idnits 2.17.1 draft-ietf-alto-cost-calendar-02.txt: Checking boilerplate required by RFC 5378 and the IETF Trust (see https://trustee.ietf.org/license-info): ---------------------------------------------------------------------------- No issues found here. Checking nits according to https://www.ietf.org/id-info/1id-guidelines.txt: ---------------------------------------------------------------------------- No issues found here. Checking nits according to https://www.ietf.org/id-info/checklist : ---------------------------------------------------------------------------- ** The document seems to lack a Security Considerations section. ** There are 10 instances of too long lines in the document, the longest one being 10 characters in excess of 72. Miscellaneous warnings: ---------------------------------------------------------------------------- == The copyright year in the IETF Trust and authors Copyright Line does not match the current year == Line 96 has weird spacing: '...nt cost map...' == Line 353 has weird spacing: '...NString cos...' == Line 354 has weird spacing: '...NString tim...' == Line 355 has weird spacing: '...NNumber num...' == Line 577 has weird spacing: '...Boolean cal...' == (6 more instances...) -- The document date (July 3, 2017) is 2482 days in the past. Is this intentional? Checking references for intended status: Proposed Standard ---------------------------------------------------------------------------- (See RFCs 3967 and 4897 for information about using normative references to lower-maturity documents in RFCs) == Missing Reference: 'TODO' is mentioned on line 956, but not defined == Missing Reference: 'OPTIONAL' is mentioned on line 652, but not defined ** Downref: Normative reference to an Informational RFC: RFC 5693 -- Duplicate reference: RFC7285, mentioned in 'RFC7285', was also mentioned in 'ID-alto-protocol'. Summary: 3 errors (**), 0 flaws (~~), 9 warnings (==), 2 comments (--). Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 Network Working Group S. Randriamasy 3 Internet-Draft Nokia Bell Labs 4 Intended status: Standards Track R. Yang 5 Expires: January 4, 2018 Yale University 6 Q. Wu 7 Huawei 8 L. Deng 9 China Mobile 10 N. Schwan 11 Thales Deutschland 12 July 3, 2017 14 ALTO Cost Calendar 15 draft-ietf-alto-cost-calendar-02 17 Abstract 19 The goal of Application-Layer Traffic Optimization (ALTO) is to 20 bridge the gap between network and applications by provisioning 21 network related information in order to allow applications to make 22 network informed decisions. The present draft extends the ALTO cost 23 information so as to broaden the decision possibilities of 24 applications to not only decide 'where' to connect to, but also 25 'when'. This is useful to applications that need to schedule their 26 data transfers and connections and have a degree of freedom to do so. 27 ALTO guidance to schedule application traffic can also efficiently 28 help for load balancing and resources efficiency. Besides, the ALTO 29 Cost Calendar allows to schedule the ALTO requests themselves and 30 thus to save a number of ALTO transactions. 32 This draft proposes new capabilities and attributes on filtered cost 33 maps and endpoint costs enabling an ALTO Server to provide "Cost 34 Calendars". These capabilities are applicable to time-sensitive ALTO 35 metrics. With ALTO Cost Calendars, an ALTO Server exposes ALTO Cost 36 Values in JSON arrays where each value corresponds to a given time 37 interval. The time intervals as well as other Calendar attributes 38 are specified in the IRD and ALTO Server responses. 40 Requirements Language 42 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 43 "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this 44 document are to be interpreted as described in RFC 2119 [RFC2119]. 46 Status of This Memo 48 This Internet-Draft is submitted in full conformance with the 49 provisions of BCP 78 and BCP 79. 51 Internet-Drafts are working documents of the Internet Engineering 52 Task Force (IETF). Note that other groups may also distribute 53 working documents as Internet-Drafts. The list of current Internet- 54 Drafts is at http://datatracker.ietf.org/drafts/current/. 56 Internet-Drafts are draft documents valid for a maximum of six months 57 and may be updated, replaced, or obsoleted by other documents at any 58 time. It is inappropriate to use Internet-Drafts as reference 59 material or to cite them other than as "work in progress." 61 This Internet-Draft will expire on January 4, 2018. 63 Copyright Notice 65 Copyright (c) 2017 IETF Trust and the persons identified as the 66 document authors. All rights reserved. 68 This document is subject to BCP 78 and the IETF Trust's Legal 69 Provisions Relating to IETF Documents 70 (http://trustee.ietf.org/license-info) in effect on the date of 71 publication of this document. Please review these documents 72 carefully, as they describe your rights and restrictions with respect 73 to this document. Code Components extracted from this document must 74 include Simplified BSD License text as described in Section 4.e of 75 the Trust Legal Provisions and are provided without warranty as 76 described in the Simplified BSD License. 78 Table of Contents 80 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3 81 2. Overview of ALTO Cost Calendars . . . . . . . . . . . . . . . 4 82 2.1. ALTO Cost Calendar information features . . . . . . . . . 5 83 2.2. ALTO Calendar design characteristics . . . . . . . . . . 6 84 2.2.1. ALTO Cost Calendar for all cost modes . . . . . . . . 6 85 2.2.2. Compatibility with legacy ALTO Clients . . . . . . . 7 86 3. ALTO Calendar specification: IRD extensions . . . . . . . . . 7 87 3.1. Calendar attributes in the IRD resources capabilities . . 7 88 3.2. Calendars in a delegate IRD . . . . . . . . . . . . . . . 