IPFIX Working Group B. Claise Internet-Draft G. Dhandapani Intended Status: Standards Track S. Yates Expires: April 15, 2010 P. Aitken Cisco Systems, Inc. October 15, 2009 Export of Structured Data in IPFIX draft-ietf-ipfix-structured-data-00.txt Status of this Memo This Internet-Draft is submitted to IETF in full conformance with the provisions of BCP 78 and 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." 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Abstract This document specifies an extension to IP Flow Information eXport (IPFIX) protocol specification in [RFC5101] and the IPFIX information model specified in [RFC5102] to support hierarchical structured data and lists (sequences) of Information Elements in data records. This extension allows definition of complex data structures such as variable-length lists and specification of hierarchical containment relationships between Templates. 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]. Expires April 15, 2010 [Page 2] Internet-Draft October 2009 Table of Contents 1. Overview...................................................7 1.1. IPFIX Documents Overview..............................7 1.2. Relationship between IPFIX and PSAMP..................8 2. Terminology................................................8 2.1. New Terminology.......................................8 3. Introduction...............................................9 3.1. The IPFIX Track......................................10 3.2. The IPFIX Limitations................................10 3.3. The Proposal.........................................13 4. Linkage with the Information Model........................13 4.1. New Abstract Data Types..............................13 4.1.1. basicList.......................................14 4.1.2. subTemplateList.................................14 4.1.3. subTemplateMultiList ...........................14 4.2. New Data Type Semantic...............................14 4.2.1. List............................................14 4.3. New Information Elements.............................14 4.3.1. basicList.......................................15 4.3.2. subTemplateList.................................15 4.3.3. subTemplateMultiList ...........................15 4.4. Encoding of IPFIX Data Types.........................15 4.4.1. basicList.......................................16 4.4.2. subTemplateList.................................18 4.4.3. subTemplateMultiList ...........................19 5. Structured Data Format....................................21 5.1. Length Encoding Considerations.......................21 5.2. Recursive Structured Data ...........................22 5.3. Structured Data Information Elements Applicability in Options Template Sets.....................................22 5.4. Usage Guidelines for Equivalent Data Representations.23 5.5. Padding..............................................24 6. Template Management.......................................25 7. The Collecting Process's Side.............................25 8. Structured Data Encoding Examples.........................25 8.1. Encoding BasicList ..................................26 8.2. Encoding subTemplateList.............................27 8.3. Encoding subTemplateMultiList........................30 8.4. Encoding an Options Template Set using Structured Data35 9. Relationship with the Other IFPIX Documents...............39 9.1. Relationship with Reducing Redundancy................39 9.1.1. Encoding Structured Data Element using Common Properties.............................................39 9.1.2. Encoding Common Properties elements With Structured Data Element. .........................................39 Expires April 15, 2010 [Page 3] Internet-Draft October 2009 9.2. Relationship with Guidelines for IPFIX Testing .....41 9.3. Relationship with Bidirectional Flow Export.........42 9.4. Relationship with IPFIX Mediation Function..........43 10. IANA Considerations.....................................43 10.1. New Abstract Data Types............................43 10.1.1. basicList.....................................43 10.1.2. subTemplateList...............................44 10.1.3. subTemplateMultiList..........................44 10.2. New Data Type Semantics............................44 10.2.1. list..........................................44 10.3. New Information Elements ..........................44 10.3.1. basicList.....................................44 10.3.2. subTemplateList...............................45 10.3.3. subTemplateMultiList..........................45 11. Security Considerations.................................45 12. References..............................................45 12.1. Normative References...............................45 12.2. Informative References.............................46 13. Acknowledgement ........................................47 14. Authors' Addresses......................................47 Appendix A. XML Specification of IPFIX Information Elements and Abstract Data Types.....................................48 Appendix B. Example of Biflow Encoding using Structured Data Information Elements...................................50 Appendix C. Encoding IPS Alert using Structured Data Information Elements........................................53 Expires April 15, 2010 [Page 4] Internet-Draft October 2009 Table of Figures Figure A: basicList Information Element Encoding...............16 Figure B: basicList Encoding with Enterprise Number............17 Figure C: Variable-Length basicList Information Element Encoding (Length < 255 octets) ......................................17 Figure D: Variable-Length basicList Information Element Encoding (Length 0 to 65535 octets)..................................18 Figure E: subTemplateList