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Information Model for Packet Sampling Exports.
T. Dietz, B. Claise, P. Aitken, F. Dressler, G. Carle. March 2009.

 
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Network Working Group T. Dietz Request for Comments: 5477 NEC Europe Ltd. Category: Standards Track B. Claise P. Aitken Cisco Systems, Inc. F. Dressler University of Erlangen-Nuremberg G. Carle Technical University of Munich March 2009 Information Model for Packet Sampling Exports Status of This Memo This document specifies an Internet standards track protocol for the Internet community, and requests discussion and suggestions for improvements. Please refer to the current edition of the "Internet Official Protocol Standards" (STD 1) for the standardization state and status of this protocol. Distribution of this memo is unlimited. Copyright Notice Copyright (c) 2009 IETF Trust and the persons identified as the document authors. All rights reserved. This document is subject to BCP 78 and the IETF Trust's Legal Provisions Relating to IETF Documents in effect on the date of publication of this document (http://trustee.ietf.org/license-info). Please review these documents carefully, as they describe your rights and restrictions with respect to this document. This document may contain material from IETF Documents or IETF Contributions published or made publicly available before November 10, 2008. The person(s) controlling the copyright in some of this material may not have granted the IETF Trust the right to allow modifications of such material outside the IETF Standards Process. Without obtaining an adequate license from the person(s) controlling the copyright in such materials, this document may not be modified outside the IETF Standards Process, and derivative works of it may not be created outside the IETF Standards Process, except to format it for publication as an RFC or to translate it into languages other than English. Dietz, et al. Standards Track [Page 1]
RFC 5477 PSAMP Information Model March 2009 Abstract This memo defines an information model for the Packet SAMPling (PSAMP) protocol. It is used by the PSAMP protocol for encoding sampled packet data and information related to the Sampling process. As the PSAMP protocol is based on the IP Flow Information eXport (IPFIX) protocol, this information model is an extension to the IPFIX information model. Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 2. PSAMP Documents Overview . . . . . . . . . . . . . . . . . . . 4 3. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 4 3.1. Conventions Used in This Document . . . . . . . . . . . . 5 4. Relationship between PSAMP and IPFIX . . . . . . . . . . . . . 5 5. Properties of a PSAMP Information Element . . . . . . . . . . 5 6. Type Space . . . . . . . . . . . . . . . . . . . . . . . . . . 5 7. Overloading Information Elements . . . . . . . . . . . . . . . 6 8. The PSAMP Information Elements . . . . . . . . . . . . . . . . 6 8.1. Identifiers (301-303) . . . . . . . . . . . . . . . . . . 7 8.1.1. selectionSequenceId . . . . . . . . . . . . . . . . . 7 8.1.2. selectorId . . . . . . . . . . . . . . . . . . . . . . 8 8.1.3. informationElementId . . . . . . . . . . . . . . . . . 8 8.2. Sampling Configuration (304-311) . . . . . . . . . . . . . 9 8.2.1. selectorAlgorithm . . . . . . . . . . . . . . . . . . 9 8.2.2. samplingPacketInterval . . . . . . . . . . . . . . . . 11 8.2.3. samplingPacketSpace . . . . . . . . . . . . . . . . . 11 8.2.4. samplingTimeInterval . . . . . . . . . . . . . . . . . 12 8.2.5. samplingTimeSpace . . . . . . . . . . . . . . . . . . 12 8.2.6. samplingSize . . . . . . . . . . . . . . . . . . . . . 13 8.2.7. samplingPopulation . . . . . . . . . . . . . . . . . . 13 8.2.8. samplingProbability . . . . . . . . . . . . . . . . . 13 8.3. Hash Configuration (326-334) . . . . . . . . . . . . . . . 14 8.3.1. digestHashValue . . . . . . . . . . . . . . . . . . . 14 8.3.2. hashIPPayloadOffset . . . . . . . . . . . . . . . . . 15 8.3.3. hashIPPayloadSize . . . . . . . . . . . . . . . . . . 15 8.3.4. hashOutputRangeMin . . . . . . . . . . . . . . . . . . 15 8.3.5. hashOutputRangeMax . . . . . . . . . . . . . . . . . . 16 8.3.6. hashSelectedRangeMin . . . . . . . . . . . . . . . . . 16 8.3.7. hashSelectedRangeMax . . . . . . . . . . . . . . . . . 16 8.3.8. hashDigestOutput . . . . . . . . . . . . . . . . . . . 17 8.3.9. hashInitialiserValue . . . . . . . . . . . . . . . . . 17 8.4. Timestamps (322-325) . . . . . . . . . . . . . . . . . . . 18 8.4.1. observationTimeSeconds . . . . . . . . . . . . . . . . 18 8.4.2. observationTimeMilliseconds . . . . . . . . . . . . . 18 8.4.3. observationTimeMicroseconds . . . . . . . . . . . . . 19 8.4.4. observationTimeNanoseconds . . . . . . . . . . . . . . 19 Dietz, et al. Standards Track [Page 2]
RFC 5477 PSAMP Information Model March 2009 8.5. Packet Data (313-314, 316-317) . . . . . . . . . . . . . . 19 8.5.1. ipHeaderPacketSection . . . . . . . . . . . . . . . . 20 8.5.2. ipPayloadPacketSection . . . . . . . . . . . . . . . . 20 8.5.3. mplsLabelStackSection . . . . . . . . . . . . . . . . 21 8.5.4. mplsPayloadPacketSection . . . . . . . . . . . . . . . 21 8.6. Statistics (318-321, 336-338) . . . . . . . . . . . . . . 22 8.6.1. selectorIdTotalPktsObserved . . . . . . . . . . . . . 22 8.6.2. selectorIdTotalPktsSelected . . . . . . . . . . . . . 23 8.6.3. absoluteError . . . . . . . . . . . . . . . . . . . . 23 8.6.4. relativeError . . . . . . . . . . . . . . . . . . . . 24 8.6.5. upperCILimit . . . . . . . . . . . . . . . . . . . . . 24 8.6.6. lowerCILimit . . . . . . . . . . . . . . . . . . . . . 25 8.6.7. confidenceLevel . . . . . . . . . . . . . . . . . . . 26 9. Security Considerations . . . . . . . . . . . . . . . . . . . 26 10. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 27 10.1. Related Considerations . . . . . . . . . . . . . . . . . . 27 10.2. PSAMP-Related Considerations . . . . . . . . . . . . . . . 27 11. References . . . . . . . . . . . . . . . . . . . . . . . . . . 27 11.1. Normative References . . . . . . . . . . . . . . . . . . . 27 11.2. Informative References . . . . . . . . . . . . . . . . . . 28 Appendix A. Formal Specification of PSAMP Information Elements . 29 1. Introduction Packet Sampling techniques are required for various measurement scenarios. The Packet Sampling (PSAMP) protocol provides mechanisms for packet selection using different Filtering and Sampling techniques. A standardized way for the export and storage of the Information Elements defined in Section 8 is required. The definition of the PSAMP information and data model is based on the IPFIX information model [RFC5102]. The PSAMP protocol document [RFC5476] specifies how to use the IPFIX protocol in the PSAMP context. This document examines the IPFIX information model [RFC5102] and extends it to meet the PSAMP requirements. Therefore, the structure of this document is strongly based on the IPFIX document. It complements the PSAMP protocol specification by providing an appropriate PSAMP information model. The main part of this document, Section 8, defines the list of Information Elements to be transmitted by the PSAMP protocol. Sections 5 and 6 describe the data types and Information Element properties used within this document and their relationship to the IPFIX information model. Although the PSAMP charter specified no requirements for measuring packet errors (such as drops, malformed, etc.), and this document does not cover such data, if there is need for collecting and exporting packet error information, the appropriate Information Dietz, et al. Standards Track [Page 3]
RFC 5477 PSAMP Information Model March 2009 Elements can be requested from IANA, and exported with the PSAMP protocol. The main body of Section 8 was generated from an XML document. The XML-based specification of the PSAMP Information Elements can be used for automatically checking syntactical correctness of the specification. Furthermore it can be used -- in combination with the IPFIX information model -- for automated code generation. The resulting code can be used in PSAMP protocol implementations to deal with processing PSAMP information elements. For that reason, the XML document that served as the source for Section 8 is attached to this document in Appendix A. Note that although partially generated from the attached XML documents, the main body of this document is normative while the appendix is informational. 2. PSAMP Documents Overview This document is one out of a series of documents from the PSAMP group. [RFC5474]: "A Framework for Packet Selection and Reporting" describes the PSAMP framework for network elements to select subsets of packets by statistical and other methods, and to export a stream of reports on the selected packets to a Collector. [RFC5475]: "Sampling and Filtering Techniques for IP Packet Selection" describes the set of packet selection techniques supported by PSAMP. [RFC5476]: "Packet Sampling (PSAMP) Protocol Specifications" specifies the export of packet information from a PSAMP Exporting Process to a PSAMP Collecting Process. RFC 5477 (this document): "Information Model for Packet Sampling Exports" defines an information and data model for PSAMP. 3. Terminology IPFIX-specific terminology used in this document is defined in Section 2 of [RFC5101]. PSAMP-specific terminology used in this document is defined in Section 3.2 of [RFC5476]. In this document, as in [RFC5101] and [RFC5476], the first letter of each IPFIX- and PSAMP-specific term is capitalized. Dietz, et al. Standards Track [Page 4]
