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Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 Internet Engineering Task Force F. Le Faucheur, Ed. 3 Internet-Draft Cisco Systems 4 Intended status: Standards Track G. Bertrand, Ed. 5 Expires: September 4, 2014 I. Oprescu, Ed. 6 Orange 7 R. Peterkofsky 8 Skytide, Inc. 9 March 3, 2014 11 CDNI Logging Interface 12 draft-ietf-cdni-logging-10 14 Abstract 16 This memo specifies the Logging interface between a downstream CDN 17 (dCDN) and an upstream CDN (uCDN) that are interconnected as per the 18 CDN Interconnection (CDNI) framework. First, it describes a 19 reference model for CDNI logging. Then, it specifies the CDNI 20 Logging File format and the actual protocol for exchange of CDNI 21 Logging Files. 23 Status of This Memo 25 This Internet-Draft is submitted in full conformance with the 26 provisions of BCP 78 and BCP 79. 28 Internet-Drafts are working documents of the Internet Engineering 29 Task Force (IETF). Note that other groups may also distribute 30 working documents as Internet-Drafts. The list of current Internet- 31 Drafts is at http://datatracker.ietf.org/drafts/current/. 33 Internet-Drafts are draft documents valid for a maximum of six months 34 and may be updated, replaced, or obsoleted by other documents at any 35 time. It is inappropriate to use Internet-Drafts as reference 36 material or to cite them other than as "work in progress." 38 This Internet-Draft will expire on September 4, 2014. 40 Copyright Notice 42 Copyright (c) 2014 IETF Trust and the persons identified as the 43 document authors. All rights reserved. 45 This document is subject to BCP 78 and the IETF Trust's Legal 46 Provisions Relating to IETF Documents 47 (http://trustee.ietf.org/license-info) in effect on the date of 48 publication of this document. Please review these documents 49 carefully, as they describe your rights and restrictions with respect 50 to this document. Code Components extracted from this document must 51 include Simplified BSD License text as described in Section 4.e of 52 the Trust Legal Provisions and are provided without warranty as 53 described in the Simplified BSD License. 55 Table of Contents 57 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3 58 1.1. Terminology . . . . . . . . . . . . . . . . . . . . . . . 3 59 1.2. Requirements Language . . . . . . . . . . . . . . . . . . 4 60 2. CDNI Logging Reference Model . . . . . . . . . . . . . . . . 5 61 2.1. CDNI Logging interactions . . . . . . . . . . . . . . . . 5 62 2.2. Overall Logging Chain . . . . . . . . . . . . . . . . . . 8 63 2.2.1. Logging Generation and During-Generation Aggregation 9 64 2.2.2. Logging Collection . . . . . . . . . . . . . . . . . 10 65 2.2.3. Logging Filtering . . . . . . . . . . . . . . . . . . 10 66 2.2.4. Logging Rectification and Post-Generation Aggregation 11 67 2.2.5. Log-Consuming Applications . . . . . . . . . . . . . 12 68 2.2.5.1. Maintenance/Debugging . . . . . . . . . . . . . . 12 69 2.2.5.2. Accounting . . . . . . . . . . . . . . . . . . . 12 70 2.2.5.3. Analytics and Reporting . . . . . . . . . . . . . 12 71 2.2.5.4. Security . . . . . . . . . . . . . . . . . . . . 13 72 2.2.5.5. Legal Logging Duties . . . . . . . . . . . . . . 13 73 2.2.5.6. Notions common to multiple Log Consuming 74 Applications . . . . . . . . . . . . . . . . . . 13 75 3. CDNI Logging File . . . . . . . . . . . . . . . . . . . . . . 15 76 3.1. Rules . . . . . . . . . . . . . . . . . . . . . . . . . . 15 77 3.2. CDNI Logging File Structure . . . . . . . . . . . . . . . 16 78 3.3. CDNI Logging File Directives . . . . . . . . . . . . . . 19 79 3.4. CDNI Logging Records . . . . . . . . . . . . . . . . . . 22 80 3.4.1. HTTP Request Logging Record . . . . . . . . . . . . . 23 81 3.5. CDNI Logging File Example . . . . . . . . . . . . . . . . 31 82 4. CDNI Logging File Exchange Protocol . . . . . . . . . . . . . 32 83 4.1. CDNI Logging Feed . . . . . . . . . . . . . . . . . . . . 33 84 4.1.1. Atom Formatting . . . . . . . . . . . . . . . . . . . 33 85 4.1.2. Updates to Log Files and the Feed . . . . . . . . . . 33 86 4.1.3. Redundant Feeds . . . . . . . . . . . . . . . . . . . 34 87 4.1.4. Example CDNI Logging Feed . . . . . . . . . . . . . . 34 88 4.2. CDNI Logging File Pull . . . . . . . . . . . . . . . . . 36 89 5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 37 90 5.1. CDNI Logging Directive Names Registry . . . . . . . . . . 37 91 5.2. CDNI Logging Record-Types Registry . . . . . . . . . . . 38 92 5.3. CDNI Logging Field Names Registry . . . . . . . . . . . . 39 93 5.4. CDNI Logging MIME Media Type . . . . . . . . . . . . . . 40 94 6. Security Considerations . . . . . . . . . . . . . . . . . . . 40 95 6.1. Authentication, Confidentiality, Integrity Protection . . 40 96 6.2. Denial of Service . . . . . . . . . . . . . . . . . . . . 41 97 6.3. Privacy . . . . . . . . . . . . . . . . . . . . . . . . . 41 98 7. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 42 99 8. References . . . . . . . . . . . . . . . . . . . . . . . . . 42 100 8.1. Normative References . . . . . . . . . . . . . . . . . . 42 101 8.2. Informative References . . . . . . . . . . . . . . . . . 43 102 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 44 104 1. Introduction 106 This memo specifies the CDNI Logging interface between a downstream 107 CDN (dCDN) and an upstream CDN (uCDN). First, it describes a 108 reference model for CDNI logging. Then, it specifies the CDNI 109 Logging File format and the actual protocol for exchange of CDNI 110 Logging Files. 112 The reader should be familiar with the following documents: 114 o CDNI problem statement [RFC6707] and framework 115 [I-D.ietf-cdni-framework] identify a Logging interface, 117 o Section 8 of [I-D.ietf-cdni-requirements] specifies a set of 118 requirements for Logging, 120 o [RFC6770] outlines real world use-cases for interconnecting CDNs. 121 These use cases require the exchange of Logging information 122 between the dCDN and the uCDN. 124 As stated in [RFC6707], "the CDNI Logging interface enables details 125 of logs or events to be exchanged between interconnected CDNs". 127 The present document describes: 129 o The CDNI Logging reference model (Section 2), 131 o The CDNI Logging File format (Section 3), 133 o The CDNI Logging File Exchange protocol (Section 4). 135 1.1. Terminology 137 In this document, the first letter of each CDNI-specific term is 138 capitalized. We adopt the terminology described in [RFC6707] and 139 [I-D.ietf-cdni-framework], and extend it with the additional terms 140 defined below. 142 Intra-CDN Logging information: logging information generated and 143 collected within a CDN. The format of the Intra-CDN Logging 144 information may be different to the format of the CDNI Logging 145 information. 147 CDNI Logging information: logging information exchanged across CDNs 148 using the CDNI Logging Interface. 150 Logging information: logging information generated and collected 151 within a CDN or obtained from another CDN using the CDNI Logging 152 Interface. 154 CDNI Logging Field: an atomic element of information that can be 155 included in a CDNI Logging Record. The time an event/task started, 156 the IP address of an End User to whom content was delivered, and the 157 URI of the content delivered are examples of CDNI Logging Fields. 159 CDNI Logging Record: an information record providing information 160 about a specific event. This comprises a collection of CDNI Logging 161 Fields. 163 CDNI Logging File: a file containing CDNI Logging Records, as well as 164 additional information facilitating the processing of the CDNI 165 Logging Records. 167 CDN Reporting: the process of providing the relevant information that 168 will be used to create a formatted content delivery report provided 169 to the CSP in deferred time. Such information typically includes 170 aggregated data that can cover a large period of time (e.g., from 171 hours to several months). Uses of Reporting include the collection 172 of charging data related to CDN services and the computation of Key 173 Performance Indicators (KPIs). 175 CDN Monitoring: the process of providing or displaying content 176 delivery information in a timely fashion with respect to the 177 corresponding deliveries. Monitoring typically includes visibility 178 of the deliveries in progress for service operation purposes. It 179 presents a view of the global health of the services as well as 180 information on usage and performance, for network services 181 supervision and operation management. In particular, monitoring data 182 can be used to generate alarms. 184 1.2. Requirements Language 186 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 187 "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this 188 document are to be interpreted as described in RFC 2119 [RFC2119]. 190 2. CDNI Logging Reference Model 192 2.1. CDNI Logging interactions 194 The CDNI logging reference model between a given uCDN and a given 195 dCDN involves the following interactions: 197 o customization by the uCDN of the CDNI Logging information to be 198 provided by the dCDN to the uCDN (e.g., control of which CDNI 199 Logging Fields are to be communicated to the uCDN for a given task 200 performed by the dCDN or control of which types of events are to 201 be logged). The dCDN takes into account this CDNI Logging 202 customization information to determine what Logging information to 203 provide to the uCDN, but it may, or may not, take into account 204 this CDNI Logging customization information to influence what CDN 205 logging information is to be generated and collected within the 206 dCDN (e.g., even if the uCDN requests a restricted subset of the 207 logging information, the dCDN may elect to generate a broader set 208 of logging information). The mechanism to support the 209 customization by the uCDN of CDNI Logging information is outside 210 the scope of this document and left for further study. Until such 211 a mechanism is available, the uCDN and dCDN are expected to agree 212 off-line on what exact set of CDNI Logging information is to be 213 provided by the dCDN to the uCDN, and to rely on management plane 214 actions to configure the CDNI Logging functions in the dCDN to 215 generate this information set and in the uCDN to expect this 216 information set. 218 o generation and collection by the dCDN of the intra-CDN Logging 219 information related to the completion of any task performed by the 220 dCDN on behalf of the uCDN (e.g., delivery of the content to an 221 End User) or related to events happening in the dCDN that are 222 relevant to the uCDN (e.g., failures or unavailability in dCDN). 