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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 19, 2015 I. Oprescu, Ed. 6 Orange 7 R. Peterkofsky 8 Skytide, Inc. 9 March 18, 2015 11 CDNI Logging Interface 12 draft-ietf-cdni-logging-17 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 19, 2015. 40 Copyright Notice 42 Copyright (c) 2015 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 . . . . . . . . . . . . . 13 71 2.2.5.4. Content Protection . . . . . . . . . . . . . . . 13 72 2.2.5.5. Notions common to multiple Log Consuming 73 Applications . . . . . . . . . . . . . . . . . . 13 74 3. CDNI Logging File . . . . . . . . . . . . . . . . . . . . . . 15 75 3.1. Rules . . . . . . . . . . . . . . . . . . . . . . . . . . 15 76 3.2. CDNI Logging File Structure . . . . . . . . . . . . . . . 17 77 3.3. CDNI Logging Directives . . . . . . . . . . . . . . . . . 19 78 3.4. CDNI Logging Records . . . . . . . . . . . . . . . . . . 23 79 3.4.1. HTTP Request Logging Record . . . . . . . . . . . . . 24 80 3.5. CDNI Logging File Example . . . . . . . . . . . . . . . . 33 81 3.6. Cascaded CDNI Logging Files Example . . . . . . . . . . . 35 82 4. Protocol for Exchange of CDNI Logging File After Full 83 Collection . . . . . . . . . . . . . . . . . . . . . . . . . 38 84 4.1. CDNI Logging Feed . . . . . . . . . . . . . . . . . . . . 39 85 4.1.1. Atom Formatting . . . . . . . . . . . . . . . . . . . 39 86 4.1.2. Updates to Log Files and the Feed . . . . . . . . . . 39 87 4.1.3. Redundant Feeds . . . . . . . . . . . . . . . . . . . 40 88 4.1.4. Example CDNI Logging Feed . . . . . . . . . . . . . . 40 89 4.2. CDNI Logging File Pull . . . . . . . . . . . . . . . . . 42 90 5. Protocol for Exchange of CDNI Logging File During Collection 43 91 6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 44 92 6.1. CDNI Logging Directive Names Registry . . . . . . . . . . 44 93 6.2. CDNI Logging File Version Registry . . . . . . . . . . . 44 94 6.3. CDNI Logging Record-Types Registry . . . . . . . . . . . 45 95 6.4. CDNI Logging Field Names Registry . . . . . . . . . . . . 46 96 6.5. CDNI Logging MIME Media Type . . . . . . . . . . . . . . 47 98 7. Security Considerations . . . . . . . . . . . . . . . . . . . 47 99 7.1. Authentication, Authorization, Confidentiality, Integrity 100 Protection . . . . . . . . . . . . . . . . . . . . . . . 48 101 7.2. Denial of Service . . . . . . . . . . . . . . . . . . . . 49 102 7.3. Privacy . . . . . . . . . . . . . . . . . . . . . . . . . 49 103 8. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 50 104 9. References . . . . . . . . . . . . . . . . . . . . . . . . . 50 105 9.1. Normative References . . . . . . . . . . . . . . . . . . 50 106 9.2. Informative References . . . . . . . . . . . . . . . . . 51 107 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 53 109 1. Introduction 111 This memo specifies the CDNI Logging interface between a downstream 112 CDN (dCDN) and an upstream CDN (uCDN). First, it describes a 113 reference model for CDNI logging. Then, it specifies the CDNI 114 Logging File format and the actual protocol for exchange of CDNI 115 Logging Files. 117 The reader should be familiar with the following documents: 119 o CDNI problem statement [RFC6707] and framework [RFC7336] identify 120 a Logging interface, 122 o Section 8 of [RFC7337] specifies a set of requirements for 123 Logging, 125 o [RFC6770] outlines real world use-cases for interconnecting CDNs. 126 These use cases require the exchange of Logging information 127 between the dCDN and the uCDN. 129 As stated in [RFC6707], "the CDNI Logging interface enables details 130 of logs or events to be exchanged between interconnected CDNs". 132 The present document describes: 134 o The CDNI Logging reference model (Section 2), 136 o The CDNI Logging File format (Section 3), 138 o The CDNI Logging File Exchange protocol (Section 4). 140 1.1. Terminology 142 In this document, the first letter of each CDNI-specific term is 143 capitalized. We adopt the terminology described in [RFC6707] and 144 [RFC7336], and extend it with the additional terms defined below. 146 Intra-CDN Logging information: logging information generated and 147 collected within a CDN. The format of the Intra-CDN Logging 148 information may be different to the format of the CDNI Logging 149 information. 151 CDNI Logging information: logging information exchanged across CDNs 152 using the CDNI Logging Interface. 154 Logging information: logging information generated and collected 155 within a CDN or obtained from another CDN using the CDNI Logging 156 Interface. 158 CDNI Logging Field: an atomic element of information that can be 159 included in a CDNI Logging Record. The time an event/task started, 160 the IP address of an End User to whom content was delivered, and the 161 Uniform Resource Identifier (URI) of the content delivered, are 162 examples of CDNI Logging Fields. 164 CDNI Logging Record: an information record providing information 165 about a specific event. This comprises a collection of CDNI Logging 166 Fields. 168 CDNI Logging File: a file containing CDNI Logging Records, as well as 169 additional information facilitating the processing of the CDNI 170 Logging Records. 172 CDN Reporting: the process of providing the relevant information that 173 will be used to create a formatted content delivery report provided 174 to the CSP in deferred time. Such information typically includes 175 aggregated data that can cover a large period of time (e.g., from 176 hours to several months). Uses of Reporting include the collection 177 of charging data related to CDN services and the computation of Key 178 Performance Indicators (KPIs). 180 CDN Monitoring: the process of providing or displaying content 181 delivery information in a timely fashion with respect to the 182 corresponding deliveries. Monitoring typically includes visibility 183 of the deliveries in progress for service operation purposes. It 184 presents a view of the global health of the services as well as 185 information on usage and performance, for network services 186 supervision and operation management. In particular, monitoring data 187 can be used to generate alarms. 189 1.2. Requirements Language 191 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 192 "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this 193 document are to be interpreted as described in RFC 2119 [RFC2119]. 195 2. CDNI Logging Reference Model 197 2.1. CDNI Logging interactions 199 The CDNI logging reference model between a given uCDN and a given 200 dCDN involves the following interactions: 202 o customization by the uCDN of the CDNI Logging information to be 203 provided by the dCDN to the uCDN (e.g., control of which CDNI 204 Logging Fields are to be communicated to the uCDN for a given task 205 performed by the dCDN or control of which types of events are to 206 be logged). The dCDN takes into account this CDNI Logging 207 customization information to determine what Logging information to 208 provide to the uCDN, but it may, or may not, take into account 209 this CDNI Logging customization information to influence what CDN 210 logging information is to be generated and collected within the 211 dCDN (e.g., even if the uCDN requests a restricted subset of the 212 logging information, the dCDN may elect to generate a broader set 213 of logging information). The mechanism to support the 214 customization by the uCDN of CDNI Logging information is outside 215 the scope of this document and left for further study. Until such 216 a mechanism is available, the uCDN and dCDN are expected to agree 217 off-line on what exact set of CDNI Logging information is to be 218 provided by the dCDN to the uCDN, and to rely on management plane 219 actions to configure the CDNI Logging functions in the dCDN to 220 generate this information set and in the uCDN to expect this 221 information set. 223 o generation and collection by the dCDN of the intra-CDN Logging 224 information related to the completion of any task performed by the 225 dCDN on behalf of the uCDN (e.g., delivery of the content to an 226 End User) or related to events happening in the dCDN that are 227 relevant to the uCDN (e.g., failures or unavailability in dCDN). 228 This takes place within the dCDN and does not directly involve 229 CDNI interfaces. 231 o communication by the dCDN to the uCDN of the Logging information 232 collected by the dCDN relevant to the uCDN. This is supported by 233 the CDNI Logging interface and in the scope of the present 234 document. For example, the uCDN may use this Logging information 235 to charge the CSP, to perform analytics and monitoring for 236 operational reasons, to provide analytics and monitoring views on 237 its content delivery to the CSP or to perform trouble-shooting. 238 This document exclusively specifies non-real-time exchange of 239 Logging information. Closer to real-time exchange of Logging 240 information (say sub-minute or sub-second) is outside the scope of 241 the present document and left for further study. This document 242 exclusively specifies exchange of Logging information related to 243 content delivery. Exchange of Logging information related to 244 operational events (e.g., dCDN request routing function 245 unavailable, content acquisition failure by dCDN) for audit or 246 operational reactive adjustments by uCDN is outside the scope of 247 the present document and left for further study. 249 o customization by the dCDN of the CDNI Logging information to be 250 provided by the uCDN on behalf of the dCDN. The mechanism to 251 support the customization by the dCDN of CDNI Logging information 252 is outside the scope of this document and left for further study. 254 o generation and collection by the uCDN of Intra-CDN Logging 255 information related to the completion of any task performed by the 256 uCDN on behalf of the dCDN (e.g., serving of content by uCDN to 257 dCDN for acquisition purposes by dCDN) or related to events 258 happening in the uCDN that are relevant to the dCDN. This takes 259 place within the uCDN and does not directly involve CDNI 260 interfaces. 262 o communication by the uCDN to the dCDN of the Logging information 263 collected by the uCDN relevant to the dCDN. For example, the dCDN 264 might potentially benefit from this information for security 265 auditing or content acquisition troubleshooting. This is outside 266 the scope of this document and left for further study. 268 Figure 1 provides an example of CDNI Logging interactions (focusing 269 only on the interactions that are in the scope of this document) in a 270 particular scenario where four CDNs are involved in the delivery of 271 content from a given CSP: the uCDN has a CDNI interconnection with 272 dCDN-1 and dCDN-2. In turn, dCDN-2 has a CDNI interconnection with 273 dCDN-3, where dCDN-2 is acting as an upstream CDN relative to dCDN-3. 274 In this example, uCDN, dCDN-1, dCDN-2 and dCDN-3 all participate in 275 the delivery of content for the CSP. In this example, the CDNI 276 Logging interface enables the uCDN to obtain Logging information from 277 all the dCDNs involved in the delivery. In the example, the uCDN 278 uses the Logging information: 280 o to analyze the performance of the delivery performed by the dCDNs 281 and to adjust its operations after the fact (e.g., request 282 routing) as appropriate, 284 o to provide (non-real-time) reporting and monitoring information to 285 the CSP. 287 For instance, the uCDN merges Logging information, extracts relevant 288 KPIs, and presents a formatted report to the CSP, in addition to a 289 bill for the content delivered by uCDN itself or by its dCDNs on the 290 CSP's behalf. The uCDN may also provide Logging information as raw 291 log files to the CSP, so that the CSP can use its own logging 292 analysis tools. 294 +-----+ 295 | CSP | 296 +-----+ 297 ^ Reporting and monitoring data 298 * Billing 299 ,--*--. 300 Logging ,-' `-. 301 Data =>( uCDN )<= Logging 302 // `-. _,-' \\ Data 303 || `-'-'-' || 304 ,-----. ,-----. 305 ,-' `-. ,-' `-. 306 ( dCDN-1 ) ( dCDN-2 )<== Logging 307 `-. ,-' `-. _,-' \\ Data 308 `--'--' `--'-' || 309 ,-----. 310 ,' `-. 