RFC 5477 PSAMP Information Model March 2009 3.1. Conventions Used in This Document The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in RFC 2119 [RFC2119]. 4. Relationship between PSAMP and IPFIX As described in the PSAMP protocol [RFC5476], a PSAMP Report can be seen as a very special IPFIX Data Record. It represents an IPFIX Flow containing only a single packet. Therefore, the IPFIX information model can be used as a basis for PSAMP Reports. Nevertheless, there are properties required in PSAMP Reports that cannot be modeled using the current IPFIX information model. This document describes extensions to the IPFIX information model that allow the modeling of information and data required by PSAMP. Some of these extensions allow the export of what may be considered sensitive information. Refer to the Security Considerations section for a fuller discussion. Note that the export of sampled or filtered PSAMP Reports may not need all the Information Elements defined by the IPFIX information model [RFC5102], as discussed in Sections 6.2 and 6.3 of the PSAMP Framework [RFC5474]. 5. Properties of a PSAMP Information Element The PSAMP Information Elements are defined in accordance with Sections 2.1 to 2.3 of the IPFIX information model [RFC5102] to which reference should be made for more information. Nevertheless, we strongly recommend defining the optional "units" property for every Information Element (if applicable). The Data Types defined in Section 3.1 of the IPFIX information model [RFC5102] are also used for the PSAMP Information Elements. 6. Type Space The PSAMP Information Elements MUST be constructed from the basic abstract data types and data type semantics described in Section 3 of the IPFIX information model [RFC5102]. To ensure consistency between IPFIX and PSAMP, the data types are not repeated in this document. The encoding of these data types is described in the IPFIX protocol [RFC5101]. Dietz, et al. Standards Track [Page 5]
RFC 5477 PSAMP Information Model March 2009 7. Overloading Information Elements Information Elements SHOULD NOT be overloaded with multiple meanings or re-used for multiple purposes. Different Information Elements SHOULD be allocated for each requirement. Although the presence of certain other Information Elements allows the selection method to be inferred, a separate Information Element is provided for the selectorAlgorithm to include as scope for the Selector Report Interpretation [RFC5476]. Even if the Information Elements are specified with a specific selection method (i.e., a specific value of selectorAlgorithm) in mind, these Information Elements are not restricted to the selection method and MAY be used for different selection methods in the future. 8. The PSAMP Information Elements This section describes the Information Elements used by the PSAMP protocol. For each Information Element specified in Sections 8.1 - 8.6 below, a unique identifier is allocated in accordance with Section 4 of the IPFIX information model [RFC5102]. The assignments are controlled by IANA as an extension of the IPFIX information model. The Information Elements specified by the IPFIX information model [RFC5102] are used by the PSAMP protocol where applicable. To avoid inconsistencies between the IPFIX and the PSAMP information and data models, only those Information Elements that are not already described by the IPFIX information model are defined here. Dietz, et al. Standards Track [Page 6]
RFC 5477 PSAMP Information Model March 2009 Below is the list of additional PSAMP Information Elements: +-----+----------------------------+-----+----------------------------+ | ID | Name | ID | Name | +-----+----------------------------+-----+----------------------------+ | 301 | selectionSequenceId | 321 | relativeError | | 302 | selectorId | 322 | observationTimeSeconds | | 303 | informationElementId | 323 | observationTimeMilliseconds| | 304 | selectorAlgorithm | 324 | observationTimeMicroseconds| | 305 | samplingPacketInterval | 325 | observationTimeNanoseconds | | 306 | samplingPacketSpace | 326 | digestHashValue | | 307 | samplingTimeInterval | 327 | hashIPPayloadOffset | | 308 | samplingTimeSpace | 328 | hashIPPayloadSize | | 309 | samplingSize | 329 | hashOutputRangeMin | | 310 | samplingPopulation | 330 | hashOutputRangeMax | | 311 | samplingProbability | 331 | hashSelectedRangeMin | | 313 | ipHeaderPacketSection | 332 | hashSelectedRangeMax | | 314 | ipPayloadPacketSection | 333 | hashDigestOutput | | 316 | mplsLabelStackSection | 334 | hashInitialiserValue | | 317 | mplsPayloadPacketSection | 336 | upperCILimit | | 318 | selectorIdTotalPktsObserved| 337 | lowerCILimit | | 319 | selectorIdTotalPktsSelected| 338 | confidenceLevel | | 320 | absoluteError | | | +-----+----------------------------+-----+----------------------------+ 8.1. Identifiers (301-303) Information Elements in this section serve as identifiers. All of them have an integral abstract data type and data type semantics "identifier". +-----+----------------------------+-----+----------------------------+ | ID | Name | ID | Name | +-----+----------------------------+-----+----------------------------+ | 301 | selectionSequenceId | 303 | informationElementId | | 302 | selectorId | | | +-----+----------------------------+-----+----------------------------+ 8.1.1. selectionSequenceId Description: From all the packets observed at an Observation Point, a subset of the packets is selected by a sequence of one or more Selectors. The selectionSequenceId is a unique value per Observation Domain, specifying the Observation Point and the sequence of Selectors through which the packets are selected. Dietz, et al. Standards Track [Page 7]
RFC 5477 PSAMP Information Model March 2009 Abstract Data Type: unsigned64 Data Type Semantics: identifier ElementId: 301 Status: current 8.1.2. selectorId Description: The Selector ID is the unique ID identifying a Primitive Selector. Each Primitive Selector must have a unique ID in the Observation Domain. Abstract Data Type: unsigned16 Data Type Semantics: identifier ElementId: 302 Status: current 8.1.3. informationElementId Description: This Information Element contains the ID of another Information Element. Abstract Data Type: unsigned16 Data Type Semantics: identifier ElementId: 303 Status: current Dietz, et al. Standards Track [Page 8]
RFC 5477 PSAMP Information Model March 2009 8.2. Sampling Configuration (304-311) Information Elements in this section can be used for describing the Sampling configuration of a Selection Process. +-----+----------------------------+-----+----------------------------+ | ID | Name | ID | Name | +-----+----------------------------+-----+----------------------------+ | 304 | selectorAlgorithm | 308 | samplingTimeSpace | | 305 | samplingPacketInterval | 309 | samplingSize | | 306 | samplingPacketSpace | 310 | samplingPopulation | | 307 | samplingTimeInterval | 311 | samplingProbability | +-----+----------------------------+-----+----------------------------+ 8.2.1. selectorAlgorithm Description: This Information Element identifies the packet selection methods (e.g., Filtering, Sampling) that are applied by the Selection Process. Most of these methods have parameters. Further Information Elements are needed to fully specify packet selection with these methods and all their parameters. The methods listed below are defined in [RFC5475]. For their parameters, Information Elements are defined in the information model document. The names of these Information Elements are listed for each method identifier. Further method identifiers may be added to the list below. It might be necessary to define new Information Elements to specify their parameters. The selectorAlgorithm registry is maintained by IANA. New assignments for the registry will be administered by IANA and are subject to Expert Review [RFC5226]. The registry can be updated when specifications of the new method(s) and any new Information Elements are provided. The group of experts must double check the selectorAlgorithm definitions and Information Elements with already defined selectorAlgorithms and Information Elements for completeness, accuracy, and redundancy. Those experts will initially be drawn from the Working Group Chairs and document editors of the IPFIX and PSAMP Working Groups. Dietz, et al. Standards Track [Page 9]
