Network Working Group T. Dietz Internet-Draft NEC Europe Ltd. Expires: September 7, 2006 F. Dressler University of Erlangen-Nuremberg G. Carle University of Tuebingen B. Claise P. Aitken Cisco Systems March 6, 2006 Information Model for Packet Sampling Exports Status of this Memo By submitting this Internet-Draft, each author represents that any applicable patent or other IPR claims of which he or she is aware have been or will be disclosed, and any of which he or she becomes aware will be disclosed, in accordance with Section 6 of BCP 79. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF), its areas, and its working groups. Note that other groups may also distribute working documents as Internet- Drafts. Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress." The list of current Internet-Drafts can be accessed at http://www.ietf.org/ietf/1id-abstracts.txt. The list of Internet-Draft Shadow Directories can be accessed at http://www.ietf.org/shadow.html. This Internet-Draft will expire on September 7, 2006. Copyright Notice Copyright (C) The Internet Society (2006). Abstract This memo defines an information model for the Packet Sampling (PSAMP) protocol. It is used by the PSAMP protocol for encoding Dietz, et al. draft-ietf-psamp-info-04.txt [Page 1] Internet-Draft PSAMP Information Model March 2006 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. Table of Contents 1. Open Issues . . . . . . . . . . . . . . . . . . . . . . . . 4 1.1 IPFIX . . . . . . . . . . . . . . . . . . . . . . . . . . 4 1.2 PSAMP . . . . . . . . . . . . . . . . . . . . . . . . . . 4 2. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 4 3. PSAMP Documents Overview . . . . . . . . . . . . . . . . . . 5 4. Relationship between PSAMP and IPFIX . . . . . . . . . . . . 5 5. Terminology . . . . . . . . . . . . . . . . . . . . . . . . 6 6. Properties of a PSAMP Information Element . . . . . . . . . 7 7. Type Space . . . . . . . . . . . . . . . . . . . . . . . . . 7 8. Overloading Information Elements . . . . . . . . . . . . . . 7 9. The PSAMP Information Elements . . . . . . . . . . . . . . . 8 9.1 PSAMP Usage of IPFIX Attributes . . . . . . . . . . . . . 8 9.2 Additional PSAMP Information Elements . . . . . . . . . . 9 9.2.1 observationPointId . . . . . . . . . . . . . . . . . . 9 9.2.2 selectionSequenceId . . . . . . . . . . . . . . . . . 9 9.2.3 selectorId . . . . . . . . . . . . . . . . . . . . . . 9 9.2.4 informationElementId . . . . . . . . . . . . . . . . . 9 9.2.5 selectorAlgorithm . . . . . . . . . . . . . . . . . . 10 9.2.6 samplingPacketInterval . . . . . . . . . . . . . . . . 10 9.2.7 samplingPacketSpace . . . . . . . . . . . . . . . . . 11 9.2.8 samplingTimeInterval . . . . . . . . . . . . . . . . . 11 9.2.9 samplingTimeSpace . . . . . . . . . . . . . . . . . . 11 9.2.10 samplingSize . . . . . . . . . . . . . . . . . . . . 12 9.2.11 samplingPopulation . . . . . . . . . . . . . . . . . 12 9.2.12 samplingProbability . . . . . . . . . . . . . . . . 12 9.2.13 [unused] . . . . . . . . . . . . . . . . . . . . . . 13 9.2.14 ipHeaderPacketSection . . . . . . . . . . . . . . . 13 9.2.15 ipPayloadPacketSection . . . . . . . . . . . . . . . 13 9.2.16 dataLinkFrameSection . . . . . . . . . . . . . . . . 13 9.2.17 mplsLabelStackSection . . . . . . . . . . . . . . . 14 9.2.18 mplsPayloadPacketSection . . . . . . . . . . . . . . 14 9.2.19 packetsObserved . . . . . . . . . . . . . . . . . . 15 9.2.20 packetsSelected . . . . . . . . . . . . . . . . . . 15 9.2.21 fixedError . . . . . . . . . . . . . . . . . . . . . 15 Dietz, et al. draft-ietf-psamp-info-04.txt [Page 2] Internet-Draft PSAMP Information Model March 2006 9.2.22 relativeError . . . . . . . . . . . . . . . . . . . 15 9.2.23 observationTimeSeconds . . . . . . . . . . . . . . . 16 9.2.24 observationTimeMilliSeconds . . . . . . . . . . . . 16 9.2.25 observationTimeMicroSeconds . . . . . . . . . . . . 16 9.2.26 observationTimeNanoSeconds . . . . . . . . . . . . . 16 9.2.27 digestHashValue . . . . . . . . . . . . . . . . . . 16 9.2.28 hashIPPayloadOffset . . . . . . . . . . . . . . . . 17 9.2.29 hashIPPayloadSize . . . . . . . . . . . . . . . . . 17 9.2.30 hashInitialiserValue . . . . . . . . . . . . . . . . 17 9.2.31 hashOutputRangeMin . . . . . . . . . . . . . . . . . 17 9.2.32 hashOutputRangeMax . . . . . . . . . . . . . . . . . 17 9.2.33 hashSelectedRangeMin . . . . . . . . . . . . . . . . 17 9.2.34 hashSelectedRangeMax . . . . . . . . . . . . . . . . 18 9.2.35 hashDigestOutput . . . . . . . . . . . . . . . . . . 18 10. Security Considerations . . . . . . . . . . . . . . . . . . 18 11. IANA Considerations . . . . . . . . . . . . . . . . . . . . 18 12. References . . . . . . . . . . . . . . . . . . . . . . . . . 19 12.1 Normative References . . . . . . . . . . . . . . . . . . 19 12.2 Informative References . . . . . . . . . . . . . . . . . 20 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . 21 A. Formal Specification of PSAMP Information Elements . . . . . 22 Intellectual Property and Copyright Statements . . . . . . . 