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If it is intended as a requirements expression, it should be rewritten using one of the combinations defined in RFC 2119; otherwise it should not be all-uppercase. -- The document date (March 1, 2017) is 2606 days in the past. Is this intentional? Checking references for intended status: Proposed Standard ---------------------------------------------------------------------------- (See RFCs 3967 and 4897 for information about using normative references to lower-maturity documents in RFCs) -- Possible downref: Non-RFC (?) normative reference: ref. 'IANA-PEN' -- Possible downref: Non-RFC (?) normative reference: ref. 'IPFIX-Sets' Summary: 0 errors (**), 0 flaws (~~), 1 warning (==), 4 comments (--). Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 Internet Engineering Task Force (IETF) P. Aitken 3 Internet-Draft Brocade Communications Systems, Inc. 4 Intended status: Standards Track March 1, 2017 5 Expires: September 2, 2017 7 Utilizing Pre-defined Templates with IPFIX 8 draft-aitken-ipfix-pre-defined-templates-00 10 Abstract 12 This document specifies a way to pre-define well-known IPFIX 13 Templates which can be pre-shared with Collectors, thus avoiding the 14 need for Exporters to send those Templates to Collectors. This saves 15 export bandwidth and reduces Collector complexity. 17 Status of This Memo 19 This Internet-Draft is submitted in full conformance with the 20 provisions of BCP 78 and BCP 79. 22 Internet-Drafts are working documents of the Internet Engineering 23 Task Force (IETF). Note that other groups may also distribute 24 working documents as Internet-Drafts. The list of current Internet- 25 Drafts is at http://datatracker.ietf.org/drafts/current/. 27 Internet-Drafts are draft documents valid for a maximum of six months 28 and may be updated, replaced, or obsoleted by other documents at any 29 time. It is inappropriate to use Internet-Drafts as reference 30 material or to cite them other than as "work in progress." 32 This Internet-Draft will expire on September 2, 2017. 34 Copyright Notice 36 Copyright (c) 2017 IETF Trust and the persons identified as the 37 document authors. All rights reserved. 39 This document is subject to BCP 78 and the IETF Trust's Legal 40 Provisions Relating to IETF Documents 41 (http://trustee.ietf.org/license-info) in effect on the date of 42 publication of this document. Please review these documents 43 carefully, as they describe your rights and restrictions with respect 44 to this document. Code Components extracted from this document must 45 include Simplified BSD License text as described in Section 4.e of 46 the Trust Legal Provisions and are provided without warranty as 47 described in the Simplified BSD License. 49 Table of Contents 51 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 52 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3 53 3. Methodology . . . . . . . . . . . . . . . . . . . . . . . . . 3 54 4. Set Header Format . . . . . . . . . . . . . . . . . . . . . . 3 55 5. Template Record Format . . . . . . . . . . . . . . . . . . . 5 56 6. Data Record Format . . . . . . . . . . . . . . . . . . . . . 6 57 7. Options Template Record Format . . . . . . . . . . . . . . . 7 58 8. Options Data Record Format . . . . . . . . . . . . . . . . . 9 59 9. The Exporter's Side . . . . . . . . . . . . . . . . . . . . . 10 60 10. The Collector's Side . . . . . . . . . . . . . . . . . . . . 10 61 11. Template Management . . . . . . . . . . . . . . . . . . . . . 11 62 11.1. Template Withdrawal . . . . . . . . . . . . . . . . . . 11 63 12. Security Considerations . . . . . . . . . . . . . . . . . . . 11 64 13. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 11 65 14. References . . . . . . . . . . . . . . . . . . . . . . . . . 11 66 14.1. Normative References . . . . . . . . . . . . . . . . . . 11 67 14.2. Informative References . . . . . . . . . . . . . . . . . 12 68 Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 12 70 1. Introduction 72 IPFIX Exporters send Templates containing an ordered sequence of 73 pairs which specify the data to be communicated from 74 the IPFIX Exporter to an IPFIX Collector. 76 Templates are useful when the IPFIX Exporter is configurable in the 77 field, such that the data it will export cannot be known beforehand. 79 However, many devices are deployed with fixed configurations, 80 particularly IoT devices, sensors, and smart meters. Nevertheless, 81 the IPFIX Protocol [RFC7011] requires such devices to export a 82 Template defining the data to be Exported - which is wasteful since 83 the data format is fixed and well-known ahead of time, and each 84 device exports exactly the same data. Additional export bandwidth is 85 consumed by the Template export, and the IPFIX Collector will receive 86 the same Template from multiple devices. 88 The bandwidth overhead is particularly inefficient in the case of 89 short-lived export streams, where the Exporter creates a new export 90 session containing a Template and a few Data Records. In the worst 91 case, every Data Record is preceded by the corresponding Template. 92 This inefficiency can easily be avoided if the Template is well-known 93 before the device is even deployed in the field. 