9 89 3.3. Example IRD with ALTO Cost Calendars . . . . . . . . . . 9 90 4. ALTO Calendar specification: Service Information Resources . 12 91 4.1. Calendar extensions for Filtered Cost Maps . . . . . . . 12 92 4.1.1. Calendar extensions in Filtered cost map requests . . 13 93 4.1.2. Calendar extensions in Filtered Cost map responses . 13 94 4.1.3. Use case and example: FCM with a bandwidth Calendar . 15 95 4.2. Calendar extensions in the Endpoint Cost Map Service . . 17 96 4.2.1. Calendar specific input in Endpoint cost map 97 requests . . . . . . . . . . . . . . . . . . . . . . 17 98 4.2.2. Calendar attributes in the Endpoint Cost Map response 17 99 4.2.3. Use case and example: ECS with a routingcost Calendar 18 100 4.2.4. Use case and example: ECS with a multi-cost calendar 101 for routingcost and latency . . . . . . . . . . . . . 21 102 5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 23 103 5.1. Information for IANA on proposed Cost Types . . . . . . . 23 104 5.2. Information for IANA on proposed Endpoint Properties . . 23 105 6. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 23 106 7. References . . . . . . . . . . . . . . . . . . . . . . . . . 23 107 7.1. Normative References . . . . . . . . . . . . . . . . . . 23 108 7.2. Informative References . . . . . . . . . . . . . . . . . 24 109 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 24 111 1. Introduction 113 IETF is currently standardizing the ALTO protocol which aims at 114 providing guidance to overlay applications needing to select one or 115 several hosts from a set of candidates able to provide a desired 116 resource. This guidance is based on parameters that affect 117 performance and efficiency of the data transmission between the hosts 118 such as the topological distance. The goal of ALTO is to improve the 119 Quality of Experience (QoE) in the application while optimizing 120 resource usage in the underlying network infrastructure. 122 The ALTO protocol in [RFC7285] specifies a Network Map which defines 123 groupings of endpoints in provider-defined network regions (called 124 PIDs). The Cost Map Service, Endpoint Cost Service (ECS) and 125 Endpoint Ranking Service then provide ISP-defined costs and rankings 126 for connections among the specified endpoints and PIDs and thus 127 incentives for application clients to connect to ISP preferred 128 locations, e.g. to reduce their costs. ALTO intentionally avoids 129 provisioning realtime information as explained in the ALTO Problem 130 Statement [RFC5693] and ALTO Requirements [RFC5693].Thus the current 131 Cost Map and Endpoint Cost Service are providing, for a given Cost 132 Type, exactly one path cost value. Applications have to query one of 133 these two services to retrieve the currently valid cost values. They 134 therefore need to plan their ALTO information requests according to 135 their own estimation of the frequency of cost value change. 137 With [RFC7285], an ALTO client should interpret the returned costs as 138 those at the query moment. However, Network costs can fluctuate, 139 e.g. due to diurnal patterns of traffic demand or planned events such 140 as network maintenance, holidays or highly publicized events. 141 Providing network costs for only the current time thus may not be 142 sufficient, in particular for applications that can schedule their 143 traffic in a span of time, for example by deferring backup to night 144 during traffic trough. 146 In case the ALTO Cost value changes are predicable over a certain 147 period of time and the application does not require immediate data 148 transfer, it can save time to get the whole set of cost values over 149 this period in one single ALTO response. Using this set to schedule 150 data transfers allows optimising the network resources usage and QoE. 151 ALTO Clients and Servers can also minimize their workload by reducing 152 and accordingly scheduling their data exchanges. 154 This document extends RFC7285 to allow an ALTO server to provide 155 network costs for a given duration of time. A sequence of network 156 costs across a time span for a given pair of network locations is 157 named an "ALTO Cost Calendar". The Filtered Cost Map Service and 158 Endpoint Cost Service are extended to provide Cost Calendars. In 159 addition to this functional ALTO enhancement, we expect to further 160 gain on storage and on the wire data exchange by gathering multiple 161 Cost Values for one Cost Type into one single ALTO Server response. 163 In this draft an "ALTO Cost Calendar" is specified by information 164 resources capabilities that are applicable to time-sensitive ALTO 165 metrics. An ALTO Cost Calendar exposes ALTO Cost Values in JSON 166 arrays where each value corresponds to a given time interval. The 167 time intervals as well as other Calendar attributes are specified in 168 the IRD and in the Server response to allow the ALTO Client to 169 interpret the received ALTO values. Last, the proposed extensions 170 for ALTO Calendars are applicable to any Cost Mode and they ensure 171 backwards compatibility with legacy ALTO clients. 173 In the rest of this document, Section 2 provides the design 174 characteristics. Sections 3 and 4 define the formal specifications 175 for the IRD and the information resources. Section 5 provides non- 176 normative use cases to illustrate the usage of cost calendars. IANA 177 considerations and security considerations will be completed in 178 further versions. 180 2. Overview of ALTO Cost Calendars 182 An ALTO Cost calendar provided by the ALTO Server provides 2 183 information items: 185 o an array of values for a given metric, where each value 186 corresponds to a time interval, where the value array can 187 sometimes be a cyclic pattern that repeats a certain number of 188 times. 