36 Dietz, et al. draft-ietf-psamp-info-04.txt [Page 3] Internet-Draft PSAMP Information Model March 2006 1. Open Issues This section covers some open issues which have to be solved in a future version of this draft. 1.1 IPFIX o The export of sampled data may not need all information elements defined by the IPFIX information model. Thus a section within this document should give an overview of flow Information Elements defined in the IPFIX information model and their usage in the PSAMP environment. PROPOSAL: This is already covered by section 6.2 and 6.3 of draft-ietf-psamp-framework-10.txt Double check whether it's covered by [I-D.ietf-psamp-sample-tech]. o Insert or cross reference the following sections from IPFIX-INFO: * 2. Properties of IPFIX Protocol Information Elements * 2.1 Information Elements Specification Template * 2.2 Scope of Information Elements * 2.3 Naming Conventions for Information Elements * 3. Type Space * 4. Information Element Identifiers o Verify consistency with definitions in * draft-ietf-psamp-sample-tech-07.txt * draft-ietf-psamp-framework-10.txt 1.2 PSAMP o Should the ipHeaderPacketSection and mplsLabelStackSection also report payload contents if the specified section length is longer than the header or stack size, respectively? 2. Introduction Packet sampling techniques are required for various measurement scenarios. The packet sampling (PSAMP) protocol provides mechanisms for the packet selection using different filtering and sampling techniques. A standard way for the export and storage of such sampled packet data is required. The definition of the PSAMP information and data model is based on the IP Flow Information eXport (IPFIX) protocol [I-D.ietf-ipfix-protocol]. The PSAMP protocol document [I-D.ietf-psamp-protocol] describes how to use the IPFIX protocol in the PSAMP context. This document examines the IPFIX information model [I-D.ietf-ipfix- info] 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, Dietz, et al. draft-ietf-psamp-info-04.txt [Page 4] Internet-Draft PSAMP Information Model March 2006 section 9, defines the list of Information Elements to be transmitted by the PSAMP protocol. Sections 7 and 6 describe the data types and Information Element properties used within this document and their relationship to the IPFIX information model. The main body of section 9 was generated from a 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 an 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 source for section 9 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 appendices are informational. 3. PSAMP Documents Overview [I-D.ietf-psamp-framework]: "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. [I-D.ietf-psamp-sample-tech]: "Sampling and Filtering Techniques for IP Packet Selection", describes the set of packet selection techniques supported by PSAMP. [I-D.ietf-psamp-protocol]: "Packet Sampling (PSAMP) Protocol Specifications" specifies the export of packet information from a PSAMP Exporting Process to a PSAMP Collecting Process. [I-D.ietf-psamp-info]: "Information Model for Packet Sampling Exports" (this document), defines an information and data model for PSAMP. [I-D.ietf-psamp-mib]: "Definitions of Managed Objects for Packet Sampling" describes the PSAMP Management Information Base 4. Relationship between PSAMP and IPFIX As described in the PSAMP protocol draft [I-D.ietf-psamp-protocol] a PSAMP data record can be seen as a very special IPFIX flow record. It represents an IPFIX flow containing only a single packet. Therefore, the IPFIX information model can be used as a basis for Dietz, et al. draft-ietf-psamp-info-04.txt [Page 5] Internet-Draft PSAMP Information Model March 2006 PSAMP reports. Nevertheless, there are properties required in PSAMP reports which cannot be modelled using the current IPFIX information model. This document describes extensions to the IPFIX model which allow the modelling 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. 5. Terminology As the IPFIX export protocol is used to export the PSAMP information, the relevant IPFIX terminology from [I-D.ietf-ipfix-protocol] is copied over in this document. IETF: The Internet Engineering Task Force http://www.ietf.org IPFIX: The IETF IP Flow Information eXport working group http://www.ietf.org/html.charters/ipfix-charter.html PSAMP: The IETF Packet SAMPling working group http://www.ietf.org/html.charters/psamp-charter.html IANA: Internet Assigned Numbers Authority http://www.iana.org RFC: Requests for Comments http://www.rfc-editor.org ISO: International Organisation for Stadardisation http://www.iso.org IEC: International Electrotechnical Commission http://www.iec.ch Information Element An Information Element is a protocol and encoding independent description of an attribute which may appear in an IPFIX Record. Collecting Process A Collecting Process receives Flow Records from one or more Exporting Processes. Dietz, et al. draft-ietf-psamp-info-04.txt [Page 6] Internet-Draft PSAMP Information Model March 2006 Observation Point An Observation Point is a location in the network where IP packets can be observed. Selector Observation Domain An Observation Domain is the largest set of Observation Points for which Flow information can be aggregated by a Metering Process. A Selector defines the action of a Selection Process on a single packet of its input. Primitive Selector A Selector is primitive if it is not a Composite Selector. EDITORS NOTE: This section to be completed. 