223 This takes place within the dCDN and does not directly involve 224 CDNI interfaces. 226 o communication by the dCDN to the uCDN of the Logging information 227 collected by the dCDN relevant to the uCDN. This is supported by 228 the CDNI Logging interface and in the scope of the present 229 document. For example, the uCDN may use this Logging information 230 to charge the CSP, to perform analytics and monitoring for 231 operational reasons, to provide analytics and monitoring views on 232 its content delivery to the CSP or to perform trouble-shooting. 233 This document exclusively specifies non-real-time exchange of 234 Logging information. Closer to real-time exchange of Logging 235 information (say sub-minute or sub-second) is outside the scope of 236 the present document and left for further study. This document 237 exclusively specifies exchange of Logging information related to 238 content delivery. Exchange of Logging information related to 239 operational events (e.g., dCDN request routing function 240 unavailable, content acquisition failure by dCDN) for audit or 241 operational reactive adjustments by uCDN is outside the scope of 242 the present document and left for further study. 244 o customization by the dCDN of the CDNI Logging information to be 245 provided by the uCDN on behalf of the dCDN. The mechanism to 246 support the customization by the dCDN of CDNI Logging information 247 is outside the scope of this document and left for further study. 249 o generation and collection by the uCDN of Intra-CDN Logging 250 information related to the completion of any task performed by the 251 uCDN on behalf of the dCDN (e.g., serving of content by uCDN to 252 dCDN for acquisition purposes by dCDN) or related to events 253 happening in the uCDN that are relevant to the dCDN. This takes 254 place within the uCDN and does not directly involve CDNI 255 interfaces. 257 o communication by the uCDN to the dCDN of the Logging information 258 collected by the uCDN relevant to the dCDN. For example, the dCDN 259 might potentially benefit from this information for security 260 auditing or content acquisition troubleshooting. This is outside 261 the scope of this document and left for further study. 263 Figure 1 provides an example of CDNI Logging interactions (focusing 264 only on the interactions that are in the scope of this document) in a 265 particular scenario where four CDNs are involved in the delivery of 266 content from a given CSP: the uCDN has a CDNI interconnection with 267 dCDN-1 and dCDN-2. In turn, dCDN2 has a CDNI interconnection with 268 dCDN3. In this example, uCDN, dCDN-1, dCDN-2 and dCDN-3 all 269 participate in the delivery of content for the CSP. In this example, 270 the CDNI Logging interface enables the uCDN to obtain Logging 271 information from all the dCDNs involved in the delivery. In the 272 example, the uCDN uses the Logging information: 274 o to analyze the performance of the delivery performed by the dCDNs 275 and to adjust its operations after the fact (e.g., request 276 routing) as appropriate, 278 o to provide (non-real-time) reporting and monitoring information to 279 the CSP. 281 For instance, the uCDN merges Logging information, extracts relevant 282 KPIs, and presents a formatted report to the CSP, in addition to a 283 bill for the content delivered by uCDN itself or by its dCDNs on the 284 CSP's behalf. The uCDN may also provide Logging information as raw 285 log files to the CSP, so that the CSP can use its own logging 286 analysis tools. 288 +-----+ 289 | CSP | 290 +-----+ 291 ^ Reporting and monitoring data 292 * Billing 293 ,--*--. 294 Logging ,-' `-. 295 Data =>( uCDN )<= Logging 296 // `-. _,-' \\ Data 297 || `-'-'-' || 298 ,-----. ,-----. 299 ,-' `-. ,-' `-. 300 ( dCDN-1 ) ( dCDN-2 )<== Logging 301 `-. ,-' `-. _,-' \\ Data 302 `--'--' `--'-' || 303 ,-----. 304 ,' `-. 305 ( dCDN-3 ) 306 `. ,-' 307 `--'--' 309 ===> CDNI Logging Interface 310 ***> outside the scope of CDNI 312 Figure 1: Interactions in CDNI Logging Reference Model 314 A dCDN (e.g., dCDN-2) integrates the relevant Logging information 315 obtained from its dCDNs (i.e., dCDN-3) in the Logging information 316 that it provides to the uCDN, so that the uCDN ultimately obtains all 317 Logging information relevant to a CSP for which it acts as the 318 authoritative CDN. 320 Note that the format of Logging information that a CDN provides over 321 the CDNI interface might be different from the one that the CDN uses 322 internally. In this case, the CDN needs to reformat the Logging 323 information before it provides this information to the other CDN over 324 the CDNI Logging interface. Similarly, a CDN might reformat the 325 Logging information that it receives over the CDNI Logging interface 326 before injecting it into its log-consuming applications or before 327 providing some of this Logging information to the CSP. Such 328 reformatting operations introduce latency in the logging distribution 329 chain and introduce a processing burden. Therefore, there are 330 benefits in specifying CDNI Logging formats that are suitable for use 331 inside CDNs and also are close to the intra-CDN Logging formats 332 commonly used in CDNs today. 334 2.2. Overall Logging Chain 336 This section discusses the overall logging chain within and across 337 CDNs to clarify how CDN Logging information is expected to fit in 338 this overall chain. Figure 2 illustrates the overall logging chain 339 within the dCDN, across CDNs using the CDNI Logging interface and 340 within the uCDN. Note that the logging chain illustrated in the 341 Figure is obviously only an example and varies depending on the 342 specific environments. For example, there may be more or fewer 343 instantiations of each entity (e.g., there may be 4 Log consuming 344 applications in a given CDN). As another example, there may be one 345 instance of Rectification process per Log Consuming Application 346 instead of a shared one. 348 Log Consuming Log Consuming 349 App App 350 ^ ^ 351 | | 352 Rectification---------- 353 ^ 354 | 355 Filtering 356 ^ 357 | 358 Collection 359 ^ ^ 360 | | 361 | Generation 362 | 363 | uCDN 364 CDNI Logging ------------------------------------------------------- 365 exchange dCDN 366 ^ 367 | Log Consuming Log Consuming 368 | App App 369 | ^ ^ 370 | | | 371 Rectification Rectification--------- 372 ^ ^ 373 | | 374 Filtering 375 ^ 376 | 377 Collection 378 ^ ^ 379 | | 380 Generation Generation 382 Figure 2: CDNI Logging in the overall Logging Chain 384 The following subsections describe each of the processes potentially 385 involved in the logging chain of Figure 2. 387 2.2.1. Logging Generation and During-Generation Aggregation 389 CDNs typically generate Logging information for all significant task 390 completions, events, and failures. Logging information is typically 391 generated by many devices in the CDN including the surrogates, the 392 request routing system, and the control system. 394 The amount of Logging information generated can be huge. Therefore, 395 during contract negotiations, interconnected CDNs often agree on a 396 retention duration for Logging information, and/or potentially on a 397 maximum volume of Logging information that the dCDN must keep. If 398 this volume is exceeded, the dCDN is expected to alert the uCDN but 399 may not keep more Logging information for the considered time period. 400 In addition, CDNs may aggregate Logging information and transmit only 401 summaries for some categories of operations instead of the full 402 Logging information. Note that such aggregation leads to an 403 information loss, which may be problematic for some usages of the 404 Logging information (e.g., debugging). 406 [RFC6983] discusses logging for HTTP Adaptive Streaming (HAS). In 407 accordance with the recommendations articulated there, it is expected 408 that a surrogate will generate separate Logging information for 409 delivery of each chunk of HAS content. This ensures that separate 410 Logging information can then be provided to interconnected CDNs over 411 the CDNI Logging interface. Still in line with the recommendations 412 of [RFC6983], the Logging information for per-chunck delivery may 413 include some information (a Content Collection IDentifier and a 414 Session IDentifier) intended to facilitate subsequent post-generation 415 aggregation of per-chunk logs into per-session logs. Note that a CDN 416 may also elect to generate aggregate per-session logs when performing 417 HAS delivery, but this needs to be in addition to, and not instead 418 of, the per-chunk delivery logs. We note that aggregate per-session 419 logs for HAS delivery are for further study and outside the scope of 420 this document. 422 2.2.2. Logging Collection 424 This is the process that continuously collects Logging information 425 generated by the log-generating entities within a CDN. 427 In a CDNI environment, in addition to collecting Logging information 428 from log-generating entities within the local CDN, the Collection 429 process also collects Logging information provided by another CDN, or 430 other CDNs, through the CDNI Logging interface. This is illustrated 431 in Figure 2 where we see that the Collection process of the uCDN 432 collects Logging information from log-generating entities within the 433 uCDN as well as Logging information coming from the dCDNs through the 434 CDNI Logging interface. 436 2.2.3. Logging Filtering 438 A CDN may be required to only present different subsets of the whole 439 Logging information collected to various log-consuming applications. 440 This is achieved by the Filtering process. 