190 o attributes describing the time scope of the calendar such as the 191 size and number of the intervals and the date of the starting 192 point of the calendar, allowing an ALTO Client to properly 193 interpret the values. 195 An ALTO Cost Calendar can be used like a "time table" to figure out 196 the best time to schedule data transfers and also to proactively 197 manage application traffic given predictable events such as flash 198 crowds, traffic intensive holidays and network maintenance. It may 199 be viewed as a synthetic abstraction of real measurements that can be 200 historic or be a prediction for upcoming time periods. 202 Most likely, the ALTO Cost Calendar would be used for the Endpoint 203 Cost Service, assuming that a limited set of feasible Endpoints for a 204 non-real time application is already identified, that they do not 205 need to be accessed immediately and that their access can be 206 scheduled within a given time period. The Filtered Cost Map service 207 is also applicable as long as the size of the Map allows it. 209 2.1. ALTO Cost Calendar information features 211 The Calendar attributes are provided in the IRD and in ALTO Server 212 responses. The IRD announces attributes with dateless values in its 213 information resources capabilities, where as attributes with time 214 dependent values are provided in the "meta" of Server responses. The 215 ALTO Cost Calendar attributes provide the following information: 217 o attributes to interpret the time scope of the Calendar value 218 array: 220 * generic time zone, 222 * applicable time interval for each calendar value: combining 223 numbers and time units to reflect for example: 1 hour, 2 224 minutes, 10 seconds, 1 week, 1 month, 226 * duration of the Calendar: e.g. the number of intervals provided 227 in the calendar. 229 o "calendar-start-date": specifying when the calendar starts, that 230 is to which date the first value of the cost calendar is 231 applicable. 233 o "repeated": an optional attribute indicating for how many 234 iterations the provided calendar will have the same values. The 235 server may use it to allow the client to schedule its next request 236 and thus save its own workload by avoiding to process useless 237 requests. 239 2.2. ALTO Calendar design characteristics 241 The protocol extension placeholders for an ALTO Calendar are: the 242 IRD, the ALTO requests and responses for Cost calendars. 244 Extensions are designed to be light and ensure backwards 245 compatibility with base protocol ALTO Clients and with other 246 extensions. It uses section 8.3.7 "Parsing of Unknown Fields" of 247 RFC7285 that writes: "Extensions may include additional fields within 248 JSON objects defined in this document. ALTO implementations MUST 249 ignore unknown fields when processing ALTO messages." 251 The calendar-specific capabilities are integrated in the information 252 resources of the IRD and in the "meta" member of ALTO responses to 253 Cost Calendars requests. A calendar and its capabilities are 254 associated with a given information resource and within this 255 information resource with a given cost type. This design has several 256 advantages: 258 o it does not introduce a new mode, 260 o it does not introduce new media types, 262 o it allows an ALTO Server to offer calendar capabilities on a cost 263 type, with attributes values adapted to each information resource. 265 The Applicable Calendared information resources are: 267 o the Filtered Cost Map, 269 o the Endpoint Cost Map. 271 The ALTO Server can choose in which frequency it provides cost 272 Calendars to ALTO Clients. It may either provide calendar updates 273 starting at the request date, or carefully schedule its updates so as 274 to take profit from a potential repetition/periodicity of calendar 275 values. 277 2.2.1. ALTO Cost Calendar for all cost modes 279 Calendars are well-suited for values encoded in the 'numerical' mode. 280 However, Calendars can also represent any metric considered as time- 281 varying by an ALTO Server. For example, types of Cost values such as 282 JSONBool can also be expressed as calendars, as states may be "true" 283 or "false" depending on given time periods or likewise, values 284 represented by strings, such as "medium", "high", "low", "blue", 285 "open" . 287 Note also that a Calendar is applicable as well to time-varying 288 metrics provided in the 'ordinal' mode, if these values are time- 289 varying and their update is carefully managed by the ALTO Server. 291 2.2.2. Compatibility with legacy ALTO Clients 293 The ALTO protocol extensions for Cost Calendars have been defined so 294 as to ensure that Calendar capable ALTO Servers can provide legacy 295 ALTO Clients with legacy information resources as well. That is a 296 legacy ALTO Client can request resources and receive responses as 297 specified in RFC7285. 299 A Calendar-aware ALTO Server MUST implement the base protocol 300 specified in RFC7285. 302 When a metric is available as a calendar, it MUST be available as a 303 single value as well. 305 For compatibility with legacy ALTO Clients specified in RFC7285, 306 calendared information resources are not applicable for full Cost 307 Maps for the following reason: a legacy ALTO client would receive a 308 Calendared Cost Map via an HTTP 'GET' command. As specified in 309 section 8.3.7 of RFC7285, it will ignore the Calendar Attributes 310 indicated in the "meta" of the responses. Therefore, lacking 311 information on calendar attributes, it will not be able to correctly 312 interpret and process the values of the received array of calendar 313 cost values. 315 Therefore, calendared information resources MUST be requested via the 316 Filtered Cost Map Service or the Endpoint Cost Service, using a POST 317 method. 