311 ( dCDN-3 ) 312 `. ,-' 313 `--'--' 315 ===> CDNI Logging Interface 316 ***> outside the scope of CDNI 318 Figure 1: Interactions in CDNI Logging Reference Model 320 A downstream CDN relative to uCDN (e.g., dCDN-2) integrates the 321 relevant Logging information obtained from its own downstream CDNs 322 (i.e., dCDN-3) in the Logging information that it provides to the 323 uCDN, so that the uCDN ultimately obtains all Logging information 324 relevant to a CSP for which it acts as the authoritative CDN. Such 325 aggregation is further discussed in Section 3.6. 327 Note that the format of Logging information that a CDN provides over 328 the CDNI interface might be different from the one that the CDN uses 329 internally. In this case, the CDN needs to reformat the Logging 330 information before it provides this information to the other CDN over 331 the CDNI Logging interface. Similarly, a CDN might reformat the 332 Logging information that it receives over the CDNI Logging interface 333 before injecting it into its log-consuming applications or before 334 providing some of this Logging information to the CSP. Such 335 reformatting operations introduce latency in the logging distribution 336 chain and introduce a processing burden. Therefore, there are 337 benefits in specifying CDNI Logging formats that are suitable for use 338 inside CDNs and also are close to the intra-CDN Logging formats 339 commonly used in CDNs today. 341 2.2. Overall Logging Chain 343 This section discusses the overall logging chain within and across 344 CDNs to clarify how CDN Logging information is expected to fit in 345 this overall chain. Figure 2 illustrates the overall logging chain 346 within the dCDN, across CDNs using the CDNI Logging interface and 347 within the uCDN. Note that the logging chain illustrated in the 348 Figure is obviously only an example and varies depending on the 349 specific environments. For example, there may be more or fewer 350 instantiations of each entity (e.g., there may be 4 Log consuming 351 applications in a given CDN). As another example, there may be one 352 instance of Rectification process per Log Consuming Application 353 instead of a shared one. 355 Log Consuming Log Consuming 356 App App 357 ^ ^ 358 | | 359 Rectification---------- 360 ^ 361 | 362 Filtering 363 ^ 364 | 365 Collection 366 ^ ^ 367 | | 368 | Generation 369 | 370 | uCDN 371 CDNI Logging --------------------------------------------------- 372 exchange dCDN 373 ^ 374 | Log Consuming Log Consuming 375 | App App 376 | ^ ^ 377 | | | 378 Rectification Rectification--------- 379 ^ ^ 380 | | 381 Filtering 382 ^ 383 | 384 Collection 385 ^ ^ 386 | | 387 Generation Generation 389 Figure 2: CDNI Logging in the overall Logging Chain 391 The following subsections describe each of the processes potentially 392 involved in the logging chain of Figure 2. 394 2.2.1. Logging Generation and During-Generation Aggregation 396 CDNs typically generate Logging information for all significant task 397 completions, events, and failures. Logging information is typically 398 generated by many devices in the CDN including the surrogates, the 399 request routing system, and the control system. 401 The amount of Logging information generated can be huge. Therefore, 402 during contract negotiations, interconnected CDNs often agree on a 403 retention duration for Logging information, and/or potentially on a 404 maximum volume of Logging information that the dCDN ought to keep. 405 If this volume is exceeded, the dCDN is expected to alert the uCDN 406 but may not keep more Logging information for the considered time 407 period. In addition, CDNs may aggregate Logging information and 408 transmit only summaries for some categories of operations instead of 409 the full Logging information. Note that such aggregation leads to an 410 information loss, which may be problematic for some usages of the 411 Logging information (e.g., debugging). 413 [RFC6983] discusses logging for HTTP Adaptive Streaming (HAS). In 414 accordance with the recommendations articulated there, it is expected 415 that a surrogate will generate separate Logging information for 416 delivery of each chunk of HAS content. This ensures that separate 417 Logging information can then be provided to interconnected CDNs over 418 the CDNI Logging interface. Still in line with the recommendations 419 of [RFC6983], the Logging information for per-chunk delivery may 420 include some information (a Content Collection IDentifier and a 421 Session IDentifier) intended to facilitate subsequent post-generation 422 aggregation of per-chunk logs into per-session logs. Note that a CDN 423 may also elect to generate aggregate per-session logs when performing 424 HAS delivery, but this needs to be in addition to, and not instead 425 of, the per-chunk delivery logs. We note that aggregate per-session 426 logs for HAS delivery are for further study and outside the scope of 427 this document. 429 2.2.2. Logging Collection 431 This is the process that continuously collects Logging information 432 generated by the log-generating entities within a CDN. 434 In a CDNI environment, in addition to collecting Logging information 435 from log-generating entities within the local CDN, the Collection 436 process also collects Logging information provided by another CDN, or 437 other CDNs, through the CDNI Logging interface. This is illustrated 438 in Figure 2 where we see that the Collection process of the uCDN 439 collects Logging information from log-generating entities within the 440 uCDN as well as Logging information coming from the dCDNs through the 441 CDNI Logging interface. 443 2.2.3. Logging Filtering 445 A CDN may be required to only present different subsets of the whole 446 Logging information collected to various log-consuming applications. 447 This is achieved by the Filtering process. 449 In particular, the Filtering process can also filter the right subset 450 of Logging information that needs to be provided to a given 451 interconnected CDN. For example, the filtering process in the dCDN 452 can be used to ensure that only the Logging information related to 453 tasks performed on behalf of a given uCDN are made available to that 454 uCDN (thereby filtering out all the Logging information related to 455 deliveries by the dCDN of content for its own CSPs). Similarly, the 456 Filtering process may filter or partially mask some fields, for 457 example, to protect End Users' privacy when communicating CDNI 458 Logging information to another CDN. Filtering of Logging information 459 prior to communication of this information to other CDNs via the CDNI 460 Logging interface requires that the downstream CDN can recognize the 461 subset of Logging information that relate to each interconnected CDN. 463 The CDN will also filter some internal scope information such as 464 information related to its internal alarms (security, failures, load, 465 etc). 467 In some use cases described in [RFC6770], the interconnected CDNs do 468 not want to disclose details on their internal topology. The 469 filtering process can then also filter confidential data on the 470 dCDNs' topology (number of servers, location, etc.). In particular, 471 information about the requests served by each Surrogate may be 472 confidential. Therefore, the Logging information needs to be 473 protected so that data such as Surrogates' hostnames are not 474 disclosed to the uCDN. In the "Inter-Affiliates Interconnection" use 475 case, this information may be disclosed to the uCDN because both the 476 dCDN and the uCDN are operated by entities of the same group. 478 2.2.4. Logging Rectification and Post-Generation Aggregation 480 If Logging information is generated periodically, it is important 481 that the sessions that start in one Logging period and end in another 482 are correctly reported. If they are reported in the starting period, 483 then the Logging information of this period will be available only 484 after the end of the session, which delays the Logging information 485 generation. A simple approach is to provide the complete Logging 486 Record for a session in the Logging Period of the session end. 488 A Logging rectification/update mechanism could be useful to reach a 489 good trade-off between the Logging information generation delay and 490 the Logging information accuracy. 492 In the presence of HAS, some log-consuming applications can benefit 493 from aggregate per-session logs. For example, for analytics, per- 494 session logs allow display of session-related trends which are much 495 more meaningful for some types of analysis than chunk-related trends. 496 In the case where aggregate logs have been generated directly by the 497 log-generating entities, those can be used by the applications. In 498 the case where aggregate logs have not been generated, the 499 Rectification process can be extended with a Post-Generation 500 Aggregation process that generates per-session logs from the per- 501 chunk logs, possibly leveraging the information included in the per- 502 chunk logs for that purpose (Content Collection IDentifier and a 503 Session IDentifier). However, in accordance with [RFC6983], this 504 document does not define exchange of such aggregate logs on the CDNI 505 Logging interface. We note that this is for further study and 506 outside the scope of this document. 508 2.2.5. Log-Consuming Applications 510 2.2.5.1. Maintenance/Debugging 512 Logging information is useful to permit the detection (and limit the 513 risk) of content delivery failures. In particular, Logging 514 information facilitates the detection of configuration issues. 516 To detect faults, Logging information needs to report success and 517 failure of CDN delivery operations. The uCDN can summarize such 518 information into KPIs. For instance, Logging information needs to 519 allow the computation of the number of times, during a given time 520 period, that content delivery related to a specific service succeeds/ 521 fails. 523 Logging information enables the CDN providers to identify and 524 troubleshoot performance degradations. In particular, Logging 525 information enables tracking of traffic data (e.g., the amount of 526 traffic that has been forwarded by a dCDN on behalf of an uCDN over a 527 given period of time), which is particularly useful for CDN and 528 network planning operations. 530 Some of these maintenance and debugging applications only require 531 aggregate logging information highly compatible with anonymization of 532 IP addresses (as supported by the present document and specified in 533 Section 3.4.1). However, in some situations, it may be useful, where 534 compatible with privacy protection, to access some CDNI Logging 535 Records containing full non-anonymized IP addresses. For example, 536 this may be useful for detailed fault tracking of a particular end 537 user content delivery issue. 539 2.2.5.2. Accounting 541 Logging information is essential for accounting, to permit inter-CDN 542 billing and CSP billing by uCDNs. For instance, Logging information 543 provided by dCDNs enables the uCDN to compute the total amount of 544 traffic delivered by every dCDN for a particular Content Provider, as 545 well as, the associated bandwidth usage (e.g., peak, 95th 546 percentile), and the maximum number of simultaneous sessions over a 547 given period of time. 549 2.2.5.3. Analytics and Reporting 551 The goal of analytics is to gather any relevant information to track 552 audience, analyze user behavior, and monitor the performance and 553 quality of content delivery. For instance, Logging information 554 enables the CDN providers to report on content consumption (e.g., 555 delivered sessions per content) in a specific geographic area. 557 The goal of reporting is to gather any relevant information to 558 monitor the performance and quality of content delivery and allow 559 detection of delivery issues. For instance, reporting could track 560 the average delivery throughput experienced by End Users in a given 561 region for a specific CSP or content set over a period of time. 563 2.2.5.4. Content Protection 565 The goal of content protection is to prevent and monitor unauthorized 566 access, misuse, modification, and denial of access to a content. A 567 set of information is logged in a CDN for security purposes. In 568 particular, a record of access to content is usually collected to 569 permit the CSP to detect infringements of content delivery policies 570 and other abnormal End User behaviors. 