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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: February 3, 2010 H. Tschofenig 7 Nokia Siemens Networks 8 T. Tsou 9 Huawei 10 A. Doria 11 Lulea University of Technology 12 G. Zorn, Ed. 13 Network Zen 14 August 2, 2009 16 Diameter Quality of Service Application 17 draft-ietf-dime-diameter-qos-10.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 February 3, 2010. 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 . . . . . . . . . 22 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 User Agent is one kind of 167 Application 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 the ones requested QoS 340 (depending on the authorization decision). Once the requested 341 resource is granted, the Resource Management function provides 342 accounting information to 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 can be 536 associated with a corresponding QoS signaling session. Note that the 537 authorization token might either refer to established state 538 concerning the authorization decision or the token might itself carry 539 the authorized parameters (protected by a digital signature or a 540 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 Authorization. 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 Diameter QoS application MUST route AAA requests to the 641 Authorizing Entity, based on the provided identity of the QoS 642 requesting entity or the identity of the AE encoded in the 643 provided authorization token. 645 Flexible Authentication Support 646 The Diameter QoS application 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 Diameter QoS application MUST exchange sufficient information 655 between the AE and the enforcing entity (and vice versa) to 656 compute an authorization decision and to execute this decision. 658 Triggering an Authorization Process 659 The Diameter QoS application MUST allow periodic and event 660 triggered execution of the authorization process, originated at 661 the enforcing entity or even at the AE. 663 Associating QoS Reservations and Application State 664 The Diameter QoS application MUST carry information sufficient for 665 an AppS to identify the appropriate application session and 666 associate it with a particular QoS reservation. 668 Dynamic Authorization 669 It MUST be possible for the Diameter QoS application to push 670 updates towards the NE(s) from authorizing entities. 672 Bearer Gating 673 The Diameter QoS application MUST allow the AE to gate (i.e., 674 enable/disable) authorized application flows based on, e.g., 675 application state transitions. 677 Accounting Records 678 The Diameter QoS application may define QoS accounting records 679 containing duration, volume (byte count) usage information and 680 description of the QoS attributes (e.g., bandwidth, delay, loss 681 rate) that were 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 Diameter QoS application MUST allow the NE to report failures, 689 such as loss of connectivity due to movement of a mobile node or 690 other reasons for packet loss, to the authorizing entity. 692 Accounting Correlation 693 The Diameter QoS application may support the exchange of 694 sufficient information to allow for correlation between accounting 695 records generated by the NEs and accounting records generated by 696 an AppS. 698 Interaction with other AAA Applications 699 Interaction with other AAA applications such as Diameter Network 700 Access (NASREQ) application [RFC4005] is required for exchange of 701 authorization, authentication and accounting information. 703 In deployment scenarios where authentication of the QoS reservation 704 requesting entity (e.g., the user) is done by means outside the 705 Diameter QoS application protocol interaction, the AE is contacted 706 only with a request for QoS authorization. Authentication might have 707 taken place already via the interaction with the Diameter NASREQ 708 application or as part of the QoS signaling protocol (e.g., Transport 709 Layer Security (TLS) [RFC5246] in the General Internet Signaling 710 Transport (GIST) protocol [I-D.ietf-nsis-ntlp]). 712 Authentication of the QoS reservation requesting entity to the AE is 713 necessary if a particular Diameter QoS application protocol cannot be 714 related (or if there is no intention to relate it) to a prior 715 authentication. In this case the AE MUST authenticate the QoS 716 reservation requesting entity in order to authorize the QoS request 717 as part of the Diameter QoS protocol interaction. 719 The document refers to three types of sessions that need to be 720 properly correlated. 722 QoS Signaling Session 723 The time period during which a QoS signaling protocol establishes, 724 maintains and deletes a QoS reservation state at the QoS network 725 element is referred to as QoS signaling session. Different QoS 726 signaling protocols use different ways to identify QoS signaling 727 sessions. The same applies to different usage environments. 728 Currently, this document supports three types of QoS session 729 identifiers, namely a signaling session id (e.g., the Session 730 Identifier used by the NSIS protocol suite), a flow id (e.g., 731 identifier assigned by an application to a certain flow as used in 732 the 3GPP) and a flow description based on the IP parameters of the 733 flow's end points. 735 Diameter Authorization Session 736 The time period, for which a Diameter server authorizes a 737 requested service (i.e., QoS resource reservation) is referred to 738 as a Diameter authorization session. It is identified by a 739 Session-Id included in all Diameter messages used for management 740 of the authorized service (initial authorization, re- 741 authorization, termination), see [RFC3588]. 743 Application-layer Session 744 The application layer session identifies the duration of an 745 application layer service which requires provision of certain QoS. 746 An application layer session identifier is provided by the QoS 747 requesting entity in the QoS signaling messages, for example as 748 part of the authorization token. In general, the application 749 session identifier is opaque to the QoS aware NEs. It is included 750 in the authorization request message sent to the AE and helps it 751 to correlate the QoS authorization request to the application 752 session state information. 754 Correlating these sessions is done at each of the three involved 755 entities: The QoS requesting entity correlates the application with 756 the QoS signaling sessions. The QoS NE correlates the QoS signaling 757 session with the Diameter authorization sessions. The AE SHOULD bind 758 the information about the three sessions together. Note that in 759 certain scenarios not all of the sessions are present. For example, 760 the application session might not be visible to QoS signaling 761 protocol directly if there is no binding between the application 762 session and the QoS requesting entity using the QoS signaling 763 protocol. 765 4. QoS Application Session Establishment and Management 767 4.1. Parties Involved 769 Authorization models supported by this application include three 770 parties: 771 o Resource Requesting Entity 772 o Network Elements (Diameter QoS application (DQA) client) 773 o Authorizing Entity (Diameter QoS application (DQA) server) 775 Note that the QoS RRE is only indirectly involved in the message 776 exchange. This entity provides the trigger to initiate the Diameter 777 QoS protocol interaction by transmitting QoS signaling messages. The 778 Diameter QoS application is only executed between the Network Element 779 (i.e., DQA client) and the Authorizing Entity (i.e., DQA server). 781 The QoS RRE may communicate with the AE using application layer 782 signaling for negotiation of service parameters. As part of this 783 application layer protocol interaction, for example using SIP, 784 authentication and authorization might take place. This message 785 exchange is, however, outside the scope of this document. The 786 protocol communication between the QoS resource requesting entity and 787 the QoS NE might be accomplished using the NSIS protocol suite, RSVP 788 or a link layer signaling protocol. A description of these protocols 789 is also outside the scope of this document. 