442 In particular, the Filtering process can also filter the right subset 443 of Logging information that needs to be provided to a given 444 interconnected CDN. For example, the filtering process in the dCDN 445 can be used to ensure that only the Logging information related to 446 tasks performed on behalf of a given uCDN are made available to that 447 uCDN (thereby filtering out all the Logging information related to 448 deliveries by the dCDN of content for its own CSPs). Similarly, the 449 Filtering process may filter or partially mask some fields, for 450 example, to protect End Users' privacy when communicating CDNI 451 Logging information to another CDN. Filtering of Logging information 452 prior to communication of this information to other CDNs via the CDNI 453 Logging interface requires that the downstream CDN can recognize the 454 subset of Logging information that relate to each interconnected CDN. 456 The CDN will also filter some internal scope information such as 457 information related to its internal alarms (security, failures, load, 458 etc). 460 In some use cases described in [RFC6770], the interconnected CDNs do 461 not want to disclose details on their internal topology. The 462 filtering process can then also filter confidential data on the 463 dCDNs' topology (number of servers, location, etc.). In particular, 464 information about the requests served by each Surrogate may be 465 confidential. Therefore, the Logging information must be protected 466 so that data such as Surrogates' hostnames are not disclosed to the 467 uCDN. In the "Inter-Affiliates Interconnection" use case, this 468 information may be disclosed to the uCDN because both the dCDN and 469 the uCDN are operated by entities of the same group. 471 2.2.4. Logging Rectification and Post-Generation Aggregation 473 If Logging information is generated periodically, it is important 474 that the sessions that start in one Logging period and end in another 475 are correctly reported. If they are reported in the starting period, 476 then the Logging information of this period will be available only 477 after the end of the session, which delays the Logging information 478 generation. 480 A Logging rectification/update mechanism could be useful to reach a 481 good trade-off between the Logging information generation delay and 482 the Logging information accuracy. 484 In the presence of HAS, some log-consuming applications can benefit 485 from aggregate per-session logs. For example, for analytics, per- 486 session logs allow display of session-related trends which are much 487 more meaningful for some types of analysis than chunk-related trends. 488 In the case where aggregate logs have been generated directly by the 489 log-generating entities, those can be used by the applications. In 490 the case where aggregate logs have not been generated, the 491 Rectification process can be extended with a Post-Generation 492 Aggregation process that generates per-session logs from the per- 493 chunk logs, possibly leveraging the information included in the per- 494 chunk logs for that purpose (Content Collection IDentifier and a 495 Session IDentifier). However, in accordance with [RFC6983], this 496 document does not define exchange of such aggregate logs on the CDNI 497 Logging interface. We note that this is for further study and 498 outside the scope of this document.. 500 2.2.5. Log-Consuming Applications 502 2.2.5.1. Maintenance/Debugging 504 Logging information is useful to permit the detection (and limit the 505 risk) of content delivery failures. In particular, Logging 506 information facilitates the detection of configuration issues. 508 To detect faults, Logging information needs to report success and 509 failure of CDN delivery operations. The uCDN can summarize such 510 information into KPIs. For instance, Logging information needs to 511 allow the computation of the number of times, during a given time 512 period, that content delivery related to a specific service succeeds/ 513 fails. 515 Logging information enables the CDN providers to identify and 516 troubleshoot performance degradations. In particular, Logging 517 information enables tracking of traffic data (e.g., the amount of 518 traffic that has been forwarded by a dCDN on behalf of an uCDN over a 519 given period of time), which is particularly useful for CDN and 520 network planning operations. 522 2.2.5.2. Accounting 524 Logging information is essential for accounting, to permit inter-CDN 525 billing and CSP billing by uCDNs. For instance, Logging information 526 provided by dCDNs enables the uCDN to compute the total amount of 527 traffic delivered by every dCDN for a particular Content Provider, as 528 well as, the associated bandwidth usage (e.g., peak, 95th 529 percentile), and the maximum number of simultaneous sessions over a 530 given period of time. 532 2.2.5.3. Analytics and Reporting 534 The goal of analytics is to gather any relevant information to track 535 audience, analyze user behavior, and monitor the performance and 536 quality of content delivery. For instance, Logging information 537 enables the CDN providers to report on content consumption (e.g., 538 delivered sessions per content) in a specific geographic area. 540 The goal of reporting is to gather any relevant information to 541 monitor the performance and quality of content delivery and allow 542 detection of delivery issues. For instance, reporting could track 543 the average delivery throughput experienced by End Users in a given 544 region for a specific CSP or content set over a period of time. 546 2.2.5.4. Security 548 The goal of security is to prevent and monitor unauthorized access, 549 misuse, modification, and denial of access of a service. A set of 550 information is logged for security purposes. In particular, a record 551 of access to content is usually collected to permit the CSP to detect 552 infringements of content delivery policies and other abnormal End 553 User behaviors. 555 2.2.5.5. Legal Logging Duties 557 Depending on the country considered, the CDNs may have to retain 558 specific Logging information during a legal retention period, to 559 comply with judicial requisitions. 561 2.2.5.6. Notions common to multiple Log Consuming Applications 563 2.2.5.6.1. Logging Information Views 565 Within a given log-consuming application, different views may be 566 provided to different users depending on privacy, business, and 567 scalability constraints. 569 For example, an analytics tool run by the uCDN can provide one view 570 to an uCDN operator that exploits all the Logging information 571 available to the uCDN, while the tool may provide a different view to 572 each CSP exploiting only the Logging information related to the 573 content of the given CSP. 575 As another example, maintenance and debugging tools may provide 576 different views to different CDN operators, based on their 577 operational role. 579 2.2.5.6.2. Key Performance Indicators (KPIs) 581 This section presents, for explanatory purposes, a non-exhaustive 582 list of Key Performance Indicators (KPIs) that can be extracted/ 583 produced from logs. 585 Multiple log-consuming applications, such as analytics, monitoring, 586 and maintenance applications, often compute and track such KPIs. 588 In a CDNI environment, depending on the situation, these KPIs may be 589 computed by the uCDN or by the dCDN. But it is usually the uCDN that 590 computes KPIs, because the uCDN and dCDN may have different 591 definitions of the KPIs and the computation of some KPIs requires a 592 vision of all the deliveries performed by the uCDN and all its dCDNs. 594 Here is a list of important examples of KPIs: 596 o Number of delivery requests received from End Users in a given 597 region for each piece of content, during a given period of time 598 (e.g., hour/day/week/month) 600 o Percentage of delivery successes/failures among the aforementioned 601 requests 603 o Number of failures listed by failure type (e.g., HTTP error code) 604 for requests received from End Users in a given region and for 605 each piece of content, during a given period of time (e.g., hour/ 606 day/week/month) 608 o Number and cause of premature delivery termination for End Users 609 in a given region and for each piece of content, during a given 610 period of time (e.g., hour/day/week/month) 612 o Maximum and mean number of simultaneous sessions established by 613 End Users in a given region, for a given Content Provider, and 614 during a given period of time (e.g., hour/day/week/month) 616 o Volume of traffic delivered for sessions established by End Users 617 in a given region, for a given Content Provider, and during a 618 given period of time (e.g., hour/day/week/month) 620 o Maximum, mean, and minimum delivery throughput for sessions 621 established by End Users in a given region, for a given Content 622 Provider, and during a given period of time (e.g., hour/day/week/ 623 month) 625 o Cache-hit and byte-hit ratios for requests received from End Users 626 in a given region for each piece of content, during a given period 627 of time (e.g., hour/day/week/month) 629 o Top 10 most popularly requested contents (during a given day/week/ 630 month) 632 o Terminal type (mobile, PC, STB, if this information can be 633 acquired from the browser type header, for example). 635 Additional KPIs can be computed from other sources of information 636 than the Logging information, for instance, data collected by a 637 content portal or by specific client-side application programming 638 interfaces. Such KPIs are out of scope for the present document. 