572 2.2.5.5. Notions common to multiple Log Consuming Applications 574 2.2.5.5.1. Logging Information Views 576 Within a given log-consuming application, different views may be 577 provided to different users depending on privacy, business, and 578 scalability constraints. 580 For example, an analytics tool run by the uCDN can provide one view 581 to an uCDN operator that exploits all the Logging information 582 available to the uCDN, while the tool may provide a different view to 583 each CSP exploiting only the Logging information related to the 584 content of the given CSP. 586 As another example, maintenance and debugging tools may provide 587 different views to different CDN operators, based on their 588 operational role. 590 2.2.5.5.2. Key Performance Indicators (KPIs) 592 This section presents, for explanatory purposes, a non-exhaustive 593 list of Key Performance Indicators (KPIs) that can be extracted/ 594 produced from logs. 596 Multiple log-consuming applications, such as analytics, monitoring, 597 and maintenance applications, often compute and track such KPIs. 599 In a CDNI environment, depending on the situation, these KPIs may be 600 computed by the uCDN or by the dCDN. But it is usually the uCDN that 601 computes KPIs, because the uCDN and dCDN may have different 602 definitions of the KPIs and the computation of some KPIs requires a 603 vision of all the deliveries performed by the uCDN and all its dCDNs. 605 Here is a list of important examples of KPIs: 607 o Number of delivery requests received from End Users in a given 608 region for each piece of content, during a given period of time 609 (e.g., hour/day/week/month) 611 o Percentage of delivery successes/failures among the aforementioned 612 requests 614 o Number of failures listed by failure type (e.g., HTTP error code) 615 for requests received from End Users in a given region and for 616 each piece of content, during a given period of time (e.g., 617 hour/day/week/month) 619 o Number and cause of premature delivery termination for End Users 620 in a given region and for each piece of content, during a given 621 period of time (e.g., hour/day/week/month) 623 o Maximum and mean number of simultaneous sessions established by 624 End Users in a given region, for a given Content Provider, and 625 during a given period of time (e.g., hour/day/week/month) 627 o Volume of traffic delivered for sessions established by End Users 628 in a given region, for a given Content Provider, and during a 629 given period of time (e.g., hour/day/week/month) 631 o Maximum, mean, and minimum delivery throughput for sessions 632 established by End Users in a given region, for a given Content 633 Provider, and during a given period of time (e.g., hour/day/week/ 634 month) 636 o Cache-hit and byte-hit ratios for requests received from End Users 637 in a given region for each piece of content, during a given period 638 of time (e.g., hour/day/week/month) 640 o Top 10 most popularly requested contents (during a given day/week/ 641 month) 643 o Terminal type (mobile, PC, STB, if this information can be 644 acquired from the browser type inferred from the User Agent 645 string, for example). 647 Additional KPIs can be computed from other sources of information 648 than the Logging information, for instance, data collected by a 649 content portal or by specific client-side application programming 650 interfaces. Such KPIs are out of scope for the present document. 652 The KPIs used depend strongly on the considered log-consuming 653 application -- the CDN operator may be interested in different 654 metrics than the CSP is. In particular, CDN operators are often 655 interested in delivery and acquisition performance KPIs, information 656 related to Surrogates' performance, caching information to evaluate 657 the cache-hit ratio, information about the delivered file size to 658 compute the volume of content delivered during peak hour, etc. 660 Some of the KPIs, for instance those providing an instantaneous 661 vision of the active sessions for a given CSP's content, are useful 662 essentially if they are provided in a timely manner. By contrast, 663 some other KPIs, such as those averaged on a long period of time, can 664 be provided in non-real-time. 666 3. CDNI Logging File 668 3.1. Rules 670 This specification uses the Augmented Backus-Naur Form (ABNF) 671 notation and core rules of [RFC5234]. In particular, the present 672 document uses the following rules from [RFC5234]: 674 CR = %x0D ; carriage return 676 ALPHA = %x41-5A / %x61-7A ; A-Z / a-z 678 DIGIT = %x30-39 ; 0-9 680 DQUOTE = %x22 ; " (Double Quote) 682 CRLF = CR LF ; Internet standard newline 683 HEXDIG = DIGIT / "A" / "B" / "C" / "D" / "E" / "F" 685 HTAB = %x09 ; horizontal tab 687 LF = %x0A ; linefeed 689 OCTET = %x00-FF ; 8 bits of data 691 The present document also uses the following rules from [RFC3986]: 693 host = as specified in section 3.2.2 of [RFC3986]. 695 IPv4address = as specified in section 3.2.2 of [RFC3986]. 697 IPv6address = as specified in section 3.2.2 of [RFC3986]. 699 The present document also defines the following additional rules: 701 ADDRESS = IPv4address / IPv6address 703 ALPHANUM = ALPHA / DIGIT 705 DATE = 4DIGIT "-" 2DIGIT "-" 2DIGIT 707 Dates are encoded as "full-date" specified in [RFC3339]. 709 DEC = 1*DIGIT ["." *DIGIT] 711 NAMEFORMAT = ALPHANUM *(ALPHANUM / "_" / "-") 713 QSTRING = DQUOTE *NDQUOTE DQUOTE 715 NDQUOTE = / 2DQUOTE ; whereby a 716 DQUOTE is conveyed inside a QSTRING unambiguously by repeating it. 718 [Editor's Note: The definition of NDQUOTE is being discussed as 719 part of IESG review and needs editing] 721 NHTABSTRING = *NHTAB 723 NHTAB = 725 TIME = 2DIGIT ":" 2DIGIT ":" 2DIGIT ["." *DIGIT] 727 Times are encoded as "partial-time" specified in [RFC3339]. 729 3.2. CDNI Logging File Structure 731 As defined in Section 1.1: a CDNI Logging Field is as an atomic 732 logging information element, a CDNI Logging Record is a collection of 733 CDNI Logging Fields containing all logging information corresponding 734 to a single logging event, and a CDNI Logging File contains a 735 collection of CDNI Logging Records. This structure is illustrated in 736 Figure 3. The use of a file structure for transfer of CDNI Logging 737 information is selected since this is the most common practise today 738 for exchange of logging information within and across CDNs. 740 +----------------------------------------------------------+ 741 |CDNI Logging File | 742 | | 743 | #Directive 1 | 744 | #Directive 2 | 745 | ... | 746 | #Directive P | 747 | | 748 | +------------------------------------------------------+ | 749 | |CDNI Logging Record 1 | | 750 | | +-------------+ +-------------+ +-------------+ | | 751 | | |CDNI Logging | |CDNI Logging | ... |CDNI Logging | | | 752 | | | Field 1 | | Field 2 | | Field N | | | 753 | | +-------------+ +-------------+ +-------------+ | | 754 | +------------------------------------------------------+ | 755 | | 756 | +------------------------------------------------------+ | 757 | |CDNI Logging Record 2 | | 758 | | +-------------+ +-------------+ +-------------+ | | 759 | | |CDNI Logging | |CDNI Logging | ... |CDNI Logging | | | 760 | | | Field 1 | | Field 2 | | Field N | | | 761 | | +-------------+ +-------------+ +-------------+ | | 762 | +------------------------------------------------------+ | 763 | | 764 | ... | 765 | | 766 | #Directive P+1 | 767 | | 768 | ... | 769 | | 770 | +------------------------------------------------------+ | 771 | |CDNI Logging Record M | | 772 | | +-------------+ +-------------+ +-------------+ | | 773 | | |CDNI Logging | |CDNI Logging | ... |CDNI Logging | | | 774 | | | Field 1 | | Field 2 | | Field N | | | 775 | | +-------------+ +-------------+ +-------------+ | | 776 | +------------------------------------------------------+ | 777 | | 778 | | 779 | #Directive P+Q | 780 +----------------------------------------------------------+ 782 Figure 3: Structure of Logging Files 784 The CDNI Logging File format is inspired from the W3C Extended Log 785 File Format [ELF]. However, it is fully specified by the present 786 document. Where the present document differs from the W3C Extended 787 Log File Format, an implementation of the CDNI Logging interface MUST 788 comply with the present document. The W3C Extended Log File Format 789 was used as a starting point, reused where possible and expanded when 790 necessary. 792 Using a format that resembles the W3C Extended Log File Format is 793 intended to keep CDNI logging format close to the intra-CDN Logging 794 information format commonly used in CDNs today, thereby minimizing 795 systematic translation at CDN/CDNI boundary. 797 A CDNI Logging File MUST contain a sequence of lines containing US- 798 ASCII characters [CHAR_SET] terminated by CRLF. [Editor's Note: This 799 needs editing to explain explain how CRLF/HTAB inside a QSTRING does 800 not act as a separator. ] 802 Each line of a CDNI Logging File MUST contain either a directive or a 803 CDNI Logging Record. 805 Directives record information about the CDNI Logging process itself. 806 Lines containing directives MUST begin with the "#" character. 807 Directives are specified in Section 3.3. 809 Logging Records provide actual details of the logged event. Logging 810 Records are specified in Section 3.4. 812 The CDNI Logging File ("CDNILOGFILE") structure is defined by the 813 following rules: 815 DIRLINE = "#" directive CRLF 817 DIRGROUP = 1*DIRLINE 819 RECLINE = CDNILOGREC CRLF 821 RECGROUP = *RECLINE 823 CDNILOGFILE = 1*(DIRGROUP RECGROUP) 825 See Section 3.4 for the definition of CDNILOGREC. 827 3.3. CDNI Logging Directives 829 The CDNI Logging directives are defined by the following rules: 831 directive = DIRNAME ":" HTAB DIRVAL 833 DIRNAME = NAMEFORMAT 834 DIRNAME = 837 DIRVAL = 841 An implementation of the CDNI Logging interface MUST support all of 842 the following directives, listed below by their directive name: 844 o Version: 846 * format: NHTABSTRING 848 * directive value: indicates the version of the CDNI Logging File 849 format. The entity transmitting a CDNI Logging File as per the 850 present document MUST set the value to "CDNI/1.0". In the 851 future, other versions of CDNI Logging File might be specified; 852 those would use a value different to "CDNI/1.0" allowing the 853 entity receiving the CDNI Logging File to identify the 854 corresponding version. 856 * occurrence: there MUST be one and only one instance of this 857 directive per CDNI Logging File. It MUST be the first line of 858 the CDNI Logging File. 860 o UUID: 862 * format: NHTABSTRING 864 * directive value: this a Uniform Resource Name (URN) from the 865 Universally Unique IDentifier (UUID) URN namespace specified in 866 [RFC4122]). The UUID contained in the URN uniquely identifies 867 the CDNI Logging File. 869 * occurrence: there MUST be one and only one instance of this 870 directive per CDNI Logging File. 872 o Claimed-Origin: 874 * format: host 876 * directive value: this contains the claimed identification of 877 the entity transmitting the CDNI Logging File (e.g., the host 878 in a dCDN supporting the CDNI Logging interface) or the entity 879 responsible for transmitting the CDNI Logging File (e.g., the 880 dCDN). 882 * occurrence: there MUST be zero or exactly one instance of this 883 directive per CDNI Logging File. This directive MAY be 884 included by the dCDN. It MUST NOT be included or modified by 885 the uCDN. 887 o Established-Origin: 889 * format: host 891 * directive value: this contains the identification, as 892 established by the entity receiving the CDNI Logging File, of 893 the entity transmitting the CDNI Logging File (e.g., the host 894 in a dCDN supporting the CDNI Logging interface) or the entity 895 responsible for transmitting the CDNI Logging File (e.g., the 896 dCDN). 