Encoding.............................18 Figure F: Variable-Length subTemplateList Information Element Encoding (Length < 255 octets)..............................19 Figure G: Variable-Length subTemplateList Information Element Encoding (Length 0 to 65535 octets) ........................19 Figure H: subTemplateMultiList Encoding........................20 Figure I: Variable-Length subTemplateMultiList Information Element Encoding (Length < 255 octets)..............................21 Figure J: Variable-Length subTemplateMultiList Information Element Encoding (Length 0 to 65535 octets) ........................21 Figure K: Encoding basicList, Template Record..................26 Figure L: Encoding basicList, Data Record......................27 Figure M: Encoding subTemplateList, Template for One-Way Delay Metrics ....................................................28 Figure N: Encoding subTemplateList, Template Record............28 Figure O: Encoding subTemplateList, Data Set...................30 Figure P: Encoding subTemplateMultiList, Template for Classification Attributes...................................32 Figure Q: Encoding subTemplateMultiList, Template for Sampling Attributes..................................................33 Figure R: Encoding subTemplateMultiList, Template for Flow Record34 Figure S: Encoding subTemplateMultiList, Data Set..............34 Figure T: PSAMP SSRI to be encoded.............................36 Figure U: Options Template Record for PSAMP SSRI using subTemplateMultiList........................................37 Figure V: PSAMP SSRI, Template Record for interface............37 Figure W: PSAMP SSRI, Template Record for linecard ............37 Figure X: PSAMP SSRI, Template Record for linecard and interface38 Figure Y: Example of a PSAMP SSRI Data Record, Encoded using a subTemplateMultiList........................................38 Figure Z: Common and Specific Properties Exported Together [RFC5473]...................................................40 Figure ZA: Common and Specific Properties Exported Separately according to [RFC5473]......................................40 Figure ZB: Common and Specific Properties Exported with Structured Data Information Element....................................40 Figure B0: Using a subTemplateList to represent a Biflow.......51 Figure B1: Template for the Biflow Fields......................52 Figure B2: Template for the Key Fields.........................52 Expires April 15, 2010 [Page 5] Internet-Draft October 2009 Figure B3: Biflow Data Set Encoded using Structured Data.......53 Figure C0: Encoding IPS Alert, Template for Target ............55 Figure C1: Encoding IPS Alert, Template for Attacker...........55 Figure C2: Encoding IPS Alert, Template for Participant........56 Figure C3: Encoding IPS Alert, Template for IPS Alert..........56 Figure C4: Encoding IPS Alert, Data Set........................57 Expires April 15, 2010 [Page 6] Internet-Draft October 2009 TO DO - Incorporate the WG consensus regarding the Selector ID Length - Does the WG want to include logical OR in this draft? - The template IDs used in appendix B could be modified to make them continue from the earlier examples. However, reviewing the template IDs already used, I saw: 8.1 = 258 8.2 = 259, 260 8.3 = 261, 262, 263, 264 8.4 = 270, 271, 272, 273 #B = 300, 301. So there's clearly a gap where 265 through 269 weren't used or were removed. Also Template could start at 256. 1. Overview 1.1. IPFIX Documents Overview The IPFIX Protocol [RFC5101] provides network administrators with access to IP Flow information. The architecture for the export of measured IP Flow information out of an IPFIX Exporting Process to a Collecting Process is defined in the IPFIX Architecture [RFC5470], per the requirements defined in RFC 3917 [RFC3917]. The IPFIX Architecture [RFC5470] specifies how IPFIX Data Records and Templates are carried via a congestion-aware transport protocol from IPFIX Exporting Processes to IPFIX Collecting Processes. IPFIX has a formal description of IPFIX Information Elements, their name, type and additional semantic information, as specified in the IPFIX information model [RFC5102]. In order to gain a level of confidence in the IPFIX implementation, probe the conformity and robustness, and allow interoperability, the Guidelines for IPFIX Testing [RFC5471] presents a list of tests for implementers of compliant Exporting Processes and Collecting Processes. The Bidirectional Flow Export [RFC5103] specifies a method for exporting bidirectional flow (biflow) information using the IP Flow Information Export (IPFIX) protocol, representing each Biflow using a single Flow Record. Expires April 15, 2010 [Page 7] Internet-Draft October 2009 The "Reducing Redundancy in IP Flow Information Export (IPFIX) and Packet Sampling (PSAMP) Reports" [RFC5473] specifies a bandwidth saving method for exporting Flow or packet information, by separating information common to several Flow Records from information specific to an individual Flow Record: common Flow information is exported only once. 1.2. Relationship between IPFIX and PSAMP The specification in this document applies to the IPFIX protocol specifications [RFC5101]. All specifications from [RFC5101] apply unless specified otherwise in this document. The Packet Sampling (PSAMP) protocol [RFC5476] specifies the export of packet information from a PSAMP Exporting Process to a PSAMP Collecting Process. Like IPFIX, PSAMP has a formal description of its information elements, their name, type and additional semantic information. The PSAMP information model is defined in [RFC5477]. As the PSAMP protocol specifications [RFC5476] are based on the IPFIX protocol specifications, the specifications in this document are also valid for the PSAMP protocol. Indeed, the major difference between IPFIX and PSAMP is that the IPFIX protocol exports Flow Records while the PSAMP protocol exports Packet Reports. From a pure export point of view, IPFIX will not distinguish a Flow Record composed of several packets aggregated together, from a Flow Record composed of a single packet. So the PSAMP export can be seen as a special IPFIX Flow Record containing information about a single packet. 