6. Properties of a PSAMP Information Element The PSAMP Information Elements are in accordance with the definitions of IPFIX. Therefore we do not repeat the properties in this draft. Nevertheless, we strongly recommend to define the optional "unit" element for every information element (if applicable). 7. Type Space The PSAMP Information Elements MUST be constructed from the basic data types described in the IPFIX Information Model [I-D.ietf-ipfix- info]. To avoid duplicated work and to keep consistency between IPFIX and PSAMP the data types are not repeated in this document. 8. Overloading Information Elements Information Elements won't be overloaded with multiple meanings or re-used for multiple purposes. Different Information Elements will be allocated for each requirement. In particular, special information will be encoded in new Information Elements as necessary, and not be encoded in the selection method. Although the prescence of certain other Information Elements allows the selection method to be inferred, a separate Information Element is provided for the selectorAlgorithm, e.g. for including in scope info and depicting the contents of composites. Dietz, et al. draft-ietf-psamp-info-04.txt [Page 7] Internet-Draft PSAMP Information Model March 2006 9. The PSAMP Information Elements This section describes the Information Elements used by the PSAMP exporting functions. Basically, the Information Elements described by the IPFIX information model [I-D.ietf-ipfix-info] are used by the PSAMP export functions where applicable. To avoid inconsistencies between the IPFIX and the PSAMP information and data models, only those Information Elements are defined here that are not already described by the IPFIX information model. 9.1 PSAMP Usage of IPFIX Attributes Some Information Elements defined by the IPFIX information model are not needed by the PSAMP protocol. This section lists additional Information Elements that are needed in the PSAMP context and introduces their usage. List of additional PSAMP Information Elements: o 300 - observationPointId o 301 - selectionSequenceId o 302 - selectorId o 303 - informationElementId o 304 - selectorAlgorithm o 305 - samplingPacketInterval o 306 - samplingPacketSpace o 307 - samplingTimeInterval o 308 - samplingTimeSpace o 309 - samplingSize o 310 - samplingPopulation o 311 - samplingProbability o 312 - [unused] o 313 - ipHeaderPacketSection o 314 - ipPayloadPacketSection o 315 - dataLinkFrameSection o 316 - mplsLabelStackSection o 317 - mplsPayloadPacketSection o 318 - packetsObserved o 319 - packetsSelected o 320 - fixedError o 321 - relativeError o 322 - timeSeconds o 323 - timeMilliSeconds o 324 - timeMicroSeconds o 325 - timeNanoSeconds Dietz, et al. draft-ietf-psamp-info-04.txt [Page 8] Internet-Draft PSAMP Information Model March 2006 o 326 - digestHashValue o 327 - hashIPPayloadOffset o 328 - hashIPPayloadSize o 329 - hashInitialiserValue o 330 - hashOutputRangeMin o 331 - hashOutputRangeMax o 332 - hashSelectedRangeMin o 333 - hashSelectedRangeMax o 334 - hashDigestOutput 9.2 Additional PSAMP Information Elements 9.2.1 observationPointId Description: ID of the observation process. Unique in the observation domain. Abstract Data Type: unsigned64 ElementId: 300 Status: current 9.2.2 selectionSequenceId Description: From all the packets observed at an Observation Point, a subset of packets is selected by a sequence of one or more Selectors. The selectionSequenceId is a unique value per Observation Domain, describing the Observation Point and the sequence of Selectors through which the packets are selected. Abstract Data Type: unsigned64 ElementId: 301 Status: current 9.2.3 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 9.2.4 informationElementId Dietz, et al. draft-ietf-psamp-info-04.txt [Page 9] Internet-Draft PSAMP Information Model March 2006 Description: Contains the ID of another Information Element. Abstract Data Type: unsigned16 Data Type Semantics: identifier ElementId: 303 Status: current 9.2.5 selectorAlgorithm Description: Specifies the selector algorithm (e.g., filter, sampler, hash) that was used on a packet. It is exported in the options data flow record to specify how a collector has to interpret a data flow record. The following selector algorithms are currently defined: * 1 Systematic count-based sampling * 2 Systematic time-based sampling * 3 Random n-out-of-N sampling * 4 Uniform probabilistic sampling * 5 Property match filtering * 6 Hash based filtering using BOB * 7 Hash based filtering using IPSX * 8 Hash based filtering using CRC EDITOR'S NOTE: This list may be