898 * occurrence: there MUST be zero or exactly one instance of this 899 directive per CDNI Logging File. This directive MAY be added 900 by the uCDN (e.g., before storing the CDNI Logging File). It 901 MUST NOT be included by the dCDN. The mechanisms used by the 902 uCDN to establish and validate the entity responsible for the 903 CDNI Logging File is outside the scope of the present document. 904 We observe that, in particular, this may be achieved through 905 authentication mechanisms that are part of the transport layer 906 of the CDNI Logging File pull mechanism (Section 4.2). 908 o Record-Type: 910 * format: NAMEFORMAT 912 * directive value: indicates the type of the CDNI Logging Records 913 that follow this directive, until another Record-Type directive 914 (or the end of the CDNI Logging File). This can be any CDNI 915 Logging Record type registered in the CDNI Logging Record-types 916 registry (Section 6.3). For example this may be 917 "cdni_http_request_v1" as specified in Section 3.4.1. 919 * occurrence: there MUST be at least one instance of this 920 directive per CDNI Logging File. The first instance of this 921 directive MUST precede a Fields directive and MUST precede all 922 CDNI Logging Records. 924 o Fields: 926 * format: FIENAME *(HTAB FIENAME) ; where FIENAME can take any 927 CDNI Logging field name registered in the CDNI Logging Field 928 Names registry (Section 6.4). 930 * directive value: this lists the names of all the fields for 931 which a value is to appear in the CDNI Logging Records that 932 follow the instance of this directive (until another instance 933 of this directive). The names of the fields, as well as their 934 occurrences, MUST comply with the corresponding rules specified 935 in the document referenced in the CDNI Logging Record-types 936 registry (Section 6.3) for the corresponding CDNI Logging 937 Record-Type. 939 * occurrence: there MUST be at least one instance of this 940 directive per Record-Type directive. The first instance of 941 this directive for a given Record-Type MUST appear before any 942 CDNI Logging Record for this Record-Type. One situation where 943 more than one instance of the Fields directive can appear 944 within a given CDNI Logging File, is when there is a change, in 945 the middle of a fairly large logging period, in the agreement 946 between the uCDN and the dCDN about the set of Fields that are 947 to be exchanged. The multiple occurrences allow records with 948 the old set of fields and records with the new set of fields to 949 be carried inside the same Logging File. 951 o SHA256-Hash: 953 * format: 32HEXDIG 955 * directive value: This directive permits the detection of a 956 corrupted CDNI Logging File. This can be useful, for instance, 957 if a problem occurs on the filesystem of the dCDN Logging 958 system and leads to a truncation of a logging file. The valid 959 SHA256-Hash value is included in this directive by the entity 960 that transmits the CDNI Logging File. It MUST be computed by 961 applying the SHA-256 ([RFC6234]) cryptographic hash function on 962 the CDNI Logging File, including all the directives and logging 963 records, up to the SHA256-Hash directive itself, excluding the 964 SHA256-Hash directive itself. The SHA256-Hash value MUST be 965 represented as a US-ASCII encoded hexadecimal number, 64 digits 966 long (representing a 256 bit hash value). The entity receiving 967 the CDNI Logging File also computes in a similar way the 968 SHA-256 hash on the received CDNI Logging File and compares 969 this hash to the value of the SHA256-Hash directive. If the 970 two values are equal, then the received CDNI Logging File is to 971 be considered non-corrupted. If the two values are different, 972 the received CDNI Logging File is to be considered corrupted. 973 The behavior of the entity that received a corrupted CDNI 974 Logging File is outside the scope of this specification; we 975 note that the entity MAY attempt to pull again the same CDNI 976 Logging File from the transmitting entity. If the entity 977 receiving a non-corrupted CDNI Logging File adds an 978 Established-Origin directive, it MUST then recompute and update 979 the SHA256-Hash directive so it also protects the added 980 Established-Origin directive. 982 * occurrence: there MUST be zero or exactly one instance of this 983 directive. There SHOULD be exactly one instance of this 984 directive. One situation where that directive could be omitted 985 is where integrity protection is already provided via another 986 mechanism (for example if an integrity hash is associated to 987 the CDNI Logging File out of band through the CDNI Logging Feed 988 ( Section 4.1) leveraging ATOM extensions such as those 989 proposed in [I-D.snell-atompub-link-extensions]. When present, 990 the SHA256-Hash field MUST be the last line of the CDNI Logging 991 File. 993 An uCDN-side implementation of the CDNI Logging interface MUST reject 994 a CDNI Logging File that does not comply with the occurences 995 specified above for each and every directive. For example, an uCDN- 996 side implementation of the CDNI Logging interface receiving a CDNI 997 Logging file with zero occurence of the Version directive, or with 998 two occurences of the SHA256-Hash, MUST reject this CDNI Logging 999 File. 1001 An entity receiving a CDNI Logging File with a value set to 1002 "CDNI/1.0" MUST process the CDNI Logging File as per the present 1003 document. An entity receiving a CDNI Logging File with a value set 1004 to a different value MUST process the CDNI Logging File as per the 1005 specification referenced in the CDNI Logging File Version registry 1006 (see Section 6.1) if the implementation supports this specification 1007 and MUST reject the CDNI Logging File otherwise. 1009 3.4. CDNI Logging Records 1011 A CDNI Logging Record consists of a sequence of CDNI Logging Fields 1012 relating to that single CDNI Logging Record. 1014 CDNI Logging Fields MUST be separated by the "horizontal tabulation 1015 (HTAB)" character. [Editor's Note: This needs editing to explain 1016 explain how CRLF/HTAB inside a QSTRING does not act as a separator. 1017 ] 1019 To facilitate readability, a prefix scheme is used for CDNI Logging 1020 field names in a similar way to the one used in W3C Extended Log File 1021 Format [ELF]. The semantics of the prefix in the present document 1022 is: 1024 o "c-" refers to the User Agent that issues the request (corresponds 1025 to the "client" of W3C Extended Log Format) 1027 o "d-" refers to the dCDN (relative to a given CDN acting as a uCDN) 1029 o "s-" refers to the dCDN Surrogate that serves the request 1030 (corresponds to the "server" of W3C Extended Log Format) 1032 o "u-" refers to the uCDN (relative to a given CDN acting as a dCDN) 1034 o "cs-" refers to communication from the User Agent towards the dCDN 1035 Surrogate 1037 o "sc-" refers to communication from the dCDN Surrogate towards the 1038 User Agent 1040 An implementation of the CDNI Logging interface as per the present 1041 specification MUST support the CDNI HTTP Request Logging Record as 1042 specified in Section 3.4.1. 1044 A CDNI Logging Record (CDNILOGREC) is defined by the following rules: 1046 CDNILOGREC = FIEVAL *(HTAB FIEVAL) 1048 FIEVAL = 1052 3.4.1. HTTP Request Logging Record 1054 This section defines the CDNI Logging Record of Record-Type 1055 "cdni_http_request_v1". It is applicable to content delivery 1056 performed by the dCDN using HTTP/1.0([RFC1945]), 1057 HTTP/1.1([RFC7230],[RFC7231], [RFC7232], [RFC7233], [RFC7234], 1058 [RFC7235]) or HTTPS ([RFC2818], [RFC7230]). We observe that, in the 1059 case of HTTPS delivery, there may be value in logging additional 1060 information specific to the operation of HTTP over TLS and we note 1061 that this is outside the scope of the present document and may be 1062 addressed in a future document defining another CDNI Logging Record 1063 or another version of the HTTP Request Logging Record. 1065 The "cdni_http_request_v1" Record-Type is also expected to be 1066 applicable to HTTP/2 [I-D.ietf-httpbis-http2] (which is still under 1067 development at the time of writing the present document) since a 1068 fundamental design tenet of HTTP/2 is to preserve the HTTP/1.1 1069 semantics. We observe that, in the case of HTTP/2 delivery, there 1070 may be value in logging additional information specific to the 1071 additional functionality of HTTP/2 (e.g. information related to 1072 connection identification, to stream identification, to stream 1073 priority and to flow control). We note that such additional 1074 information is outside the scope of the present document and may be 1075 addressed in a future document defining another CDNI Logging Record 1076 or another version of the HTTP Request Logging Record. 1078 The "cdni_http_request_v1" Record-Type contains the following CDNI 1079 Logging Fields, listed by their field name: 1081 o date: 1083 * format: DATE 1085 * field value: the date at which the processing of request 1086 completed on the Surrogate. 1088 * occurrence: there MUST be one and only one instance of this 1089 field. 1091 o time: 1093 * format: TIME 1095 * field value: the time at which the processing of request 1096 completed on the Surrogate. 1098 * occurrence: there MUST be one and only one instance of this 1099 field. 1101 o time-taken: 1103 * format: DEC 1105 * field value: decimal value of the duration, in seconds, between 1106 the start of the processing of the request and the completion 1107 of the request processing (e.g., completion of delivery) by the 1108 Surrogate. 1110 * occurrence: there MUST be one and only one instance of this 1111 field. 1113 o c-ip: 1115 * format: ADDRESS 1117 * field value: the source IPv4 or IPv6 address (i.e., the 1118 "client" address) in the request received by the Surrogate. 1120 * occurrence: there MUST be one and only one instance of this 1121 field. 1123 o c-ip-anonymizing: 1125 * format: 1*DIGIT 1127 * field value: the number of rightmost bits of the IPv4 address 1128 in the c-ip field that are zeroed-out in order to anonymize the 1129 logging record. The mechanism by which the two ends of the 1130 CDNI Logging interface agree on whether anonymization is to be 1131 supported and the number of bits that need to be zeroed-out for 1132 this purpose are outside the scope of the present document. 1133 IPv4 addresses SHOULD be anonymized to /24 boundary (i.e., with 1134 c-ip-anonymizing set to 8), and IPv6 addresses SHOULD be 1135 anonymized to a /48 boundary (i.e., with c-ip-anonymizing set 1136 to 80). 1138 * occurrence: there MUST be zero or exactly one instance of this 1139 field. 1141 o c-port: 1143 * format: 1*DIGIT 1145 * field value: the source TCP port (i.e., the "client" port) in 1146 the request received by the Surrogate. 1148 * occurrence: there MUST be zero or exactly one instance of this 1149 field. 1151 o c-port-anonymizing: 1153 * format: 1*DIGIT 1155 * field value: the number of rightmost bits of the port in the 1156 c-port field that are zeroed-out in order to anonymize the 1157 logging record. The mechanism by which the two ends of the 1158 CDNI Logging interface agree on whether anonymization is to be 1159 supported and the number of bits that need to be zeroed-out for 1160 this purpose are outside the scope of the present document. 1162 * occurrence: there MUST be zero or exactly one instance of this 1163 field. 1165 o s-ip: 1167 * format: ADDRESS 1169 * field value: the IPv4 or IPv6 address of the Surrogate that 1170 served the request (i.e., the "server" address). 1172 * occurrence: there MUST be zero or exactly one instance of this 1173 field. 1175 o s-hostname: 1177 * format: host 1179 * field value: the hostname of the Surrogate that served the 1180 request (i.e., the "server" hostname). 1182 * occurrence: there MUST be zero or exactly one instance of this 1183 field. 1185 o s-port: 1187 * format: 1*DIGIT 1189 * field value: the destination TCP port (i.e., the "server" port) 1190 in the request received by the Surrogate. 1192 * occurrence: there MUST be zero or exactly one instance of this 1193 field. 1195 o cs-method: 1197 * format: NHTABSTRING 1199 * field value: this is the method of the request received by the 1200 Surrogate. In the case of HTTP delivery, this is the HTTP 1201 method in the request. 