RFC 5477 PSAMP Information Model March 2009 The following packet selection methods identifiers are defined here: +----+------------------------+------------------------+ | ID | Method | Parameters | +----+------------------------+------------------------+ | 1 | Systematic count-based | samplingPacketInterval | | | Sampling | samplingPacketSpace | +----+------------------------+------------------------+ | 2 | Systematic time-based | samplingTimeInterval | | | Sampling | samplingTimeSpace | +----+------------------------+------------------------+ | 3 | Random n-out-of-N | samplingSize | | | Sampling | samplingPopulation | +----+------------------------+------------------------+ | 4 | Uniform probabilistic | samplingProbability | | | Sampling | | +----+------------------------+------------------------+ | 5 | Property Match | no agreed parameters | | | Filtering | | +----+------------------------+------------------------+ | Hash-based Filtering | hashInitialiserValue | +----+------------------------+ hashIPPayloadOffset | | 6 | using BOB | hashIPPayloadSize | +----+------------------------+ hashSelectedRangeMin | | 7 | using IPSX | hashSelectedRangeMax | +----+------------------------+ hashOutputRangeMin | | 8 | using CRC | hashOutputRangeMax | +----+------------------------+------------------------+ There is a broad variety of possible parameters that could be used for Property match Filtering (5), but currently there are no agreed parameters specified. Abstract Data Type: unsigned16 Data Type Semantics: identifier ElementId: 304 Status: current Dietz, et al. Standards Track [Page 10]
RFC 5477 PSAMP Information Model March 2009 8.2.2. samplingPacketInterval Description: This Information Element specifies the number of packets that are consecutively sampled. A value of 100 means that 100 consecutive packets are sampled. For example, this Information Element may be used to describe the configuration of a systematic count-based Sampling Selector. Abstract Data Type: unsigned32 Data Type Semantics: quantity ElementId: 305 Status: current Units: packets 8.2.3. samplingPacketSpace Description: This Information Element specifies the number of packets between two "samplingPacketInterval"s. A value of 100 means that the next interval starts 100 packets (which are not sampled) after the current "samplingPacketInterval" is over. For example, this Information Element may be used to describe the configuration of a systematic count-based Sampling Selector. Abstract Data Type: unsigned32 Data Type Semantics: quantity ElementId: 306 Status: current Units: packets Dietz, et al. Standards Track [Page 11]
RFC 5477 PSAMP Information Model March 2009 8.2.4. samplingTimeInterval Description: This Information Element specifies the time interval in microseconds during which all arriving packets are sampled. For example, this Information Element may be used to describe the configuration of a systematic time-based Sampling Selector. Abstract Data Type: unsigned32 Data Type Semantics: quantity ElementId: 307 Status: current Units: microseconds 8.2.5. samplingTimeSpace Description: This Information Element specifies the time interval in microseconds between two "samplingTimeInterval"s. A value of 100 means that the next interval starts 100 microseconds (during which no packets are sampled) after the current "samplingTimeInterval" is over. For example, this Information Element may used to describe the configuration of a systematic time-based Sampling Selector. Abstract Data Type: unsigned32 Data Type Semantics: quantity ElementId: 308 Status: current Units: microseconds Dietz, et al. Standards Track [Page 12]
RFC 5477 PSAMP Information Model March 2009 8.2.6. samplingSize Description: This Information Element specifies the number of elements taken from the parent Population for random Sampling methods. For example, this Information Element may be used to describe the configuration of a random n-out-of-N Sampling Selector. Abstract Data Type: unsigned32 Data Type Semantics: quantity ElementId: 309 Status: current Units: packets 8.2.7. samplingPopulation Description: This Information Element specifies the number of elements in the parent Population for random Sampling methods. For example, this Information Element may be used to describe the configuration of a random n-out-of-N Sampling Selector. Abstract Data Type: unsigned32 Data Type Semantics: quantity ElementId: 310 Status: current Units: packets 8.2.8. samplingProbability Description: This Information Element specifies the probability that a packet is sampled, expressed as a value between 0 and 1. The probability is equal for every packet. A value of 0 means no packet was sampled since the probability is 0. Dietz, et al. Standards Track [Page 13]
RFC 5477 PSAMP Information Model March 2009 For example, this Information Element may be used to describe the configuration of a uniform probabilistic Sampling Selector. Abstract Data Type: float64 Data Type Semantics: quantity ElementId: 311 Status: current 8.3. Hash Configuration (326-334) The following Information Elements can be used for describing the Sampling configuration of a Selection Process. The individual parameters are explained in more detail in Sections 6.2, 3.8, and 7.1 of [RFC5475]. +-----+----------------------------+-----+----------------------------+ | ID | Name | ID | Name | +-----+----------------------------+-----+----------------------------+ | 326 | digestHashValue | 331 | hashSelectedRangeMin | | 327 | hashIPPayloadOffset | 332 | hashSelectedRangeMax | | 328 | hashIPPayloadSize | 333 | hashDigestOutput | | 329 | hashOutputRangeMin | 334 | hashInitialiserValue | | 330 | hashOutputRangeMax | | | +-----+----------------------------+-----+----------------------------+ 8.3.1. digestHashValue Description: This Information Element specifies the value from the digest hash function. See also Sections 6.2, 3.8, and 7.1 of [RFC5475]. Abstract Data Type: unsigned64 Data Type Semantics: quantity ElementId: 326 Status: current Dietz, et al. Standards Track [Page 14]
RFC 5477 PSAMP Information Model March 2009 8.3.2. hashIPPayloadOffset Description: This Information Element specifies the IP payload offset used by a Hash-based Selection Selector. See also Sections 6.2, 3.8, and 7.1 of [RFC5475]. Abstract Data Type: unsigned64 Data Type Semantics: quantity ElementId: 327 Status: current 8.3.3. hashIPPayloadSize Description: This Information Element specifies the IP payload size used by a Hash-based Selection Selector. See also Sections 6.2, 3.8, and 7.1 of [RFC5475]. Abstract Data Type: unsigned64 Data Type Semantics: quantity ElementId: 328 Status: current 8.3.4. hashOutputRangeMin Description: This Information Element specifies the value for the beginning of a hash function's potential output range. See also Sections 6.2, 3.8, and 7.1 of [RFC5475]. Abstract Data Type: unsigned64 Data Type Semantics: quantity Dietz, et al. Standards Track [Page 15]
RFC 5477 PSAMP Information Model March 2009 ElementId: 329 Status: current 8.3.5. hashOutputRangeMax Description: This Information Element specifies the value for the end of a hash function's potential output range. See also Sections 6.2, 3.8, and 7.1 of [RFC5475]. Abstract Data Type: unsigned64 Data Type Semantics: quantity ElementId: 330 Status: current 8.3.6. hashSelectedRangeMin Description: This Information Element specifies the value for the beginning of a hash function's selected range. See also Sections 6.2, 3.8, and 7.1 of [RFC5475]. Abstract Data Type: unsigned64 Data Type Semantics: quantity ElementId: 331 Status: current 8.3.7. hashSelectedRangeMax Description: This Information Element specifies the value for the end of a hash function's selected range. See also Sections 6.2, 3.8, and 7.1 of [RFC5475]. Abstract Data Type: unsigned64 Dietz, et al. Standards Track [Page 16]
RFC 5477 PSAMP Information Model March 2009 Data Type Semantics: quantity ElementId: 332 Status: current 8.3.8. hashDigestOutput Description: This Information Element contains a boolean value that is TRUE if the output from this hash Selector has been configured to be included in the packet report as a packet digest, else FALSE. See also Sections 6.2, 3.8, and 7.1 of [RFC5475]. Abstract Data Type: boolean Data Type Semantics: quantity ElementId: 333 Status: current 8.3.9. hashInitialiserValue Description: This Information Element specifies the initialiser value to the hash function. See also Sections 6.2, 3.8, and 7.1 of [RFC5475]. Abstract Data Type: unsigned64 Data Type Semantics: quantity ElementId: 334 Status: current Dietz, et al. Standards Track [Page 17]