2. Terminology IPFIX-specific terminology used in this document is defined in section 2 of the IPFIX protocol specification [RFC5101] and section 3 of PSAMP protocol specification [RFC5476]. As in [RFC5101], these IPFIX-specific terms have the first letter of a word capitalized when used in this document. 2.1. New Terminology Structured Data Information Element Expires April 15, 2010 [Page 8] Internet-Draft October 2009 One of the Information Elements supporting structured data, i.e., the basicList, subTemplateList, or subTemplateMultiList Information Elements. 3. Introduction While collecting the interface counters every five minutes has proven to be useful in the past, more and more granular information is required from network elements for a series of applications: performance assurance, capacity planning, security, billing, or simply monitoring. However, the amount of information has become so important that, when dealing with highly granular information such as Flow information, a push mechanism (as opposed to a pull mechanism, such as SNMP) is the only solution for routers... whose primary function is to route packet. Indeed, polling short-live Flows via SNMP is not an option: high end routers can support hundreds of thousands of Flows simultaneously. Furthermore, in order to reduce the export bandwidth requirements, the network elements have to integrate mediation functions, to aggregate the collected information, both in space and time. Typically, it would be beneficial if access routers could export Flow Records, composed of the counters before and after the WAN optimization mechanism, instead of exporting two Flow Records with identical tuple information. In terms of aggregation in time, let us imagine that, for performance assurance, the network management application must receive the performance metrics associated with a specific flow, every millisecond. Since the performance metrics will be constantly changing, there is a new dimension to the Flow definition: we are not dealing anymore with a single Flow lasting a few seconds or a few minutes, but with a multitude of one millisecond sub flows for which the performance metrics are reported. Which current protocol is suitable for these requirements: push mechanism, highly granular information, and huge number of similar records? IPFIX, as specified in RFC5101 would give part of the solution. Expires April 15, 2010 [Page 9] Internet-Draft October 2009 3.1. The IPFIX Track The IPFIX working group has specified a protocol to export IP Flow information [RFC5101]. This protocol is designed to export information about IP traffic Flows and related measurement data, where a Flow is defined by a set of key attributes (e.g. source and destination IP address, source and destination port, etc.). The IPFIX protocol specification [RFC5101] specifies that IP traffic measurements for Flows are exported using a TLV (type, length, value) format. The information is exported using a Template Record that is sent once to export the {type, length} pairs that define the data format for the Information Elements in a Flow. The Data Records specify values for each Flow. Based on the Requirements for IP Flow Information Export (IPFIX) [RFC3917], the IPFIX protocol has been optimized to export Flow related information. However, thanks to its Template mechanism, the IPFIX protocol can export any type of information, as long as the relevant Information Element is specified in the IPFIX information model [RFC5102], registered with IANA, or specified as an enterprise-specific Information Element. For each Information Element, the IPFIX information model [RFC5102] defines a numeric identifier, an abstract data type, an encoding mechanism for the data type, and any semantic constraints. Only basic, single- valued data types, e.g., numbers, strings, and network addresses are currently supported. 3.2. The IPFIX Limitations The IPFIX protocol specification [RFC5101] does not support the encoding of hierarchical structured data and arbitrary-length lists (sequences) of Information Elements as fields within a Template Record. As it is currently specified, a Data Record is a "flat" list of single-valued attributes. However, it is a common data modeling requirement to compose complex hierarchies of data types, with multiple occurrences, e.g., 0..* cardinality allowed for instances of each Information Element in the hierarchy. A typical example is the MPLS label stack entries model. An early NetFlow implementation used two Information Elements to represent the MPLS label stack entry: a "label stack entry position" followed by a "label stack value". However, several drawbacks were discovered. Firstly, the Information Elements in the Template Record had to be imposed so that the position would always precede the value. However, some encoding optimizations Expires April 15, 2010 [Page 10] Internet-Draft October 2009 are based on the permutation of Information Element order. Secondly, a new semantic intelligence, not described in the information model, had to be hardcoded in the Collecting Process: the label value at the position "X" in the stack is contained in the "label stack value" Information Element following by a "label stack entry position" Information Element containing the value "X". Therefore, this model was abandoned. The selected solution in the IPFIX information model [RFC5102] is