791 4.2. Session Establishment 793 The Pull and Push modes use a different set of command codes for 794 session establishment. For other operations, such as session 795 modification and termination, they use the same set of command codes. 797 The selection of Pull mode or Push mode operation is based on the 798 trigger of the QoS Authorization session. When a QoS-Authorization- 799 Request (QAR, see Section 5.1) message with a new session ID is 800 received, the AE operates in the Pull mode; when other triggers are 801 received, the AE operates in the Push mode. Similarly, when a QoS- 802 Install-Request (QIR, see Section 5.3} with a new session ID is 803 received, the NE operates in the Push mode; when other triggers are 804 received, the NE operation in the Pull mode. 806 The QoS authorization session is typically established per subscriber 807 base (i.e.all requests with the same user ID), but it is also 808 possible to be established on per node or per request base. The 809 concurrent sessions between an NE and an AE are identified by 810 different Session-ID. 812 4.2.1. Session Establishment for Pull Mode 814 A request for a QoS reservation or local events received by a NE can 815 trigger the initiation of a Diameter QoS authorization session. The 816 NE converts the required objects from the QoS signaling message to 817 Diameter AVPs and generates a QAR message. 819 Figure 6 shows the protocol interaction between a Resource Requesting 820 Entity, a Network Element and the Authorizing Entity. 822 The AE's identity, information about the application session and/or 823 identity and credentials of the QoS RRE, requested QoS parameters, 824 signaling session identifier and/or QoS enabled data flows 825 identifiers MAY be encapsulated into respective Diameter AVPs and 826 included in the Diameter message sent to the AE. The QAR is sent to 827 a Diameter server that can either be the home server of the QoS 828 requesting entity or an AppS. 830 +------------------------------------------+------------------------+ 831 | QoS-specific Input Data | Diameter AVPs | 832 +------------------------------------------+------------------------+ 833 | Authorizing entity ID (e.g., | Destination-Host | 834 | Destination-Host taken from | Destination-Realm | 835 | authorization token, Destination-Realm | | 836 | or derived from the NAI of the QoS | | 837 | requesting entity) | | 838 | | | 839 | Authorization Token Credentials of the | QoS-Authorization-Data | 840 | QoS requesting entity | User-Name | 841 | | | 842 | QoS parameters | QoS-Resources | 843 +------------------------------------------+------------------------+ 845 Table 1: Mapping Input Data to QoS AVPs--Pull Mode 847 Authorization processing starts at the Diameter QoS server when it 848 receives the QAR. Based on the information in the QoS- 849 Authentication-Data, User-Name and QoS-Resources AVPs the server 850 determines the authorized QoS resources and flow state (enabled/ 851 disabled) from locally available information (e.g., policy 852 information that may be previously established as part of an 853 application layer signaling exchange, or the user's subscription 854 profile). The QoS-Resources AVP is defined in 855 [I-D.ietf-dime-qos-attributes]. The authorization decision is then 856 reflected in the response returned to the Diameter client with the 857 QoS-Authorization-Answer message (QAA). 859 Authorizing 860 End-Host Network Element Entity 861 requesting QoS ( Diameter ( Diameter 862 QoS Client) QoS Server) 863 | | | 864 +---QoS-Reserve---->| | 865 | +- - - - - QAR - - - - - >| 866 | |(QoS-Resources, | 867 | | QoS-Auth-Data,User-ID)| 868 | | +--------+--------------+ 869 | | | Authorize request | 870 | | | Keep session data | 871 | | |/Authz-time,Session-Id/| 872 | | +--------+--------------+ 873 | |< - - - - QAA - - - - - -+ 874 | |(Result-Code, | 875 | |QoS-Resources,Authz-time)| 876 | +-------+---------+ 877 | |Install QoS state| 878 | | + | 879 | | Authz. session | 880 | | /Authz-time/ | QoS Responder 881 | | | Node 882 | +-------+---------+ | 883 | +----------QoS-Reserve---....--->| 884 | | | 885 | |<---------QoS-Response--....----| 886 |<--QoS-Response----+ | 887 | | | 888 |=====================Data Flow==============....===>| 889 | | 890 | +- - - - - QAR - - - - - >| 891 | |(START,QoS-Resources) | 892 | | | 893 | | +--------+--------------+ 894 | | | Report for successful | 895 | | | QoS reservation | 896 | | |Update of reserved QoS | 897 | | | resources | 898 | | +--------+--------------+ 899 | |< - - - - QAA - - - - - -+ 900 | | | 902 Figure 6: Initial QoS Request Authorization for Pull Mode 904 The Authorizing Entity keeps authorization session state and SHOULD 905 save additional information for management of the session (e.g., 906 Signaling-Session-Id, authentication data) as part of the session 907 state information. 909 The final result of the authorization request is provided in the 910 Result-Code AVP of the QAA message sent by the Authorizing Entity. 911 In case of successful authorization (i.e., Result-Code = 912 DIAMETER_LIMITED_SUCCESS, (see Section 7.1)), information about the 913 authorized QoS resources and the status of the authorized flow 914 (enabled/disabled) is provided in the QoS-Resources AVP of the QAA 915 message. The QoS information provided via the QAA is installed by 916 the QoS Traffic Control function of the NE. The value 917 DIAMETER_LIMITED_SUCCESS indicates that the AE expects confirmation 918 via another QAR message for successful QoS resource reservation and 919 for final reserved QoS resources (see below). 921 One important piece of information returned from the Authorizing 922 Entity is the authorization lifetime (carried inside the QAA). The 923 authorization lifetime allows the NE to determine how long the 924 authorization decision is valid for this particular QoS reservation. 925 A number of factors may influence the authorized session duration, 926 such as the user's subscription plan or currently available credits 927 at the user's account (see Section 8). The authorization duration is 928 time-based as specified in [RFC3588]. For an extension of the 929 authorization period, a new QoS-Authorization-Request/Answer message 930 exchange SHOULD be initiated. Further aspects of QoS authorization 931 session maintenance is discussed in Section 4.3, Section 4.4 and 932 Section 8. 934 The indication of a successful QoS reservation and activation of the 935 data flow is provided by the transmission of a QAR message, which 936 reports the parameters of the established QoS state: reserved 937 resources, duration of the reservation, and identification of the QoS 938 enabled flow/QoS signaling session. The Diameter QoS server 939 acknowledges the reserved QoS resources with the QA Answer (QAA) 940 message where the Result-Code is set to 'DIAMETER_SUCCESS'. Note 941 that the reserved QoS resources reported in this QAR message MAY be 942 different than those authorized with the initial QAA message, due to 943 the QoS signaling specific behavior (e.g., receiver-initiated 944 reservations with One-Path-With-Advertisements) or specific process 945 of QoS negotiation along the data path. 947 4.2.2. Session Establishment for Push Mode 949 The Diameter QoS server in the AE initiates a Diameter QoS 950 authorization session upon the request for QoS reservation triggered 951 by application layer signaling or by local events, and generates a 952 QoS-Install-Request (QIR) message to Diameter QoS client in the NE in 953 which it maps required objects to Diameter payload objects. 955 Figure 7 shows the protocol interaction between the AE, a Network 956 Element and a RRE. 958 The NE's identity, information about the application session and/or 959 identity and credentials of the QoS resource requesting entity, 960 requested QoS parameters, signaling session identifier and/or QoS 961 enabled data flows identifiers MAY be encapsulated into respective 962 Diameter AVPs and included into the Diameter message sent from a 963 Diameter QoS server in the Authorizing Entity to a Diameter QoS 964 client in the NE. This requires that the AE has knowledge of 965 specific information for allocating and identifying the NE that 966 should be contacted and the data flow for which the QoS reservation 967 should be established. This information can be statically configured 968 or dynamically discovered, see Section 4.2.3 for details. 