extended in the final version. The parameters for most of these algorithms are defined in this information model. Some parameters for these algorithms are not covered by this information model since they very much depend on the underlying hardware. In future, this list will be maintained by IANA. IANA can update this information element as long as there's a new RFC specifying the algorithm and any new Information Elements which are required. Abstract Data Type: unsigned16 Data Type Semantics: identifier ElementId: 304 Status: current 9.2.6 samplingPacketInterval Description: Dietz, et al. draft-ietf-psamp-info-04.txt [Page 10] Internet-Draft PSAMP Information Model March 2006 Number of packets that are consecutively sampled. For example a value of 100 means that 100 contiguous packets are sampled. This information element is used to describe the configuration of a systematic count-based sampling selector. Abstract Data Type: unsigned32 ElementId: 305 Status: current Units: packets 9.2.7 samplingPacketSpace Description: The number of packets between two "samplingPacketInterval"s. A value of 100 means that the next interval starts after 100 packets (which are not sampled) when the current "samplingPacketInterval" is over. This information element is used to describe the configuration of a systematic count-based sampling selector. Abstract Data Type: unsigned32 ElementId: 306 Status: current Units: packets 9.2.8 samplingTimeInterval Description: Time interval in microseconds in which all arriving packets are sampled. This information element is used to describe the configuration of a systematic time-based sampling selector. Abstract Data Type: dateTimeMicroSeconds ElementId: 307 Status: current Units: microseconds 9.2.9 samplingTimeSpace Description: The time interval in microseconds between two "samplingTimeInterval"s. A value of 100 means that the next interval starts after 100 microseconds (in which no packets are sampled) when the current "samplingTimeInterval" is over. Dietz, et al. draft-ietf-psamp-info-04.txt [Page 11] Internet-Draft PSAMP Information Model March 2006 This information element is used to describe the configuration of a systematic time-based sampling selector. Abstract Data Type: dateTimeMicroSeconds ElementId: 308 Status: current Units: microseconds 9.2.10 samplingSize Description: The number of elements taken from the parent population for random sampling algorithms. This information element is used to describe the configuration of a random n-out-of-N sampling selector. Abstract Data Type: unsigned32 ElementId: 309 Status: current Units: packets 9.2.11 samplingPopulation Description: The number of elements in the parent population for random sampling algorithms. This information element is used to describe the configuration of a random n-out-of-N sampling selector. Abstract Data Type: unsigned32 ElementId: 310 Status: current Units: packets 9.2.12 samplingProbability Description: 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. This information element is used to describe the configuration of a uniform probabilistic sampling selector. Abstract Data Type: float64 Dietz, et al. draft-ietf-psamp-info-04.txt [Page 12] Internet-Draft PSAMP Information Model March 2006 ElementId: 311 Status: current 9.2.13 [unused] Description: This ID is not currently in use. Abstract Data Type: ElementId: 312 Status: unused 9.2.14 ipHeaderPacketSection Description: This information element carries a series of octets from the start of the IP header of a sampled packet. The size of the exported section may be constrained due to limitations in the IPFIX protocol. Abstract Data Type: variable length octetArray ElementId: 313 Status: current 9.2.15 ipPayloadPacketSection Description: This information element 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 which follows the IPv4 header and any options, which [RFC0791] refers to as "data" or "data octets". e.g., see the examples in [RFC0791] APPENDIX A. The size of the exported section may be constrained due to limitations in the IPFIX protocol. If insufficient octets are available for the length specified in the template, the packet section must be sent with a new template using either a fixed length Information Element of the necessary size or a variable length Information Element. It's not permissible to pad a short packet section to a longer length. Abstract Data Type: variable length octetArray ElementId: 314 Status: current 9.2.16 dataLinkFrameSection Dietz, et al. draft-ietf-psamp-info-04.txt [Page 13] Internet-Draft PSAMP Information Model March 2006 Description: This information element carries the first n octets from the data link frame of a sampled packet. The data link layer is defined in [ISO/IEC.7498-1:1994]. The size of the exported section may be constrained due to limitations in the IPFIX protocol. If insufficient octets are available for the length specified in the template, the packet section must be sent with a new template using either a fixed length Information Element of the necessary size or a variable length Information Element. It's not permissible to pad a short packet section to a longer length. Abstract Data Type: variable length octetArray ElementId: 315 Status: current 9.2.17 mplsLabelStackSection Description: This information element carries the first n octets from the MPLS label stack of a sampled packet. 