a long series of Information Elements: mplsTopLabelStackSection, mplsLabelStackSection2, mplsLabelStackSection3, mplsLabelStackSection4, mplsLabelStackSection5, mplsLabelStackSection6, mplsLabelStackSection7, mplsLabelStackSection8, mplsLabelStackSection9, mplsLabelStackSection10. While this model removes any ambiguity, it overloads the IPFIX information model with repetitive information. Furthermore, if mplsLabelStackSection11 is required, IANA will not be able to assign the new Information Element next to the other ones in the registry, which might cause some confusion. Clearly a real structured data type composed of ("label stack entry position", "label stack value") pairs, potentially repeated multiple times in Flow Records would be more efficient from an information model point of view. Some more examples enter the same category: how to encode the list of output interfaces in a multicast Flow, how to encode the list of BGP Autonomous Systems (AS) in a BGP Flow, how to encode the BGP communities in a BGP Flow, etc? The one-way delay passive measurement, which is described in the IPFIX Applicability [RFC5472], is yet another example that would benefit from a structured data encoding. Assuming synchronized clocks, the Collector can deduce the one-way delay from the following two Information Elements, collected from two different Observation Points: - Packet arrival time: observationTimeMicroseconds [RFC5477] - Packet ID: digestHashValue [RFC5477] Ideally, the measurement at the second Observation Point should start a little bit later than at the first Observation Point, allowing the packets to arrive at the destination. In practice, this implies that many pairs of (observationTimeMicroseconds, digestHashValue) must be exported for each Observation Point, even if some optimization based on Hash-Based Filtering [RFC5475] is used. Instead of exporting repetitive information as part of every single Flow Record (for example, the 5 tuple), an optimized Expires April 15, 2010 [Page 11] Internet-Draft October 2009 flow record composed of a structured data type such as the following would save a lot of bandwidth: 5 tuple observationTimeMicroseconds 1, digestHashValue 1 observationTimeMicroseconds 2, digestHashValue 2 observationTimeMicroseconds 3, digestHashValue 3 ... , ... As a last example, here is a more complex case of hierarchical structured data encoding. Consider the example scenario of an IPS (Intrusion Prevention System) alert data structure containing multiple participants, where each participant contains multiple attackers and multiple targets, with each target potentially composed of multiple applications, as depicted below: alert signatureId protocolIdentifier riskRating participant 1 attacker 1 sourceIPv4Address applicationId ... attacker N sourceIPv4Address applicationId target 1 destinationIPv4Address applicationId 1 ... applicationId n ... target N destinationIPv4Address applicationId 1 ... applicationId n participant 2 ... To export this information in IPFIX, the data would need to be flattened (thus losing the hierarchical relationships) and a new Expires April 15, 2010 [Page 12] Internet-Draft October 2009 IPFIX Template created for each alert, according to the number of applicationID elements in each target, the number of targets and attackers in each participant and the number of participants in each alert. Clearly each Template will be unique to each alert, and a large amount of CPU, memory and export bandwidth will be wasted creating, exporting, maintaining, and withdrawing the Templates. See Appendix C8. for a specific example related to this case study. 3.3. The Proposal This document specifies an IPFIX extension to support hierarchical structured data and variable-length lists by defining three new Information Elements and three corresponding new abstract data types called basicList, subTemplateList, and subTemplateMultiList. These are defined in section 4.1. New Abstract Data Types. It is important to note that whereas the Information Elements and abstract data types defined in the IPFIX information model [RFC5102] represent single values, these new abstract data types are structural in nature and primarily contain references to other Information Elements and to Templates. By referencing other Information Elements and Templates from an Information Element's data content, it is possible to define complex data structures such as variable-length lists and to specify hierarchical containment relationships between Templates. Therefore, this document prefers the more generic "Data Record" term to the "Flow Record" term. 4. Linkage with the Information Model As in the IPFIX Protocol specification [RFC5101], the new Information Elements specified in section 4.3. below MUST be sent in canonical format in network-byte order (also known as the big- endian byte ordering). 4.1. New Abstract Data Types This document specifies three new abstract data types, as described below. Expires April 15, 2010 [Page 13] Internet-Draft October 2009 4.1.1. basicList The type "basicList" represents a list of zero or more instances of any single Information Element, primarily used for single- valued data types. For example, a list of port numbers, a list of interface indexes, a list of AS in a BGP AS-PATH, etc. 4.1.2. subTemplateList The type "subTemplateList" represents a list of zero or more instances of a structured data type, where the data type of each list element is the same and corresponds with a single Template Record. For example, a structured data type composed of multiple pairs of ("MPLS label stack entry position", "MPLS label stack value"), a structured data type composed of performance metrics, a structured data type composed of multiple pairs of IP address, etc. 4.1.3. subTemplateMultiList The type "subTemplateMultiList" represents a list of zero or more instances of a structured data type, where the data type of each list element can be different and corresponds with different template definitions. For example, a structured data type composed of multiple access-list entries, where entries can be composed of different criteria types. 