970 +-----------------------------------------+-------------------------+ 971 | QoS-specific Input Data | Diameter AVPs | 972 +-----------------------------------------+-------------------------+ 973 | Network Element ID | Destination-Host | 974 | | Destination-Realm | 975 | | | 976 | Authorization Token Credentials of the | QoS-Authorization-Data | 977 | QoS requesting entity | User-Name | 978 | | | 979 | QoS parameters | QoS-Resources | 980 +-----------------------------------------+-------------------------+ 982 Table 2: Mapping Input Data to QoS AVPs--Push Mode 984 Authorization processing starts at the Diameter QoS server when it 985 receives a request from a RRE through an AppS (e.g., SIP Invite) or 986 is triggered by a local event (e.g., pre-configured timer). Based on 987 the received information the server determines the authorized QoS 988 resources and flow state (enabled/disabled) from locally available 989 information (e.g., policy information that may be previously 990 established as part of an application layer signaling exchange, or 991 the user's subscription profile). The authorization decision is then 992 reflected in the QoS-Install-Request message (QIR) to the Diameter 993 QoS client. 995 Authorizing 996 End-Host Network Element Entity 997 requesting QoS ( Diameter ( Diameter 998 QoS Client) QoS Server) 999 | | | 1000 | | |<-- Trigger -- 1001 | | +--------+--------------+ 1002 | | | Authorize request | 1003 | | | Keep session data | 1004 | | |/Authz-time,Session-Id/| 1005 | | +--------+--------------+ 1006 | | | 1007 | |<-- - -- - QIR - - - - - -+ 1008 | |(Initial Request,Decision | 1009 | |(QoS-Resources,Authz-time)| 1010 | +-------+---------+ 1011 | |Install QoS state| 1012 | | + | 1013 | | Authz. session | 1014 | | /Authz-time/ | 1015 | | | 1016 | +-------+---------+ 1017 | + - - - - QIA - - - - - ->| 1018 | | (Result-Code, | 1019 | | QoS-Resources) | 1020 | | +--------+--------------+ 1021 | | | Report for successful | 1022 | | | QoS reservation | 1023 | | |Update of reserved QoS | 1024 | | | resources | 1025 | | +--------+--------------+ 1026 | | QoS Responder 1027 | | Node 1028 | | | 1029 |=====================Data Flow==============....===>| 1030 | | 1031 | (+- - - - - QAR - - - - - >|) 1032 | (|(START,QoS-Resources) |) 1033 | (|< - - - - QAA - - - - - -+) 1034 | | | 1036 Figure 7: Initial QoS Request Authorization for Push Mode 1038 The AE keeps authorization session state and SHOULD save additional 1039 information for management of the session (e.g., 1040 Signaling-Session-Id, authentication data) as part of the session 1041 state information. 1043 The final result of the authorization decision is provided in the 1044 QoS-Resources AVP of the QIR message sent by the AE. The QoS 1045 information provided via the QIR is installed by the QoS Traffic 1046 Control function of the NE. 1048 One important piece of information from the AE is the authorization 1049 lifetime (carried inside the QIR). The authorization lifetime allows 1050 the NE to determine how long the authorization decision is valid for 1051 this particular QoS reservation. A number of factors may influence 1052 the authorized session duration, such as the user's subscription plan 1053 or currently available credits at the user's account (see Section 8). 1054 The authorization duration is time-based as specified in [RFC3588]. 1055 For an extension of the authorization period, a new QoS-Install- 1056 Request/Answer message or QoS-Authorization-Request/Answer message 1057 exchange SHOULD be initiated. Further aspects of QoS authorization 1058 session maintenance is discussed in Section 4.3, Section 4.4 and 1059 Section 8. 1061 The indication of QoS reservation and activation of the data flow can 1062 be provided by the QoS-Install-Answer message immediately. In the 1063 case of successful enforcement, the Result-Code (= DIAMETER_SUCCESS, 1064 (see Section 7.1)) information is provided in the QIA message. Note 1065 that the reserved QoS resources reported in the QIA message may be 1066 different than those initially authorized with the QIR message, due 1067 to the QoS signaling specific behavior (e.g., receiver-initiated 1068 reservations with One-Path-With-Advertisements) or specific process 1069 of QoS negotiation along the data path. When path coupled signaling 1070 is used for QoS reservation along the data path, QAR/QAA MAY be used 1071 to update the results of QoS reservation and enforcement following 1072 the establishment of data flows. In the case Multiple AEs control 1073 the same NE, the NE should make the selection on the authorization 1074 decision to be enforced based on the priority of the request. 1076 4.2.3. Discovery and Selection of Peer Diameter QoS Application Node 1078 Discovery of Diameter QoS application nodes 1080 The Diameter QoS application node may obtain information of its peer 1081 nodes (e.g., FQDN, IP address) through static configuration or 1082 dynamic discovery as described in [RFC3588]. In particular, the NE 1083 shall perform the relevant operation for Pull mode; the AE shall 1084 perform the relevant operations for Push mode. 1086 Selection of peer Diameter QoS application node 1088 Upon receipt of a trigger to initiate a new Diameter QoS 1089 authorization session, the Diameter QoS application node selects and 1090 retrieves the location information of the peer node and based on some 1091 index information provided by the RRE. For instance, it can be the 1092 Authorization Entity's ID stored in the authorization token, the end- 1093 user's identity (e.g., NAI [RFC4282]) or a globally routable IP 1094 address. 1096 4.3. Session Re-authorization 1098 Client and server-side initiated re-authorizations are considered in 1099 the design of the Diameter QoS application. Whether the re- 1100 authorization events are transparent for the resource requesting 1101 entity or result in specific actions in the QoS signaling protocol is 1102 outside the scope of the Diameter QoS application. It is directly 1103 dependent on the capabilities of the QoS signaling protocol. 1105 There are a number of options for policy rules according to which the 1106 NE (AAA client) contacts the AE for re-authorization. These rules 1107 depend on the semantics and contents of the QAA message sent by the 1108 AE: 1110 a. The QAA message contains the authorized parameters of the flow 1111 and its QoS and sets their limits (presumably upper). With these 1112 parameters the AE specifies the services that the NE can provide 1113 and will be financially compensated for. Therefore, any change 1114 or request for change of the parameters of the flow and its QoS 1115 that do not conform to the authorized limits requires contacting 1116 the AE for authorization. 1117 b. The QAA message contains authorized parameters of the flow and 1118 its QoS. The rules that determine whether parameters' changes 1119 require re-authorization are agreed out of band, based on a 1120 Service Level Agreement (SLA) between the domains of the NE and 1121 the AE. 1122 c. The QAA message contains the authorized parameters of the flow 1123 and its QoS. Any change or request for change of these 1124 parameters requires contacting the AE for re-authorization. 1125 d. In addition to the authorized parameters of the flow and its QoS, 1126 the QAA message contains policy rules that determine the NEs 1127 actions in case of change or request for change in authorized 1128 parameters. 1130 Provided options are not exhaustive. Elaborating on any of the 1131 listed approaches is deployment /solution specific and is not 1132 considered in the current document. 1134 In addition, the AE may use a RAR to perform re-authorization with 1135 the authorized parameters directly when the re-authorization is 1136 triggered by service request or local events/policy rules. 