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. Abstract Data Type: variable length octetArray ElementId: 316 Status: current 9.2.18 mplsPayloadPacketSection Description: This information element 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. Dietz, et al. draft-ietf-psamp-info-04.txt [Page 14] Internet-Draft PSAMP Information Model March 2006 If insufficient octets are available for the length specified in the template, the packet section must be sent with a new template using either a fixed length Information Element of the necessary size or a variable length Information Element. It's not permissible to pad a short packet section to a longer length. Abstract Data Type: variable length octetArray ElementId: 317 Status: current 9.2.19 packetsObserved Description: Number of packets observed by a selector. Abstract Data Type: unsigned64 ElementId: 318 Status: current Units: packets 9.2.20 packetsSelected Description: Number of packets selected by a selector. Abstract Data Type: unsigned64 ElementId: 319 Status: current Units: packets 9.2.21 fixedError Description: Specifies the maximum possible positive or negative error interval of the reported value for a given Information Element. Abstract Data Type: float64 ElementId: 320 Status: current Units: The units of the Information Element for which the error is specified. 9.2.22 relativeError Description: Specifies the maximum possible positive or negative error ratio for a given Information Element. Dietz, et al. draft-ietf-psamp-info-04.txt [Page 15] Internet-Draft PSAMP Information Model March 2006 Abstract Data Type: float64 ElementId: 321 Status: current 9.2.23 observationTimeSeconds Description: The absolute time of an observation. Abstract Data Type: dateTimeSeconds ElementId: 322 Status: current Units: seconds 9.2.24 observationTimeMilliSeconds Description: The absolute time of an observation. Abstract Data Type: dateTimeSeconds ElementId: 323 Status: current Units: milliseconds 9.2.25 observationTimeMicroSeconds Description: The absolute time of an observation. Abstract Data Type: dateTimeSeconds ElementId: 324 Status: current Units: microseconds 9.2.26 observationTimeNanoSeconds Description: The absolute time of an observation. Abstract Data Type: dateTimeSeconds ElementId: 325 Status: current Units: nanoseconds 9.2.27 digestHashValue Description: The value from the digest hash function. Dietz, et al. draft-ietf-psamp-info-04.txt [Page 16] Internet-Draft PSAMP Information Model March 2006 Abstract Data Type: unsigned64 ElementId: 326 Status: current 9.2.28 hashIPPayloadOffset Description: The IP payload offset used by a hash based selector. Abstract Data Type: unsigned64 ElementId: 327 Status: current 9.2.29 hashIPPayloadSize Description: The IP payload size used by a hash based selector. Abstract Data Type: unsigned64 ElementId: 328 Status: current 9.2.30 hashInitialiserValue Description: The initialiser value to the hash function. Abstract Data Type: unsigned64 ElementId: 326 Status: current 9.2.31 hashOutputRangeMin Description: A value for the beginning of a hash function's potential output range. Abstract Data Type: unsigned64 ElementId: 329 Status: current 9.2.32 hashOutputRangeMax Description: A value for the end of a hash function's potential output range. Abstract Data Type: unsigned64 ElementId: 330 Status: current 9.2.33 hashSelectedRangeMin Dietz, et al. draft-ietf-psamp-info-04.txt [Page 17] Internet-Draft PSAMP Information Model March 2006 Description: A value for the beginning of a hash function's selected range. Abstract Data Type: unsigned64 ElementId: 331 Status: current 9.2.34 hashSelectedRangeMax Description: A value for the end of a hash function's selected range. Abstract Data Type: unsigned64 ElementId: 332 Status: current 9.2.35 hashDigestOutput Description: A boolean value, TRUE if the output from this hash selector has been configured to be included in the packet report as a packet digest, else FALSE. Abstract Data Type: boolean ElementId: 333 Status: current 10. Security Considerations The PSAMP information model itself does not directly introduce security issues. Rather it defines a set of attributes which may for privacy or business issues be considered sensitive information. 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] and the PSAMP WG charter. 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 protocols are defined in separate documents, specifically the IPFIX protocol document [I-D.ietf-ipfix-protocol]. 