319 3. ALTO Calendar specification: IRD extensions 321 The Calendar attributes in the IRD information resources capabilities 322 carry constant dateless values. A calendar is associated with an 323 information resource rather than a cost type. For example, a Server 324 can provide a "routingcost" calendar for the Filtered Cost Map 325 Service at a granularity of one day and a "routingcost" calendar for 326 the Endpoint Cost service at a finer granularity but for a limited 327 number of endpoints. 329 3.1. Calendar attributes in the IRD resources capabilities 331 When for an applicable resource, an ALTO Server provides a Cost 332 Calendar for a given Cost Type, it MUST indicate this in the IRD 333 capabilities of this resource, by an object of type 334 'CalendarAttributes', associated with this Cost Type and specified 335 below. 337 The capabilities of a Calendar aware information resource entry have 338 a member named "calendar-attributes" which is an array of objects of 339 type CalendarAttributes. It is necessary to use an array because of 340 resources such as Filtered Cost Map and Endpoint Cost Map, for which 341 the member "cost-type-names" is an array of 1 or more values. 343 A member "calendar-attributes" MUST appear only once for each 344 applicable cost type name of a resource entry. If "calendar- 345 attributes" are specified several times for a same "cost-type-name" 346 in the capabilities of a resource entry, the ALTO client SHOULD 347 ignore any calendar capabilities on this "cost-type-name" for this 348 resource entry. 350 CalendarAttributes calendar-attributes <1..*>; 352 object{ 353 JSONString cost-type-names <1..*>; 354 JSONString time-interval-size; 355 JSONNumber number-of-intervals; 356 } CalendarAttributes; 358 o "cost-type-name": 360 * An array of one or more elements indicating the cost-type-names 361 in the IRD entry to which the capabilities apply. 363 o "time-interval-size": 365 * is the duration of an ALTO calendar time interval, expressed as 366 a time unit appended to the number of these units. The time 367 unit, ranges from "second" to "year". The number is encoded 368 with an integer. Example values are: "5 minute" , "2 hour", 369 meaning that each calendar value applies on a time interval 370 that lasts respectively 5 minutes and 2 hours. 372 o "number-of-intervals": 374 * the integer number of values of the cost calendar array, at 375 least equal to 1. 377 - Attribute "cost-type-name" , if used, provides a better readability 378 to the calendar attributes specified in the IRD and avoids confusion 379 with calendar attributes of other cost-types. 381 - Multiplying Attributes 'time-interval-size' and 'number-of- 382 intervals' provides the duration of the provided calendar. For 383 example an ALTO Server may provide a calendar for ALTO values 384 changing every 'time-interval-size' equal to 5 minutes. If 'number- 385 of-intervals' has the value 12, then the duration of the provided 386 calendar is "1 hour". 388 3.2. Calendars in a delegate IRD 390 One option to clarify IRD resources is that a "root" ALTO Server 391 implementing base protocol resources delegates "specialized" 392 information resources such as the ones providing Cost Calendars to 393 another ALTO Server running in a subdomain specified with its URI in 394 the "root" ALTO Server. This option is described in Section 9.2.4 395 "Delegation using IRDs" of RFC7285. 397 This document provides an example, where a "root" ALTO Server runs in 398 a domain called "alto.example.com". It delegates the announcement of 399 Calendars capabilities to an ALTO Server running in a subdomain 400 called "custom.alto.example.com". The location of the "delegate 401 Calendar IRD" is assumed to be indicated in the "root" IRD by the 402 resource entry: "custom-calendared-resources". 404 Another advantage is that some Cost Types for some resources may be 405 more advantageous as Cost Calendars and it makes few sense to get 406 them as a single value. For example, Cost Types with predictable and 407 frequently changing values, calendared in short time intervals such 408 as a minute. 410 3.3. Example IRD with ALTO Cost Calendars 412 The cost types in this example are either specified in the base ALTO 413 protocol or may be proposed in other drafts see 414 [draft-ietf-alto-performance-metrics]. In this example, the 415 available cost metrics are indicated in the "meta" field by cost type 416 names "num-routingcost", "num-latency", "num-pathbandwidth" and 417 "string-quality-status". Metrics "routingcost" , 'latency' and 418 'bandwidthscore' are available in the "numerical" Cost Mode. Metric 419 "quality-status" is available in the "string" Cost Mode. 421 The example IRD includes 2 particular URIs providing calendars: 423 o "http://custom.alto.example.com/calendar/costmap/filtered": a 424 filtered cost map in which calendar capabilities are indicated for 425 cost type names: "num-routingcost", "num-pathbandwidth" and 426 "string-service-status", 428 o "http://custom.alto.example.com/calendar/endpointcost/lookup": an 429 endpoint cost map in which in which calendar capabilities are 430 indicated for cost type names: "num-routingcost", "num-latency", 431 "num-pathbandwidth", "string-service-status". 433 The design of the Calendar capabilities allows that some calendars on 434 a cost type name are available in several information resources with 435 different Calendar Attributes. This is the case for calendars on 436 "num-routingcost", "num-pathbandwidth" and "string-service-status" , 437 available in both the Filtered Cost map and Endpoint Cost map 438 service, but with different time interval sizes for "num- 439 pathbandwidth" and "string-service-status". 