1203 * occurrence: There MUST be one and only one instance of this 1204 field. 1206 o cs-uri: 1208 * format: NHTABSTRING 1210 * field value: this is the "effective request URI" of the request 1211 received by the Surrogate as specified in [RFC7230]. It 1212 complies with the "http" URI scheme or the "https" URI scheme 1213 as specified in [RFC7230]). Note that cs-uri can be privacy 1214 sensitive. In that case, and where appropriate, u-uri could be 1215 used instead of cs-uri. 1217 * occurrence: there MUST be zero or exactly one instance of this 1218 field. 1220 o u-uri: 1222 * format: NHTABSTRING 1224 * field value: this is a complete URI, derived from the 1225 "effective request URI" ([RFC7230]) of the request received by 1226 the Surrogate (i.e., the cs-uri) but transformed by the entity 1227 generating or transmitting the CDNI Logging Record, in a way 1228 that is agreed upon between the two ends of the CDNI Logging 1229 interface, so the transformed URI is meaningful to the uCDN. 1230 For example, the two ends of the CDNI Logging interface could 1231 agree that the u-uri is constructed from the cs-uri by removing 1232 the part of the hostname that exposes which individual 1233 Surrogate actually performed the delivery. The details of 1234 modification performed to generate the u-uri, as well as the 1235 mechanism to agree on these modifications between the two sides 1236 of the CDNI Logging interface are outside the scope of the 1237 present document. 1239 * occurrence: there MUST be one and only one instance of this 1240 field. 1242 o protocol: 1244 * format: NHTABSTRING 1246 * field value: this is value of the HTTP-Version field as 1247 specified in [RFC7230] of the Request-Line of the request 1248 received by the Surrogate (e.g., "HTTP/1.1"). 1250 * occurrence: there MUST be one and only one instance of this 1251 field. 1253 o sc-status: 1255 * format: 3DIGIT 1257 * field value: this is the Status-Code in the response from the 1258 Surrogate. In the case of HTTP delivery, this is the HTTP 1259 Status-Code in the HTTP response. 1261 * occurrence: There MUST be one and only one instance of this 1262 field. 1264 o sc-total-bytes: 1266 * format: 1*DIGIT 1267 * field value: this is the total number of bytes of the response 1268 sent by the Surrogate in response to the request. In the case 1269 of HTTP delivery, this includes the bytes of the Status-Line, 1270 the bytes of the HTTP headers and the bytes of the message- 1271 body. 1273 * occurrence: There MUST be one and only one instance of this 1274 field. 1276 o sc-entity-bytes: 1278 * format: 1*DIGIT 1280 * field value: this is the number of bytes of the message-body in 1281 the HTTP response sent by the Surrogate in response to the 1282 request. This does not include the bytes of the Status-Line or 1283 the bytes of the HTTP headers. 1285 * occurrence: there MUST be zero or exactly one instance of this 1286 field. 1288 o cs(): 1290 * format: QSTRING 1292 * field value: the value of the HTTP header (identified by the 1293 in the CDNI Logging field name) as it 1294 appears in the request processed by the Surrogate, but 1295 prepended by a DQUOTE and appended by a DQUOTE. For example, 1296 when the CDNI Logging field name (FIENAME) listed in the 1297 preceding Fields directive is cs(User-Agent), this CDNI Logging 1298 field value contains the value of the User-Agent HTTP header as 1299 received by the Surrogate in the request it processed, but 1300 prepended by a DQUOTE and appended by a DQUOTE. If the HTTP 1301 header as it appeared in the request processed by the Surrogate 1302 contains one or more DQUOTE, each DQUOTE MUST be escaped by an 1303 additional DQUOTE. For example, if the HTTP header contains 1304 My_Header"value", then the field value of the cs() is "My_Header""value""". The entity transmitting the 1306 CDNI Logging File MUST ensure that the of 1307 the cs(): 1317 * format: QSTRING 1319 * field value: the value of the HTTP header (identified by the 1320 in the CDNI Logging field name) as it 1321 appears in the response issued by the Surrogate to serve the 1322 request, but prepended by a DQUOTE and appended by a DQUOTE. 1323 If the HTTP header as it appeared in the request processed by 1324 the Surrogate contains one or more DQUOTE, each DQUOTE MUST be 1325 escaped by an additional DQUOTE. For example, if the HTTP 1326 header contains My_Header"value", then the field value of the 1327 cs() is "My_Header""value""". The entity 1328 transmitting the CDNI Logging File MUST ensure that the of the cs(, there MUST be 1337 zero or exactly one instance of this field. 1339 o s-ccid: 1341 * format: QSTRING 1343 * field value: this contains the value of the Content Collection 1344 IDentifier (CCID) associated by the uCDN to the content served 1345 by the Surrogate via the CDNI Metadata interface 1346 ([I-D.ietf-cdni-metadata]), prepended by a DQUOTE and appended 1347 by a DQUOTE. If the CCID conveyed in the CDNI Metadata 1348 interface contains one or more DQUOTE, each DQUOTE MUST be 1349 escaped by an additional DQUOTE. For example, if the CCID 1350 conveyed in the CDNI Metadata interface is My_CCIDD"value", 1351 then the field value of the s-ccid is "My_CCID""value""". 1353 * occurrence: there MUST be zero or exactly one instance of this 1354 field. For a given , there MUST be zero or 1355 exactly one instance of this field. 1357 o s-sid: 1359 * format: QSTRING 1361 * field value: this contains the value of a Session IDentifier 1362 (SID) generated by the dCDN for a specific HTTP session, 1363 prepended by a DQUOTE and appended by a DQUOTE. In particular, 1364 for HTTP Adaptive Streaming (HAS) session, the Session 1365 IDentifier value is included in the Logging record for every 1366 content chunk delivery of that session in view of facilitating 1367 the later correlation of all the per content chunk log records 1368 of a given HAS session. See section 3.4.2.2. of [RFC6983] for 1369 more discussion on the concept of Session IDentifier in the 1370 context of HAS. If the SID conveyed contains one or more 1371 DQUOTE, each DQUOTE MUST be escaped by an additional DQUOTE. 1372 For example, if the SID is My_SID"value", then the field value 1373 of the s-sid is "My_SID""value""". 1375 * occurrence: there MUST be zero or exactly one instance of this 1376 field. 1378 o s-cached: 1380 * format: 1DIGIT 1382 * field value: this characterises whether the Surrogate served 1383 the request using content already stored on its local cache or 1384 not. The allowed values are "0" (for miss) and "1" (for hit). 1385 "1" MUST be used when the Surrogate did serve the request using 1386 exclusively content already stored on its local cache. "0" MUST 1387 be used otherwise (including cases where the Surrogate served 1388 the request using some, but not all, content already stored on 1389 its local cache). Note that a "0" only means a cache miss in 1390 the Surrogate and does not provide any information on whether 1391 the content was already stored, or not, in another device of 1392 the dCDN, i.e., whether this was a "dCDN hit" or "dCDN miss". 1394 * occurrence: there MUST be zero or exactly one instance of this 1395 field. 1397 The "Fields" directive corresponding to a HTTP Request Logging Record 1398 MUST contain all the fields names whose occurrence is specified above 1399 as "There MUST be one and only one instance of this field". The 1400 corresponding fields value MUST be present in every HTTP Request 1401 Logging Record. 1403 The "Fields" directive corresponding to a HTTP Request Logging Record 1404 MAY list all the fields value whose occurrence is specified above as 1405 "there MUST be zero or exactly one instance of this field" or "there 1406 MAY be zero, one or any number of instances of this field". The set 1407 of such field names actually listed in the "Fields" directive is 1408 selected by the CDN generating the CDNI Logging File based on 1409 agreements between the interconnected CDNs established through 1410 mechanisms outside the scope of this specification (e.g., contractual 1411 agreements). When such a field name is not listed in the "Fields" 1412 directive, the corresponding field value MUST NOT be included in the 1413 Logging Record. When such a field name is listed in the "Fields" 1414 directive, the corresponding field value MUST be included in the 1415 Logging Record; if the value for the field is not available, this 1416 MUST be conveyed via a dash character ("-"). 1418 The fields names listed in the "Fields" directive MAY be listed in 1419 the order in which they are listed in Section 3.4.1 or MAY be listed 1420 in any other order. 1422 A dCDN-side implementation of the CDNI Logging interface MUST 1423 implement all the following Logging Fields in a CDNI Logging Record 1424 of Record-Type "cdni_http_request_v1", and MUST support the ability 1425 to include valid values for each of them: 1427 o date 1429 o time 1431 o time-taken 1433 o c-ip 1435 o c-ip-anonymizing 1437 o c-port 1439 o c-port-anonymizing 1441 o s-ip 1443 o s-hostname 1445 o s-port 1447 o cs-method 1449 o cs-uri 1451 o u-uri 1453 o protocol 1455 o sc-status 1457 o sc-total-bytes 1458 o sc-entity-bytes 1460 o cs() 1462 o sc() 1464 o s-cached 1466 A dCDN-side implementation of the CDNI Logging interface MAY support 1467 the following Logging Fields in a CDNI Logging Record of Record-Type 1468 "cdni_http_request_v1": 1470 o s-ccid 1472 o s-sid 1474 If a dCDN-side implementation of the CDNI Logging interface supports 1475 these Fields, it MUST support the ability to include valid values for 1476 them. 1478 An uCDN-side implementation of the CDNI Logging interface MUST be 1479 able to accept CDNI Logging Files with CDNI Logging Records of 1480 Record-Type "cdni_http_request_v1" containing any CDNI Logging Field 1481 defined in Section 3.4.1 as long as the CDNI Logging Record and the 1482 CDNI Logging File are compliant with the present document. 1484 In case, an uCDN-side implementation of the CDNI Logging interface 1485 receives a CDNI Logging File with HTTP Request Logging Records that 1486 do not contain field values for exactly the set of field names 1487 actually listed in the preceding "Fields" directive, the 1488 implementation MUST reject those HTTP Request Logging Records, and 1489 MUST accept the other HTTP Request Logging Records . 1491 3.5. CDNI Logging File Example 1493 Let us consider the upstream CDN and the downstream CDN labelled uCDN 1494 and dCDN-1 in Figure 1. When dCDN-1 acts as a downstream CDN for 1495 uCDN and performs content delivery on behalf of uCDN, dCDN-1 will 1496 include the CDNI Logging Records corresponding to the content 1497 deliveries performed on behalf of uCDN in the CDNI Logging Files for 1498 uCDN. An example CDNI Logging File communicated by dCDN-1 to uCDN is 1499 shown below in Figure 4. 1501 #Version:CDNI/1.0 1503 #UUID:urn:uuid:f81d4fae-7dec-11d0-a765-00a0c91e6bf6 1505 #Claimed-Origin:cdni-logging-entity.dcdn-1.example.com 1507 #Record-Type:cdni_http_request_v1 1509 #Fields:datetimetime-takenc-ip 1510 c-ip-anonymizingcs-methodu-uriprotocol 1511 sc-statussc-total-bytescs(User-Agent) 1512 cs(Referer)s-cached 1514 2013-05-1700:38:06.8259.05810.5.7.08GET 1515 http://cdni-ucdn.dcdn-1.example.com/video/movie100.mp4 1516 HTTP/1.12006729891"Mozilla/5.0 1517 (Windows; U; Windows NT 6.0; en-US) AppleWebKit/533.4 (KHTML, like 1518 Gecko) Chrome/5.0.375.127 Safari/533.4" 1519 "host1.example.com"1 1521 2013-05-1700:39:09.14515.3210.5.10.08GET 1522 http://cdni-ucdn.dcdn-1.example.com/video/movie118.mp4 1523 HTTP/1.120015799210"Mozilla/5.0 1524 (Windows; U; Windows NT 6.0; en-US) AppleWebKit/533.4 (KHTML, like 1525 Gecko) Chrome/5.0.375.127 Safari/533.4" 1526 "host1.example.com"1 1528 2013-05-1700:42:53.43752.87910.5.10.08GET 1529 http://cdni-ucdn.dcdn-1.example.com/video/picture11.mp4 1530 HTTP/1.020097234724"Mozilla/5.0 1531 (Windows; U; Windows NT 6.0; en-US) AppleWebKit/533.4 (KHTML, like 1532 Gecko) Chrome/5.0.375.127 Safari/533.4" 1533 "host5.example.com"0 1535 #SHA256-Hash:...32-hexadecimal-digit hash value... 