11. IANA Considerations This document defines an initial set of PSAMP Information Elements as specified in [I-D.ietf-psamp-sample-tech], as an extension to the IPFIX Information Elements [I-D.ietf-ipfix-info]. New assignments for PSAMP Information Elements will be administered according to Dietz, et al. draft-ietf-psamp-info-04.txt [Page 18] Internet-Draft PSAMP Information Model March 2006 rules explained in the "IANA Consideration" section of the IPFIX Information Model document [I-D.ietf-ipfix-info]. Note that the PSAMP Information Element IDs were initially started at the value 300, 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. Appendix B defines an XML schema which may be used to create consistent machine readable extensions to the IPFIX information model. This schema introduces a new namespace, which will be assigned by IANA according to [RFC3688]. In future the selectorAlgorithm registry will be maintained by IANA. IANA can update this information element as long as there's a new RFC specifying the algorithm and any new Information Elements which are required. 12. References 12.1 Normative References [I-D.ietf-psamp-sample-tech] Zseby, T., Molina, M., Duffield, N., Niccolini, S., and F. Raspall, "Sampling and Filtering Techniques for IP Packet Selection", draft-ietf-psamp-sample-tech-07 (work in progress), July 2005. [I-D.ietf-psamp-protocol] Claise, B., Quittek, J., and A. Johnson, "Packet Sampling (PSAMP) Protocol Specifications", draft-ietf-psamp-protocol-03 (work in progress), December 2005. [I-D.ietf-psamp-mib] Dietz, T. and B. Claise, "Definitions of Managed Objects for Packet Sampling", draft-ietf-psamp-mib-05 (work in progress), October 2005. [I-D.ietf-ipfix-info] Quittek, J., Bryant, S., Claise, B., and J. Meyer, "Information Model for IP Flow Information Export", draft-ietf-ipfix-info-11 (work in progress), September 2005. [I-D.ietf-ipfix-protocol] Claise, B., Bryant, S., Sadasivan, G., Leinen, S., and T. Dietz, et al. draft-ietf-psamp-info-04.txt [Page 19] Internet-Draft PSAMP Information Model March 2006 Dietz, "IPFIX Protocol Specification", draft-ietf-ipfix-protocol-19 (work in progress), September 2005. [ISO/IEC.7498-1:1994] International Organization for Standardization, "Information technology -- Open Systems Interconnection -- Basic Reference Model: The Basic Mode", ISO Standard 7498- 1:1994, June 1996. 12.2 Informative References [RFC3917] Quittek, J., Zseby, T., Claise, B., and S. Zander, "Requirements for IP Flow Information Export", RFC 3917, October 2004. [I-D.ietf-ipfix-architecture] Sadasivan, G., Brownlee, N., Claise, B., and J. Quittek, "Architecture for IP Flow Information Export", draft-ietf-ipfix-architecture-09 (work in progress), August 2005. [I-D.ietf-psamp-framework] Duffield, N., Chiou, D., Claise, B., Greenberg, A., Grossglauser, M., Marimuthu, P., Rexford, J., and G. Sadasivan, "A Framework for Packet Selection and Reporting", draft-ietf-psamp-framework-10 (work in progress), January 2005. [RFC2804] IAB and IESG, "IETF Policy on Wiretapping", RFC 2804, May 2000. [RFC0791] Postel, J., "Internet Protocol", STD 5, RFC 791, September 1981. [RFC3031] Rosen, E., Viswanathan, A., and R. Callon, "Multiprotocol Label Switching Architecture", RFC 3031, January 2001. [RFC3032] Rosen, E., Tappan, D., Rekhter, Y., Fedorkow, G., Farinacci, D., Li, T., and A. Conta, "MPLS Label Stack Encoding", RFC 3032, January 2001. [RFC3444] Pras, A. and J. Schoenwaelder, "On the Difference between Information Models and Data Models", RFC 3444, January 2003. [RFC2629] Rose, M., "Writing I-Ds and RFCs using XML", RFC 2629, June 1999. Dietz, et al. draft-ietf-psamp-info-04.txt [Page 20] Internet-Draft PSAMP Information Model March 2006 [RFC3470] Hollenbeck, S., Rose, M., and L. Masinter, "Guidelines for the Use of Extensible Markup Language (XML) within IETF Protocols", BCP 70, RFC 3470, January 2003. [RFC3688] Mealling, M., "The IETF XML Registry", BCP 81, RFC 3688, January 2004. Authors' Addresses Thomas Dietz NEC Europe Ltd. Network Laboratories Kurfuersten-Anlage 36 Heidelberg 69115 Germany Phone: +49 6221 90511-28 Email: dietz@netlab.nec.de URI: http://www.netlab.nec.de/ 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 University of Tuebingen Wilhelm-Schickard-Institute for Computer Science Auf der Morgenstelle 10C Tuebingen 71076 Germany Phone: +49 7071 29-70505 Email: carle@informatik.uni-tuebingen.de URI: http://net.informatik.uni-tuebingen.de/~carle/ Dietz, et al. draft-ietf-psamp-info-04.txt [Page 21] Internet-Draft PSAMP Information Model March 2006 Benoit Claise Cisco Systems De Kleetlaan 6a b1 Degem 1813 Belgium Phone: +32 2 704 5622 Email: bclaise@cisco.com Paul Aitken Cisco Systems 96 Commercial Quay Edinburgh EH6 6LX Scotland Phone: +44 131 561 3616 Email: paitken@cisco.com URI: http://www.cisco.com/ 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 Section 9 generated from this appendix is normative. Using a formal and machine readable syntax for the information model enables the creation of PSAMP aware tools which 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. Using XML-based specifications does not currently address possible Dietz, et al. draft-ietf-psamp-info-04.txt [Page 22] Internet-Draft PSAMP Information Model March 2006 IANA