640 The KPIs used depend strongly on the considered log-consuming 641 application -- the CDN operator may be interested in different 642 metrics than the CSP is. In particular, CDN operators are often 643 interested in delivery and acquisition performance KPIs, information 644 related to Surrogates' performance, caching information to evaluate 645 the cache-hit ratio, information about the delivered file size to 646 compute the volume of content delivered during peak hour, etc. 648 Some of the KPIs, for instance those providing an instantaneous 649 vision of the active sessions for a given CSP's content, are useful 650 essentially if they are provided in a timely manner. By contrast, 651 some other KPIs, such as those averaged on a long period of time, can 652 be provided in non-real-time. 654 3. CDNI Logging File 656 3.1. Rules 658 This specification uses the Augmented Backus-Naur Form (ABNF) 659 notation and core rules of [RFC5234]. In particular, the present 660 document uses the following rules from [RFC5234]: 662 CR = %x0D ; carriage return 664 ALPHA = %x41-5A / %x61-7A ; A-Z / a-z 666 DIGIT = %x30-39 ; 0-9 668 DQUOTE = %x22 ; " (Double Quote) 670 CRLF = CR LF ; Internet standard newline 672 HEXDIG = DIGIT / "A" / "B" / "C" / "D" / "E" / "F" 674 HTAB = %x09 ; horizontal tab 676 LF = %x0A ; linefeed 678 OCTET = %x00-FF ; 8 bits of data 680 The present document also uses the following rules from [RFC3986]: 682 host = as specified in section 3.2.2 of [RFC3986]. 684 IPv4address = as specified in section 3.2.2 of [RFC3986]. 686 IPv6address = as specified in section 3.2.2 of [RFC3986]. 688 The present document also defines the following additional rules: 690 ADDRESS = IPv4address / IPv6address 692 ALPHANUM = ALPHA / DIGIT 694 DATE = 4DIGIT "-" 2DIGIT "-" 2DIGIT 696 Dates are recorded in the format YYYY-MM-DD where YYYY, MM and 697 DD stand for the numeric year, month and day respectively. All 698 dates are specified in Universal Time Coordinated (UTC). 700 DEC = 1*DIGIT ["." *DIGIT] 702 NAMEFORMAT = ALPHANUM *(ALPHANUM / "_" / "-") 704 QSTRING = DQUOTE *NDQUOTE DQUOTE ; where 706 NDQUOTE = / 2DQUOTE ; whereby a 707 DQUOTE is conveyed inside a QSTRING unambiguously by repeating 708 it. 710 NHTABSTRING = *NHTAB ; where 712 NHTAB = 714 TIME = 2DIGIT ":" 2DIGIT ":" 2DIGIT ["." *DIGIT] 716 Times are recorded in the form HH:MM:SS or HH:MM:SS.S where HH 717 is the hour in 24 hour format, MM is minutes and SS is seconds. 718 All times are specified in Universal Time Coordinated (UTC). 720 3.2. CDNI Logging File Structure 722 As defined in Section 1.1: a CDNI Logging Field is as an atomic 723 logging information element, a CDNI Logging Record is a collection of 724 CDNI Logging Fields containing all logging information corresponding 725 to a single logging event, and a CDNI Logging File contains a 726 collection of CDNI Logging Records. This structure is illustrated in 727 Figure 3. The use of a file structure for transfer of CDNI Logging 728 information is selected since this is the most common practise today 729 for exchange of logging information within and across CDNs. 731 +----------------------------------------------------------+ 732 |CDNI Logging File | 733 | | 734 | #Directive 1 | 735 | #Directive 2 | 736 | ... | 737 | #Directive P | 738 | | 739 | +------------------------------------------------------+ | 740 | |CDNI Logging Record 1 | | 741 | | +-------------+ +-------------+ +-------------+ | | 742 | | |CDNI Logging | |CDNI Logging | ... |CDNI Logging | | | 743 | | | Field 1 | | Field 2 | | Field N | | | 744 | | +-------------+ +-------------+ +-------------+ | | 745 | +------------------------------------------------------+ | 746 | | 747 | +------------------------------------------------------+ | 748 | |CDNI Logging Record 2 | | 749 | | +-------------+ +-------------+ +-------------+ | | 750 | | |CDNI Logging | |CDNI Logging | ... |CDNI Logging | | | 751 | | | Field 1 | | Field 2 | | Field N | | | 752 | | +-------------+ +-------------+ +-------------+ | | 753 | +------------------------------------------------------+ | 754 | | 755 | ... | 756 | | 757 | #Directive P+1 | 758 | | 759 | ... | 760 | | 761 | +------------------------------------------------------+ | 762 | |CDNI Logging Record M | | 763 | | +-------------+ +-------------+ +-------------+ | | 764 | | |CDNI Logging | |CDNI Logging | ... |CDNI Logging | | | 765 | | | Field 1 | | Field 2 | | Field N | | | 766 | | +-------------+ +-------------+ +-------------+ | | 767 | +------------------------------------------------------+ | 768 | | 769 | | 770 | #Directive P+Q | 771 +----------------------------------------------------------+ 773 Figure 3: Structure of Logging Files 775 The CDNI Logging File format is inspired from the W3C Extended Log 776 File Format [ELF]. However, it is fully specified by the present 777 document. Where the present document differs from the W3C Extended 778 Log File Format, an implementation of CDNI Logging MUST comply with 779 the present document. 781 Using a format that resembles the W3C Extended Log File Format is 782 intended to keep CDNI logging format close to the intra-CDN Logging 783 information format commonly used in CDNs today, thereby minimizing 784 systematic translation at CDN/CDNI boundary. 786 A CDNI Logging File MUST contain a sequence of lines containing US- 787 ASCII characters [CHAR_SET] terminated by CRLF. 789 Each line of a CDNI Logging File MUST contain either a directive or a 790 CDNI Logging Record. 792 Directives record information about the CDNI Logging process itself. 793 Lines containing directives MUST begin with the "#" character. 794 Directives are specified in Section 3.3. 796 Logging Records provide actual details of the logged event. Logging 797 Records are specified in Section 3.4. 799 The CDNI File structure is defined by the following rules: 801 DIRLINE = "#" directive CRLF 803 DIRGROUP = 1*DIRLINE 805 RECLINE = CRLF 807 RECGROUP = *RECLINE 809 = 1* 811 3.3. CDNI Logging File Directives 813 The CDNI Logging File directives are defined by the following rules: 815 directive = DIRNAME ":" HTAB DIRVAL 817 DIRNAME = 820 DIRVAL = 824 An implementation of the CDNI Logging interface MUST support all of 825 the following directives, listed below by their directive name: 827 o Version: 829 * format: "CDNI" "/" 1*DIGIT "." 1*DIGIT 831 * directive value: indicates the version of the CDNI Logging File 832 format. The value MUST be "CDNI/1.0" for the version specified 833 in the present document. 835 * occurrence: there MUST be one and only one instance of this 836 directive per CDNI Logging File. It MUST be the first line of 837 the CDNI Logging File. 839 o UUID: 841 * format: NHTABSTRING 843 * directive value: this a Universally Unique IDentifier (UUID) 844 from the UUID Uniform Resource Name (URN) namespace specified 845 in [RFC4122]) for the CDNI Logging File. 847 * occurrence: there MUST be one and only one instance of this 848 directive per CDNI Logging File. 850 o Claimed-Origin: 852 * format: host 854 * directive value: this contains the claimed identification of 855 the entity transmitting the CDNI Logging File (e.g., the host 856 in a dCDN supporting the CDNI Logging interface) or the entity 857 responsible for transmitting the CDNI Logging File (e.g., the 858 dCDN). 860 * occurrence: there MUST be zero or exactly one instance of this 861 directive per CDNI Logging File. This directive MAY be 862 included by the dCDN. It MUST NOT be included or modified by 863 the uCDN. 865 o Verified-Origin: 867 * format: host 869 * directive value: this contains the identification, as 870 established by the entity receiving the CDNI Logging File, of 871 the entity transmitting the CDNI Logging File (e.g., the host 872 in a dCDN supporting the CDNI Logging interface) or the entity 873 responsible for transmitting the CDNI Logging File (e.g., the 874 dCDN). 876 * occurrence: there MUST be zero or exactly one instance of this 877 directive per CDNI Logging File. This directive MAY be added 878 by the uCDN (e.g., before storing the CDNI Logging File). It 879 MUST NOT be included by the dCDN. The mechanisms used by the 880 uCDN to establish and validate the entity responsible for the 881 CDNI Logging File is outside the scope of the present document. 882 We observe that, in particular, this may be achieved through 883 authentication mechanisms that are part of the CDNI Logging 884 File pull mechanism (Section 4.2). 886 o Record-Type: 888 * format: NAMEFORMAT 890 * directive value: indicates the type of the CDNI Logging Records 891 that follow this directive, until another Record-Type directive 892 (or the end of the CDNI Logging File). This can be any CDNI 893 Logging Record type registered in the CDNI Logging Record-types 894 registry (Section 5.2). "cdni_http_request_v1" MUST be 895 indicated as the Record-Type directive value for CDNI Logging 896 records corresponding to HTTP requests (e.g., a HTTP delivery 897 request) as specified in Section 3.4.1. 899 * occurrence: there MUST be at least one instance of this 900 directive per CDNI Logging File. The first instance of this 901 directive MUST precede a Fields directive and MUST precede all 902 CDNI Logging Records. 904 o Fields: 906 * format: FIENAME * ; where FIENAME can take any 907 CDNI Logging field name registered in the CDNI Logging Field 908 Names registry (Section 5.3). 910 * directive value: this lists the names of all the fields for 911 which a value is to appear in the CDNI Logging Records that 912 follow the instance of this directive (until another instance 913 of this directive). The names of the fields, as well as their 914 occurrences, MUST comply with the corresponding rules specified 915 in the document referenced in the CDNI Logging Record-types 916 registry (Section 5.2) for the corresponding CDNI Logging 917 Record-Type. 919 * occurrence: there MUST be at least one instance of this 920 directive per Record-Type directive. The first instance of 921 this directive for a given Record-Type MUST appear before any 922 CDNI Logging Record for this Record-Type. 924 o Integrity-Hash: 926 * format: 32HEXDIG 928 * directive value: This directive permits the detection of a 929 corrupted CDNI Logging File. This can be useful, for instance, 930 if a problem occurs on the filesystem of the dCDN Logging 931 system and leads to a truncation of a logging file. The valid 932 Integrity-Hash value is included in this directive by the 933 entity that transmits the CDNI Logging File. It is computed by 934 applying the MD5 ([RFC1321]) cryptographic hash function on the 935 CDNI Logging File, including all the directives and logging 936 records, up to the Integrrity-Hash directive itself, excluding 937 the Integrity-Hash directive itself. The Integrity-Hash value 938 is represented as a US-ASCII encoded hexadecimal number, 32 939 digits long (representing a 128 bit hash value). The entity 940 receiving the CDNI Logging File also computes in a similar way 941 the MD5 hash on the received CDNI Logging File and compares 942 this hash to the value of the Integrity-Hash directive. If the 943 two values are equal, then the received CDNI Logging File MUST 944 be considered non-corrupted. Note that this is not a guarantee 945 that the file has not been tampered with by a third party. If 946 the two values are different, the received CDNI Logging File 947 MUST be considered corrupted. The behavior of the entity that 948 received a corrupted CDNI Logging File is outside the scope of 949 this specification; we note that the entity MAY attempt to pull 950 again the same CDNI Logging File from the transmitting entity. 