95 This document defines a method of pre-sharing the Template with the 96 Collector ahead of time, together with enhancements to the IPFIX 97 protocol to allow data-only export, i.e. export which contains only 98 IPFIX Data Records. This saves both export bandwidth and storage at 99 the Collector, since only a single Template need be stored for many 100 devices. 102 This is an appropriate method to use when a device exports a fixed 103 IPFIX Template, or selects Templates from a fixed set of IPFIX 104 Templates; when the Templates are well known beforehand; when a large 105 number of devices share the same IPFIX Template(s); and when a single 106 Data Set is exported in each IPFIX Message. 108 This is not an appropriate method to use when the Templates that a 109 device will export are not known in advance; if the Templates to be 110 exported are not shared by many other devices; or if multiple Data 111 Sets are exported per IPFIX Message. In those cases, use regular 112 IPFIX [RFC7011]. 114 2. Terminology 116 IPFIX-specific terminology (Information Element, Template, Template 117 Record, Options Template Record, Template Set, Collector, Exporter, 118 Data Record, etc.) used in this document is defined in Section 2 of 119 [RFC7011]. As in [RFC7011], these IPFIX-specific terms have the 120 first letter of a word capitalized. 122 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 123 "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and 124 "OPTIONAL" in this document are to be interpreted as described in 125 [RFC2119]. 127 3. Methodology 129 Templates are not exported directly from the Exporting Device, but 130 are provided to the Collector ahead of time by out-of-band means. 131 Templates may be provided in a number of ways and in a number of 132 formats. e.g. they may be provided with the Exporting Device, or 133 downloaded from the manufacturer's website. They may be in a pcap or 134 XML file, or in [RFC5655] format. 136 Alternatively, the Collector may be provided with a URL or set of 137 URLs from which Templates may be downloaded on-demand. URLs may be 138 provided per Enterprise. 140 4. Set Header Format 142 Existing IPFIX Sets [RFC7011] contain a 16-bit Set ID. When 143 exporting Data Records, this contains a Template ID valued between 144 256 and 65535. Values below 256 are reserved. This range is not 145 sufficiently distinct to allow multiple entities to uniquely pre- 146 define their own Templates, and a central registry would be required 147 to control the allocation of IDs. 149 However sufficient distinction can be achieved by combining the 150 Template ID with a Private Enterprise Number [IANA-PEN]. This allows 151 each enterprise to define more than 65,000 Templates of their own 152 without reference to a third-party registry. 154 The Private Enterprise Number could be included in the IPFIX Message 155 Header or in the IPFIX Set Header. Including it in the IPFIX Message 156 Header requires a new Version number, effectively creating a new 157 protocol. Whereas retaining the existing IPFIX Version and Message 158 Header, but including the Private Enterprise Number in the Set Header 159 incurs the same small overhead (i.e., 4 octets) per Data Set while 160 retaining interoperability with existing IPFIX Collectors. This 161 method would be less optimal if multiple Data Sets were exported per 162 Message. However this method targets optimisation of single Data Set 163 exports. 165 Pre-defined export Sets contain the regular IPFIX Set ID and Length 166 per [RFC7011], together with a 32-bit Private Enterprise Number 167 [IANA-PEN] as shown in Figure 1 below. Compare this with Figure I in 168 [RFC7011]. 170 0 1 2 3 171 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 172 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 173 | Set ID | Length | 174 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 175 | Private Enterprise Number | 176 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 178 Figure 1: Pre-defined Set Header Format 180 Where: 182 Set ID 184 Is identical to the [RFC7011] definition. 186 Length 188 Is identical to the [RFC7011] definition. 190 Private Enterprise Number 191 A Private Enterprise Number [IANA-PEN] identifying the 192 Enterprise which defined the template with the given Set ID. 194 5. Template Record Format 196 The pre-defined IPFIX Template format is identical to the regular 197 IPFIX Template format [RFC7011], except that the Set Header contains 198 a Private Enterprise Number [IANA-PEN] as described in Section 4 199 above. The pre-defined Record format is shown in Figure 2 below. 201 A new IPFIX Set ID TBD1 is used to distinguish pre-defined Templates 202 from regular IPFIX Templates per [RFC7011]. 204 0 1 2 3 205 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 206 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 207 | Set ID = TBD1 | Length | 208 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 209 | Private Enterprise Number | 210 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 211 | Template ID | Field Count | 212 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 213 |E| Information Element ident. | Field Length | 214 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 215 | ... | ... | 216 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 218 Figure 2: Pre-defined IPFIX Template 220 Where: 222 Set ID = TBD1 224 Is identical to the [RFC7011] definition. 