RFC 5477 PSAMP Information Model March 2009 8.4. Timestamps (322-325) The Information Elements listed below contain timestamps. They can be used for reporting the observation time of a single packet. +-----+----------------------------+-----+----------------------------+ | ID | Name | ID | Name | +-----+----------------------------+-----+----------------------------+ | 322 | observationTimeSeconds | 324 | observationTimeMicroseconds| | 323 | observationTimeMilliseconds| 325 | observationTimeNanoseconds | +-----+----------------------------+-----+----------------------------+ 8.4.1. observationTimeSeconds Description: This Information Element specifies the absolute time in seconds of an observation. Abstract Data Type: dateTimeSeconds Data Type Semantics: quantity ElementId: 322 Status: current Units: seconds 8.4.2. observationTimeMilliseconds Description: This Information Element specifies the absolute time in milliseconds of an observation. Abstract Data Type: dateTimeMilliseconds Data Type Semantics: quantity ElementId: 323 Status: current Units: milliseconds Dietz, et al. Standards Track [Page 18]
RFC 5477 PSAMP Information Model March 2009 8.4.3. observationTimeMicroseconds Description: This Information Element specifies the absolute time in microseconds of an observation. Abstract Data Type: dateTimeMicroseconds Data Type Semantics: quantity ElementId: 324 Status: current Units: microseconds 8.4.4. observationTimeNanoseconds Description: This Information Element specifies the absolute time in nanoseconds of an observation. Abstract Data Type: dateTimeNanoseconds Data Type Semantics: quantity ElementId: 325 Status: current Units: nanoseconds 8.5. Packet Data (313-314, 316-317) The following Information Elements are all used for reporting raw content of a packet. All Information Elements containing sections of the observed packet can also be used in IPFIX [RFC5101]. If the values for those sections vary for different packets in a Flow, then the Flow Report will contain the value observed in the first packet of the Flow. Dietz, et al. Standards Track [Page 19]
RFC 5477 PSAMP Information Model March 2009 +-----+----------------------------+-----+----------------------------+ | ID | Name | ID | Name | +-----+----------------------------+-----+----------------------------+ | 313 | ipHeaderPacketSection | 316 | mplsLabelStackSection | | 314 | ipPayloadPacketSection | 317 | mplsPayloadPacketSection | +-----+----------------------------+-----+----------------------------+ 8.5.1. ipHeaderPacketSection Description: This Information Element, which may have a variable length, carries a series of octets from the start of the IP header of a sampled packet. With sufficient length, this element also reports octets from the IP payload, subject to [RFC2804]. See the Security Considerations section. The size of the exported section may be constrained due to limitations in the IPFIX protocol. The data for this field MUST NOT be padded. Abstract Data Type: octetArray ElementId: 313 Status: current 8.5.2. ipPayloadPacketSection Description: This Information Element, which may have a variable length, carries a series of octets from the start of the IP payload of a sampled packet. The IPv4 payload is that part of the packet that follows the IPv4 header and any options, which [RFC0791] refers to as "data" or "data octets". For example, see the examples in [RFC0791], Appendix A. The IPv6 payload is the rest of the packet following the 40-octet IPv6 header. Note that any extension headers present are considered part of the payload. See [RFC2460] for the IPv6 specification. Dietz, et al. Standards Track [Page 20]
RFC 5477 PSAMP Information Model March 2009 The size of the exported section may be constrained due to limitations in the IPFIX protocol. The data for this field MUST NOT be padded. Abstract Data Type: octetArray ElementId: 314 Status: current 8.5.3. mplsLabelStackSection Description: This Information Element, which may have a variable length, carries the first n octets from the MPLS label stack of a sampled packet. With sufficient length, this element also reports octets from the MPLS payload, subject to [RFC2804]. See the Security Considerations section. See [RFC3031] for the specification of MPLS packets. See [RFC3032] for the specification of the MPLS label stack. The size of the exported section may be constrained due to limitations in the IPFIX protocol. The data for this field MUST NOT be padded. Abstract Data Type: octetArray ElementId: 316 Status: current 8.5.4. mplsPayloadPacketSection Description: This Information Element, which may have a variable length, carries the first n octets from the MPLS payload of a sampled packet, being data that follows immediately after the MPLS label stack. See [RFC3031] for the specification of MPLS packets. Dietz, et al. Standards Track [Page 21]
RFC 5477 PSAMP Information Model March 2009 See [RFC3032] for the specification of the MPLS label stack. The size of the exported section may be constrained due to limitations in the IPFIX protocol. The data for this field MUST NOT be padded. Abstract Data Type: octetArray ElementId: 317 Status: current 8.6. Statistics (318-321, 336-338) Information Elements in this section can be used for reporting statistics from the Metering Process. +-----+----------------------------+-----+----------------------------+ | ID | Name | ID | Name | +-----+----------------------------+-----+----------------------------+ | 318 | selectorIdTotalPktsObserved| 336 | upperCILimit | | 319 | selectorIdTotalPktsSelected| 337 | lowerCILimit | | 320 | absoluteError | 338 | confidenceLevel | | 321 | relativeError | | | +-----+----------------------------+-----+----------------------------+ 8.6.1. selectorIdTotalPktsObserved Description: This Information Element specifies the total number of packets observed by a Selector, for a specific value of SelectorId. This Information Element should be used in an Options Template scoped to the observation to which it refers. See Section 3.4.2.1 of the IPFIX protocol document [RFC5101]. Abstract Data Type: unsigned64 Data Type Semantics: totalCounter ElementId: 318 Status: current Units: packets Dietz, et al. Standards Track [Page 22]
RFC 5477 PSAMP Information Model March 2009 8.6.2. selectorIdTotalPktsSelected Description: This Information Element specifies the total number of packets selected by a Selector, for a specific value of SelectorId. This Information Element should be used in an Options Template scoped to the observation to which it refers. See Section 3.4.2.1 of the IPFIX protocol document [RFC5101]. Abstract Data Type: unsigned64 Data Type Semantics: totalCounter ElementId: 319 Status: current Units: packets 8.6.3. absoluteError Description: This Information Element specifies the maximum possible measurement error of the reported value for a given Information Element. The absoluteError has the same unit as the Information Element with which it is associated. The real value of the metric can differ by absoluteError (positive or negative) from the measured value. This Information Element provides only the error for measured values. If an Information Element contains an estimated value (from Sampling), the confidence boundaries and confidence level have to be provided instead, using the upperCILimit, lowerCILimit, and confidenceLevel Information Elements. This Information Element should be used in an Options Template scoped to the observation to which it refers. See section 3.4.2.1 of the IPFIX protocol document [RFC5101]. Abstract Data Type: float64 Data Type Semantics: quantity ElementId: 320 Dietz, et al. Standards Track [Page 23]