441 GET /calendars-directory HTTP/1.1 442 Host: custom.alto.example.com 443 Accept: application/alto-directory+json,application/alto-error+json 444 --------------- 446 HTTP/1.1 200 OK 447 Content-Length: [TODO] 448 Content-Type: application/alto-directory+json 450 { 451 "meta" : { 452 "cost-types": { 453 "num-routingcost": { 454 "cost-mode" : "numerical", 455 "cost-metric" : "routingcost" 456 }, 457 "num-latency": { 458 "cost-mode" : "numerical", 459 "cost-metric": "latency" 460 }, 461 "num-pathbandwidth": { 462 "cost-mode" : "numerical", 463 "cost-metric": "bandwidthscore", 464 }, 465 "string-qual-status": { 466 "cost-mode" : "string", 467 "cost-metric": "quality-status", 468 } 469 ... other meta ... 470 }, 472 "resources" : { 473 "filtered-cost-map-calendar" : { 474 "uri" : "http://custom.alto.example.com/calendar/costmap/filtered", 475 "media-type" : "application/alto-costmap+json", 476 "accepts" : "application/alto-costmapfilter+json", 477 "capabilities" : { 478 "cost-constraints" : true, 479 "cost-type-names" : [ "num-routingcost", "num-pathbandwidth", 480 "string-service-status" ], 481 "calendar-attributes" : [ 482 {"cost-type-names" : [ "num-routingcost", "num-pathbandwidth" ], 483 "time-interval-size" : "1 hour", 484 "number-of-intervals" : 24 485 }, 486 {"cost-type-names" : "string-service-status", 487 "time-interval-size" : "30 minute", 488 "number-of-intervals" : 48 489 } 490 ] // end calendar-attributes 491 "uses": [ "my-default-network-map" ] 492 } 493 }, 495 "endpoint-cost-calendar-map" : { 496 "uri" : "http://custom.alto.example.com/calendar/endpointcost/lookup", 497 "media-types" : [ "application/alto-endpointcost+json" ], 498 "accepts" : [ "application/alto-endpointcostparams+json" ], 499 "capabilities" : { 500 "cost-constraints" : true, 501 "cost-type-names" : [ "num-routingcost", "num-latency", 502 "num-pathbandwidth", "string-service-status" ], 503 "calendar-attributes" : [ 504 {"cost-type-names" : "num-routingcost", 505 "time-interval-size" : "1 hour", 506 "number-of-intervals" : 24 507 }, 508 {"cost-type-names" : "latency", 509 "time-interval-size" : "5 minute", 510 "number-of-intervals" : 12 511 }, 512 {"cost-type-names" : "num-pathbandwidth", 513 "time-interval-size" : "1 minute", 514 "number-of-intervals" : 60 515 }, 516 {"cost-type-names" : "string-service-status", 517 "time-interval-size" : "2 minute", 518 "number-of-intervals" : 30 519 } 520 ] 521 "uses": [ "my-default-network-map" ] 522 } // ECM capab 523 } //info resource N 525 } // ressources 527 In this example IRD, for the filtered cost map service: 529 o the Calendar for 'num-routingcost' and 'num-pathbandwidth' is an 530 array of 24 values each provided on a time interval lasting 1 531 hour. 533 o the Calendar for "string-service-status": "is an array of 48 534 values each provided on a time interval lasting 30 minutes. 536 For the endpoint cost map service: 538 o the Calendar for 'num-routingcost': is an array of 24 values each 539 provided on a time interval lasting 1 hour. 541 o the Calendar for 'latency': is an array of 12 values each provided 542 on a time interval lasting 5 minutes. 544 o the Calendar for 'num-pathbandwidth': is an array of 60 values 545 each provided on a time interval lasting 1 minute. 547 o the Calendar for "string-service-status": "is an array of 30 548 values each provided on a time interval lasting 2 minutes. 550 4. ALTO Calendar specification: Service Information Resources 552 This section documents the individual information resources defined 553 to provide the Calendared information services defined in this 554 document. 556 The reference time zone for the provided time values is GMT because 557 the option chosen to express the time format is the HTTP header 558 fields format: 560 Date: Tue, 15 Nov 2014 08:12:31 GMT 562 4.1. Calendar extensions for Filtered Cost Maps 564 A legacy ALTO client requests and gets filtered cost map responses as 565 specified in RFC7285. 567 4.1.1. Calendar extensions in Filtered cost map requests 569 The input parameters of a "legacy" request for a filtered cost map, 570 defined by object ReqFilteredCostMap in section 11.3.2 of RFC7285, 571 are augmented with one additional member. 573 A Calendar-aware ALTO client requesting a Calendar on a given Cost 574 Type for a Filtered Cost Map resource having Calendar capabilities 575 MUST add the following field to its input parameters: 577 JSONBoolean calendared<1..*>; 579 This field is an array of 1 to N boolean values, where N is the 580 number of requested metrics. Each boolean value indicates whether or 581 not the ALTO Server should provide the values for this Cost Type as a 582 calendar. The array MUST contain exactly N boolean values, otherwise 583 the server returns an error. 585 This field MUST NOT be specified if member "calendar-attributes" is 586 not present for this information resource. 588 If this field is not present, it MUST be assumed to have only values 589 equal to "false". 591 A Calendar-aware ALTO client supporting single cost type values, as 592 specified in RFC7285, MUST provide an array of 1 element: 594 "calendared" : [true]; 596 A Calendar-aware ALTO client that is also Multi-Cost aware MUST 597 provide an array of N values set to "true" or "false", depending 598 whether it wants the applicable Cost Type values as a single or 599 calendared value. 601 4.1.2. Calendar extensions in Filtered Cost map responses 603 The calendared costs are JSONArrays instead of JSONNumbers for the 604 legacy ALTO implementation. All arrays have a number of values equal 605 to 'number-of-intervals'. 607 The "meta" field of a Calendared Filtered Cost map response MUST 608 include at least: 610 o if the ALTO Client supports cost values for one Cost Type at a 611 time only: the "meta" fields specified in RFC 7285 for these 612 information service responses: 614 * "dependent-vtags ", 615 * "cost-type" field. 617 o if the ALTO Client supports cost values for several Cost Types at 618 a time, as specified in [draft-ietf-alto-multi-cost] : the "meta" 619 fields specified in [draft-ietf-alto-multi-cost] for these 620 information service responses: 622 * "dependent-vtags ", 624 * "cost-type" field with value set to '{}', for backwards 625 compatibility with RFC7285. 