951 If the entity receiving a non-corrupted CDNI Logging File adds 952 a Verified-Origin directive, it MUST then recompute and update 953 the Integrity-Hash directive so it also protects the added 954 Verified-Origin directive. 956 * occurrence: there MUST be zero or exactly one instance of this 957 directive. There SHOULD be exactly one instance of this 958 directive. One situation where that directive could be omitted 959 is where integrity protection is already provided via another 960 mechanism (for example if an integrity hash is associated to 961 the CDNI Logging File out of band through the CDNI Logging 962 Logging Feed Section 4.1 leveraging ATOM extensions such as 963 those proposed in [I-D.snell-atompub-link-extensions]. When 964 present, this field MUST be the last line of the CDNI Logging 965 File. 967 3.4. CDNI Logging Records 969 A CDNI Logging Record consists of a sequence of CDNI Logging Fields 970 relating to that single CDNI Logging Record. 972 CDNI Logging Fields MUST be separated by the "horizontal tabulation 973 (HTAB)" character. 975 To facilitate readability, a prefix scheme is used for CDNI Logging 976 field names in a similar way to the one used in W3C Extended Log File 977 Format [ELF]. The semantics of the prefix in the present document 978 is: 980 o c: refers to the User Agent that issues the request (corresponds 981 to the "client" of W3C Extended Log Format) 983 o d: refers to the dCDN (relative to a given CDN acting as a uCDN) 985 o s: refers to the dCDN Surrogate that serves the request 986 (corresponds to the "server" of W3C Extended Log Format) 988 o u: refers to the uCDN (relative to a given CDN acting as a dCDN) 990 o cs: refers to communication from the User Agent towards the dCDN 991 Surrogate 993 o sc: refers to communication from the dCDN Surrogate towards the 994 User Agent 996 An implementation of the CDNI Logging interface as per the present 997 specification MUST support the CDNI HTTP Delivery Records as 998 specified in Section 3.4.1. 1000 A CDNI Logging Record is defined by the following rules: 1002 FIEVAL = 1004 = FIEVAL * ; where FIEVAL 1005 contains the CDNI Logging field values corresponding to the CDNI 1006 Logging field names (FIENAME) listed is the last Fields directive 1007 predecing the present CDNI Logging Record. 1009 3.4.1. HTTP Request Logging Record 1011 The HTTP Request Logging Record is a CDNI Logging Record of Record- 1012 Type "cdni_http_request_v1". It contains the following CDNI Logging 1013 Fields, listed by their field name: 1015 o date: 1017 * format: DATE 1018 * field value: the date at which the processing of request 1019 completed on the Surrogate. 1021 * occurrence: there MUST be one and only one instance of this 1022 field. 1024 o time: 1026 * format: TIME 1028 * field value: the time at which the processing of request 1029 completed on the Surrogate. 1031 * occurrence: there MUST be one and only one instance of this 1032 field. 1034 o time-taken: 1036 * format: DEC 1038 * field value: decimal value of the duration, in seconds, between 1039 the start of the processing of the request and the completion 1040 of the request processing (e.g., completion of delivery) by the 1041 Surrogate. 1043 * occurrence: there MUST be one and only one instance of this 1044 field. 1046 o c-ip: 1048 * format: ADDRESS 1050 * field value: the source IPv4 or IPv6 address (i.e., the 1051 "client" address) in the request received by the Surrogate. 1053 * occurrence: there MUST be one and only one instance of this 1054 field. 1056 o c-ip-anonymizing: 1058 * format: 1*DIGIT 1060 * field value: the number of rightmost bits of the address in the 1061 c-ip field that are zeroed-out in order to anonymize the 1062 logging record. The mechanism by which the two ends of the 1063 CDNI Logging interface agree on whether anonymization is to be 1064 supported and the number of bits that need to be zeroed-out for 1065 this purpose are outside the scope of the present document. 1067 * occurrence: there MUST be zero or exactly one instance of this 1068 field. 1070 o c-port: 1072 * format: 1*DIGIT 1074 * field value: the source TCP port (i.e., the "client" port) in 1075 the request received by the Surrogate. 1077 * occurrence: there MUST be zero or exactly one instance of this 1078 field. 1080 o s-ip: 1082 * format: ADDRESS 1084 * field value: the IPv4 or IPv6 address of the Surrogate that 1085 served the request (i.e., the "server" address). 1087 * occurrence: there MUST be zero or exactly one instance of this 1088 field. 1090 o s-hostname: 1092 * format: host 1094 * field value: the hostname of the Surrogate that served the 1095 request (i.e., the "server" hostname). 1097 * occurrence: there MUST be zero or exactly one instance of this 1098 field. 1100 o s-port: 1102 * format: 1*DIGIT 1104 * field value: the destination TCP port (i.e., the "server" port) 1105 in the request received by the Surrogate. 1107 * occurrence: there MUST be zero or exactly one instance of this 1108 field. 1110 o cs-method: 1112 * format: NHTABSTRING 1113 * field value: this is the HTTP method of the HTTP request 1114 received by the Surrogate. 1116 * occurrence: There MUST be one and only one instance of this 1117 field. 1119 o cs-uri: 1121 * format: NHTABSTRING 1123 * field value: this is the complete URL of the request received 1124 by the Surrogate. It is exactly in the format of a http_URL 1125 specified in [RFC2616]) or, when the request was a HTTPS 1126 request ([RFC2818]), it is in the format of a http_URL but with 1127 the scheme part set to "https" instead of "http". 1129 * occurrence: there MUST be zero or exactly one instance of this 1130 field. 1132 o u-uri: 1134 * format: NHTABSTRING 1136 * field value: this is a complete URL, derived from the complete 1137 URI of the request received by the Surrogate (i.e., the cs-uri) 1138 but transformed by the entity generating or transmitting the 1139 CDNI Logging Record, in a way that is agreed upon between the 1140 two ends of the CDNI Logging interface, so the transformed URI 1141 is meaningful to the uCDN. For example, the two ends of the 1142 CDNI Logging interface could agree that the u-uri is 1143 constructed from the cs-uri by removing the part of the 1144 hostname that exposes which individual Surrogate actually 1145 performed the delivery. The details of modification performed 1146 to generate the u-uri, as well as the mechanism to agree on 1147 these modifications between the two sides of the CDNI Logging 1148 interface are outside the scope of the present document. 1150 * occurrence: there MUST be one and only one instance of this 1151 field. 1153 o protocol: 1155 * format: NHTABSTRING 1157 * field value: this is value of the HTTP-Version field as 1158 specified in [RFC2616] of the Request-Line of the request 1159 received by the Surrogate (e.g., "HTTP/1.1"). 1161 * occurrence: there MUST be one and only one instance of this 1162 field. 1164 o sc-status: 1166 * format: 3DIGIT 1168 * field value: this is the HTTP Status-Code in the HTTP response 1169 from the Surrogate. 1171 * occurrence: There MUST be one and only one instance of this 1172 field. 1174 o sc-total-bytes: 1176 * format: 1*DIGIT 1178 * field value: this is the total number of bytes of the HTTP 1179 response sent by the Surrogate in response to the request. 1180 This includes the bytes of the Status-Line, the bytes of the 1181 HTTP headers and the bytes of the message-body. 1183 * occurrence: There MUST be one and only one instance of this 1184 field. 1186 o sc-entity-bytes: 1188 * format: 1*DIGIT 1190 * field value: this is the number of bytes of the message-body in 1191 the HTTP response sent by the Surrogate in response to the 1192 request. This does not include the bytes of the Status-Line or 1193 the bytes of the HTTP headers. 1195 * occurrence: there MUST be zero or exactly one instance of this 1196 field. 1198 o cs(): 1200 * format: QSTRING 1202 * field value: the value of the HTTP header (identified by the 1203 in the CDNI Logging field name) as it 1204 appears in the request processed by the Surrogate, but 1205 prepended by a DQUOTE and appended by a DQUOTE. For example, 1206 when the CDNI Logging field name (FIENAME) listed in the 1207 preceding Fields directive is cs(User-Agent), this CDNI Logging 1208 field value contains the value of the User-Agent HTTP header as 1209 received by the Surrogate in the request it processed, but 1210 prepended by a DQUOTE and appended by a DQUOTE. If the HTTP 1211 header as it appeared in the request processed by the Surrogate 1212 contains one or more DQUOTE, each DQUOTE MUST be escaped by an 1213 additional DQUOTE. For example, if the HTTP header contains 1214 My_Header"value", then the field value of the cs() is "My_Header""value""". 1217 * occurrence: there MAY be zero, one or any number of instance of 1218 this field. 1220 o sc(): 1222 * format: QSTRING 1224 * field value: the value of the HTTP header (identified by the 1225 in the CDNI Logging field name) as it 1226 appears in the response issued by the Surrogate to serve the 1227 request, but prepended by a DQUOTE and appended by a DQUOTE. 1228 If the HTTP header as it appeared in the request processed by 1229 the Surrogate contains one or more DQUOTE, each DQUOTE MUST be 1230 escaped by an additional DQUOTE. For example, if the HTTP 1231 header contains My_Header"value", then the field value of the 1232 cs() is "My_Header""value""". 1234 * occurrence: there MAY be zero, one or any number of instances 1235 of this field. For a given , there MUST be 1236 zero or exactly one instance of this field. 