RFC 5477 PSAMP Information Model March 2009 Status: current Units: The units of the Information Element for which the error is specified. 8.6.4. relativeError Description: This Information Element specifies the maximum possible positive or negative error ratio for the reported value for a given Information Element as a percentage of the measured value. The real value of the metric can differ by relativeError percent (positive or negative) from the measured value. This Information Element provides only the error for measured values. If an Information Element contains an estimated value (from Sampling), the confidence boundaries and confidence level have to be provided instead, using the upperCILimit, lowerCILimit, and confidenceLevel Information Elements. This Information Element should be used in an Options Template scoped to the observation to which it refers. See Section 3.4.2.1 of the IPFIX protocol document [RFC5101]. Abstract Data Type: float64 Data Type Semantics: quantity ElementId: 321 Status: current 8.6.5. upperCILimit Description: This Information Element specifies the upper limit of a confidence interval. It is used to provide an accuracy statement for an estimated value. The confidence limits define the range in which the real value is assumed to be with a certain probability p. Confidence limits always need to be associated with a confidence level that defines this probability p. Please note that a confidence interval only provides a probability that the real value lies within the limits. That means the real value can lie outside the confidence limits. Dietz, et al. Standards Track [Page 24]
RFC 5477 PSAMP Information Model March 2009 The upperCILimit, lowerCILimit, and confidenceLevel Information Elements should all be used in an Options Template scoped to the observation to which they refer. See Section 3.4.2.1 of the IPFIX protocol document [RFC5101]. Note that the upperCILimit, lowerCILimit, and confidenceLevel are all required to specify confidence, and should be disregarded unless all three are specified together. Abstract Data Type: float64 Data Type Semantics: quantity ElementId: 336 Status: current 8.6.6. lowerCILimit Description: This Information Element specifies the lower limit of a confidence interval. For further information, see the description of upperCILimit. The upperCILimit, lowerCILimit, and confidenceLevel Information Elements should all be used in an Options Template scoped to the observation to which they refer. See Section 3.4.2.1 of the IPFIX protocol document [RFC5101]. Note that the upperCILimit, lowerCILimit, and confidenceLevel are all required to specify confidence, and should be disregarded unless all three are specified together. Abstract Data Type: float64 Data Type Semantics: quantity ElementId: 337 Status: current Dietz, et al. Standards Track [Page 25]
RFC 5477 PSAMP Information Model March 2009 8.6.7. confidenceLevel Description: This Information Element specifies the confidence level. It is used to provide an accuracy statement for estimated values. The confidence level provides the probability p with which the real value lies within a given range. A confidence level always needs to be associated with confidence limits that define the range in which the real value is assumed to be. The upperCILimit, lowerCILimit, and confidenceLevel Information Elements should all be used in an Options Template scoped to the observation to which they refer. See Section 3.4.2.1 of the IPFIX protocol document [RFC5101]. Note that the upperCILimit, lowerCILimit, and confidenceLevel are all required to specify confidence, and should be disregarded unless all three are specified together. Abstract Data Type: float64 Data Type Semantics: quantity ElementId: 338 Status: current 9. Security Considerations The PSAMP information model itself does not directly introduce security issues. Rather, it defines a set of attributes that may for privacy or business issues be considered sensitive information. For example, exporting values of header fields may make attacks possible for the receiver of this information, which would otherwise only be possible for direct observers of the reported Flows along the data path. Specifically, the Information Elements pertaining to packet sections MUST target no more than the packet header, some subsequent bytes of the packet, and encapsulating headers if present. Full packet capture of arbitrary packet streams is explicitly out of scope, per [RFC2804]. The underlying protocol used to exchange the information described here MUST therefore apply appropriate procedures to guarantee the integrity and confidentiality of the exported information. Such procedures are defined in separate documents, specifically the IPFIX protocol document [RFC5101]. Dietz, et al. Standards Track [Page 26]
RFC 5477 PSAMP Information Model March 2009 10. IANA Considerations The PSAMP information model, as set out in this document, has two sets of assigned numbers. Considerations for assigning them are discussed in this section, using the example policies as set out in the "Guidelines for IANA Considerations" document [RFC5226]. 10.1. Related Considerations As the PSAMP protocol uses the IPFIX protocol, refer to the IANA Considerations section in [RFC5102] for the assignments of numbers used in the protocol and for the numbers used in the information model. 10.2. PSAMP-Related Considerations This document specifies an initial set of PSAMP Information Elements fulfilling the needs specified in [RFC5475], as an extension to the IPFIX Information Elements [RFC5102]. Note that the PSAMP Information Element IDs were initially started at value 301, in order to leave a gap for any ongoing IPFIX work requiring new Information Elements. It is expected that this gap in the Information Element numbering will be filled in by IANA with new IPFIX Information Elements. Each new selection method MUST be assigned a unique value in the selectorAlgorithm registry. Its configuration parameter(s), along with the way to report them with an Options Template, MUST be clearly specified. The initial content of the selectorAlgorithm registry is found in Section 8.2.1. New assignments for the PSAMP selection method will be administered by IANA and are subject to Expert Review [RFC5226]. The group of experts must double check the Information Elements definitions with already defined Information Elements for completeness, accuracy, and redundancy. Those experts will initially be drawn from the Working Group Chairs and document editors of the IPFIX and PSAMP Working Groups. The selectorAlgorithm registry is maintained by IANA and can be updated as long as specifications of the new method(s) and any new Information Elements are provided. 11. References 11.1. Normative References [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. Dietz, et al. Standards Track [Page 27]
RFC 5477 PSAMP Information Model March 2009 [RFC5226] Narten, T. and H. Alvestrand, "Guidelines for Writing an IANA Considerations Section in RFCs", BCP 26, RFC 5226, May 2008. [RFC5101] Claise, B., "Specification of the IP Flow Information Export (IPFIX) Protocol for the Exchange of IP Traffic Flow Information", RFC 5101, January 2008. [RFC5102] Quittek, J., Bryant, S., Claise, B., Aitken, P., and J. Meyer, "Information Model for IP Flow Information Export", RFC 5102, January 2008. [RFC5475] Zseby, T., Molina, M., Duffield, D., Niccolini, S., and F. Rapall, "Sampling and Filtering Techniques for IP Packet Selection", RFC 5475, March 2009. [RFC5476] Claise, B., Ed., "Packet Sampling (PSAMP) Protocol Specifications", RFC 5476, March 2009. 11.2. Informative References [RFC0791] Postel, J., "Internet Protocol", STD 5, RFC 791, September 1981. [RFC2460] Deering, S. and R. Hinden, "Internet Protocol, Version 6 (IPv6) Specification", RFC 2460, December 1998. [RFC2629] Rose, M., "Writing I-Ds and RFCs using XML", RFC 2629, June 1999. [RFC2804] IAB and IESG, "IETF Policy on Wiretapping", RFC 2804, May 2000. [RFC3031] Rosen, E., Viswanathan, A., and R. Callon, "Multiprotocol Label Switching Architecture", RFC 3031, January 2001. [RFC3032] Rosen, E., Tappan, D., Fedorkow, G., Rekhter, Y., Farinacci, D., Li, T., and A. Conta, "MPLS Label Stack Encoding", RFC 3032, January 2001. [RFC5474] Duffield, N., Ed., "A Framework for Packet Selection and Reporting", RFC 5474, March 2009. Dietz, et al. Standards Track [Page 28]
RFC 5477 PSAMP Information Model March 2009 Appendix A. Formal Specification of PSAMP Information Elements This appendix contains a formal description of the PSAMP information model XML document. Note that this appendix is of informational nature, while the text in Section 8 generated from this appendix is normative. Using a formal and machine-readable syntax for the information model enables the creation of PSAMP-aware tools that can automatically adapt to extensions to the information model, by simply reading updated information model specifications. The wide availability of XML-aware tools and libraries for client devices is a primary consideration for this choice. In particular, libraries for parsing XML documents are readily available. Also, mechanisms such as the Extensible Stylesheet Language (XSL) allow for transforming a source XML document into other documents. This draft was authored in XML and transformed according to [RFC2629]. It should be noted that the use of XML in Exporters, Collectors, or other tools is not mandatory for the deployment of PSAMP. In particular, exporting processes do not produce or consume XML as part of their operation. It is expected that PSAMP Collectors MAY take advantage of the machine readability of the information model vs. hardcoding their behavior or inventing proprietary means for accommodating extensions. <?xml version="1.0" encoding="UTF-8"?> <!-- This XML document is a product of the IETF IPFIX Working Group. Contact information: WG charter: http://www.ietf.org/html.charters/ipfix-charter.html Mailing Lists: General Discussion: ipfix@ietf.org To Subscribe: http://www1.ietf.org/mailman/listinfo/ipfix Archive: http://www1.ietf.org/mail-archive/web/ipfix/current/index.html Editor: Thomas Dietz NEC Europe Ltd. NEC Laboratories Europe Network Research Division Kurfuersten-Anlage 36 Heidelberg 69115 Germany Dietz, et al. Standards Track [Page 29]