1138 4.3.1. Client-Side Initiated Re-Authorization 1140 The AE provides the duration of the authorization session as part of 1141 the QoS-Authorization-Answer message (QAA). At any time before 1142 expiration of this period, a new QoS-Authorization-Request message 1143 (QAR) MAY be sent to the AE. The transmission of the QAR MAY be 1144 triggered when the NE receives a QoS signaling message that requires 1145 modification of the authorized parameters of an ongoing QoS session, 1146 or authorization lifetime expires. 1148 Authorizing 1149 End-Host Network Element Entity 1150 requesting QoS ( Diameter ( Diameter 1151 QoS Client) QoS Server) 1152 | | | 1153 |=====================Data Flow==========================> 1154 | | | 1155 | +-------+----------+ | 1156 | |Authz-time/CC-Time| | 1157 | | expires | | 1158 | +-------+----------+ | 1159 | +- - - - - QAR - - - - - >| 1160 | |(QoS-Resources, | 1161 | | QoS-Authz-Data,User-ID) | 1162 | +--------+--------------+ 1163 NOTE: | | Authorize request | 1164 Re-authorization | | Update session data | 1165 is transparent to | |/Authz-time,Session-Id/| 1166 the End-Host | +--------+--------------+ 1167 |< - - - - QAA - - - - - -+ 1168 | |(Result-Code, | 1169 | |QoS-Resources,Authz-time)| 1170 | +-------+---------+ | 1171 | |Update QoS state | | 1172 | | + | | 1173 | | Authz. session | | 1174 | | /Authz-time/ | | 1175 | | | | 1176 | +-------+---------+ | 1177 | | | 1178 |=====================Data Flow==========================> 1179 | | 1181 Figure 8: Client-side Initiated QoS Re-Authorization 1183 4.3.2. Server-Side Initiated Re-Authorization 1185 The AE MAY initiate a QoS re-authorization by issuing a Re-Auth- 1186 Request message (RAR) as defined in the Diameter base protocol 1187 [RFC3588], which may include the parameters of the re-authorized QoS 1188 state: reserved resources, duration of the reservation, 1189 identification of the QoS enabled flow/QoS signaling session for re- 1190 installation of the resource state by the QoS Traffic Control 1191 function of the NE. 1193 A NE that receives such a RAR message with Session-Id matching a 1194 currently active QoS session acknowledges the request by sending the 1195 Re-Auth-Answer (RAA) message towards the AE. 1197 If RAR does not include any parameters of the re-authorized QoS 1198 state, the NE MUST initiate a QoS re-authorization by sending a QoS- 1199 Authorization-Request (QAR) message towards the AE. 1201 Authorizing 1202 End-Host Network Element Entity 1203 requesting QoS ( Diameter ( Diameter 1204 QoS Client) QoS Server) 1205 | | | 1206 | | |<-- Trigger -- 1207 | | +--------+--------------+ 1208 | | | Authorize request | 1209 | | | Keep session data | 1210 | | |/Authz-time,Session-Id/| 1211 | | +--------+--------------+ 1212 | | | 1213 | |<-- - -- - RAR - - - - - -+ 1214 | |(Request,Decision | 1215 | |(QoS-Resources,Authz-time)| 1216 | +-------+---------+ 1217 | |Install QoS state| 1218 | | + | 1219 | | Authz. session | 1220 | | /Authz-time/ | 1221 | | | 1222 | +-------+---------+ 1223 | + - - - - RAA - - - - - ->| 1224 | | (Result-Code, | 1225 | | QoS-Resources) | 1226 | | +--------+--------------+ 1227 | | | Report for successful | 1228 | | | QoS reservation | 1229 | | |Update of reserved QoS | 1230 | | | resources | 1231 | | +--------+--------------+ 1232 | | | 1234 Figure 9: Server-side Initiated QoS Re-Authorization 1236 4.4. Session Termination 1238 4.4.1. Client-Side Initiated Session Termination 1240 The authorization session for an installed QoS reservation state MAY 1241 be terminated by the Diameter client by sending a Session- 1242 Termination-Request message (STR) to the Diameter server. This is a 1243 Diameter base protocol function and it is defined in [RFC3588]. 1244 Session termination can be caused by a QoS signaling messaging 1245 requesting deletion of the existing QoS reservation state or it can 1246 be caused as a result of a soft-state expiration of the QoS 1247 reservation state. 1249 Authorizing 1250 End-Host Network Element Entity 1251 requesting QoS ( Diameter ( Diameter 1252 QoS Client) QoS Server) 1253 | | | 1254 |==Data Flow==>X /Stop of the data flow/ | 1255 | | | 1256 +---QoS-Reserve---->| | 1257 | (Delete QoS +- - - - - STR - - - - - >| 1258 | reservation) | +--------+--------------+ 1259 | | | Remove authorization | 1260 |<--QoS-Response----+ | session state | 1261 | | +--------+--------------+ 1262 |< - - - - STA - - - - - -+ 1263 +-------+--------+ | 1264 |Delete QoS state| 1265 +-------+--------+ QoS Responder 1266 | Node 1267 +----------QoS-Reserve-----....--->| 1268 | (Delete QoS | 1269 | reservation) | 1270 |<---------QoS-Response----....----+ 1271 | | 1273 Figure 10: Client-Side Initiated Session Termination 1275 4.4.2. Server-Side Initiated Session Termination 1277 At anytime during a session the AE MAY send an Abort-Session-Request 1278 message (ASR) to the NE. This is a Diameter base protocol function 1279 and it is defined in [RFC3588]. Possible reasons for initiating the 1280 ASR message to the NE are insufficient credits or session termination 1281 at the application layer. The ASR message results in termination of 1282 the authorized session, release of the reserved resources at the NE 1283 and transmission of an appropriate QoS signaling message indicating a 1284 notification to other Network Elements aware of the signaling 1285 session. 1287 Authorizing 1288 End-Host Network Element Entity 1289 requesting QoS ( Diameter ( Diameter 1290 QoS Client) QoS Server) 1291 | | | 1292 |=====================Data Flow==========================> 1293 | | 1294 | |< - - - - ASR - - - - - -+ 1295 | | | 1296 |====Data Flow=====>X | QoS Responder 1297 | | | Node 1298 |<--QoS-Notify------+----------QoS-Reserve-----....--->| 1299 | | (Delete QoS | | 1300 | reservation) | 1301 +-------+--------+ | 1302 |Delete QoS state| | 1303 +-------+--------+ | 1304 +- - - - - ASA - - - - - >| 1305 | +--------+--------------+ 1306 | | Remove authorization | 1307 | | session state | 1308 | +--------+--------------+ 1309 | QoS Responder 1310 | Node 1311 |<---------QoS-Response----....----+ 1312 | | 1314 Figure 11: Server-Side Initiated Session Termination 1316 5. QoS Application Messages 1318 The Diameter QoS Application requires the definition of new mandatory 1319 AVPs and Command-codes (see Section 3 of [RFC3588]). Four new 1320 Diameter messages are defined along with Command-Codes whose values 1321 MUST be supported by all Diameter implementations that conform to 1322 this specification. 1324 +---------------------------+---------+--------+-------------+ 1325 | Command Name | Abbrev. | Code | Reference | 1326 +---------------------------+---------+--------+-------------+ 1327 | QoS-Authorization-Request | QAR | [TBD1] | Section 5.1 | 1328 | | | | | 1329 | QoS-Authorization-Answer | QAA | [TBD2] | Section 5.2 | 1330 | | | | | 1331 | QoS-Install-Request | QIR | [TBD3] | Section 5.3 | 1332 | | | | | 1333 | QoS-Install-Answer | QIA | [TBD4] | Section 5.4 | 1334 +---------------------------+---------+--------+-------------+ 1336 Table 3: Diameter QoS Commands 1338 In addition, the following Diameter Base protocol messages are used 1339 in the Diameter QoS application: 1341 +-----------------------+---------+------+-----------+ 1342 | Command-Name | Abbrev. | Code | Reference | 1343 +-----------------------+---------+------+-----------+ 1344 | Re-Auth-Request | RAR | 258 | [RFC3588] | 1345 | | | | | 1346 | Re-Auth-Answer | RAA | 258 | [RFC3588] | 1347 | | | | | 1348 | Abort-Session-Request | ASR | 274 | [RFC3588] | 1349 | | | | | 1350 | Abort-Session-Answer | ASA | 274 | [RFC3588] | 1351 | | | | | 1352 | Session-Term-Request | STR | 275 | [RFC3588] | 1353 | | | | | 1354 | Session-Term-Answer | STA | 275 | [RFC3588] | 1355 +-----------------------+---------+------+-----------+ 1357 Table 4: Diameter Base Commands 1359 Diameter nodes conforming to this specification MAY advertise support 1360 for the Diameter QoS Application by including the value of [TBD5] in 1361 the Auth-Application-Id or the Acct-Application-Id AVP of the 1362 Capabilities-Exchange-Request and Capabilities-Exchange-Answer 1363 commands, see [RFC3588]. 