implications associated with XML Namespace URIs. The use of Namespaces as an extension mechanism implies that an IANA registered Namespace URI should be available and that directory names below this base URI be assigned for relevant IETF specifications. The authors are not aware of this mechanism today. ID of the observation process. Unique in the observation domain. From all the packets observed at an Observation Point, a subset of packets is selected by a sequence of one or more Selectors. The selectionSequenceId is a unique value per Observation Domain, describing the Observation Point and the sequence of Selectors through which the packets are selected. The Selector ID is the unique ID identifying a Primitive Selector. Each Primitive Selector must have a unique ID in the observation domain. Dietz, et al. draft-ietf-psamp-info-04.txt [Page 23] Internet-Draft PSAMP Information Model March 2006 Contains the ID of another Information Element. Specifies the selector algorithm (e.g., filter, sampler, hash) that was used on a packet. It is exported in the options data flow record to specify how a collector has to interpret a data flow record. The following selector algorithms are currently defined: 1 Systematic count-based sampling 2 Systematic time-based sampling 3 Random n-out-of-N sampling 4 Uniform probabilistic sampling 5 Property match filtering 6 Hash based filtering using BOB 7 Hash based filtering using IPSX 8 Hash based filtering using CRC EDITOR'S NOTE: This list may be extended in the final version. The parameters for most of these algorithms are defined in this information model. Some parameters for these algorithms are not covered by this information model Dietz, et al. draft-ietf-psamp-info-04.txt [Page 24] Internet-Draft PSAMP Information Model March 2006 since they very much depend on the underlying hardware. In future, this list will be maintained by IANA. IANA can update this information element as long as there's a new RFC specifying the algorithm and any new Information Elements which are required. Number of packets that are consecutively sampled. For example a value of 100 means that 100 contiguous packets are sampled. This information element is used to describe the configuration of a systematic count-based sampling selector. packets The number of packets between two "samplingPacketInterval"s. A value of 100 means that the next interval starts after 100 packets (which are not sampled) when the current "samplingPacketInterval" is over. This information element is used to describe the configuration of a systematic count-based sampling selector. packets Dietz, et al. draft-ietf-psamp-info-04.txt [Page 25] Internet-Draft PSAMP Information Model March 2006 Time interval in microseconds in which all arriving packets are sampled. This information element is used to describe the configuration of a systematic time-based sampling selector. microseconds The time interval in microseconds between two "samplingTimeInterval"s. A value of 100 means that the next interval starts after 100 microseconds (in which no packets are sampled) when the current "samplingTimeInterval" is over. This information element is used to describe the configuration of a systematic time-based sampling selector. microseconds The number of elements taken from the parent population for random sampling algorithms. Dietz, et al. draft-ietf-psamp-info-04.txt [Page 26] Internet-Draft PSAMP Information Model March 2006 This information element is used to describe the configuration of a random n-out-of-N sampling selector. packets The number of elements in the parent population for random sampling algorithms. This information element is used to describe the configuration of a random n-out-of-N sampling selector. packets 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. This information element is used to describe the configuration of a uniform probabilistic sampling selector. Dietz, et al. draft-ietf-psamp-info-04.txt [Page 27] Internet-Draft PSAMP Information Model March 2006 This ID is not currently in use. This information element carries a series of octets from the start of the IP header of a sampled packet. The size of the exported section may be constrained due to limitations in the IPFIX protocol. This information element 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 which follows the IPv4 header and any options, which refers to as "data" or "data octets". e.g., see the examples in APPENDIX A. The size of the exported section may be constrained due to limitations in the IPFIX protocol. Dietz, et al. draft-ietf-psamp-info-04.txt [Page 28] Internet-Draft PSAMP Information Model March 2006 If insufficient octets are available for the length specified in the template, the packet section must be sent with a new template using either a fixed length Information Element of the necessary size or a variable length Information Element. It's not permissible to pad a short packet section to a longer length. This information element carries the first n octets from the data link frame of a