RFC 5477 PSAMP Information Model March 2009 Phone: +49 6221 4342-128 Email: Thomas.Dietz@nw.neclab.eu Benoit Claise Cisco Systems, Inc. De Kleetlaan 6a b1 Degem 1813 Belgium Phone: +32 2 704 5622 Email: bclaise@cisco.com Paul Aitken Cisco Systems, Inc. 96 Commercial Quay Edinburgh EH6 6LX Scotland Phone: +44 131 561 3616 Email: paitken@cisco.com URI: http://www.cisco.com Falko Dressler University of Erlangen-Nuremberg Dept. of Computer Sciences Martensstr. 3 Erlangen 91058 Germany Phone: +49 9131 85-27914 Email: dressler@informatik.uni-erlangen.de URI: http://www7.informatik.uni-erlangen.de/~dressler Georg Carle Technical University of Munich Institute for Informatics Boltzmannstr. 3 Garching bei Muenchen 85737 Germany Phone: +49 89 289-18030 EMail: carle@in.tum.de URI: http://www.net.in.tum.de/~carle/ Abstract: This memo defines an information model for the Packet SAMPling (PSAMP) protocol. It is used by the PSAMP protocol for encoding sampled packet data and information related to the Sampling process. As the PSAMP protocol is based on the IPFIX protocol, this information model is an extension to the IPFIX information model. Dietz, et al. Standards Track [Page 30]
RFC 5477 PSAMP Information Model March 2009 Copyright (c) 2009 IETF Trust and the persons identified as authors of the code. All rights reserved. Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met: - Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer. - Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution. - Neither the name of Internet Society, IETF or IETF Trust, nor the names of specific contributors, may be used to endorse or promote products derived from this software without specific prior written permission. THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 'AS IS' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. This version of the XML document is part of RFC 5477; see the RFC itself for full legal notices. --> <fieldDefinitions xmlns="urn:ietf:params:xml:ns:ipfix-info" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="urn:ietf:params:xml:ns:ipfix-info ipfix-info.xsd"> <field name="selectionSequenceId" dataType="unsigned64" dataTypeSemantics="identifier" elementId="301" status="current" group="identifiers"> <description> <paragraph> From all the packets observed at an Observation Point, a subset of the packets is selected by a sequence of one or more Selectors. The selectionSequenceId is a unique value per Observation Domain, specifying the Observation Point and the Dietz, et al. Standards Track [Page 31]
RFC 5477 PSAMP Information Model March 2009 sequence of Selectors through which the packets are selected. </paragraph> </description> </field> <field name="selectorId" dataType="unsigned16" dataTypeSemantics="identifier" elementId="302" status="current" group="identifiers"> <description> <paragraph> The Selector ID is the unique ID identifying a Primitive Selector. Each Primitive Selector must have a unique ID in the Observation Domain. </paragraph> </description> </field> <field name="informationElementId" dataType="unsigned16" dataTypeSemantics="identifier" elementId="303" status="current" group="identifiers"> <description> <paragraph> This Information Element contains the ID of another Information Element. </paragraph> </description> </field> <field name="selectorAlgorithm" dataType="unsigned16" dataTypeSemantics="identifier" elementId="304" status="current" group="sampling configuration"> <description> <paragraph> This Information Element identifies the packet selection methods (e.g., Filtering, Sampling) that are applied by the Selection Process. Most of these methods have parameters. Further Information Elements are needed to fully specify packet selection with these methods and all their parameters. The methods listed below are defined in [RFC5475]. For their parameters, Information Elements are defined in the information model document. The names of these Information Elements are listed for each method identifier. Dietz, et al. Standards Track [Page 32]
RFC 5477 PSAMP Information Model March 2009 Further method identifiers may be added to the list below. It might be necessary to define new Information Elements to specify their parameters. The selectorAlgorithm registry is maintained by IANA. New assignments for the registry will be administered by IANA and are subject to Expert Review [RFC5226]. The registry can be updated when specifications of the new method(s) and any new Information Elements are provided. The group of experts must double check the selectorAlgorithm definitions and Information Elements with already defined selectorAlgorithms and Information Elements for completeness, accuracy, and redundancy. Those experts will initially be drawn from the Working Group Chairs and document editors of the IPFIX and PSAMP Working Groups. The following packet selection methods identifiers are defined here: +----+------------------------+------------------------+ | ID | Method | Parameters | +----+------------------------+------------------------+ | 1 | Systematic count-based | samplingPacketInterval | | | Sampling | samplingPacketSpace | +----+------------------------+------------------------+ | 2 | Systematic time-based | samplingTimeInterval | | | Sampling | samplingTimeSpace | +----+------------------------+------------------------+ | 3 | Random n-out-of-N | samplingSize | | | Sampling | samplingPopulation | +----+------------------------+------------------------+ | 4 | Uniform probabilistic | samplingProbability | | | Sampling | | +----+------------------------+------------------------+ | 5 | Property Match | no agreed parameters | | | Filtering | | +----+------------------------+------------------------+ | Hash-based Filtering | hashInitialiserValue | +----+------------------------+ hashIPPayloadOffset | | 6 | using BOB | hashIPPayloadSize | +----+------------------------+ hashSelectedRangeMin | | 7 | using IPSX | hashSelectedRangeMax | +----+------------------------+ hashOutputRangeMin | | 8 | using CRC | hashOutputRangeMax | +----+------------------------+------------------------+ Dietz, et al. Standards Track [Page 33]
RFC 5477 PSAMP Information Model March 2009 There is a broad variety of possible parameters that could be used for Property Match Filtering (5), but currently there are no agreed parameters specified. </paragraph> </description> </field> <field name="samplingPacketInterval" dataType="unsigned32" dataTypeSemantics="quantity" elementId="305" status="current" group="sampling configuration"> <description> <paragraph> This Information Element specifies the number of packets that are consecutively sampled. A value of 100 means that 100 consecutive packets are sampled. For example, this Information Element may be used to describe the configuration of a systematic count-based Sampling Selector. </paragraph> </description> <units>packets</units> </field> <field name="samplingPacketSpace" dataType="unsigned32" dataTypeSemantics="quantity" elementId="306" status="current" group="sampling configuration"> <description> <paragraph> This Information Element specifies the number of packets between two "samplingPacketInterval"s. A value of 100 means that the next interval starts 100 packets (which are not sampled) after the current "samplingPacketInterval" is over. For example, this Information Element may be used to describe the configuration of a systematic count-based Sampling Selector. </paragraph> </description> <units>packets</units> </field> <field name="samplingTimeInterval" dataType="unsigned32" dataTypeSemantics="quantity" elementId="307" status="current" group="sampling configuration"> <description> <paragraph> This Information Element specifies the time interval in microseconds during which all arriving packets are sampled. Dietz, et al. Standards Track [Page 34]