1238 o s-ccid: 1240 * format: QSTRING 1242 * field value: this contains the value of the Content Collection 1243 IDentifier (CCID) associated by the uCDN to the content served 1244 by the Surrogate via the CDNI Metadata interface 1245 ([I-D.ietf-cdni-metadata]), prepended by a DQUOTE and appended 1246 by a DQUOTE. If the CCID conveyed in the CDNI Metadata 1247 interface contains one or more DQUOTE, each DQUOTE MUST be 1248 escaped by an additional DQUOTE. For example, if the CCID 1249 conveyed in the CDNI Metadata interface is My_CCIDD"value", 1250 then the field value of the s-ccid is "My_CCID""value""". 1252 * occurrence: there MUST be zero or exactly one instance of this 1253 field. For a given , there MUST be zero or 1254 exactly one instance of this field. 1256 o s-sid: 1258 * format: QSTRING 1260 * field value: this contains the value of a Session IDentifier 1261 (SID) generated by the dCDN for a specific HTTP session, 1262 prepended by a DQUOTE and appended by a DQUOTE. In particular, 1263 for HTTP Adaptive Streaming (HAS) session, the Session 1264 IDentifier value is included in the Logging record for every 1265 content chunk delivery of that session in view of facilitating 1266 the later correlation of all the per content chunk log records 1267 of a given HAS session. See section 3.4.2.2. of [RFC6983] for 1268 more discussion on the concept of Session IDentifier in the 1269 context of HAS. If the SID conveyed contains one or more 1270 DQUOTE, each DQUOTE MUST be escaped by an additional DQUOTE. 1271 For example, if the SID is My_SID"value", then the field value 1272 of the s-sid is "My_SID""value""". 1274 * occurrence: there MUST be zero or exactly one instance of this 1275 field. 1277 o s-cached: 1279 * format: 1DIGIT 1281 * field value: this characterises whether the Surrogate served 1282 the request using content already stored on its local cache or 1283 not. The allowed values are "0" (for miss) and "1" (for hit). 1284 "1" MUST be used when the Surrogate did serve the request using 1285 exclusively content already stored on its local cache. "0" MUST 1286 be used otherwise (including cases where the Surrogate served 1287 the request using some, but not all, content already stored on 1288 its local cache). Note that a "0" only means a cache miss in 1289 the Surrogate and does not provide any information on whether 1290 the content was already stored, or not, in another device of 1291 the dCDN, i.e., whether this was a "dCDN hit" or "dCDN miss". 1293 * occurrence: there MUST be zero or exactly one instance of this 1294 field. 1296 The "Fields" directive corresponding to a HTTP Request Logging Record 1297 MUST contain all the fields names whose occurrence is specified above 1298 as "There MUST be one and only one instance of this field". The 1299 corresponding fields value MUST be present in every HTTP Request 1300 Logging Record. 1302 The "Fields" directive corresponding to a HTTP Request Logging Record 1303 MAY list all the fields value whose occurrence is specified above as 1304 "there MUST be zero or exactly one instance of this field" or "there 1305 MAY be zero, one or any number of instances of this field". The set 1306 of such field names actually listed in the "Fields" directive is 1307 selected by the CDN generating the CDNI Logging File based on 1308 agreements between the interconnected CDNs established through 1309 mechanisms outside the scope of this specification (e.g., contractual 1310 agreements). When such a field name is not listed in the "Fields" 1311 directive, the corresponding field value MUST NOT be included in the 1312 Logging Record. When such a field name is listed in the "Fields" 1313 directive, the corresponding field value MUST be included in the 1314 Logging Record; if the value for the field is not available, this 1315 MUST be conveyed via a dash character ("-"). 1317 The fields names listed in the "Fields" directive MAY be listed in 1318 the order in which they are listed in Section 3.4.1 or MAY be listed 1319 in any other order. 1321 A dCDN-side implementation of the CDNI Logging interface MUST 1322 implement all the following Logging Fields in a CDNI Logging Record 1323 of Record-Type "cdni_http_request_v1", and MUST support the ability 1324 to include valid values for each of them: 1326 o date 1328 o time 1330 o time-taken 1332 o c-ip 1334 o c-port 1336 o s-ip 1338 o s-hostname 1340 o s-port 1342 o cs-method 1344 o cs-uri 1346 o u-uri 1348 o protocol 1350 o sc-status 1352 o sc-total-bytes 1353 o sc-entity-bytes 1355 o cs() 1357 o sc() 1359 o s-cached 1361 A dCDN-side implementation of the CDNI Logging interface MAY support 1362 the following Logging Fields in a CDNI Logging Record of Record-Type 1363 "cdni_http_request_v1": 1365 o c-ip-anonymizing 1367 o s-ccid 1369 o s-sid 1371 If a dCDN-side implementation of the CDNI Logging interface supports 1372 these Fields, it MUST support the ability to include valid values for 1373 them. 1375 An uCDN-side implementation of the CDNI Logging interface MUST be 1376 able to accept CDNI Logging Files with CDNI Logging Records of 1377 Record-Type "cdni_http_request_v1" containing any CDNI Logging Field 1378 defined in Section 3.4.1 as long as the CDNI Logging Record and the 1379 CDNI Logging File are compliant with the present document. 1381 3.5. CDNI Logging File Example 1383 #Version:CDNI/1.0 1385 #UUID:urn:uuid:f81d4fae-7dec-11d0-a765-00a0c91e6bf6 1387 #Claimed-Origin:cdni-logging-entity.dcdn.example.com 1389 #Record-Type:cdni_http_request_v1 1391 #Fields:datetimetime-takenc-ipcs- 1392 methodu-uriprotocolsc-statussc-total- 1393 bytescs(User-Agent)cs(Referer)s-cached 1395 2013-05-1700:38:06.8259.05810.5.7.1GETh 1396 ttp://cdni-ucdn.dcdn.example.com/video/movie100.mp4HTTP/ 1397 1.12006729891"Mozilla/5.0 (Windows; U; Windows NT 1398 6.0; en-US) AppleWebKit/533.4 (KHTML, like Gecko) Chrome/5.0.375.127 1399 Safari /533.4""host1.example.com"1 1400 2013-05-1700:39:09.14515.3210.5.10.5GET 1401 http://cdni-ucdn.dcdn.example.com/video/movie118.mp4HTTP/ 1402 1.120015799210"Mozilla/5.0 (Windows; U; Windows NT 1403 6.0; en-US) AppleWebKit/533.4 (KHTML, like Gecko) Chrome/5.0.375.127 1404 Safari /533.4""host1.example.com"1 1406 2013-05-1700:42:53.43752.87910.5.10.5GEThttp://cdni-ucdn.dcdn.example.com/video/picture11.mp4HTTP/ 1408 1.020097234724"Mozilla/5.0 (Windows; U; Windows NT 1409 6.0; en-US) AppleWebKit/533.4 (KHTML, like Gecko) Chrome/5.0.375.127 1410 Safari /533.4""host5.example.com"0 1412 #Integrity-Hash:fe113dfce8fec91323a4fc02261af26e 1414 4. CDNI Logging File Exchange Protocol 1416 This document specifies a protocol for the exchange of CDNI Logging 1417 Files as specified in Section 3. 1419 This protocol comprises: 1421 o a CDNI Logging feed, allowing the dCDN to notify the uCDN about 1422 the CDNI Logging Files that can be retrieved by that uCDN from the 1423 dCDN, as well as all the information necessary for retrieving each 1424 of these CDNI Logging Files. The CDNI Logging feed is specified 1425 in Section 4.1. 1427 o a CDNI Logging File pull mechanism, allowing the uCDN to obtain 1428 from the dCDN a given CDNI Logging File at the uCDN's convenience. 1429 The CDNI Logging File pull mechanisms is specified in Section 4.2. 1431 An implementation of the CDNI Logging interface on the dCDN side (the 1432 entity generating the CDNI Logging file) MUST support the server side 1433 of the CDNI Logging feed and the server side of the CDNI Logging pull 1434 mechanism. 1436 An implementation of the CDNI Logging interface on the uCDN side (the 1437 entity consuming the CDNI Logging file) MUST support the client side 1438 of the CDNI Logging feed and the client side of the CDNI Logging pull 1439 mechanism. 1441 We note that implementations of the CDNI Logging interface MAY also 1442 support other mechanisms to exchange CDNI Logging Files, for example 1443 in view of exchanging logging information with minimum time-lag 1444 (e.g., sub-minute or sub-second) between when the event occurred in 1445 the dCDN and when the corresponding Logging Record is made available 1446 to the uCDN (e.g., for log-consuming applications requiring extremely 1447 fresh logging information such as near-real-time content delivery 1448 monitoring). Such mechanisms are for further study and outside the 1449 scope of this document. 1451 4.1. CDNI Logging Feed 1453 The server-side implementation of the CDNI Logging feed MUST produce 1454 an Atom feed [RFC4287]. This feed is used to advertise log files 1455 that are available for the client-side to retrieve using the CDNI 1456 Logging pull mechanism. 1458 4.1.1. Atom Formatting 1460 A CDNI Logging feed MUST be structured as an Archived feed, as 1461 defined in [RFC5005], and MUST be formatted in Atom [RFC4287]. This 1462 means it consists of a subscription document that is regularly 1463 updated as new CDNI Logging Files become available, and information 1464 about older CDNI Logging files is moved into archive documents. Once 1465 created, archive documents are never modified. 1467 Each CDNI Logging File listed in an Atom feed MUST be described in an 1468 atom:entry container element. 1470 The atom:entry MUST contain an atom:content element whose "src" 1471 attribute is a link to the CDNI Logging File and whose "type" 1472 attribute is the MIME Media Type indicating that the entry is a CDNI 1473 Logging File. We define this MIME Media Type as "application/ 1474 cdni.LoggingFile" (See Section 5.4). 1476 For compatibility with some Atom feed readers the atom:entry MAY also 1477 contain an atom:link entry whose "href" attribute is a link to the 1478 CDNI Logging File and whose "type" attribute is the MIME Media Type 1479 indicating that the entry is a CDNI Logging File using the 1480 "application/cdni.LoggingFile" MIME Media Type (See Section 5.4). 1482 The URI used in the atom:id of the atom:entry MUST contain the UUID 1483 of the CDNI Logging File. 1485 The atom:updated in the atom:entry MUST indicate the time at which 1486 the CDNI Logging File was last updated. 