1365 The value of {TBD5] MUST be used as the Application-Id in all QAR/QAA 1366 and QIR/QIA commands. 1368 The value of zero (0) SHOULD be used as the Application-Id in all 1369 STR/STA, ASR/ASA, and RAR/RAA commands, because these commands are 1370 defined in the Diameter base protocol and no additional mandatory 1371 AVPs for those commands are defined in this document. 1373 5.1. QoS-Authorization Request (QAR) 1375 The QoS-Authorization-Request message (QAR) indicated by the Command- 1376 Code field (see Section 3 of [RFC3588]) set to [TBD1] and 'R' bit set 1377 in the Command Flags field is used by NEs to request quality of 1378 service related resource authorization for a given flow. 1380 The QAR message MUST carry information for signaling session 1381 identification, AE identification, information about the requested 1382 QoS, and the identity of the QoS requesting entity. In addition, 1383 depending on the deployment scenario, an authorization token and 1384 credentials of the QoS requesting entity SHOULD be included. 1386 The message format, presented in ABNF form [RFC4234], is defined as 1387 follows: 1389 ::= < Diameter Header: [TBD1], REQ, PXY > 1390 < Session-Id > 1391 { Auth-Application-Id } 1392 { Origin-Host } 1393 { Origin-Realm } 1394 { Destination-Realm } 1395 { Auth-Request-Type } 1396 [ Destination-Host ] 1397 [ User-Name ] 1398 * [ QoS-Resources ] 1399 [ QoS-Authorization-Data ] 1400 [ Bound-Auth-Session-Id ] 1401 * [ AVP ] 1403 5.2. QoS-Authorization Answer (QAA) 1405 The QoS-Authorization-Answer message (QAA), indicated by the Command- 1406 Code field set to [TBD2] and 'R' bit cleared in the Command Flags 1407 field is sent in response to the QoS-Authorization-Request message 1408 (QAR). If the QoS authorization request is successfully authorized, 1409 the response will include the AVPs to allow authorization of the QoS 1410 resources and transport plane gating information. 1412 The message format is defined as follows: 1414 ::= < Diameter Header: [TBD2], PXY > 1415 < Session-Id > 1416 { Auth-Application-Id } 1417 { Auth-Request-Type } 1418 { Result-Code } 1419 { Origin-Host } 1420 { Origin-Realm } 1421 * [ QoS-Resources ] 1422 [ Acct-Multisession-Id ] 1423 [ Session-Timeout ] 1424 [ Authorization-Session-Lifetime ] 1425 [ Authorization-Grace-Period ] 1426 * [ AVP ] 1428 5.3. QoS-Install Request (QIR) 1430 The QoS-Install Request message (QIR), indicated by the Command-Code 1431 field set to [TBD3] and 'R' bit set in the Command Flags field is 1432 used by AE to install or update the QoS parameters and the flow state 1433 of an authorized flow at the transport plane element. 1435 The message MUST carry information for signaling session 1436 identification or identification of the flow to which the provided 1437 QoS rules apply, identity of the transport plane element, description 1438 of provided QoS parameters, flow state and duration of the provided 1439 authorization. 1441 The message format is defined as follows: 1443 ::= < Diameter Header: [TBD3], REQ, PXY > 1444 < Session-Id > 1445 { Auth-Application-Id } 1446 { Origin-Host } 1447 { Origin-Realm } 1448 { Destination-Realm } 1449 { Auth-Request-Type } 1450 [ Destination-Host ] 1451 * [ QoS-Resources ] 1452 [ Session-Timeout ] 1453 [ Authorization-Session-Lifetime ] 1454 [ Authorization-Grace-Period ] 1455 [ Authorization-Session-Volume ] 1456 * [ AVP ] 1458 5.4. QoS-Install Answer (QIA) 1460 The QoS-Install Answer message (QIA), indicated by the Command-Code 1461 field set to [TBD4] and 'R' bit cleared in the Command Flags field is 1462 sent in response to the QoS-Install Request message (QIR) for 1463 confirmation of the result of the installation of the provided QoS 1464 reservation instructions. 1466 The message format is defined as follows: 1468 ::= < Diameter Header: [TBD4], PXY > 1469 < Session-Id > 1470 { Auth-Application-Id } 1471 { Origin-Host } 1472 { Origin-Realm } 1473 { Result-Code } 1474 * [ QoS-Resources ] 1475 * [ AVP ] 1477 5.5. Re-Auth-Request (RAR) 1479 The Re-Auth-Request message (RAR), indicated by the Command-Code 1480 field set to 258 and the 'R' bit set in the Command Flags field, is 1481 sent by the AE to the NE in order to initiate the QoS re- 1482 authorization from DQA server side. 1484 If the RAR command is received by the NE without any parameters of 1485 the re-authorized QoS state, the NE MUST initiate a QoS re- 1486 authorization by sending a QoS-Authorization-Request (QAR) message 1487 towards the AE. 1489 The message format is defined as follows: 1491 ::= < Diameter Header: 258, REQ, PXY > 1492 < Session-Id > 1493 { Auth-Application-Id } 1494 { Origin-Host } 1495 { Origin-Realm } 1496 { Destination-Realm } 1497 { Auth-Request-Type } 1498 [ Destination-Host ] 1499 * [ QoS-Resources ] 1500 [ Session-Timeout ] 1501 [ Authorization-Session-Lifetime ] 1502 [ Authorization-Grace-Period ] 1503 [ Authorization-Session-Volume ] 1505 * [ AVP ] 1507 5.6. Re-Auth-Answer (RAA) 1509 The Re-Auth-Answer message (RAA), indicated by the Command-Code field 1510 set to 258 and the 'R' bit cleared in the Command Flags field, is 1511 sent by the NE to the AE in response to the RAR command. 1513 The message format is defined as follows: 1515 ::= < Diameter Header: 258, PXY > 1516 < Session-Id > 1517 { Auth-Application-Id } 1518 { Origin-Host } 1519 { Origin-Realm } 1520 { Result-Code } 1521 * [ QoS-Resources ] 1522 * [ AVP ] 1524 6. QoS Application State Machine 1526 The QoS application defines its own state machine that is based on 1527 the authorization state machine defined in Section 8.1 of the Base 1528 Protocol ([RFC3588]). The Qos state machine uses own messages as 1529 defined in Section 5 and QoS AVPs as defined in Section 7. 1531 6.1. Supplemented States for Push Mode 1533 Using the Base Protocol state machine as a basis, the following 1534 states are supplemented to first 2 state machines in which the 1535 session state is maintained on the Server. Thses MUST be supported 1536 in any QoS application implementations in support of server initiated 1537 push mode (see (Section 4.2.2)). 1539 The following states are supplemented to the state machine on the 1540 client when state is maintained on the client as defined in Section 1541 8.1 of the Base Protocol [RFC3588]: 1543 SERVER, STATEFUL 1544 State Event Action New State 1545 ------------------------------------------------------------- 1546 Idle An application or local Send Pending 1547 event triggers an initial QIR initial 1548 QoS request to the server request 1550 Pending Received QIA with a failed Cleanup Idle 1551 Result-Code 1553 Pending Received QIA with Result-Code Update Open 1554 = SUCCESS session 1555 Pending Error in processing received Send Discon 1556 QIA with Result-Code = SUCCESS ASR 1558 The following states are supplemented to the state machine on the 1559 client when state is maintained on the server as defined in Section 1560 8.1 of the Base Protocol [RFC3588]: 1562 CLIENT, STATEFUL 1563 State Event Action New State 1564 ------------------------------------------------------------- 1565 Idle QIR initial request Send Open 1566 received and successfully QIA initial 1567 processed answer, 1568 reserve resources 1570 Idle QIR initial request Send Idle 1571 received but not QIA initial 1572 successfully processed answer with 1573 Result-Code 1574 != SUCCESS 1576 7. QoS Application AVPs 1578 Each of the AVPs identified in the QoS-Authorization-Request/Answer 1579 and QoS-Install-Request/Answer messages and the assignment of their 1580 value(s) is given in this section. 1582 7.1. Reused Base Protocol AVPs 1584 The QoS application uses a number of session management AVPs, defined 1585 in the Base Protocol ([RFC3588]). 1587 Attribute Name AVP Code Reference [RFC3588] 1588 Origin-Host 264 Section 6.3 1589 Origin-Realm 296 Section 6.4 1590 Destination-Host 293 Section 6.5 1591 Destination-Realm 283 Section 6.6 1592 Auth-Application-Id 258 Section 6.8 1593 Result-Code 268 Section 7.1 1594 Auth-Request-Type 274 Section 8.7 1595 Session-Id 263 Section 8.8 1596 Authorization-Lifetime 291 Section 8.9 1597 Authorization-Grace-Period 276 Section 8.10 1598 Session-Timeout 27 Section 8.13 1599 User-Name 1 Section 8.14 1601 The Auth-Application-Id AVP (AVP Code 258) is assigned by IANA to 1602 Diameter applications. The value of the Auth-Application-Id for the 1603 Diameter QoS application is TBD. 1605 7.2. QoS Application Defined AVPs 1607 This document reuses the AVPs defined in Section 4 of 1608 [I-D.ietf-dime-qos-attributes]. 