1537 Figure 4: CDNI Logging File Example 1539 If uCDN establishes by some means (e.g. via TLS authentication when 1540 pulling the CDNI Logging File) the identity of the entity from which 1541 it pulled the CDNI Logging File, uCDN can add to the CDNI Logging an 1542 Established-Origin directive as illustrated below: 1544 #Established-Origin:cdni-logging-entity.dcdn- 1545 1.example.com 1547 As illustrated in Figure 2, uCDN will then ingest the corresponding 1548 CDNI Logging Records into its Collection process, alongside the 1549 Logging Records generated locally by the uCDN itself. This allows 1550 uCDN to aggregate Logging Records for deliveries performed by itself 1551 (through Records generated locally) as well as for deliveries 1552 performed by its downstream CDN(s). This aggregate information can 1553 then be used (after Filtering and Rectification, as illustrated in 1554 Figure 2) by Log Consuming Applications that take into account 1555 deliveries performed by uCDN as well as by all of its downstream 1556 CDNs. 1558 We observe that the time between 1560 1. when a delivery is completed in dCDN and 1562 2. when the corresponding Logging Record is ingested by the 1563 Collection process in uCDN 1565 depends on a number of parameters such as the Logging Period agreed 1566 to by uCDN and dCDN, how much time uCDN waits before pulling the CDNI 1567 Logging File once it is advertised in the CDNI Logging Feed, and the 1568 time to complete the pull of the CDNI Logging File. Therefore, if we 1569 consider the set of Logging Records aggregated by the Collection 1570 process in uCDN in a given time interval, there could be a permanent 1571 significant timing difference between the CDNI Logging Records 1572 received from the dCDN and the Logging Records generated locally. 1573 For example, in a given time interval, the Collection process in uCDN 1574 may be aggregating Logging Records generated locally by uCDN for 1575 deliveries performed in the last hour and CDNI Logging Records 1576 generated in the dCDN for deliveries in the hour before last. 1578 3.6. Cascaded CDNI Logging Files Example 1580 Let us consider the cascaded CDN scenario of uCDN, dCDN-2 and dCDN-3 1581 as depicted in Figure 1. After completion of a delivery by dCDN-3 on 1582 behalf of dCDN-2, dCDN-3 will include a corresponding Logging Record 1583 in a CDNI Logging File that will be pulled by dCDN-2 and that is 1584 illustrated below in Figure 5. In practice, a CDNI Logging File is 1585 likely to contain a very high number of CDNI Logging Records. 1586 However, for readability, the example in Figure 5 contains a single 1587 CDNI Logging Record. 1589 #Version:CDNI/1.0 1591 #UUID:urn:uuid:65718ef-0123-9876-adce4321bcde 1593 #Claimed-Origin:cdni-logging-entity.dcdn-3.example.com 1595 #Record-Type:cdni_http_request_v1 1597 #Fields:datetimetime-takenc-ip 1598 c-ip-anonymizingcs-methodu-uriprotocol 1599 sc-statussc-total-bytescs(User-Agent) 1600 cs(Referer)s-cached 1602 2013-05-1700:39:09.11914.0710.5.10.08GET 1603 http://cdni-dcdn-2.dcdn-3.example.com/video/movie118.mp4 1604 HTTP/1.120015799210"Mozilla/5.0 1605 (Windows; U; Windows NT 6.0; en-US) AppleWebKit/533.4 (KHTML, like 1606 Gecko) Chrome/5.0.375.127 Safari /533.4" 1607 "host1.example.com"1 1609 #SHA256-Hash:...32-hexadecimal-digit hash value... 1611 Figure 5: Cascaded CDNI Logging File Example (dCDN-3 to dCDN-2) 1613 If dCDN-2 establishes by some means (e.g. via TLS authentication when 1614 pulling the CDNI Logging File) the identity of the entity from which 1615 it pulled the CDNI Logging File, dCDN-2 can add to the CDNI Logging 1616 an Established-Origin directive as illustrated below: 1618 #Established-Origin:cdni-logging-entity.dcdn- 1619 3.example.com 1621 dCDN-2 (behaving as an upstream CDN from the viewpoint of dCDN-3) 1622 will then ingest the CDNI Logging Record for the considered dCDN-3 1623 delivery into its Collection process (as illustrated in Figure 2). 1624 This Logging Record may be aggregated with Logging Records generated 1625 locally by dCDN-2 for deliveries performed by dCDN-2 itself. Say, 1626 for illustration, that the content delivery performed by dCDN-3 on 1627 behalf of dCDN-2 had actually been redirected to dCDN-2 by uCDN, and 1628 say that another content delivery has just been redirected by uCDN to 1629 dCDN-2 and that dCDN-2 elected to perform the corresponding delivery 1630 itself. Then after Filtering and Rectification (as illustrated in 1631 Figure 2), dCDN-2 will include the two Logging Records corresponding 1632 respectively to the delivery performed by dCDN-3 and the delivery 1633 performed by dCDN-2, in the next CDNI Logging File that will be 1634 communicated to uCDN. An example of such CDNI Logging File is 1635 illustrated below in Figure 6. 1637 #Version:CDNI/1.0 1639 #UUID:urn:uuid:1234567-8fedc-abab-0987654321ff 1641 #Claimed-Origin:cdni-logging-entity.dcdn-2.example.com 1643 #Record-Type:cdni_http_request_v1 1645 #Fields:datetimetime-takenc-ip 1646 c-ip-anonymizingcs-methodu-uriprotocol 1647 sc-statussc-total-bytescs(User-Agent) 1648 cs(Referer)s-cached 1650 2013-05-1700:39:09.11914.0710.5.10.08GET 1651 http://cdni-ucdn.dcdn-2.example.com/video/movie118.mp4 1652 HTTP/1.120015799210"Mozilla/5.0 1653 (Windows; U; Windows NT 6.0; en-US) AppleWebKit/533.4 (KHTML, like 1654 Gecko) Chrome/5.0.375.127 Safari /533.4" 1655 "host1.example.com"1 1657 2013-05-1701:42:53.43752.87910.5.10.08GET 1658 http://cdni-ucdn.dcdn-2.example.com/video/picture11.mp4 1659 HTTP/1.020097234724"Mozilla/5.0 1660 (Windows; U; Windows NT 6.0; en-US) AppleWebKit/533.4 (KHTML, like 1661 Gecko) Chrome/5.0.375.127 Safari /533.4" 1662 "host5.example.com"0 1664 #SHA256-Hash:...32-hexadecimal-digit hash value... 1666 Figure 6: Cascaded CDNI Logging File Example (dCDN-2 to uCDN) 1668 If uCDN establishes by some means (e.g. via TLS authentication when 1669 pulling the CDNI Logging File) the identity of the entity from which 1670 it pulled the CDNI Logging File, uCDN can add to the CDNI Logging an 1671 Established-Origin directive as illustrated below: 1673 #Established-Origin:cdni-logging-entity.dcdn- 1674 2.example.com 1676 In the example of Figure 6, we observe that: 1678 o the first Logging Record corresponds to the Logging Record 1679 communicated earlier to dCDN-2 by dCDN-3, which corresponds to a 1680 delivery redirected by uCDN to dCDN-2 and then redirected by 1681 dCDN-2 to dCDN-3. The fields values in this Logging Record are 1682 copied from the corresponding CDNI Logging REcord communicated to 1683 dCDN2 by dCDN-3, with the exception of the u-uri that now reflects 1684 the URI convention between uCDN and dCDN-2 and that presents the 1685 delivery to uCDN as if it was performed by dCDN-2 itself. This 1686 reflects the fact that dCDN-2 had taken the full responsibility of 1687 the corresponding delivery (even if in this case, dCDN-2 elected 1688 to redirect the delivery to dCDN-3 so it is actually performed by 1689 dCDN-3 on behalf of dCDN-2). 1691 o the second Logging Record corresponds to a delivery redirected by 1692 uCDN to dCDN-2 and performed by dCDN-2 itself. The time of the 1693 delivery in this Logging Record may be significantly more recent 1694 than the first Logging Record since it was generated locally while 1695 the first Logging Record was generated by dCDN-3 and had to be 1696 advertised , and then pulled and then ingested into the dCDN-2 1697 Collection process, before being aggregated with the second 1698 Logging Record. 1700 4. Protocol for Exchange of CDNI Logging File After Full Collection 1702 This section specifies a protocol for the exchange of CDNI Logging 1703 Files as specified in Section 3 after the CDNI Logging File is fully 1704 collected by the dCDN. 1706 This protocol comprises: 1708 o a CDNI Logging feed, allowing the dCDN to notify the uCDN about 1709 the CDNI Logging Files that can be retrieved by that uCDN from the 1710 dCDN, as well as all the information necessary for retrieving each 1711 of these CDNI Logging Files. The CDNI Logging feed is specified 1712 in Section 4.1. 1714 o a CDNI Logging File pull mechanism, allowing the uCDN to obtain 1715 from the dCDN a given CDNI Logging File at the uCDN's convenience. 1716 The CDNI Logging File pull mechanisms is specified in Section 4.2. 1718 An implementation of the CDNI Logging interface on the dCDN side (the 1719 entity generating the CDNI Logging file) MUST support the server side 1720 of the CDNI Logging feed (as specified in Section 4.1) and the server 1721 side of the CDNI Logging pull mechanism (as specified in 1722 Section 4.2). 1724 An implementation of the CDNI Logging interface on the uCDN side (the 1725 entity consuming the CDNI Logging file) MUST support the client side 1726 of the CDNI Logging feed (as specified in Section 4.1) and the client 1727 side of the CDNI Logging pull mechanism (as specified in 1728 Section 4.2). 1730 4.1. CDNI Logging Feed 1732 The server-side implementation of the CDNI Logging feed MUST produce 1733 an Atom feed [RFC4287]. This feed is used to advertise log files 1734 that are available for the client-side to retrieve using the CDNI 1735 Logging pull mechanism. 1737 4.1.1. Atom Formatting 1739 A CDNI Logging feed MUST be structured as an Archived feed, as 1740 defined in [RFC5005], and MUST be formatted in Atom [RFC4287]. This 1741 means it consists of a subscription document that is regularly 1742 updated as new CDNI Logging Files become available, and information 1743 about older CDNI Logging files is moved into archive documents. Once 1744 created, archive documents are never modified. 1746 Each CDNI Logging File listed in an Atom feed MUST be described in an 1747 atom:entry container element. 1749 The atom:entry MUST contain an atom:content element whose "src" 1750 attribute is a link to the CDNI Logging File and whose "type" 1751 attribute is the MIME Media Type indicating that the entry is a CDNI 1752 Logging File. We define this MIME Media Type as "application/ 1753 cdni.LoggingFile" (See Section 6.5). 1755 For compatibility with some Atom feed readers the atom:entry MAY also 1756 contain an atom:link entry whose "href" attribute is a link to the 1757 CDNI Logging File and whose "type" attribute is the MIME Media Type 1758 indicating that the entry is a CDNI Logging File using the 1759 "application/cdni.LoggingFile" MIME Media Type (See Section 6.5). 1761 The URI used in the atom:id of the atom:entry MUST contain the UUID 1762 of the CDNI Logging File. 1764 The atom:updated in the atom:entry MUST indicate the time at which 1765 the CDNI Logging File was last updated. 1767 4.1.2. Updates to Log Files and the Feed 1769 CDNI Logging Files MUST NOT be modified by the dCDN once published in 1770 the CDNI Logging feed. 1772 The frequency with which the subscription feed is updated, the period 1773 of time covered by each CDNI Logging File or each archive document, 1774 and timeliness of publishing of CDNI Logging Files are outside the 1775 scope of the present document and are expected to be agreed upon by 1776 uCDN and dCDN via other means (e.g., human agreement). 1778 The server-side implementation MUST be able to set, and SHOULD set, 1779 HTTP cache control headers on the subscription feed to indicate the 1780 frequency at which the client-side is to poll for updates. 1782 The client-side MAY use HTTP cache control headers (set by the 1783 server-side) on the subscription feed to determine the frequency at 1784 which to poll for updates. The client-side MAY instead, or in 1785 addition, use other information to determine when to poll for updates 1786 (e.g., a polling frequency that may have been negotiated between the 1787 uCDN and dCDN by mechanisms outside the scope of the present document 1788 and that is to override the indications provided in the HTTP cache 1789 control headers). 1791 The potential retention limits (e.g., sliding time window) within 1792 which the dCDN is to retain and be ready to serve an archive document 1793 is outside the scope of the present document and is expected to be 1794 agreed upon by uCDN and dCDN via other means (e.g., human agreement). 1795 The server-side implementation MUST retain, and be ready to serve, 1796 any archive document within the agreed retention limits. Outside 1797 these agreed limits, the server-side implementation MAY indicate its 1798 inability to serve (e.g., with HTTP status code 404) an archive 1799 document or MAY refuse to serve it (e.g., with HTTP status code 403 1800 or 410). 