226 The new IPFIX Set ID value of TBD1 indicates that the following 227 data defines a pre-defined Template. 229 Length 231 Is identical to the [RFC7011] definition. 233 Private Enterprise Number 235 A Private Enterprise Number [IANA-PEN] identifying the 236 Enterprise which defined the template. 238 The combination of Private Enterprise Number and Template ID 239 uniquely identifies the Template. 241 Template ID 243 Is identical to the [RFC7011] definition. 245 Field Count 247 Is identical to the [RFC7011] definition. 249 Information Element Identifier 251 Is identical to the [RFC7011] definition. 253 Field Length 255 Is identical to the [RFC7011] definition. 257 Note that the Template may contain enterprise-specific Information 258 Elements per [RFC7011]. It is NOT REQUIRED that these Information 259 Elements use the same Private Enterprise Number as used in the Set 260 Header. 262 6. Data Record Format 264 Data Records follow the IPFIX format specified in [RFC7011], except 265 that they also contain the Private Enterprise Number [IANA-PEN] as 266 described in Section 4 above. The Data Record format is shown in 267 Figure 3 below. Compare this with Figure Q in [RFC7011]. Notice 268 that since the Private Enterprise Number is part of the Set Header, 269 it appears only once nomatter how many Data Records are exported. 271 0 1 2 3 272 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 273 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 274 | Set ID = Template ID | Length | 275 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 276 | Private Enterprise Number | 277 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 278 | Record 1 - Field Value 1 | Record 1 - Field Value 2 | 279 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 280 | Record 1 - Field Value 3 | ... | 281 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 282 | Record 2 - Field Value 1 | Record 2 - Field Value 2 | 283 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 284 | Record 2 - Field Value 3 | ... | 285 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 286 | Record 3 - Field Value 1 | Record 3 - Field Value 2 | 287 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 288 | Record 3 - Field Value 3 | ... | 289 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 290 | ... | Padding (optional) | 291 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 293 Figure 3: Data Record for a pre-defined IPFIX Template 295 7. Options Template Record Format 297 The pre-defined IPFIX Options Template format is identical to the 298 regular IPFIX Options Template format [RFC7011], except that the Set 299 Header contains an Private Enterprise Number [IANA-PEN] as described 300 in Section 4 above. The pre-defined Options Record format is shown 301 in Figure 4 below. Compare this with Figure O in [RFC7011]. 303 A new IPFIX Set ID TBD2 is used to distinguish pre-defined Options 304 Templates from regular IPFIX Options Templates per [RFC7011]. 306 0 1 2 3 307 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 308 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 309 | Set ID = TBD2 | Length | 310 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 311 | Private Enterprise Number | 312 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 313 | Template ID | Field Count = N + M | 314 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 315 | Scope Field Count = N |0| Scope 1 Infor. Element id. | 316 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 317 | Scope 1 Field Length |0| Scope 2 Infor. Element id. | 318 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 319 | Scope 2 Field Length | ... | 320 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 321 | ... |1| Scope N Infor. Element id. | 322 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 323 | Scope N Field Length | Scope N Enterprise Number ... 324 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 325 ... Scope N Enterprise Number |1| Option 1 Infor. Element id. | 326 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 327 | Option 1 Field Length | Option 1 Enterprise Number ... 328 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 329 ... Option 1 Enterprise Number | ... | 330 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 331 | ... |0| Option M Infor. Element id. | 332 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 333 | Option M Field Length | Padding (optional) | 334 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 336 Figure 4: Pre-defined IPFIX Options Template 338 Where: 340 Set ID = TBD2 342 Is identical to the [RFC7011] definition. 344 The new IPFIX Set ID value of TBD2 indicates that the following 345 data defines a pre-defined Options Template. 347 Length 349 Is identical to the [RFC7011] definition. 351 Private Enterprise Number 352 A Private Enterprise Number [IANA-PEN] identifying the 353 Enterprise which defined the template. 355 The combination of Private Enterprise Number and Template ID 356 uniquely identifies the Options Template. 358 Template ID 360 Is identical to the [RFC7011] definition. 362 Field Count 364 Is identical to the [RFC7011] definition. 366 Scope Field Count 368 Is identical to the [RFC7011] definition. 370 Information Element Identifier 372 Is identical to the [RFC7011] definition. 374 Field Length 376 Is identical to the [RFC7011] definition. 