RFC 5477 PSAMP Information Model March 2009 For example, this Information Element may be used to describe the configuration of a systematic time-based Sampling Selector. </paragraph> </description> <units>microseconds</units> </field> <field name="samplingTimeSpace" dataType="unsigned32" dataTypeSemantics="quantity" elementId="308" status="current" group="sampling configuration"> <description> <paragraph> This Information Element specifies the time interval in microseconds between two "samplingTimeInterval"s. A value of 100 means that the next interval starts 100 microseconds (during which no packets are sampled) after the current "samplingTimeInterval" is over. For example, this Information Element may used to describe the configuration of a systematic time-based Sampling Selector. </paragraph> </description> <units>microseconds</units> </field> <field name="samplingSize" dataType="unsigned32" dataTypeSemantics="quantity" elementId="309" status="current" group="sampling configuration"> <description> <paragraph> This Information Element specifies the number of elements taken from the parent Population for random Sampling methods. For example, this Information Element may be used to describe the configuration of a random n-out-of-N Sampling Selector. </paragraph> </description> <units>packets</units> </field> <field name="samplingPopulation" dataType="unsigned32" dataTypeSemantics="quantity" elementId="310" status="current" group="sampling configuration"> <description> <paragraph> This Information Element specifies the number of elements in the parent Population for random Sampling methods. Dietz, et al. Standards Track [Page 35]
RFC 5477 PSAMP Information Model March 2009 For example, this Information Element may be used to describe the configuration of a random n-out-of-N Sampling Selector. </paragraph> </description> <units>packets</units> </field> <field name="samplingProbability" dataType="float64" dataTypeSemantics="quantity" elementId="311" status="current" group="sampling configuration"> <description> <paragraph> This Information Element specifies the probability that a packet is sampled, expressed as a value between 0 and 1. The probability is equal for every packet. A value of 0 means no packet was sampled since the probability is 0. For example, this Information Element may be used to describe the configuration of a uniform probabilistic Sampling Selector. </paragraph> </description> </field> <field name="ipHeaderPacketSection" dataType="octetArray" elementId="313" status="current" group="packet data"> <description> <paragraph> This Information Element, which may have a variable length, carries a series of octets from the start of the IP header of a sampled packet. With sufficient length, this element also reports octets from the IP payload, subject to [RFC2804]. See the Security Considerations section. The size of the exported section may be constrained due to limitations in the IPFIX protocol. The data for this field MUST NOT be padded. </paragraph> </description> </field> <field name="ipPayloadPacketSection" dataType="octetArray" elementId="314" status="current" group="packet data"> <description> <paragraph> This Information Element, which may have a variable length, Dietz, et al. Standards Track [Page 36]
RFC 5477 PSAMP Information Model March 2009 carries a series of octets from the start of the IP payload of a sampled packet. The IPv4 payload is that part of the packet that follows the IPv4 header and any options, which [RFC0791] refers to as "data" or "data octets". For example, see the examples in [RFC0791], Appendix A. The IPv6 payload is the rest of the packet following the 40-octet IPv6 header. Note that any extension headers present are considered part of the payload. See [RFC2460] for the IPv6 specification. The size of the exported section may be constrained due to limitations in the IPFIX protocol. The data for this field MUST NOT be padded. </paragraph> </description> </field> <field name="mplsLabelStackSection" dataType="octetArray" elementId="316" status="current" group="packet data"> <description> <paragraph> This Information Element, which may have a variable length, carries the first n octets from the MPLS label stack of a sampled packet. With sufficient length, this element also reports octets from the MPLS payload, subject to [RFC2804]. See the Security Considerations section. See [RFC3031] for the specification of MPLS packets. See [RFC3032] for the specification of the MPLS label stack. The size of the exported section may be constrained due to limitations in the IPFIX protocol. The data for this field MUST NOT be padded. </paragraph> </description> </field> <field name="mplsPayloadPacketSection" dataType="octetArray" elementId="317" status="current" group="packet data"> <description> Dietz, et al. Standards Track [Page 37]
RFC 5477 PSAMP Information Model March 2009 <paragraph> This Information Element, which may have a variable length, carries the first n octets from the MPLS payload of a sampled packet, being data that follows immediately after the MPLS label stack. See [RFC3031] for the specification of MPLS packets. See [RFC3032] for the specification of the MPLS label stack. The size of the exported section may be constrained due to limitations in the IPFIX protocol. The data for this field MUST NOT be padded. </paragraph> </description> </field> <field name="selectorIdTotalPktsObserved" dataType="unsigned64" dataTypeSemantics="totalCounter" elementId="318" status="current" group="statistics"> <description> <paragraph> This Information Element specifies the total number of packets observed by a Selector, for a specific value of SelectorId. This Information Element should be used in an Options Template scoped to the observation to which it refers. See Section 3.4.2.1 of the IPFIX protocol document [RFC5101]. </paragraph> </description> <units>packets</units> </field> <field name="selectorIdTotalPktsSelected" dataType="unsigned64" dataTypeSemantics="totalCounter" elementId="319" status="current" group="statistics"> <description> <paragraph> This Information Element specifies the total number of packets selected by a Selector, for a specific value of SelectorId. This Information Element should be used in an Options Template scoped to the observation to which it refers. See Section 3.4.2.1 of the IPFIX protocol document [RFC5101]. </paragraph> </description> <units>packets</units> Dietz, et al. Standards Track [Page 38]
RFC 5477 PSAMP Information Model March 2009 </field> <field name="absoluteError" dataType="float64" dataTypeSemantics="quantity" elementId="320" status="current" group="statistics"> <description> <paragraph> This Information Element specifies the maximum possible measurement error of the reported value for a given Information Element. The absoluteError has the same unit as the Information Element with which it is associated. The real value of the metric can differ by absoluteError (positive or negative) from the measured value. This Information Element provides only the error for measured values. If an Information Element contains an estimated value (from Sampling), the confidence boundaries and confidence level have to be provided instead, using the upperCILimit, lowerCILimit, and confidenceLevel Information Elements. This Information Element should be used in an Options Template scoped to the observation to which it refers. See Section 3.4.2.1 of the IPFIX protocol document [RFC5101]. </paragraph> </description> <units> The units of the Information Element for which the error is specified. </units> </field> <field name="relativeError" dataType="float64" dataTypeSemantics="quantity" elementId="321" status="current" group="statistics"> <description> <paragraph> This Information Element specifies the maximum possible positive or negative error ratio for the reported value for a given Information Element as a percentage of the measured value. The real value of the metric can differ by relativeError percent (positive or negative) from the measured value. This Information Element provides only the error for measured values. If an Information Element contains an estimated value (from Sampling), the confidence boundaries and confidence level have to be provided instead, using the upperCILimit, lowerCILimit, and confidenceLevel Information Elements. Dietz, et al. Standards Track [Page 39]