1802 4.1.3. Redundant Feeds 1804 The server-side implementation MAY present more than one CDNI Logging 1805 feed for redundancy. Each CDNI Logging File MAY be published in more 1806 than one feed. 1808 A client-side implementation MAY support such redundant CDNI Logging 1809 feeds. If it supports redundant CDNI Logging feed, the client-side 1810 can use the UUID of the CDNI Logging File, presented in the atom:id 1811 element of the Atom feed, to avoid unnecessarily pulling and storing 1812 a given CDNI Logging File more than once. 1814 4.1.4. Example CDNI Logging Feed 1816 Figure 7 illustrates an example of the subscription document of a 1817 CDNI Logging feed. 1819 1820 1821 CDNI Logging Feed 1822 2013-03-23T14:46:11Z 1823 urn:uuid:663ae677-40fb-e99a-049d-c5642916b8ce 1824 1826 1828 1830 CDNI Log Feed 1831 Generator 1832 dcdn.example 1833 1834 CDNI Logging File for uCDN at 1835 2013-03-23 14:15:00 1836 urn:uuid:12345678-1234-abcd-00aa-01234567abcd 1837 2013-03-23T14:15:00Z 1838 1841 CDNI Logging File for uCDN at 1842 2013-03-23 14:15:00 1843 1844 1845 CDNI Logging File for uCDN at 1846 2013-03-23 14:30:00 1847 urn:uuid:87654321-4321-dcba-aa00-dcba7654321 1848 2013-03-23T14:30:00Z 1849 1852 CDNI Logging File for uCDN at 1853 2013-03-23 14:30:00 1854 1855 ... 1856 1857 ... 1858 1859 1861 Figure 7: Example subscription document of a CDNI Logging Feed 1863 4.2. CDNI Logging File Pull 1865 A client-side implementation of the CDNI Logging interface MAY pull, 1866 at its convenience, a CDNI Logging File that is published by the 1867 server-side in the CDNI Logging Feed (in the subscription document or 1868 an archive document). To do so, the client-side: 1870 o MUST implement HTTP/1.1 ([RFC7230],[RFC7231], [RFC7232], 1871 [RFC7233], [RFC7234], [RFC7235]), MAY also support other HTTP 1872 versions (e.g., HTTP/2 [I-D.ietf-httpbis-http2]) and MAY negotiate 1873 which HTTP version is actually used. This allows operators and 1874 implementers to choose to use later versions of HTTP to take 1875 advantage of new features, while still ensuring interoperability 1876 with systems that only support HTTP/1.1. 1878 o MUST use the URI that was associated to the CDNI Logging File 1879 (within the "src" attribute of the corresponding atom:content 1880 element) in the CDNI Logging Feed; 1882 o MUST support exchange of CDNI Logging Files with no content 1883 encoding applied to the representation; 1885 o MUST support exchange of CDNI Logging Files with "gzip" content 1886 encoding (as defined in [RFC7230]) applied to the representation. 1888 Note that a client-side implementation of the CDNI Logging interface 1889 MAY pull a CDNI Logging File that it has already pulled. 1891 The server-side implementation MUST respond to valid pull request by 1892 a client-side implementation for a CDNI Logging File published by the 1893 server-side in the CDNI Logging Feed (in the subscription document or 1894 an archive document). The server-side implementation: 1896 o MUST implement HTTP/1.1 to handle the client-side request and MAY 1897 also support other HTTP versions (e.g., HTTP/2); 1899 o MUST include the CDNI Logging File identified by the request URI 1900 inside the body of the HTTP response; 1902 o MUST support exchange of CDNI Logging Files with no content 1903 encoding applied to the representation; 1905 o MUST support exchange of CDNI Logging Files with "gzip" content 1906 encoding (as defined in [RFC7231]) applied to the representation. 1908 Content negotiation approaches defined in [RFC7231] (e.g., using 1909 Accept-Encoding request-header field or Content-Encoding entity- 1910 header field) MAY be used by the client-side and server-side 1911 implementations to establish the content-coding to be used for a 1912 particular exchange of a CDNI Logging File. 1914 Applying compression content encoding (such as "gzip") is expected to 1915 mitigate the impact of exchanging the large volumes of logging 1916 information expected across CDNs. This is expected to be 1917 particularly useful in the presence of HTTP Adaptive Streaming (HAS) 1918 which, as per the present version of the document, will result in a 1919 separate CDNI Log Record for each HAS segment delivery in the CDNI 1920 Logging File. 1922 The potential retention limits (e.g., sliding time window, maximum 1923 aggregate file storage quotas) within which the dCDN is to retain and 1924 be ready to serve a CDNI Logging File previously advertised in the 1925 CDNI Logging Feed is outside the scope of the present document and is 1926 expected to be agreed upon by uCDN and dCDN via other means (e.g., 1927 human agreement). The server-side implementation MUST retain, and be 1928 ready to serve, any CDNI Logging File within the agreed retention 1929 limits. Outside these agreed limits, the server-side implementation 1930 MAY indicate its inability to serve (e.g., with HTTP status code 404) 1931 a CDNI Logging File or MAY refuse to serve it (e.g., with HTTP status 1932 code 403 or 410). 1934 5. Protocol for Exchange of CDNI Logging File During Collection 1936 We note that, in addition to the CDNI Logging File exchange protocol 1937 specified in Section 4, implementations of the CDNI Logging interface 1938 may also support other mechanisms to exchange CDNI Logging Files. In 1939 particular, such mechanisms might allow the exchange of the CDNI 1940 Logging File to start before the file is fully collected. This can 1941 allow CDNI Logging Records to be communicated by the dCDN to the uCDN 1942 as they are gathered by the dCDN without having to wait until all the 1943 CDNI Logging Records of the same logging period are collected in the 1944 corresponding CDNI Logging File. This approach is commonly referred 1945 to as "tailing" of the file. 1947 Such an approach could be used, for example, to exchange logging 1948 information with a significantly reduced time-lag (e.g., sub-minute 1949 or sub-second) between when the event occurred in the dCDN and when 1950 the corresponding CDNI Logging Record is made available to the uCDN. 1951 This can satisfy log-consuming applications requiring extremely fresh 1952 logging information such as near-real-time content delivery 1953 monitoring. Such mechanisms are for further study and outside the 1954 scope of this document. 1956 6. IANA Considerations 1958 6.1. CDNI Logging Directive Names Registry 1960 The IANA is requested to create a new registry, CDNI Logging 1961 Directive Names. 1963 The initial contents of the CDNI Logging Directives registry comprise 1964 the names of the directives specified in Section 3.3 of the present 1965 document, and are as follows: 1967 +------------------------------+-----------+ 1968 | Directive Name | Reference | 1969 +------------------------------+-----------+ 1970 | Version | RFC xxxx | 1971 | UUID | RFC xxxx | 1972 | Claimed-Origin | RFC xxxx | 1973 | Established-Origin | RFC xxxx | 1974 | Record-Type | RFC xxxx | 1975 | Fields | RFC xxxx | 1976 | SHA256-Hash | RFC xxxx | 1977 +------------------------------+-----------+ 1979 Figure 8 1981 [Instructions to IANA: Replace "RFC xxxx" above by the RFC number of 1982 the present document] 1984 Within the registry, names are to be allocated by IANA according to 1985 the "Specification Required" policy specified in [RFC5226]. 1986 Directive names are to be allocated by IANA with a format of 1987 NAMEFORMAT (see Section 3.1). 1989 Each specification that defines a new CDNI Logging directive needs to 1990 contain a description for the new directive with the same set of 1991 information as provided in Section 3.3 (i.e., format, directive value 1992 and occurrence). 1994 6.2. CDNI Logging File Version Registry 1996 The IANA is requested to create a new registry, CDNI Logging File 1997 Version. 1999 The initial contents of the CDNI Logging Logging File Version 2000 registry comprise the value "CDNI/1.0" specified in Section 3.3 of 2001 the present document, and are as follows: 2003 +-----------------+-----------+----------------------------------+ 2004 | Version | Reference | Description | 2005 +-----------------+-----------+----------------------------------+ 2006 | CDNI/1.0 | RFC xxxx | CDNI Logging File version 1.0 | 2007 | | | as specified in RFC xxxx | 2008 +-----------------+-----------+----------------------------------+ 2010 Figure 9 2012 [Instructions to IANA: Replace "RFC xxxx" above by the RFC number of 2013 the present document] 2015 Within the registry, Version values are to be allocated by IANA 2016 according to the "Specification Required" policy specified in 2017 [RFC5226]. Version values are to be allocated by IANA with a format 2018 of NAMEFORMAT (see Section 3.1). 2020 6.3. CDNI Logging Record-Types Registry 2022 The IANA is requested to create a new registry, CDNI Logging Record- 2023 Types. 2025 The initial contents of the CDNI Logging Record-Types registry 2026 comprise the names of the CDNI Logging Record types specified in 2027 Section 3.4 of the present document, and are as follows: 2029 +----------------------+-----------+----------------------------------+ 2030 | Record-Types | Reference | Description | 2031 +----------------------+-----------+----------------------------------+ 2032 | cdni_http_request_v1 | RFC xxxx | CDNI Logging Record version 1 | 2033 | | | for content delivery using HTTP | 2034 +----------------------+-----------+----------------------------------+ 2036 Figure 10 2038 [Instructions to IANA: Replace "RFC xxxx" above by the RFC number of 2039 the present document] 2041 Within the registry, Record-Types are to be allocated by IANA 2042 according to the "Specification Required" policy specified in 2043 [RFC5226]. Record-Types are to be allocated by IANA with a format of 2044 NAMEFORMAT (see Section 3.1). 2046 Each specification that defines a new Record-Type needs to contain a 2047 description for the new Record-Type with the same set of information 2048 as provided in Section 3.4.1. This includes: 2050 o a list of all the CDNI Logging Fields that can appear in a CDNI 2051 Logging Record of the new Record-Type 2053 o for all these Fields: a specification of the occurrence for each 2054 Field in the new Record-Type 2056 o for every newly defined Field, i.e., for every Field that results 2057 in a registration in the CDNI Logging Field Names Registry 2058 (Section 6.4): a specification of the field name, format and field 2059 value. 2061 6.4. CDNI Logging Field Names Registry 2063 The IANA is requested to create a new registry, CDNI Logging Field 2064 Names. 2066 This registry is intended to be shared across the currently defined 2067 Record-Type (i.e., cdni_http_request_v1) as well as potential other 2068 CDNI Logging Record-Types that may be defined in separate 2069 specifications. When a Field from this registry is used by another 2070 CDNI Logging Record-Type, it is to be used with the exact semantics 2071 and format specified in the document that registered this field and 2072 that is identified in the Reference column of the registry. If 2073 another CDNI Logging Record-Type requires a Field with semantics that 2074 are not strictly identical, or a format that is not strictly 2075 identical then this new Field is to be registered in the registry 2076 with a different Field name. When a Field from this registry is used 2077 by another CDNI Logging Record-Type, it can be used with different 2078 occurence rules. 