627 * "multi-cost-types" field. 629 o If the client request does not provide member "calendared" or if 630 it provides it with a value equal to 'false', for all the 631 requested Cost Types, then the ALTO Server response is exactly as 632 specified in RFC 7285 [ID-alto-protocol] and 633 [draft-ietf-alto-multi-cost]. 635 o If the value of member "calendared" is equal to 'false' for a 636 given requested Cost Type, the ALTO Server must return, for these 637 Cost Types, a single cost value as specified in RFC 7285. 639 In addition, the "meta" field of a Calendared Filtered Cost map 640 response MUST include the member "calendar-response-attributes" for 641 the requested information resource, together with the values provided 642 by the ALTO Server for these attributes. This member is an array of 643 objects of type "CalendarResponseAttributes", defined as follows: 645 CalendarResponseAttributes calendar-response-attributes <1..*>; 647 object{ 648 JSONString cost-type-names; 649 JSONString calendar-start-time; 650 JSONString time-interval-size; 651 JSONNumber number-of-intervals; 652 [JSONNumber repeated;] [OPTIONAL] 653 } CalendarResponseAttributes; 655 Object CalendarResponseAttributes has the following attributes: 657 o "cost-type-names": member indicating the cost-type-names to which 658 the capabilities apply. 660 o "calendar-start-time": indicates the date at which the first value 661 of the calendar applies. By default, the value provided for the 662 "calendar-start-time" attribute SHOULD be no later than the 663 request date. 665 o "time-interval-size": as specified in section "Calendar attributes 666 in the IRD resources capabilities", 668 o "number-of-intervals": as specified in section "Calendar 669 attributes in the IRD resources capabilities", 671 o "repeated": is an optional field provided for Calendars. It is an 672 integer N greater or equal to '1' that indicates how many 673 iterations of the calendar value array starting at the date 674 indicated by "calendar-start-time" have the same values. The 675 number N includes the provided iteration. 677 Using the member "repeated" helps minimizing on the wire data 678 exchange: by providing it, an ALTO Server will avoid unecessary 679 processing of requests for Calendars with unchanged values while it 680 allows ALTO Clients to save their resources as well. 682 For example: if the "calendar-start-time" member has value "Mon, 30 683 Jun 2014 at 00:00:00 GMT" and if the value of member "repeated" is 684 equal to 4, it means that the calendar values are the same values on 685 Monday, Tuesday, Wednesday and Thursday. The ALTO Client thus may 686 use the same calendar for the next 4 duration periods following 687 "calendar-start-time". 689 4.1.3. Use case and example: FCM with a bandwidth Calendar 691 An example of non-real time information that can be provisioned in a 692 'calendar' is the expected path bandwidth. While the transmission 693 rate can be measured in real time by end systems, the operator of a 694 data center is in the position of formulating preferences for given 695 paths, at given time periods for example to avoid traffic peaks due 696 to diurnal usage patterns. In this example, we assume that an ALTO 697 Client requests a bandwidth calendar as specified in the IRD to 698 schedule its bulk data transfers as described in the use cases. 700 In the example IRD, calendars for cost type name "num-pathbandwidth" 701 are available for the information resources: "filtered-cost-calendar- 702 map" and "endpoint-cost-calendar-map". The ALTO Client requests a 703 calendar for "num-pathbandwidth" via a POST request for a filtered 704 cost map. 706 We suppose in this example that the ALTO Client sends its request on 707 Tuesday July 1st 2014 at 13:15 709 POST /calendar/costmap/filtered HTTP/1.1 710 Host: alto.example.com 711 Content-Length: [TODO] 712 Content-Type: application/alto-costmapfilter+json 713 Accept: application/alto-costmap+json,application/alto-error+json 715 { 716 "cost-type" : {"cost-mode" : "numerical", "cost-metric" : "bandwidthscore"}, 717 "calendared" : [true], 719 "pids" : { 720 "srcs" : [ "PID1", "PID2" ], 721 "dsts" : [ "PID1", "PID2", "PID3" ] 722 } 723 } 725 HTTP/1.1 200 OK 726 Content-Length: [TODO] 727 Content-Type: application/alto-costmap+json 729 { 730 "meta" : { 731 "dependent-vtags" : [...], 732 "cost-type" : {"cost-mode" : "numerical", "cost-metric" : "bandwidthscore"}, 733 "calendar-response-attributes" : [ 734 "calendar-start-time" : Tue, 1 Jul 2014 13:00:00 GMT, 735 "time-interval-size" : "2 hour", 736 "numb-intervals" : 12 737 ] 738 }, 740 "cost-map" : { 741 "PID1": { "PID1": [v1,v2, ... v12], 742 "PID2": [v1,v2, ... v12], 743 "PID3": [v1,v2, ... v12] }, 744 "PID2": { "PID1": [v1,v2, ... v12], 745 "PID2": [v1,v2, ... v12], 746 "PID3": [v1,v2, ... v12] } 747 } 748 } 750 4.2. Calendar extensions in the Endpoint Cost Map Service 752 This document extends the Endpoint Cost Service, as defined in 753 {11.5.1} of [RFC7285], by adding new input parameters and 754 capabilities, and by returning JSONArrays instead of JSONNumbers as 755 the cost values. The media type {11.5.1.1} and HTTP method 756 {11.5.1.2} are unchanged. 758 4.2.1. Calendar specific input in Endpoint cost map requests 760 The extensions to the requests for calendared Endpoint Cost Maps are 761 the same as for the Filtered Cost Map Service, specified in section 762 XXXX of this draft. 764 The ReqEndpointCostMap object for a Calendared ECM request will have 765 the following format: 767 object { 768 [CostType cost-type;] 769 [CostType multi-cost-types<1..*>;] 770 [JSONBoolean calendared<1..*>;] 771 EndpointFilter endpoints; 772 } ReqEndpointCostMap; 774 object { 775 [TypedEndpointAddr srcs<0..*>;] 776 [TypedEndpointAddr dsts<0..