RFC 5477 PSAMP Information Model March 2009 This Information Element should be used in an Options Template scoped to the observation to which it refers. See Section 3.4.2.1 of the IPFIX protocol document [RFC5101]. </paragraph> </description> </field> <field name="observationTimeSeconds" dataType="dateTimeSeconds" dataTypeSemantics="quantity" elementId="322" status="current" group="timestamps"> <description> <paragraph> This Information Element specifies the absolute time in seconds of an observation. </paragraph> </description> <units>seconds</units> </field> <field name="observationTimeMilliseconds" dataType="dateTimeMilliseconds" dataTypeSemantics="quantity" elementId="323" status="current" group="timestamps"> <description> <paragraph> This Information Element specifies the absolute time in milliseconds of an observation. </paragraph> </description> <units>milliseconds</units> </field> <field name="observationTimeMicroseconds" dataType="dateTimeMicroseconds" dataTypeSemantics="quantity" elementId="324" status="current" group="timestamps"> <description> <paragraph> This Information Element specifies the absolute time in microseconds of an observation. </paragraph> </description> <units>microseconds</units> </field> <field name="observationTimeNanoseconds" dataType="dateTimeNanoseconds" dataTypeSemantics="quantity" elementId="325" status="current" group="timestamps"> <description> <paragraph> Dietz, et al. Standards Track [Page 40]
RFC 5477 PSAMP Information Model March 2009 This Information Element specifies the absolute time in nanoseconds of an observation. </paragraph> </description> <units>nanoseconds</units> </field> <field name="digestHashValue" dataType="unsigned64" dataTypeSemantics="quantity" elementId="326" status="current" group="hash configuration"> <description> <paragraph> This Information Element specifies the value from the digest hash function. See also Sections 6.2, 3.8, and 7.1 of [RFC5475]. </paragraph> </description> </field> <field name="hashIPPayloadOffset" dataType="unsigned64" dataTypeSemantics="quantity" elementId="327" status="current" group="hash configuration"> <description> <paragraph> This Information Element specifies the IP payload offset used by a Hash-based Selection Selector. See also Sections 6.2, 3.8, and 7.1 of [RFC5475]. </paragraph> </description> </field> <field name="hashIPPayloadSize" dataType="unsigned64" dataTypeSemantics="quantity" elementId="328" status="current" group="hash configuration"> <description> <paragraph> This Information Element specifies the IP payload size used by a Hash-based Selection Selector. See also Sections 6.2, 3.8, and 7.1 of [RFC5475] </paragraph> </description> </field> Dietz, et al. Standards Track [Page 41]
RFC 5477 PSAMP Information Model March 2009 <field name="hashOutputRangeMin" dataType="unsigned64" dataTypeSemantics="quantity" elementId="329" status="current" group="hash configuration"> <description> <paragraph> This Information Element specifies the value for the beginning of a hash function's potential output range. See also Sections 6.2, 3.8, and 7.1 of [RFC5475]. </paragraph> </description> </field> <field name="hashOutputRangeMax" dataType="unsigned64" dataTypeSemantics="quantity" elementId="330" status="current" group="hash configuration"> <description> <paragraph> This Information Element specifies the value for the end of a hash function's potential output range. See also Sections 6.2, 3.8, and 7.1 of [RFC5475]. </paragraph> </description> </field> <field name="hashSelectedRangeMin" dataType="unsigned64" dataTypeSemantics="quantity" elementId="331" status="current" group="hash configuration"> <description> <paragraph> This Information Element specifies the value for the beginning of a hash function's selected range. See also Sections 6.2, 3.8, and 7.1 of [RFC5475]. </paragraph> </description> </field> <field name="hashSelectedRangeMax" dataType="unsigned64" dataTypeSemantics="quantity" elementId="332" status="current" group="hash configuration"> <description> <paragraph> This Information Element specifies the value for the end of a hash function's selected range. Dietz, et al. Standards Track [Page 42]
RFC 5477 PSAMP Information Model March 2009 See also Sections 6.2, 3.8, and 7.1 of [RFC5475]. </paragraph> </description> </field> <field name="hashDigestOutput" dataType="boolean" dataTypeSemantics="quantity" elementId="333" status="current" group="hash configuration"> <description> <paragraph> This Information Element contains a boolean value that is TRUE if the output from this hash Selector has been configured to be included in the packet report as a packet digest, else FALSE. See also Sections 6.2, 3.8, and 7.1 of [RFC5475]. </paragraph> </description> </field> <field name="hashInitialiserValue" dataType="unsigned64" dataTypeSemantics="quantity" elementId="334" status="current" group="hash configuration"> <description> <paragraph> This Information Element specifies the initialiser value to the hash function. See also Sections 6.2, 3.8, and 7.1 of [RFC5475]. </paragraph> </description> </field> <field name="upperCILimit" dataType="float64" dataTypeSemantics="quantity" elementId="336" status="current" group="statistics"> <description> <paragraph> This Information Element specifies the upper limit of a confidence interval. It is used to provide an accuracy statement for an estimated value. The confidence limits define the range in which the real value is assumed to be with a certain probability p. Confidence limits always need to be associated with a confidence level that defines this probability p. Please note that a confidence interval only provides a probability that the real value lies within the Dietz, et al. Standards Track [Page 43]
RFC 5477 PSAMP Information Model March 2009 limits. That means the real value can lie outside the confidence limits. The upperCILimit, lowerCILimit, and confidenceLevel Information Elements should all be used in an Options Template scoped to the observation to which they refer. See Section 3.4.2.1 of the IPFIX protocol document [RFC5101]. Note that the upperCILimit, lowerCILimit, and confidenceLevel are all required to specify confidence, and should be disregarded unless all three are specified together. </paragraph> </description> </field> <field name="lowerCILimit" dataType="float64" dataTypeSemantics="quantity" elementId="337" status="current" group="statistics"> <description> <paragraph> This Information Element specifies the lower limit of a confidence interval. For further information, see the description of upperCILimit. The upperCILimit, lowerCILimit, and confidenceLevel Information Elements should all be used in an Options Template scoped to the observation to which they refer. See Section 3.4.2.1 of the IPFIX protocol document [RFC5101]. Note that the upperCILimit, lowerCILimit, and confidenceLevel are all required to specify confidence, and should be disregarded unless all three are specified together. </paragraph> </description> </field> <field name="confidenceLevel" dataType="float64" dataTypeSemantics="quantity" elementId="338" status="current" group="statistics"> <description> <paragraph> This Information Element specifies the confidence level. It is used to provide an accuracy statement for estimated values. The confidence level provides the probability p with which the real value lies within a given range. A confidence level always needs to be associated with confidence limits that define the range in which the real value is assumed to be. Dietz, et al. Standards Track [Page 44]
RFC 5477 PSAMP Information Model March 2009 The upperCILimit, lowerCILimit, and confidenceLevel Information Elements should all be used in an Options Template scoped to the observation to which they refer. See Section 3.4.2.1 of the IPFIX protocol document [RFC5101]. Note that the upperCILimit, lowerCILimit, and confidenceLevel are all required to specify confidence, and should be disregarded unless all three are specified together. </paragraph> </description> </field> </fieldDefinitions> Authors' Addresses Thomas Dietz NEC Europe Ltd. NEC Laboratories Europe Network Research Division Kurfuersten-Anlage 36 Heidelberg 69115 Germany Phone: +49 6221 4342-128 EMail: Thomas.Dietz@nw.neclab.eu URI: http://www.nw.neclab.eu Benoit Claise Cisco Systems, Inc. De Kleetlaan 6a b1 Degem 1813 Belgium Phone: +32 2 704 5622 EMail: bclaise@cisco.com Paul Aitken Cisco Systems, Inc. 96 Commercial Quay Edinburgh EH6 6LX Scotland Phone: +44 131 561 3616 EMail: paitken@cisco.com URI: http://www.cisco.com/ Dietz, et al. Standards Track [Page 45]
RFC 5477 PSAMP Information Model March 2009 Falko Dressler University of Erlangen-Nuremberg Dept. of Computer Sciences Martensstr. 3 Erlangen 91058 Germany Phone: +49 9131 85-27914 EMail: dressler@informatik.uni-erlangen.de URI: http://www7.informatik.uni-erlangen.de/~dressler Georg Carle Technical University of Munich Institute for Informatics Boltzmannstr. 3 Garching bei Muenchen 85737 Germany Phone: +49 89 289-18030 EMail: carle@in.tum.de URI: http://www.net.in.tum.de/~carle/ Dietz, et al. Standards Track [Page 46]

   

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