378 Note that the Options Template may contain enterprise-specific 379 Information Elements per [RFC7011]. It is NOT REQUIRED that these 380 Information Elements use the same Private Enterprise Number as used 381 in the Set Header. 383 8. Options Data Record Format 385 Options Data Records follow the IPFIX format specified in [RFC7011], 386 except that they also contain the Private Enterprise Number 387 [IANA-PEN] as described in Section 4 above. The Data Record format 388 is shown in Figure 5 below. Notice that since the Private Enterprise 389 Number is part of the Set Header, it appears only once nomatter how 390 many Data Records are exported. 392 0 1 2 3 393 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 394 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 395 | Set ID = Options Template ID | Length | 396 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 397 | Private Enterprise Number | 398 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 399 | Record 1 - Scope Field Value 1| Record 1 - Scope Field Value 2| 400 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 401 | ... | Record 1 - Scope Field Value N| 402 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 403 | Record 1 - Field Value 1 | Record 1 - Field Value 2 | 404 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 405 | ... | Record 1 - Field Value M | 406 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 407 | Record 2 - Scope Field Value 1| Record 2 - Scope Field Value 2| 408 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 409 | ... | Record 2 - Scope Field Value N| 410 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 411 | Record 2 - Field Value 1 | Record 2 - Field Value 2 | 412 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 413 | ... | Record 2 - Field Value M | 414 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 415 | ... | ... | 416 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 417 | ... | Padding (optional) | 418 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 420 Figure 5: Data Record for a pre-defined IPFIX Options Template 422 9. The Exporter's Side 424 Exporters MUST NOT send pre-defined Templates to Collectors. 426 Exporters MAY export Data Records using a mixture of pre-defined 427 Templates and regular IPFIX Templates. 429 Note that regular IPFIX Template IDs and pre-defined Template IDs 430 share a single Template ID number space. It is RECOMMENDED that 431 Exporter manufacturers reserve a block of Template IDs for pre- 432 defined Templates, perhaps preferring lower Template IDs for regular 433 IPFIX Templates and higher Template IDs for pre-defined Templates. 435 10. The Collector's Side 437 Collectors MUST NOT expect pre-defined Templates to be sent from 438 Exporters. 440 If a Collector receives a pre-defined Template from an Exporter, it 441 MUST ignore that Template and MAY raise an error. If the pre-defined 442 Template is already known to the Collector and does not match the 443 Template received from the Exporter, then the Collector MUST shut 444 down the connection, raise an error, and MUST NOT attempt to decode 445 the associated Data Records. 447 If a Collector does not have the required pre-defined Template when 448 the corresponding Data Records are received, it MAY store those Data 449 Records for future decoding. The Collector MAY raise a warning or an 450 error as required. A Collector MUST NOT assume that a Template is 451 pre-defined because it is missing from the export stream. 453 11. Template Management 455 Once a pre-defined Template ID has been published, the format of that 456 Template MUST NOT be changed since this would invalidate the export 457 from all devices currently using that Template. 459 Although a pre-defined Template MAY be obsoleted, its Template ID can 460 never be reused. 462 11.1. Template Withdrawal 464 Pre-defined Templates cannot be withdrawn. Exporters MUST NOT send 465 an IPFIX Template Withdrawal message [RFC7011] for a pre-defined 466 Template. A Collector which receives an IPFIX Template Withdrawal 467 Message for a pre-defined Template MUST ignore that Message and MAY 468 raise an error. 470 12. Security Considerations 472 For this extension to the IPFIX protocol, the same security 473 considerations as for the IPFIX protocol apply [RFC7011]. 475 13. IANA Considerations 477 IANA MUST define Set IDs TBD1 and TBD2 in the [IPFIX-Sets] registry. 479 14. References 481 14.1. Normative References 483 [IANA-PEN] 484 IANA, "Private Enterprise Numbers", 485 . 487 [IPFIX-Sets] 488 IANA, "IPFIX Set IDs registry", 489 . 492 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 493 Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/ 494 RFC2119, March 1997, 495 . 497 [RFC7011] Claise, B., Ed., Trammell, B., Ed., and P. Aitken, 498 "Specification of the IP Flow Information Export (IPFIX) 499 Protocol for the Exchange of Flow Information", STD 77, 500 RFC 7011, DOI 10.17487/RFC7011, September 2013, 501 . 503 14.2. Informative References 505 [RFC5655] Trammell, B., Boschi, E., Mark, L., Zseby, T., and A. 506 Wagner, "Specification of the IP Flow Information Export 507 (IPFIX) File Format", RFC 5655, DOI 10.17487/RFC5655, 508 October 2009, . 510 Author's Address 512 Paul Aitken 513 Brocade Communications Systems, Inc. 514 19a Canning Street, Level 3 515 Edinburgh, Scotland EH3 8EG 516 United Kingdom 518 Phone: +44 203 005 0731 519 Email: paitken@brocade.com