*>;] 777 } EndpointFilter; 779 4.2.2. Calendar attributes in the Endpoint Cost Map response 781 The "meta" field of a Calendared Endpoint Cost map response MUST 782 include at least: 784 o if the ALTO Client supports cost values for one Cost Type at a 785 time only: the "meta" fields specified in {11.5.1.6} of RFC 7285 786 for the Endpoint Cost response: 788 * "cost-type" field. 790 o if the ALTO Client supports cost values for several Cost Types at 791 a time, as specified in [draft-ietf-alto-multi-cost] : the "meta" 792 fields specified in [draft-ietf-alto-multi-cost] for the the 793 Endpoint Cost response: 795 * "cost-type" field with value set to '{}', for backwards 796 compatibility with RFC7285. 798 * "multi-cost-types" field. 800 If the client request does not provide member "calendared" or if it 801 provides it with a value equal to 'false', for all the requested Cost 802 Types, then the ALTO Server response is exactly as specified in RFC 803 7285 [ID-alto-protocol] and [draft-ietf-alto-multi-cost]. 805 If the ALTO client provides member "calendared" in the input 806 parameters with a value equal to 'true' for given requested Cost 807 Types, the "meta" member of a Calendared Endpoint Cost Map response 808 MUST include, for these Cost Types, the same additional member 809 "calendar-response-attributes", as specified for the Filtered Cost 810 Map Service. The Server response is thus changed as follows, w.r.t 811 RFC 7285 and [draft-ietf-alto-multi-cost]: 813 o the "meta" member has one additional field 814 "CalendarResponseAttributes", as specified for the Filtered Cost 815 Map Service, 817 o the calendared costs are JSONArrays instead of JSONNumbers for the 818 legacy ALTO implementation. All arrays have a number of values 819 equal to 'number-of-intervals'. 821 If the value of member "calendared" is equal to 'false' for a given 822 requested Cost Type, the ALTO Server must return, for these Cost 823 Types, a single cost value as specified in RFC 7285. 825 4.2.3. Use case and example: ECS with a routingcost Calendar 827 Let us assume an Application Client is located in an end system with 828 limited resources and having an access to the network that is either 829 intermittent or provides an acceptable quality in limited but 830 predictable time periods. Therefore, it needs to both schedule its 831 resources greedy networking activities and its ALTO transactions. 833 The Application Client has the choice to trade content or resources 834 with a set of Endpoints and needs to decide with which one it will 835 connect and at what time. For instance, the Endpoints are spread in 836 different time-zones, or have intermittent access. In this example, 837 the 'routingcost' is assumed to be time-varying, with values provided 838 as ALTO Calendars. 840 The ALTO Client associated with the Application Client queries an 841 ALTO Calendar on 'routingcost' and will get the Calendar covering the 842 24 hours time period "containing" the date and time of the ALTO 843 client request. 845 For Cost Type 'num-routingcost', the solicited ALTO Server has 846 defined 3 different daily patterns each represented by a Calendar, to 847 cover the week of Monday June 30th at 00:00 to Sunday July 6th 23:59: 849 - C1 for Monday, Tuesday, Wednesday, Thursday, (week days) 851 - C2 for Saturday, Sunday, (week end) 853 - C3 for Friday (maintenance outage on July 4, 2014 from 02:00:00 GMT 854 to 04:00:00 GMT, or big holiday such as New Year evening). 856 In the following example, the ALTO Client sends its request on 857 Tuesday July 1st 2014 at 13:15. 859 POST /calendar/endpointcost/lookup HTTP/1.1 860 Host: alto.example.com 861 Content-Length: [TODO] 862 Content-Type: application/alto-endpointcostparams+json 863 Accept: application/alto-endpointcost+json,application/alto-error+json 865 { 866 "cost-type" : {"cost-mode" : "numerical", "cost-metric" : "routingcost"}, 867 "calendared" : [true], 868 "endpoints" : { 869 "srcs": [ "ipv4:192.0.2.2" ], 870 "dsts": [ 871 "ipv4:192.0.2.89", 872 "ipv4:198.51.100.34", 873 "ipv4:203.0.113.45", 874 "ipv6:2000::1:2345:6789:abcd" 875 ] 876 } 877 } 879 HTTP/1.1 200 OK 880 Content-Length: [TODO] 881 Content-Type: application/alto-endpointcost+json 883 { 884 "meta" : { 885 "cost-type" : {"cost-mode" : "numerical", "cost-metric" : "routingcost"}, 886 "calendar-response-attributes" : [ 887 { "calendar-start-time" : Mon, 30 Jun 2014 00:00:00 GMT, 888 "time-interval-size" : "1 hour", 889 "numb-intervals" : 24, 890 "repeated": 4 } 891 ], 892 } // end meta 894 "endpoint-cost-map" : { 895 "ipv4:192.0.2.2": { 896 "ipv4:192.0.2.89" : [v1, v2, ... v24], 897 "ipv4:198.51.100.34" : [v1, v2, ... v24], 898 "ipv4:203.0.113.45" : [v1, v2, ... v24], 899 "ipv6:2000::1:2345:6789:abcd" : [v1, v2, ... v24] 900 } 901 } 902 } 903 When the Client gets the Calendar for "routingcost", it sees that the 904 "calendar-start-time" is Monday at 00h00 GMT and member "repeated" is 905 equal to '4'. It understands that the provided values are valid 906 until Thursday included and will only need to get a Calendar update 907 on Friday. 909 4.2.4. Use case and example: ECS with a multi-cost calendar for 910 routingcost and latency 912 In this example, it is assumed that the ALTO Server implements multi- 913 cost capabilities, as specified in [draft-ietf-alto-multi-cost] . 914 That is, an ALTO client can request and receive values for several 915 cost types in one single transaction. An illustrating use case is a 916 path selection done on the basis of 2 metrics: routing cost and 917 latency. 919 As in the previous example, the IRD indicates that the ALTO Server 920 provides "routingcost" Calendars in terms of 24 time intervals of 1 921 hour each. 923 For metric "latency", the IRD indicates that the ALTO Server provides 924 Calendars in terms of 12 time intervals values lasting each 5 925 minutes. 