sampled packet. The data link layer is defined in . The size of the exported section may be constrained due to limitations in the IPFIX protocol. If insufficient octets are available for the length specified in the template, the packet section must be sent with a new template using either a fixed length Information Element of the necessary size or a variable length Information Element. It's not permissible to pad a short packet section to a longer length. Dietz, et al. draft-ietf-psamp-info-04.txt [Page 29] Internet-Draft PSAMP Information Model March 2006 This information element carries the first n octets from the MPLS label stack of a sampled packet. See for the specification of MPLS packets. See for the specification of the MPLS label stack. The size of the exported section may be constrained due to limitations in the IPFIX protocol. This information element carries the first n octets from the MPLS payload of a sampled packet, being data that follows immediately after the MPLS label stack. See for the specification of MPLS packets. Dietz, et al. draft-ietf-psamp-info-04.txt [Page 30] Internet-Draft PSAMP Information Model March 2006 See for the specification of the MPLS label stack. The size of the exported section may be constrained due to limitations in the IPFIX protocol. If insufficient octets are available for the length specified in the template, the packet section must be sent with a new template using either a fixed length Information Element of the necessary size or a variable length Information Element. It's not permissible to pad a short packet section to a longer length. Number of packets observed by a selector. packets Number of packets selected by a selector. packets Specifies the maximum possible positive or negative error interval of the reported value for a given Information Dietz, et al. draft-ietf-psamp-info-04.txt [Page 31] Internet-Draft PSAMP Information Model March 2006 Element. The units of the Information Element for which the error is specified. Specifies the maximum possible positive or negative error ratio for a given Information Element. The absolute time of an observation. seconds The absolute time of an observation. milliseconds The absolute time of an observation. Dietz, et al. draft-ietf-psamp-info-04.txt [Page 32] Internet-Draft PSAMP Information Model March 2006 microseconds The absolute time of an observation. nanoseconds The value from the digest hash function. The IP payload offset used by a hash based selector. The IP payload size used by a hash based selector. The initialiser value to the hash function. Dietz, et al. draft-ietf-psamp-info-04.txt [Page 33] Internet-Draft PSAMP Information Model March 2006 A value for the beginning of a hash function's potential output range. A value for the end of a hash function's potential output range. A value for the beginning of a hash function's selected range. A value for the end of a hash function's selected range. A boolean value, TRUE if the output from this hash selector Dietz, et al. draft-ietf-psamp-info-04.txt [Page 34] Internet-Draft PSAMP Information Model March 2006 has been configured to be included in the packet report as a packet digest, else FALSE. Dietz, et al. draft-ietf-psamp-info-04.txt [Page 35] Internet-Draft PSAMP Information Model March 2006 Intellectual Property Statement The IETF takes no position regarding the validity or scope of any Intellectual Property Rights or other rights that might be claimed to pertain to the implementation or use of the technology described in this document or the extent to which any license under such rights might or might not be available; nor does it represent that it has made any independent effort to identify any such rights. Information on the procedures with respect to rights in RFC documents can be found in BCP 78 and BCP 79. Copies of IPR disclosures made to the IETF Secretariat and any assurances of licenses to be made available, or the result of an attempt made to obtain a general license or permission for the use of such proprietary rights by implementers or users of this specification can be obtained from the IETF on-line IPR repository at http://www.ietf.org/ipr. The IETF invites any interested party to bring to its attention any copyrights, patents or patent applications, or other proprietary rights that may cover technology that may be required to implement this standard. Please address the information to the IETF at ietf-ipr@ietf.org. Disclaimer of Validity This document and the information contained herein are provided on an "AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY AND THE INTERNET ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. Copyright Statement Copyright (C) The Internet Society (2006). This document is subject to the rights, licenses and restrictions contained in BCP 78, and except as set forth therein, the authors retain all their rights. Acknowledgment Funding for the RFC Editor function is currently provided by the Internet Society. Dietz, et al. draft-ietf-psamp-info-04.txt [Page 36]