1610 This section lists the AVPs that are introduced specifically for the 1611 QoS application. The following new AVPs are defined: Bound-Auth- 1612 Session-Id and the QoS-Authorization-Data AVP. 1614 The following table describes the Diameter AVPs newly defined in this 1615 document for usage with the QoS Application, their AVP code values, 1616 types, possible flag values, and whether the AVP may be encrypted. 1618 +-------------------+ 1619 | AVP Flag rules | 1620 +----------------------------------------------|----+--------+-----+ 1621 | AVP Section | | SHLD| MUST| 1622 | Attribute Name Code Defined Data Type |MUST| NOT| NOT| 1623 +----------------------------------------------+----+--------+-----+ 1624 |QoS-Authorization-Data TBD 7.2 OctetString| M | | V | 1625 |Bound-Auth-Session-Id TBD 7.2 UTF8String | M | | V | 1626 +----------------------------------------------+----+--------+-----+ 1627 |M - Mandatory bit. An AVP with "M" bit set and its value MUST be | 1628 | supported and recognized by a Diameter entity in order the | 1629 | message, which carries this AVP, to be accepted. | 1630 |V - Vendor specific bit that indicates whether the AVP belongs to | 1631 | a address space. | 1632 +------------------------------------------------------------------+ 1634 QoS-Authz-Data 1635 The QoS-Authorization-Data AVP (AVP Code TBD) is of type 1636 OctetString. It is a container that carries application session 1637 or user specific data that has to be supplied to the AE as input 1638 to the computation of the authorization decision. 1640 Bound-Authentication-Session-Id 1641 The Bound-Authentication-Session AVP (AVP Code TBD) is of type 1642 UTF8String. It carries the id of the Diameter authentication 1643 session that is used for the network access authentication (NASREQ 1644 authentication session). It is used to tie the QoS authorization 1645 request to a prior authentication of the end host done by a co- 1646 located application for network access authentication (Diameter 1647 NASREQ) at the QoS NE. 1649 8. Accounting 1651 A NE MAY start an accounting session by sending an Accounting-Request 1652 message (ACR) after successful QoS reservation and activation of the 1653 data flow (see Figure 6 and Figure 7). After every successful re- 1654 authorization procedure (see Figure 8 and Figure 9), the NE MAY 1655 initiate an interim accounting message exchange. After successful 1656 session termination (see Figure 10 and Figure 11), the NE may 1657 initiate a final exchange of accounting messages for terminating of 1658 the accounting session and reporting final records for the usage of 1659 the QoS resources reserved. It should be noted that the two sessions 1660 (authorization and accounting) have independent management by the 1661 Diameter base protocol, which allows for finalizing the accounting 1662 session after the end of the authorization session. 1664 The detailed QoS accounting procedures are out of scope in this 1665 document. 1667 9. Examples 1669 9.1. Example Call Flow for Pull Mode 1671 This section presents an example of the interaction between the end 1672 host and Diameter QoS application entities using Pull mode. The 1673 application layer signaling is, in this example, provided using SIP. 1674 Signaling for a QoS resource reservation is done using the QoS NSLP. 1675 The authorization of the QoS reservation request is done by the 1676 Diameter QoS application (DQA). 1678 End-Host SIP Server Correspondent 1679 requesting QoS (DQA Server) Node 1681 | | | 1682 ..|....Application layer SIP signaling.......|..............|.. 1683 . | Invite (SDP) | | . 1684 . +.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-> | . 1685 . | 100 Trying | | . 1686 . <.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-+ Invite (SDP)| . 1687 . | +-.-.-.....-.-.> . 1688 . | | 180 SDP' | . 1689 . | <-.-.-.....-.-.+ . 1690 . | +--------+--------+ | . 1691 . | |Authorize session| | . 1692 . | | parameters | | . 1693 . | 180 (Session parameters) +--------+--------+ | . 1694 . <.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-+ | . 1695 ..|..........................................|... ..........|.. 1696 | | | 1697 | +------------+ | | 1698 | | NE | | | 1699 | |(DQA Client)| | | 1700 | +------+-----+ | | 1701 | | | | 1702 |QoS NSLP Reserve | | | 1703 +------------------> QAR | | 1704 | (POLICY_DATA>v +- - - - -<>- - - -> | 1705 | QSPEC) v >===>(Destination-Host, | | 1706 | v >=======>QoS-Authorization-Data++------------+ | 1707 | >===========>QoS-Resources) |Authorize | | 1708 | | |QoS resources| | 1709 | | ++------------+ | 1710 | | QAA | | 1711 | <- - - - -<>- - - -+ | 1712 | |(Result-Code, | | 1713 | |QoS-Resources, | | 1714 | |Authorization-Lifetime)| | 1715 | +---------+--------+ | | 1716 | |Install QoS state1| | | 1717 | |+ Authz. session | | | 1718 | +---------+--------+ | | 1719 | |QoS NSLP Reserve | 1720 | +---------------..............---------> 1721 | | | 1722 | | QoS NSLP Response| 1723 |QoS NSLP Response <---------------..............---------+ 1724 <------------------+ | 1725 | | QoS NSLP Query| 1726 |QoS NSLP Query <---------------..............---------+ 1727 <------------------+ | 1728 |QoS NSLP Reserve | | 1729 +------------------> QAR | | 1730 | +- - - - -<>- - - -> | 1731 | | +---+---------+ | 1732 | | |Authorize | | 1733 | | |QoS resources| | 1734 | | QAA +---+---------+ | 1735 | <- - - - -<>- - - -+ | 1736 | +---------+--------+ | | 1737 | |Install QoS state2| | 1738 | |+ Authz. session | | 1739 | +---------+--------+ | 1740 | | QoS NSLP Reserve | 1741 | +---------------..............---------> 1742 | | QoS NSLP Response| 1743 |QoS NSLP Response <---------------..............---------+ 1744 <------------------+ | 1745 | | | 1746 /------------------+--Data Flow---------------------------\ 1747 \------------------+--------------------------------------/ 1748 | | | 1750 .-.-.-.-. SIP signaling 1751 --------- QoS NSLP signaling 1752 - - - - - Diameter QoS Application messages 1753 ========= Mapping of objects between QoS and AAA protocol 1755 Figure 12: QoS Authorization Example - Pull Mode 1757 The communication starts with SIP signaling between the two end 1758 points and the SIP server for negotiation and authorization of the 1759 requested service and its parameters (see Figure 12). As a part of 1760 the process, the SIP server verifies whether the user at Host A is 1761 authorized to use the requested service (and potentially the ability 1762 to be charged for the service usage). Negotiated session parameters 1763 are provided to the end host. 1765 Subsequently, Host A initiates a QoS signaling message towards Host 1766 B. It sends a QoS NSLP Reserve message, in which it includes 1767 description of the required QoS (QSPEC object) and authorization data 1768 for negotiated service session (part of the POLICY_DATA object). 1769 Authorization data includes, as a minimum, the identity of the AE 1770 (e.g., the SIP server) and an identifier of the application service 1771 session for which QoS resources are requested. 1773 A QoS NSLP Reserve message is intercepted and processed by the first 1774 QoS aware Network Element. The NE uses the Diameter QoS application 1775 to request authorization for the received QoS reservation request. 1776 The identity of the AE (in this case the SIP server that is co- 1777 located with a Diameter server) is put into the Destination-Host AVP, 1778 any additional session authorization data is encapsulated into the 1779 QoS-Authorization-Data AVP and the description of the QoS resources 1780 is included into QoS-Resources AVP. These AVPs are included into a 1781 QoS Authorization Request message, which is sent to the AE. 1783 A QAR message will be routed through the AAA network to the AE. The 1784 AE verifies the requested QoS against the QoS resources negotiated 1785 for the service session and replies with QoS-Authorization answer 1786 (QAA) message. It carries the authorization result (Result-Code AVP) 1787 and the description of the authorized QoS parameters (QoS-Resources 1788 AVP), as well as duration of the authorization session 1789 (Authorization-Lifetime AVP). 