1488 4.1.2. Updates to Log Files and the Feed 1490 CDNI Logging Files MUST NOT be modified by the dCDN once published in 1491 the CDNI Logging feed. 1493 The frequency with which the subscription feed is updated, the period 1494 of time covered by each CDNI Logging File or each archive document, 1495 and timeliness of publishing of CDNI Logging Files are outside the 1496 scope of the present document and are expected to be agreed upon by 1497 uCDN and dCDN via other means (e.g., human agreement). 1499 The server-side implementation SHOULD use HTTP cache control headers 1500 on the subscription feed to indicate the frequency at which the 1501 client-side is to poll for updates. 1503 The potential retention limits (e.g., sliding time window) within 1504 which the dCDN is to retain and be ready to serve an archive document 1505 is outside the scope of the present document and is expected to be 1506 agreed upon by uCDN and dCDN via other means (e.g., human agreement). 1507 The server-side implementation MUST retain, and be ready to serve, 1508 any archive document within the agreed retention limits. Outside 1509 these agreed limits, the server-side implementation MAY indicate its 1510 inability to serve (e.g., with HTTP status code 404) an archive 1511 document or MAY refuse to serve it (e.g., with HTTP status code 403 1512 or 410). 1514 4.1.3. Redundant Feeds 1516 The server-side implementation MAY present more than one CDNI Logging 1517 feed and for redundancy. CDNI Logging Files MAY be published in more 1518 than one feed. 1520 A client-side implementation MAY support such redundant CDNI Logging 1521 feeds. If it supports redundant CDNI Logging feed, the client-side 1522 SHOULD use the UUID of the CDNI Logging File, presented in the 1523 atom:id element of the Atom feed, to avoid unnecessarily pulling and 1524 storing each CDNI Logging File more than once. 1526 4.1.4. Example CDNI Logging Feed 1528 Figure 4 illustrates an example of the subscription document of a 1529 CDNI Logging feed. 1531 1532 > 1534 CDNI Logging Feed 1535 2013-03-23T14:46:11Z 1536 urn:uuid:663ae677-40fb-e99a-049d-c5642916b8ce 1537 1539 1541 1543 CDNI Log Feed 1544 Generator 1545 dcdn.example 1546 1547 CDNI Logging File for uCDN at 1548 2013-03-23 14:15:00 1549 urn:uuid:12345678-1234-abcd-00aa-01234567abcd 1550 2013-03-23T14:15:00Z 1551 1554 CDNI Logging File for uCDN at 1555 2013-03-23 14:15:00 1556 1557 1558 CDNI Logging File for uCDN at 1559 2013-03-23 14:30:00 1560 urn:uuid:87654321-4321-dcba-aa00-dcba7654321 1561 2013-03-23T14:30:00Z 1562 1565 CDNI Logging File for uCDN at 1566 2013-03-23 14:30:00 1567 1568 ... 1569 1570 ... 1571 1572 1574 Figure 4: Example subscription document of a CDNI Logging Feed 1576 4.2. CDNI Logging File Pull 1578 A client-side implementation of the CDNI Logging interface MAY pull, 1579 at its convenience, a CDNI Logging File that is published by the 1580 server-side in the CDNI Logging Feed (in the subscription document or 1581 an archive document). To do so, the client-side: 1583 o MUST use HTTP v1.1 [RFC2616]; 1585 o SHOULD use TLS (i.e., use what is loosely referred to as "HTTPS") 1586 as per [RFC2818] whenever protection of the CDNI Logging 1587 information is required (see Section 6.1); 1589 o MUST use the URI that was associated to the CDNI Logging File 1590 (within the "src" attribute of the corresponding atom:content 1591 element) in the CDNI Logging Feed; 1593 o MUST support exchange of CDNI Logging Files with no content 1594 encoding applied to the representation; 1596 o SHOULD support exchange of CDNI Logging Files with "gzip" content 1597 encoding (as defined in [RFC2616]) applied to the representation. 1599 Note that a client-side implementation of the CDNI Logging interface 1600 MAY pull a CDNI Logging File that it has already pulled. 1602 The server-side implementation MUST respond to valid pull request by 1603 a client-side implementation for a CDNI Logging File published by the 1604 server-side in the CDNI Logging Feed (in the subscription document or 1605 an archive document). The server-side implementation: 1607 o MUST handle the client-side request as per HTTP v1.1; 1609 o MUST include the CDNI Logging File identified by the request URI 1610 inside the body of the HTTP response; 1612 o MUST support exchange of CDNI Logging Files with no content 1613 encoding applied to the representation; 1615 o SHOULD support exchange of CDNI Logging Files with "gzip" content 1616 encoding (as defined in [RFC2616]) applied to the representation. 1618 Content negotiation approaches defined in [RFC2616] (e.g., using 1619 Accept-Encoding request-header field or Content-Encoding entity- 1620 header field) MAY be used by the client-side and server-side 1621 implementations to establish the content-coding to be used for a 1622 particular exchange of a CDNI Logging File. 1624 Applying compression content encoding (such as "gzip") is expected to 1625 mitigate the impact of exchanging the large volumes of logging 1626 information expected across CDNs. This is expected to be 1627 particularly useful in the presence of HTTP Adaptive Streaming (HAS) 1628 which, as per the present version of the document, will result in a 1629 separate CDNI Log Record for each HAS segment delivery in the CDNI 1630 Logging File. 1632 The potential retention limits (e.g., sliding time window, maximum 1633 aggregate file storage quotas) within which the dCDN is to retain and 1634 be ready to serve a CDNI Logging File previously advertised in the 1635 CDNI Logging Feed is outside the scope of the present document and is 1636 expected to be agreed upon by uCDN and dCDN via other means (e.g., 1637 human agreement). The server-side implementation MUST retain, and be 1638 ready to serve, any CDNI Logging File within the agreed retention 1639 limits. Outside these agreed limits, the server-side implementation 1640 MAY indicate its inability to serve (e.g., with HTTP status code 404) 1641 a CDNI Logging File or MAY refuse to serve it (e.g., with HTTP status 1642 code 403 or 410). 1644 5. IANA Considerations 1646 5.1. CDNI Logging Directive Names Registry 1648 The IANA is requested to create a new registry, CDNI Logging 1649 Directive Names. 1651 The initial contents of the CDNI Logging File Directives registry 1652 comprise the names of the directives specified in Section 3.3 of the 1653 present document, and are as follows: 1655 +------------------------------+-----------+ 1656 | Directive Name + Reference | 1657 +------------------------------+-----------+ 1658 | Version + RFC xxxx | 1659 | UUID + RFC xxxx | 1660 | Claimed-Origin + RFC xxxx | 1661 | Verified-Origin + RFC xxxx | 1662 | Record-Type + RFC xxxx | 1663 | Fields + RFC xxxx | 1664 | Integrity-Hash + RFC xxxx | 1665 +------------------------------+-----------+ 1667 Figure 5 1669 [Instructions to IANA: Replace "RFC xxxx" above by the RFC number of 1670 the present document] 1671 Within the registry, names are to be allocated by IANA according to 1672 the "Specification Required" policy specified in [RFC5226]. 1673 Directive names are to be allocated by IANA with a format of 1674 NAMEFORMAT (see Section 3.1). 1676 Each specification that defines a new CDNI Logging directive needs to 1677 contain a description for the new directive with the same set of 1678 information as provided in Section 3.3 (i.e., format, directive value 1679 and occurrence). 1681 5.2. CDNI Logging Record-Types Registry 1683 The IANA is requested to create a new registry, CDNI Logging Record- 1684 Types. 1686 The initial contents of the CDNI Logging Record-Types registry 1687 comprise the names of the CDNI Logging Record types specified in 1688 Section 3.4 of the present document, and are as follows: 1690 +------------------------------+-----------+ 1691 | Record-Types + Reference | 1692 +------------------------------+-----------+ 1693 | cdni_http_request_v1 + RFC xxxx | 1694 +------------------------------+-----------+ 1696 Figure 6 1698 [Instructions to IANA: Replace "RFC xxxx" above by the RFC number of 1699 the present document] 1701 Within the registry, Record-Types are to be allocated by IANA 1702 according to the "Specification Required" policy specified in 1703 [RFC5226]. Record-Types are to be allocated by IANA with a format of 1704 NAMEFORMAT (see Section 3.1). 1706 Each specification that defines a new Record-Type needs to contain a 1707 description for the new Record-Type with the same set of information 1708 as provided in Section 3.4.1. This includes: 1710 o a list of all the CDNI Logging Fields that can appear in a CDNI 1711 Logging Record of the new Record-Type 1713 o for all these Fields: a specification of the occurrence for each 1714 Field in the new Record-Type 1716 o for every newly defined Field, i.e., for every Field that results 1717 in a registration in the CDNI Logging Field Names Registry 1718 (Section 5.3): a specification of the field name, format and field 1719 value. 1721 5.3. CDNI Logging Field Names Registry 1723 The IANA is requested to create a new registry, CDNI Logging Field 1724 Names. 1726 The initial contents of the CDNI Logging Fields Names registry 1727 comprise the names of the CDNI Logging fields specified in 1728 Section 3.4 of the present document, and are as follows: 1730 +---------------------------------------------+-----------+ 1731 | Field Name + Reference | 1732 +---------------------------------------------+-----------+ 1733 | date + RFC xxxx | 1734 | time + RFC xxxx | 1735 | time-taken + RFC xxxx | 1736 | c-ip + RFC xxxx | 1737 | c-ip-anonymizing + RFC xxxx | 1738 | c-port + RFC xxxx | 1739 | s-ip + RFC xxxx | 1740 | s-hostname + RFC xxxx | 1741 | s-port + RFC xxxx | 1742 | cs-method + RFC xxxx | 1743 | cs-uri + RFC xxxx | 1744 | u-uri + RFC xxxx | 1745 | protocol + RFC xxxx | 1746 | sc-status + RFC xxxx | 1747 | sc-total-bytes + RFC xxxx | 1748 | sc-entity-bytes + RFC xxxx | 1749 | cs() + RFC xxxx | 1750 | sc() + RFC xxxx | 1751 | s-ccid + RFC xxxx | 1752 | s-sid + RFC xxxx | 1753 | s-cached + RFC xxxx | 1754 +---------------------------------------------+-----------+ 1756 Figure 7 1758 [Instructions to IANA: Replace "RFC xxxx" above by the RFC number of 1759 the present document] 1761 Within the registry, names are to be allocated by IANA according to 1762 the "Specification Required" policy specified in [RFC5226]. Field 1763 names are to be allocated by IANA with a format of NHTABSTRING (see 1764 Section 3.1). 