2080 The initial contents of the CDNI Logging Fields Names registry 2081 comprise the names of the CDNI Logging fields specified in 2082 Section 3.4 of the present document, and are as follows: 2084 +------------------------------------------+-----------+ 2085 | Field Name | Reference | 2086 +------------------------------------------+-----------+ 2087 | date | RFC xxxx | 2088 | time | RFC xxxx | 2089 | time-taken | RFC xxxx | 2090 | c-ip | RFC xxxx | 2091 | c-ip-anonymizing | RFC xxxx | 2092 | c-port | RFC xxxx | 2093 | s-ip | RFC xxxx | 2094 | s-hostname | RFC xxxx | 2095 | s-port | RFC xxxx | 2096 | cs-method | RFC xxxx | 2097 | cs-uri | RFC xxxx | 2098 | u-uri | RFC xxxx | 2099 | protocol | RFC xxxx | 2100 | sc-status | RFC xxxx | 2101 | sc-total-bytes | RFC xxxx | 2102 | sc-entity-bytes | RFC xxxx | 2103 | cs() | RFC xxxx | 2104 | sc() | RFC xxxx | 2105 | s-ccid | RFC xxxx | 2106 | s-sid | RFC xxxx | 2107 | s-cached | RFC xxxx | 2108 +------------------------------------------+-----------+ 2110 Figure 11 2112 [Instructions to IANA: Replace "RFC xxxx" above by the RFC number of 2113 the present document] 2115 Within the registry, names are to be allocated by IANA according to 2116 the "Specification Required" policy specified in [RFC5226]. Field 2117 names are to be allocated by IANA with a format of NHTABSTRING (see 2118 Section 3.1). 2120 6.5. CDNI Logging MIME Media Type 2122 The IANA is requested to allocate the "application/cdni.LoggingFile" 2123 MIME Media Type (whose use is specified in Section 4.1.1 of the 2124 present document) in the MIME Media Types registry. 2126 7. Security Considerations 2127 7.1. Authentication, Authorization, Confidentiality, Integrity 2128 Protection 2130 An implementation of the CDNI Logging interface MUST support TLS 2131 transport of the CDNI Logging feed (Section 4.1) and of the CDNI 2132 Logging File pull (Section 4.2) as per [RFC2818] and [RFC7230]. 2134 The use of TLS for transport of the CDNI Logging feed and CDNI 2135 Logging File pull allows: 2137 o the dCDN and uCDN to authenticate each other 2139 and, once they have mutually authenticated each other, it allows:: 2141 o the dCDN and uCDN to authorize each other (to ensure they are 2142 transmitting/receiving CDNI Logging File to/from an authorized 2143 CDN) 2145 o the CDNI Logging information to be transmitted with 2146 confidentiality 2148 o the integrity of the CDNI Logging information to be protected 2149 during the exchange. 2151 In an environment where any such protection is required, the use of a 2152 mutually authenticated encrypted transport MUST be used to ensure 2153 confidentiality of the logging information. TLS MUST be used 2154 (including authentication of the remote end) by the server- side and 2155 the client-side of the CDNI Logging feed, as well as the server- side 2156 and the client-side of the CDNI Logging File pull mechanism. 2158 The general TLS usage guidance in [I-D.ietf-uta-tls-bcp] SHOULD be 2159 followed. 2161 The SHA256-Hash directive inside the CDNI Logging File provides 2162 additional integrity protection, this time targeting potential 2163 corruption of the CDNI logging information during the CDNI Logging 2164 File generation, storage or exchange. This mechanism does not itself 2165 allow restoration of the corrupted CDNI Logging information, but it 2166 allows detection of such corruption and therefore triggering of 2167 appropriate corrective actions (e.g., discard of corrupted 2168 information, attempt to re-obtain the CDNI Logging information). 2169 Note that the SHA256-Hash does not protect against tampering by a 2170 third party, since such a third party could have recomputed and 2171 updated the SHA256-Hash after tampering. Protection against third 2172 party tampering can be achieved as discussed above through the use of 2173 TLS. 2175 7.2. Denial of Service 2177 This document does not define specific mechanism to protect against 2178 Denial of Service (DoS) attacks on the Logging Interface. However, 2179 the CDNI Logging feed and CDNI Logging pull endpoints are typically 2180 to be accessed only by a very small number of valid remote endpoints 2181 and therefore can be easily protected against DoS attacks through the 2182 usual conventional DOS protection mechanisms such as firewalling or 2183 use of Virtual Private Networks (VPNs). 2185 Protection of dCDN Surrogates against spoofed delivery requests is 2186 outside the scope of the CDNI Logging interface. 2188 7.3. Privacy 2190 CDNs have the opportunity to collect detailed information about the 2191 downloads performed by End Users. The provision of this information 2192 to another CDN introduces potential End Users privacy protection 2193 concerns. 2195 The use of mutually authenticated TLS to establish a secure session 2196 for the transport of the CDNI Logging feed and CDNI Logging pull as 2197 discussed in Section 7.1 access to the logging information. This 2198 provides confidentiality while the logging information is in transit 2199 and prevents any other party than the authorised uCDN to gain access 2200 to the logging information. 2202 We observe that when CDNI interconnection is realised as per 2203 [RFC7336], the uCDN handles the initial End User requests (before it 2204 is redirected to the dCDN) so, regardless of which information is, or 2205 is not, communicated to the uCDN through the CDNI Logging interface, 2206 the uCDN has visibility on significant information such as the IP 2207 address of the End User request and the URL of the request. 2209 Nonetheless, if the dCDN and uCDN agree that anonymization is 2210 required to avoid making some detailed information available to the 2211 uCDN (such as how many bytes of the content have been watched by an 2212 End User and/or at what time) or is required to meet some legal 2213 obligations, then the uCDN and dCDN can agree to exchange anonymized 2214 End Users IP address in CDNI Logging Files and the c-ip-anonymization 2215 field can be used to convey the number of bits that have been 2216 anonymized so that the meaningful information can still be easily 2217 extracted from the anonymized addressses (e.g., for geolocation aware 2218 analytics). 2220 We note that anonymization of End Users IP address does not fully 2221 protect against deriving potentially sensitive information about 2222 traffic patterns; in general, increasing the number of bits that are 2223 anonymized can mitigate the risks of deriving such sensitive traffic 2224 pattern information. 2226 We also note that independently of IP addresses, the query string 2227 portion of the URL that may be conveyed inside the cs-uri and u-uri 2228 fields of CDNI Logging Files, or the HTTP cookies( [RFC6265]) that 2229 may be conveyed inside the cs() field of CDNI 2230 Logging Fields, may contain personnal information or information that 2231 can be exploited to derive personal information. Where this is a 2232 concern, the CDNI Logging interface specification allows the dCDN to 2233 not include the cs-uri and to include a u-uri that removes (or hides) 2234 the sensitive part of the query string and allows the dCDN to not 2235 include the cs() fields corresponding to HTTP 2236 headers associated with cookies. 2238 8. Acknowledgments 2240 This document borrows from the W3C Extended Log Format [ELF]. 2242 Rob Murray significantly contributed into the text of Section 4.1. 2244 The authors thank Ben Niven-Jenkins, Kevin Ma, David Mandelberg and 2245 Ray van Brandenburg for their ongoing input. 2247 Finally, we also thank Sebastien Cubaud, Pawel Grochocki, Christian 2248 Jacquenet, Yannick Le Louedec, Anne Marrec , Emile Stephan, Fabio 2249 Costa, Sara Oueslati, Yvan Massot, Renaud Edel, Joel Favier and the 2250 contributors of the EU FP7 OCEAN project for their input in the early 2251 versions of this document. 2253 9. References 2255 9.1. Normative References 2257 [I-D.ietf-uta-tls-bcp] 2258 Sheffer, Y., Holz, R., and P. Saint-Andre, 2259 "Recommendations for Secure Use of TLS and DTLS", draft- 2260 ietf-uta-tls-bcp-11 (work in progress), February 2015. 2262 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 2263 Requirement Levels", BCP 14, RFC 2119, March 1997. 2265 [RFC3339] Klyne, G., Ed. and C. Newman, "Date and Time on the 2266 Internet: Timestamps", RFC 3339, July 2002. 2268 [RFC3986] Berners-Lee, T., Fielding, R., and L. Masinter, "Uniform 2269 Resource Identifier (URI): Generic Syntax", STD 66, RFC 2270 3986, January 2005. 2272 [RFC4122] Leach, P., Mealling, M., and R. Salz, "A Universally 2273 Unique IDentifier (UUID) URN Namespace", RFC 4122, July 2274 2005. 2276 [RFC4287] Nottingham, M., Ed. and R. Sayre, Ed., "The Atom 2277 Syndication Format", RFC 4287, December 2005. 2279 [RFC5005] Nottingham, M., "Feed Paging and Archiving", RFC 5005, 2280 September 2007. 2282 [RFC5226] Narten, T. and H. Alvestrand, "Guidelines for Writing an 2283 IANA Considerations Section in RFCs", BCP 26, RFC 5226, 2284 May 2008. 2286 [RFC5234] Crocker, D. and P. Overell, "Augmented BNF for Syntax 2287 Specifications: ABNF", STD 68, RFC 5234, January 2008. 2289 [RFC5288] Salowey, J., Choudhury, A., and D. McGrew, "AES Galois 2290 Counter Mode (GCM) Cipher Suites for TLS", RFC 5288, 2291 August 2008. 2293 [RFC7230] Fielding, R. and J. Reschke, "Hypertext Transfer Protocol 2294 (HTTP/1.1): Message Syntax and Routing", RFC 7230, June 2295 2014. 2297 [RFC7231] Fielding, R. and J. Reschke, "Hypertext Transfer Protocol 2298 (HTTP/1.1): Semantics and Content", RFC 7231, June 2014. 2300 [RFC7232] Fielding, R. and J. Reschke, "Hypertext Transfer Protocol 2301 (HTTP/1.1): Conditional Requests", RFC 7232, June 2014. 2303 [RFC7233] Fielding, R., Lafon, Y., and J. Reschke, "Hypertext 2304 Transfer Protocol (HTTP/1.1): Range Requests", RFC 7233, 2305 June 2014. 2307 [RFC7234] Fielding, R., Nottingham, M., and J. Reschke, "Hypertext 2308 Transfer Protocol (HTTP/1.1): Caching", RFC 7234, June 2309 2014. 2311 [RFC7235] Fielding, R. and J. Reschke, "Hypertext Transfer Protocol 2312 (HTTP/1.1): Authentication", RFC 7235, June 2014. 2314 9.2. Informative References 2316 [CHAR_SET] 2317 "IANA Character Sets registry", 2318 . 2321 [ELF] Phillip M. Hallam-Baker, and Brian Behlendorf, "Extended 2322 Log File Format, W3C (work in progress), WD-logfile- 2323 960323", . 2325 [I-D.ietf-cdni-metadata] 2326 Niven-Jenkins, B., Murray, R., Caulfield, M., and K. Ma, 2327 "CDN Interconnection Metadata", draft-ietf-cdni- 2328 metadata-09 (work in progress), March 2015. 2330 [I-D.ietf-httpbis-http2] 2331 Belshe, M., Peon, R., and M. Thomson, "Hypertext Transfer 2332 Protocol version 2", draft-ietf-httpbis-http2-17 (work in 2333 progress), February 2015. 2335 [I-D.snell-atompub-link-extensions] 2336 Snell, J., "Atom Link Extensions", draft-snell-atompub- 2337 link-extensions-09 (work in progress), June 2012. 2339 [RFC1945] Berners-Lee, T., Fielding, R., and H. Nielsen, "Hypertext 2340 Transfer Protocol -- HTTP/1.0", RFC 1945, May 1996. 2342 [RFC2818] Rescorla, E., "HTTP Over TLS", RFC 2818, May 2000. 2344 [RFC6234] Eastlake, D. and T. Hansen, "US Secure Hash Algorithms 2345 (SHA and SHA-based HMAC and HKDF)", RFC 6234, May 2011. 2347 [RFC6265] Barth, A., "HTTP State Management Mechanism", RFC 6265, 2348 April 2011. 2350 [RFC6707] Niven-Jenkins, B., Le Faucheur, F., and N. Bitar, "Content 2351 Distribution Network Interconnection (CDNI) Problem 2352 Statement", RFC 6707, September 2012. 2354 [RFC6770] Bertrand, G., Stephan, E., Burbridge, T., Eardley, P., Ma, 2355 K., and G. Watson, "Use Cases for Content Delivery Network 2356 Interconnection", RFC 6770, November 2012. 2358 [RFC6983] van Brandenburg, R., van Deventer, O., Le Faucheur, F., 2359 and K. Leung, "Models for HTTP-Adaptive-Streaming-Aware 2360 Content Distribution Network Interconnection (CDNI)", RFC 2361 6983, July 2013. 2363 [RFC7336] Peterson, L., Davie, B., and R. van Brandenburg, 2364 "Framework for Content Distribution Network 2365 Interconnection (CDNI)", RFC 7336, August 2014. 2367 [RFC7337] Leung, K. and Y. Lee, "Content Distribution Network 2368 Interconnection (CDNI) Requirements", RFC 7337, August 2369 2014. 2371 Authors' Addresses 2373 Francois Le Faucheur (editor) 2374 Cisco Systems 2375 E.Space Park - Batiment D 2376 6254 Allee des Ormes - BP 1200 2377 Mougins cedex 06254 2378 FR 2380 Phone: +33 4 97 23 26 19 2381 Email: flefauch@cisco.com 2383 Gilles Bertrand (editor) 2384 Orange 2385 38-40 rue du General Leclerc 2386 Issy les Moulineaux 92130 2387 FR 2389 Phone: +33 1 45 29 89 46 2390 Email: gilles.bertrand@orange.com 2392 Iuniana Oprescu (editor) 2393 Orange 2394 38-40 rue du General Leclerc 2395 Issy les Moulineaux 92130 2396 FR 2398 Phone: +33 6 89 06 92 72 2399 Email: iuniana.oprescu@orange.com 2401 Roy Peterkofsky 2402 Skytide, Inc. 2403 One Kaiser Plaza, Suite 785 2404 Oakland CA 94612 2405 USA 2407 Phone: +01 510 250 4284 2408 Email: roy@skytide.com