1791 The NE interacts with the traffic control function and installs the 1792 authorized QoS resources and forwards the QoS NSLP Reserve message 1793 further along the data path. Moreover, the NE may serve as a 1794 signaling proxy and process the QoS signaling (e.g. initiation or 1795 termination of QoS signaling) based on the QoS decision received from 1796 the authorizing entity. 1798 9.2. Example Call Flow for Push Mode 1800 This section presents an example of the interaction between the end- 1801 host and Diameter QoS application entities using Push mode. The 1802 application layer signaling is, in this example, provided using SIP. 1803 Signaling for a QoS resource reservation is done using the QoS NSLP. 1804 The authorization of the QoS reservation request is done by the 1805 Diameter QoS application (DQA). 1807 End-Host NE SIP Server Correspondent 1808 requesting QoS (DQA Client) (DQA Server) Node 1809 | | | | 1810 ..|....Application layer SIP signaling..........|..............|.. 1811 . | Invite(SDP offer)| | | . 1812 . +.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.> | . 1813 . | 100 Trying | | | . 1814 . <.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.+ | . 1815 . |.............................................|..............| . 1816 | | +---------+-------------+| 1817 | | | Authorize request || 1818 | | | Keep session data || 1819 | | |/Authz-time,Session-Id/|| 1820 | | +---------+-------------+| 1821 | | | | 1822 | |<-- - -- - QIR - -- - -- -+ | 1823 | |(Initial Request,Decision | | 1824 | |(QoS-Resources,Authz-time)| | 1825 | +-------+---------+ | | 1826 | |Install QoS state| | | 1827 | | + | | | 1828 | | Authz. session | | | 1829 | | /Authz-time/ | | | 1830 | +-------+---------+ | | 1831 | + - - -- - QIA - - - - - ->| | 1832 | | (Result-Code, | | 1833 | | QoS-Resources) | | 1834 | | +----------+------------+ | 1835 | | | Report for successful | | 1836 | | | QoS reservation | | 1837 | | |Update of reserved QoS | | 1838 | | | resources | | 1839 | | +----------+------------+ | 1840 . | | | Invite (SDP) | . 1841 . | | +-.-.-.....-.-.> . 1842 . | 180 (Ringing) | | . 1843 . <.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.<.-.-.-.-.-.-.-+ . 1844 . | | | 200 OK (SDP)| . 1845 . | | <-.-.-.....-.-.+ . 1846 | | +--------+-----------+ | 1847 | | |re-Authorize session| | 1848 | | | parameters | | 1849 | | +--------+-----------+ | 1850 | <- - - - - - RAR - - - - - + | 1851 | +---------+--------+ | | 1852 | |Activate QoS state| | | 1853 | +---------+--------+ | | 1854 | +- - - - - - RAA - - - - - > | 1855 . | 200 (SDP answer) | | | . 1856 . <.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.+ | . 1858 | | | 1859 /------------------+-----Data Flow---------------------------\ 1860 \------------------+-----------------------------------------/ 1861 | | | 1863 .-.-.-.-. SIP signaling 1864 - - - - - Diameter QoS Application messages 1866 Figure 13: QoS Authorization Example - Push Mode 1868 The communication starts with SIP signaling between the two end 1869 points and the SIP server for negotiation and authorization of the 1870 requested service and its parameters (see Figure 13). As a part of 1871 the process, the SIP server verifies whether the user at Host A is 1872 authorized to use the requested service (and potentially the ability 1873 to be charged for the service usage). The DQA server is triggered to 1874 authorize the QoS request based on session parameters (i.e., SDP 1875 offer), initiate a Diameter QoS authorization session and install 1876 authorized QoS state to the Network Element via QIR message. 1878 The DQA server may obtain the info of peer DQA client from pre- 1879 configured information or query the DNS based on Host A's identity or 1880 IP address (In this case a DQA server is co-located with a SIP server 1881 and a DQA client is co-located with a NE). The identity of Network 1882 Element is put into the Destination-Host AVP, the description of the 1883 QoS resources is included into QoS-Resources AVP, as well as duration 1884 of the authorization session (Authorization-Lifetime AVP). The NE 1885 interacts with the traffic control function and reserves the 1886 authorized QoS resources accordingly, for instance, the NE may serve 1887 as a signaling proxy and process the QoS signaling (e.g. initiation 1888 or termination of QoS signaling) based on the QoS decision received 1889 from the authorizing entity. 1891 With successful QoS authorization, the SDP offer in SIP Invite is 1892 forwarded to Host B. Host B sends back a 18x (ringing) message 1893 towards Host A and processes the SDP. Once Host B accepts the call, 1894 it sends back a 200 OK, in which it includes description of the 1895 accepted session parameters (i.e. SDP answer). 1897 The DQA server may verify the accepted QoS against the pre-authorized 1898 QoS resources, and sends a Diameter RAR message to the DQA client in 1899 the NE for activating the installed policies and commit the resource 1900 allocation. With successful QoS enforcement, the 200 OK is forwarded 1901 towards Host A. 1903 Note that the examples above show a sender-initiated reservation from 1904 the end host towards the corresponding node and a receiver-initiated 1905 reservation from the correspondent node towards the end host. 1907 10. IANA Considerations 1909 This section contains the namespaces that have either been created in 1910 this specification or had their values assigned to existing 1911 namespaces managed by IANA. 1913 10.1. AVP Codes 1915 IANA is requested to allocate two AVP codes to the following: 1917 Registry: 1918 AVP Code Attribute Name Reference 1919 ----------------------------------------------------------- 1920 to be assigned QoS-Authorization-Data Section 7.2 1921 to be assigned Bound-Auth-Session-Id Section 7.2 1923 10.2. AVP Specific Values 1925 IANA is requested to allocate the following sub-registry values. 1927 Sub-registry: Auth-Application-Id AVP Values (code 258) 1928 Registry: 1929 AVP Values Attribute Name Reference 1930 ------------- ------------------------------------------- 1931 to be assigned DIAMETER-QOS-NOSUPPORT Section 5 1932 to be assigned DIAMETER-QOS-SUPPORT Section 5 1934 Sub-registry: Acct-Application-Id AVP Values (code 259) 1935 Registry: 1936 AVP Values Attribute Name Reference 1937 ------------- ------------------------------------------- 1938 to be assigned DIAMETER-QOS-NOSUPPORT Section 5 1939 to be assigned DIAMETER-QOS-SUPPORT Section 5 1941 10.3. AVP Flags 1943 There are no new AVP flags defined for either the QoS-Authorization- 1944 Data AVP or the Bound-Ath-Session-ID AVP. 1946 10.4. Application IDs 1948 IANA is requested to allocate the following application ID using the 1949 next value from the 7-16777215 range. 1951 Registry: 1952 ID values Name Reference 1953 ----------------------------------------------------------- 1954 to be assigned Diameter QoS application Section 5 1956 10.5. Command Codes 1958 IANA is requested to allocate command code values for the following 1959 from the range 289-299. 1961 Registry: 1962 Code Value Name Reference 1963 ----------------------------------------------------------- 1964 TBD QoS-Authorization-Request (QAR) Section 5.1 1965 TBD QoS-Authorization-Answer (QAA) Section 5.2 1966 TBD QoS-Install-Request (QIR) Section 5.3 1967 TBD QoS-Install-Answer (QIA) Section 5.4 1969 11. Security Considerations 1971 This document describes a mechanism for performing authorization of a 1972 QoS reservation at a third party entity. Therefore, sufficient 1973 information needs to be made available to the Authorizing Entity to 1974 can make such an authorization decision. Information may come from 1975 various sources, including the application layer signaling, the 1976 Diameter protocol (with its security mechanisms), from policy 1977 information stored available with a AAA server and from a QoS 1978 signaling protocol. 