927 In the following example transaction, the ALTO Client sends its 928 request on Tuesday July 1st 2014 at 13:15. 930 POST calendar/endpointcost/lookup HTTP/1.1 931 Host: alto.example.com 932 Content-Length: [TODO] 933 Content-Type: application/alto-endpointcostparams+json 934 Accept: application/alto-endpointcost+json,application/alto-error+json 936 { 937 "cost-type" : {}, 938 "multi-cost-types" : [ 939 {"cost-mode" : "numerical", "cost-metric" : "routingcost"}, 940 {"cost-mode" : "numerical", "cost-metric" : "latency"} 941 ], 942 "calendared" : [true, true], 943 "endpoints" : { 944 "srcs": [ "ipv4:192.0.2.2" ], 945 "dsts": [ 946 "ipv4:192.0.2.89", 947 "ipv4:198.51.100.34", 948 "ipv4:203.0.113.45", 949 "ipv6:2000::1:2345:6789:abcd" 950 ] 952 } 953 } 955 HTTP/1.1 200 OK 956 Content-Length: [TODO] 957 Content-Type: application/alto-endpointcost+json 959 { 960 "meta" : { 961 "multi-cost-types" : [ 962 {"cost-mode" : "numerical", "cost-metric" : "routingcost"}, 963 {"cost-mode" : "numerical", "cost-metric" : "latency"} 964 ], 965 "calendar-response-attributes" : [ 966 { "cost-type-name : num-routingcost" 967 "calendar-start-time" : Mon, 30 Jun 2014 00:00:00 GMT, 968 "time-interval-size" : "1 hour", 969 "numb-intervals" : 24, 970 "repeated": 4 }, 971 { "cost-type-name : num-latency" 972 "calendar-start-time" : Tue, 1 Jul 2014 13:00:00 GMT, 973 "time-interval-size" : "5 minute", 974 "numb-intervals" : 12} 975 ], 976 } // end meta 978 "endpoint-cost-map" : { 979 "ipv4:192.0.2.2": { 980 "ipv4:192.0.2.89" : [[r1, r2, ... r24], [l1, l2, ... l12]], 981 "ipv4:198.51.100.34" : [[r1, r2, ... r24], [l1, l2, ... l12]], 982 "ipv4:203.0.113.45" : [[r1, r2, ... r24], [l1, l2, ... l12]], 983 "ipv6:2000::1:2345:6789:abcd" : [[r1, r2, ... r24], [l1, l2, ... l12]] 984 } 985 } 986 } 988 When receiving the response, the client sees that the calendar values 989 for 'routing cost' are repeated for 4 iterations. Therefore, in its 990 next requests until the routing cost calendar is expected to change, 991 the client will only need to request a calendar for "latency". 993 Without the ALTO Calendar extensions, the ALTO client would have no 994 clue on the dynamicity of the metric value change and would spend 995 needless time requesting values at an inappropriate pace. In 996 addition, without the Multi-Cost ALTO capabilities, the ALTO client 997 would duplicate this waste of time as it would need to send one 998 request per cost metric. 1000 5. IANA Considerations 1002 Information for the ALTO Endpoint property registry maintained by the 1003 IANA and related to the new Endpoints supported by the acting ALTO 1004 server. These definitions will be formulated according to the syntax 1005 defined in Section on "ALTO Endpoint Property Registry" of [RFC7285] 1006 , 1008 Information for the ALTO Cost Type Registry maintained by the IANA 1009 and related to the new Cost Types supported by the acting ALTO 1010 server. These definitions will be formulated according to the syntax 1011 defined in Section on "ALTO Cost Type Registry" of [RFC7285], 1013 5.1. Information for IANA on proposed Cost Types 1015 When a new ALTO Cost Type is defined, accepted by the ALTO working 1016 group and requests for IANA registration MUST include the following 1017 information, detailed in Section 11.2: Identifier, Intended 1018 Semantics, Security Considerations. 1020 5.2. Information for IANA on proposed Endpoint Properties 1022 Likewise, an ALTO Endpoint Property Registry could serve the same 1023 purposes as the ALTO Cost Type registry. Application to IANA 1024 registration for Endpoint Properties would follow a similar process. 1026 6. Acknowledgements 1028 Many thanks to Diego Lopez, He Peng, Haibin Song, Dawn Chan, Li Geng 1029 and Yichen Qian for fruitful discussions and review feedback. 1031 7. References 1033 7.1. Normative References 1035 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 1036 Requirement Levels", BCP 14, RFC 2119, 1037 DOI 10.17487/RFC2119, March 1997, 1038 . 1040 [RFC5693] Seedorf, J. and E. Burger, "Application-Layer Traffic 1041 Optimization (ALTO) Problem Statement", RFC 5693, 1042 DOI 10.17487/RFC5693, October 2009, 1043 . 1045 7.2. Informative References 1047 [draft-ietf-alto-multi-cost] 1048 S. Randriamasy, W. Roome, N. Schwan, "Multi-Cost ALTO 1049 (work in progress), draft-ietf-alto-multi-cost", September 1050 2016. 1052 [draft-ietf-alto-performance-metrics] 1053 Q. Wu, Y. Yang, Y. Lee, D. Dhody, S. Randriamasy, "ALTO 1054 Performance Cost Metrics (work in progress)", September 1055 2016. 1057 [draft-yang-alto-topology] 1058 Y. Yang, "ALTO Topology Considerations (work in 1059 progress)", July 2013. 1061 [ID-alto-protocol] 1062 R.Alimi, R. Penno, Y. Yang, Eds., "ALTO Protocol, RFC 1063 7285", September 2014. 1065 [RFC7285] R. Alimi, R. Yang, R. Penno, Eds., "ALTO Protocol", 1066 September 2014. 1068 [sdnrg] "Software Defined Network Research Group, 1069 http://trac.tools.ietf.org/group/irtf/trac/wiki/sdnrg". 1071 [slides-88-alto-5-topology] 1072 G. Bernstein, Y. Lee, Y. Yang, , "ALTO Topology Service: 1073 Use Cases, Requirements and Framework (presentation slides 1074 IETF88 ALTO WG session), 1075 http://tools.ietf.org/agenda/88/slides/ 1076 slides-88-alto-5.pdf", November 2013. 1078 Authors' Addresses 1080 Sabine Randriamasy 1081 Nokia Bell Labs 1082 Route de Villejust 1083 NOZAY 91460 1084 FRANCE 1086 Email: Sabine.Randriamasy@nokia-bell-labs.com 1087 Richard Yang 1088 Yale University 1089 51 Prospect st 1090 New Haven, CT 06520 1091 USA 1093 Email: yry@cs.yale.edu 1095 Qin Wu 1096 Huawei 1097 101 Software Avenue, Yuhua District 1098 Nanjing, Jiangsu 210012 1099 China 1101 Email: sunseawq@huawei.com 1103 Lingli Deng 1104 China Mobile 1105 China 1107 Email: denglingli@chinamobile.com 1109 Nico Schwan 1110 Thales Deutschland 1112 Email: nico.schwan@thalesgroup.com