1766 The above registry is intended to be shared across the currently 1767 defined Record-Type (i.e., cdni_http_request_v1) as well as potential 1768 other CDNI Logging Record-Types that may be defined in separate 1769 specifications. When a Field from this registry is used by another 1770 CDNI Logging Record-Type, it is to be used with the exact semantics 1771 and format specified in the document that registered this field and 1772 that is identified in the Reference column of the registry. If 1773 another CDNI Logging Record-Type requires a Field with semantics that 1774 are not strictly identical, or a format that is not strictly 1775 identical then this new Field is to be registered in the registry 1776 with a different Field name. When a Field from this registry is used 1777 by another CDNI Logging Record-Type, it can be used with different 1778 occurence rules. 1780 5.4. CDNI Logging MIME Media Type 1782 The IANA is requested to allocate the "application/cdni.LoggingFile" 1783 MIME Media Type (whose use is specified in Section 4.1.1 of the 1784 present document) in the MIME Media Types registry. 1786 6. Security Considerations 1788 6.1. Authentication, Confidentiality, Integrity Protection 1790 The use of TLS as per [RFC2818] for transport of the CDNI Logging 1791 feed mechanism (Section 4.1) and CDNI Logging File pull mechanism 1792 (Section 4.2) allows: 1794 o the dCDN and uCDN to authenticate each other (to ensure they are 1795 transmitting/receiving CDNI Logging File from an authenticated 1796 CDN) 1798 o the CDNI Logging information to be transmitted with 1799 confidentiality 1801 o the integrity of the CDNI Logging information to be protected 1802 during the exchange 1804 In an environment where any such protection is required, TLS SHOULD 1805 be used for transport of the CDNI Logging feed and the CDNI Logging 1806 File pull. Both parties of the transaction (uCDN and dCDN) SHOULD 1807 use mutual authentication. 1809 A CDNI Logging implementation MUST support TLS transport of the CDNI 1810 Logging feed and the CDNI Logging File pull. 1812 Alternate methods MAY be used for ensuring the confidentiality of the 1813 information in the logging files such as setting up an IPsec tunnel 1814 between the two CDNs or using a physically secured internal network 1815 between two CDNs that are owned by the same corporate entity. 1817 The Integrity-Hash directive inside the CDNI Logging File provides 1818 additional integrity protection, this time targeting potential 1819 corruption of the CDNI logging information during the CDNI Logging 1820 File generation. This mechanism does not allow restoration of the 1821 corrupted CDNI Logging information, but it allows detection of such 1822 corruption and therefore triggering of appropriate correcting actions 1823 (e.g., discard of corrupted information, attempt to re-obtain the 1824 CDNI Logging information). 1826 6.2. Denial of Service 1828 This document does not define specific mechanism to protect against 1829 Denial of Service (DoS) attacks on the Logging Interface. However, 1830 the CDNI Logging feed and CDNI Logging pull endpoints can be 1831 protected against DoS attacks through the use of TLS transport and/or 1832 via mechanisms outside the scope of the CDNI Logging interface such 1833 as firewalling or use of Virtual Private Networks (VPNs). 1835 Protection of dCDN Surrogates against spoofed delivery requests is 1836 outside the scope of the CDNI Logging interface. 1838 6.3. Privacy 1840 CDNs have the opportunity to collect detailed information about the 1841 downloads performed by End Users. The provision of this information 1842 to another CDN introduces potential End Users privacy protection 1843 concerns. We observe that when CDNI interconnection is realised as 1844 per [I-D.ietf-cdni-framework], the uCDN handles the initial End User 1845 requests (before it is redirected to the dCDN) so, regardless of 1846 which information is, or is not, communicated to the uCDN through the 1847 CDNI Logging interface, the uCDN has visibility on significant 1848 information such as the IP address of the End User request and the 1849 URL of the request. 1851 Nonetheless, if the dCDN and uCDN agree that anonymization is 1852 required to avoid making some detailed information available to the 1853 uCDN (such as how many bytes of the content have been watched by an 1854 End User and/or at what time) or is required to meet some legal 1855 obligations, then the uCDN and dCDN can agree to exchange anonymized 1856 End Users IP address in CDNI Logging Files and the c-ip-anonymization 1857 field can be used to convey the number of bits that have been 1858 anonymized so that the meaningful information can still be easily 1859 extracted from the anonymized addressses (e.g., for geolocation aware 1860 analytics). 1862 We note that anonymization of End Users IP address does not fully 1863 protect against deriving potentially sensitive information about 1864 traffic patterns; in general, increasing the number of bits that are 1865 anonymized can mitigate the risks of deriving such sensitive traffic 1866 pattern information. 1868 We also note that independently of IP addresses, the query string 1869 portion of the URL that may be conveyed inside the cs-uri and u-uri 1870 fields of CDNI Logging Files, or the HTTP cookies( [RFC6265]) that 1871 may be conveyed inside the cs() field of CDNI 1872 Logging Fields, may contain personnal information or information that 1873 can be exploited to derive personal information. Where this is a 1874 concern, the CDNI Logging interface specification allows the dCDN to 1875 not include the cs-uri and to include a u-uri that removes (or hides) 1876 the sensitive part of the query string and allows the dCDN to not 1877 include the cs() fields corresponding to HTTP 1878 headers associated with cookies. 1880 7. Acknowledgments 1882 This document borrows from the W3C Extended Log Format [ELF]. 1884 Rob Murray significantly contributed into the text of Section 4.1. 1886 The authors thank Ben Niven-Jenkins, Kevin Ma, David Mandelberg and 1887 Ray van Brandenburg for their ongoing input. 1889 Finally, we also thank Sebastien Cubaud, Pawel Grochocki, Christian 1890 Jacquenet, Yannick Le Louedec, Anne Marrec , Emile Stephan, Fabio 1891 Costa, Sara Oueslati, Yvan Massot, Renaud Edel, Joel Favier and the 1892 contributors of the EU FP7 OCEAN project for their input in the early 1893 versions of this document. 1895 8. References 1897 8.1. Normative References 1899 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 1900 Requirement Levels", BCP 14, RFC 2119, March 1997. 1902 [RFC2616] Fielding, R., Gettys, J., Mogul, J., Frystyk, H., 1903 Masinter, L., Leach, P., and T. Berners-Lee, "Hypertext 1904 Transfer Protocol -- HTTP/1.1", RFC 2616, June 1999. 1906 [RFC3986] Berners-Lee, T., Fielding, R., and L. Masinter, "Uniform 1907 Resource Identifier (URI): Generic Syntax", STD 66, RFC 1908 3986, January 2005. 1910 [RFC4122] Leach, P., Mealling, M., and R. Salz, "A Universally 1911 Unique IDentifier (UUID) URN Namespace", RFC 4122, July 1912 2005. 1914 [RFC4287] Nottingham, M., Ed. and R. Sayre, Ed., "The Atom 1915 Syndication Format", RFC 4287, December 2005. 1917 [RFC5005] Nottingham, M., "Feed Paging and Archiving", RFC 5005, 1918 September 2007. 1920 [RFC5226] Narten, T. and H. Alvestrand, "Guidelines for Writing an 1921 IANA Considerations Section in RFCs", BCP 26, RFC 5226, 1922 May 2008. 1924 [RFC5234] Crocker, D. and P. Overell, "Augmented BNF for Syntax 1925 Specifications: ABNF", STD 68, RFC 5234, January 2008. 1927 8.2. Informative References 1929 [CHAR_SET] 1930 "IANA Character Sets registry", . 1933 [ELF] Phillip M. Hallam-Baker, and Brian Behlendorf, "Extended 1934 Log File Format, W3C (work in progress), WD- 1935 logfile-960323", . 1937 [I-D.ietf-cdni-framework] 1938 Peterson, L., Davie, B., and R. Brandenburg, "Framework 1939 for CDN Interconnection", draft-ietf-cdni-framework-10 1940 (work in progress), March 2014. 1942 [I-D.ietf-cdni-metadata] 1943 Niven-Jenkins, B., Murray, R., Watson, G., Caulfield, M., 1944 Leung, K., and K. Ma, "CDN Interconnect Metadata", draft- 1945 ietf-cdni-metadata-06 (work in progress), February 2014. 1947 [I-D.ietf-cdni-requirements] 1948 Leung, K. and Y. Lee, "Content Distribution Network 1949 Interconnection (CDNI) Requirements", draft-ietf-cdni- 1950 requirements-17 (work in progress), January 2014. 1952 [I-D.snell-atompub-link-extensions] 1953 Snell, J., "Atom Link Extensions", draft-snell-atompub- 1954 link-extensions-09 (work in progress), June 2012. 1956 [RFC1321] Rivest, R., "The MD5 Message-Digest Algorithm", RFC 1321, 1957 April 1992. 1959 [RFC2818] Rescorla, E., "HTTP Over TLS", RFC 2818, May 2000. 1961 [RFC6265] Barth, A., "HTTP State Management Mechanism", RFC 6265, 1962 April 2011. 1964 [RFC6707] Niven-Jenkins, B., Le Faucheur, F., and N. Bitar, "Content 1965 Distribution Network Interconnection (CDNI) Problem 1966 Statement", RFC 6707, September 2012. 1968 [RFC6770] Bertrand, G., Stephan, E., Burbridge, T., Eardley, P., Ma, 1969 K., and G. Watson, "Use Cases for Content Delivery Network 1970 Interconnection", RFC 6770, November 2012. 1972 [RFC6983] van Brandenburg, R., van Deventer, O., Le Faucheur, F., 1973 and K. Leung, "Models for HTTP-Adaptive-Streaming-Aware 1974 Content Distribution Network Interconnection (CDNI)", RFC 1975 6983, July 2013. 1977 Authors' Addresses 1979 Francois Le Faucheur (editor) 1980 Cisco Systems 1981 E.Space Park - Batiment D 1982 6254 Allee des Ormes - BP 1200 1983 Mougins cedex 06254 1984 FR 1986 Phone: +33 4 97 23 26 19 1987 Email: flefauch@cisco.com 1989 Gilles Bertrand (editor) 1990 Orange 1991 38-40 rue du General Leclerc 1992 Issy les Moulineaux 92130 1993 FR 1995 Phone: +33 1 45 29 89 46 1996 Email: gilles.bertrand@orange.com 1997 Iuniana Oprescu (editor) 1998 Orange 1999 38-40 rue du General Leclerc 2000 Issy les Moulineaux 92130 2001 FR 2003 Phone: +33 6 89 06 92 72 2004 Email: iuniana.oprescu@orange.com 2006 Roy Peterkofsky 2007 Skytide, Inc. 2008 One Kaiser Plaza, Suite 785 2009 Oakland CA 94612 2010 USA 2012 Phone: +01 510 250 4284 2013 Email: roy@skytide.com