1980 Below there is a discussion about considerations for the Diameter QoS 1981 interaction between an Authorizing Entity and a Network Element. 1982 Security between the Authorizing Entity and the Network Element has a 1983 number of components: authentication, authorization, integrity and 1984 confidentiality. 1986 Authentication refers to confirming the identity of an originator for 1987 all datagrams received from the originator. Lack of authentication 1988 of Diameter messages between the Authorizing Entity and the Network 1989 Element can seriously jeopardize the fundamental service rendered by 1990 the Network Element. A consequence of not authenticating the message 1991 sender by the Network Element would be that an attacker could spoof 1992 the identity of a "legitimate" Authorizing Entity in order to 1993 allocate resources, change resource assignments or free resources. 1994 The adversary can also manipulate the state at the Network Element in 1995 such a way that it leads to a denial of service attack by, for 1996 example, setting the allowed bandwidth to zero or allocating the 1997 entire bandwidth available to a single flow. 1999 A consequence of not authenticating the Network Element to an 2000 Authorizing Entity is that an attacker could impact the policy based 2001 admission control procedure operated by the Authorizing Entity that 2002 provides a wrong view of the resources used in the network. Failing 2003 to provide the required credentials should be subject to logging. 2005 Authorization refers to whether a particular Authorizing Entity is 2006 authorized to signal a Network Element with requests for one or more 2007 applications, adhering to a certain policy profile. Failing the 2008 authorization process might indicate a resource theft attempt or 2009 failure due to administrative and/or credential deficiencies. In 2010 either case, the Network Element should take the proper measures to 2011 log such attempts. 2013 Integrity is required to ensure that a Diameter message has not been 2014 maliciously altered. The result of a lack of data integrity 2015 enforcement in an untrusted environment could be that an imposter 2016 will alter the messages exchanged between a Network Entity and an 2017 Authorizing Entity potentially causing a denial of service. 2019 Confidentiality protection of Diameter messages ensures that the 2020 signaling data is accessible only to the authorized entities. When 2021 signaling messages from the Application Server, via the Authorizing 2022 Entity towards the Network Element traverse untrusted networks, lack 2023 of confidentiality will allow eavesdropping and traffic analysis. 2024 Additionally, Diamater QoS messages may carry authorization tokens 2025 that require confidentiality protection. 2027 Diameter offers security mechanisms to deal with the functionality 2028 demanded in the paragraphs above. In particular, Diameter offers 2029 communication security between neighboring Diameter peers using 2030 Transport Layer Security (TLS) or IPsec. Authorization capabilities 2031 are application specific and part of the overal implementation. 2033 12. Acknowledgements 2035 The authors would like to thank John Loughney and Allison Mankin for 2036 their input to this document. In September 2005 Robert Hancock, 2037 Jukka Manner, Cornelia Kappler, Xiaoming Fu, Georgios Karagiannis and 2038 Elwyn Davies provided a detailed review. Robert also provided us 2039 with good feedback earlier in 2005. Jerry Ash provided us review 2040 comments late 2005/early 2006. Rajith R provided some inputs to the 2041 document early 2007 2043 13. Contributors 2045 The authors would like to thank Tseno Tsenov and Frank Alfano for 2046 starting the Diameter Quality of Service work within the IETF, for 2047 your significant draft contributions and for being the driving force 2048 for the first few draft versions. 2050 14. References 2052 14.1. Normative References 2054 [I-D.ietf-dime-qos-attributes] 2055 Korhonen, J., Tschofenig, H., Arumaithurai, M., Jones, M., 2056 and A. Lior, "Quality of Service Attributes for Diameter", 2057 draft-ietf-dime-qos-attributes-13 (work in progress), 2058 July 2009. 2060 [I-D.ietf-dime-qos-parameters] 2061 Korhonen, J., Tschofenig, H., and E. Davies, "Quality of 2062 Service Parameters for Usage with Diameter", 2063 draft-ietf-dime-qos-parameters-11 (work in progress), 2064 May 2009. 2066 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 2067 Requirement Levels", BCP 14, RFC 2119, March 1997. 2069 [RFC3588] Calhoun, P., Loughney, J., Guttman, E., Zorn, G., and J. 2070 Arkko, "Diameter Base Protocol", RFC 3588, September 2003. 2072 [RFC4005] Calhoun, P., Zorn, G., Spence, D., and D. Mitton, 2073 "Diameter Network Access Server Application", RFC 4005, 2074 August 2005. 2076 [RFC4234] Crocker, D., Ed. and P. Overell, "Augmented BNF for Syntax 2077 Specifications: ABNF", RFC 4234, October 2005. 2079 14.2. Informative References 2081 [I-D.ietf-nsis-ntlp] 2082 Schulzrinne, H. and M. Stiemerling, "GIST: General 2083 Internet Signalling Transport", draft-ietf-nsis-ntlp-20 2084 (work in progress), June 2009. 2086 [I-D.ietf-nsis-qos-nslp] 2087 Manner, J., Karagiannis, G., and A. McDonald, "NSLP for 2088 Quality-of-Service Signaling", draft-ietf-nsis-qos-nslp-16 2089 (work in progress), February 2008. 2091 [RFC2205] Braden, B., Zhang, L., Berson, S., Herzog, S., and S. 2092 Jamin, "Resource ReSerVation Protocol (RSVP) -- Version 1 2093 Functional Specification", RFC 2205, September 1997. 2095 [RFC2211] Wroclawski, J., "Specification of the Controlled-Load 2096 Network Element Service", RFC 2211, September 1997. 2098 [RFC2212] Shenker, S., Partridge, C., and R. Guerin, "Specification 2099 of Guaranteed Quality of Service", RFC 2212, 2100 September 1997. 2102 [RFC2474] Nichols, K., Blake, S., Baker, F., and D. Black, 2103 "Definition of the Differentiated Services Field (DS 2104 Field) in the IPv4 and IPv6 Headers", RFC 2474, 2105 December 1998. 2107 [RFC2753] Yavatkar, R., Pendarakis, D., and R. Guerin, "A Framework 2108 for Policy-based Admission Control", RFC 2753, 2109 January 2000. 2111 [RFC2865] Rigney, C., Willens, S., Rubens, A., and W. Simpson, 2112 "Remote Authentication Dial In User Service (RADIUS)", 2113 RFC 2865, June 2000. 2115 [RFC3261] Rosenberg, J., Schulzrinne, H., Camarillo, G., Johnston, 2116 A., Peterson, J., Sparks, R., Handley, M., and E. 2117 Schooler, "SIP: Session Initiation Protocol", RFC 3261, 2118 June 2002. 2120 [RFC3313] Marshall, W., "Private Session Initiation Protocol (SIP) 2121 Extensions for Media Authorization", RFC 3313, 2122 January 2003. 2124 [RFC3520] Hamer, L-N., Gage, B., Kosinski, B., and H. Shieh, 2125 "Session Authorization Policy Element", RFC 3520, 2126 April 2003. 2128 [RFC3521] Hamer, L-N., Gage, B., and H. Shieh, "Framework for 2129 Session Set-up with Media Authorization", RFC 3521, 2130 April 2003. 2132 [RFC4282] Aboba, B., Beadles, M., Arkko, J., and P. Eronen, "The 2133 Network Access Identifier", RFC 4282, December 2005. 2135 [RFC4566] Handley, M., Jacobson, V., and C. Perkins, "SDP: Session 2136 Description Protocol", RFC 4566, July 2006. 2138 [RFC5246] Dierks, T. and E. Rescorla, "The Transport Layer Security 2139 (TLS) Protocol Version 1.2", RFC 5246, August 2008. 2141 Authors' Addresses 2143 Dong Sun (editor) 2144 Alcatel-Lucent 2145 600 Mountain Ave 2146 Murray Hill, NJ 07974 2147 USA 2149 Phone: +1 908 582 2617 2150 Email: dongsun@alcatel-lucent.com 2152 Peter J. McCann 2153 Motorola Labs 2154 1301 E. Algonquin Rd 2155 Schaumburg, IL 60196 2156 USA 2158 Phone: +1 847 576 3440 2159 Email: pete.mccann@motorola.com 2161 Hannes Tschofenig 2162 Nokia Siemens Networks 2163 Linnoitustie 6 2164 Espoo 02600 2165 Finland 2167 Phone: +358 (50) 4871445 2168 Email: Hannes.Tschofenig@gmx.net 2169 URI: http://www.tschofenig.priv.at 2171 Tina Tsou 2172 Huawei 2173 Shenzhen, 2174 P.R.C 2176 Email: tena@huawei.com 2177 Avri Doria 2178 Lulea University of Technology 2179 Arbetsvetenskap 2180 Lulea, SE-97187 2181 Sweden 2183 Email: avri@ltu.se 2185 Glen Zorn (editor) 2186 Network Zen 2187 1310 East Thomas Street 2188 #306 2189 Seattle, Washington 98102 2190 USA 2192 Phone: +1 (206) 377-9035 2193 Email: gwz@net-zen.net