2185 USA 2187 Email: gwz@arubanetworks.com