4.2. New Data Type Semantic This document specifies a new data type semantic, as described below. 4.2.1. List A list represents an arbitrary-length sequence of structured data elements, either composed of regular Information Elements or composed of data conforming to a Template Record. 4.3. New Information Elements This document specifies three new Information Elements, as described below. Expires April 15, 2010 [Page 14] Internet-Draft October 2009 4.3.1. basicList A basicList specifies a generic Information Element with a basicList abstract data type as defined in section 4.1.1. and list semantics as defined in section 4.2.1. For example, a list of port numbers, list of interface indexes, etc. EDITOR'S NOTE: while waiting for IANA to assign this new Information Element identifier, the value XXX is used in all the examples. 4.3.2. subTemplateList A subTemplateList specifies a generic Information Element with a subTemplateList abstract data type as defined in section 4.1.2. and list semantics as defined in section 4.2.1. EDITOR'S NOTE: while waiting for IANA to assign this new Information Element identifier, the value YYY is used in all the examples. 4.3.3. subTemplateMultiList A subTemplateMultiList specifies a generic Information Element with a subTemplateMultiList abstract data type as defined in section 4.1.3. and list semantics as defined in section 4.2.1. EDITOR'S NOTE: while waiting for IANA to assign this new Information Element identifier, the value ZZZ is used in all the examples. 4.4. Encoding of IPFIX Data Types The following sections define the encoding of the data types defined in section 4.1. above. When the encoding of a Structured Data Information Element has a fixed length (because, for example, it contains the same number of fixed-length elements, or if the permutations of elements in the list always produces the same total length), the element length can be encoded in the corresponding Template Record. However, when representing variable-length data, hierarchical data, and Expires April 15, 2010 [Page 15] Internet-Draft October 2009 repeated data with variable element counts, we RECOMMEND these are encoded as a Variable-Length Information Element as described in section 7 of [RFC5101], with the length carried in one or three octets before the Structured Data Information Element encoding. 4.4.1. basicList The basicList Information Element defined in section 4.3.1. represents a list of zero or more instances of an Information Element and is encoded as follows: 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0| Field ID | Element Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | BasicList Content ... | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | ... | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure A: basicList Information Element Encoding Field ID The Field ID is the Information Element identifier of the Information Element(s) contained in the list. Element Length The Element Length indicates the length of each element or contains the value 0xFFFF if the length is encoded as for a variable-length Information Element. BasicList Content A Collection Process decodes list elements from the BasicList Content until no further data remains. A field count is not included but can be derived when the Information Element is decoded. Note that in the diagram above, the Field ID is shown with the Enterprise bit (most significant bit) set to 0. If instead the Enterprise bit is set to 1, a four-byte Enterprise Number MUST be encoded immediately after the Element Length as shown below. See Expires April 15, 2010 [Page 16] Internet-Draft October 2009 the "Field Specifier Format" section in the IPFIX Protocol [RFC5101] for additional information. 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |1| Field ID | Element Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Enterprise Number | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | BasicList Content ... | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | ... | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure B: basicList Encoding with Enterprise Number Also note that, if a basicList has zero elements, the encoded data contains the Field ID, the Element Length and the four-byte Enterprise Number (if present); the BasicList Content is empty. The Element Length field is effectively part of a header, so even in the case of a zero-element list with no Enterprise Number, it MUST NOT be omitted. If the basicList is encoded as a Variable-Length Information Element in less than 255 octets, it is encoded with the Length per section 7 of [RFC5101] as follows: 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Length (< 255)| basicList Information Element | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | ... continuing as needed | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure C: Variable-Length basicList Information Element Encoding (Length < 255 octets) If the basicList is encoded as a Variable-Length Information Element in 255 or more octets, it is encoded with the Length per section 7 of [RFC5101] as follows: 0 1 2 3 Expires April 15, 2010 [Page 17] Internet-Draft October 2009 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | 255 | Length (0 to 65535) | ... | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | basicList Information Element | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure D: Variable-Length basicList Information Element Encoding (Length 0 to 65535 octets) 4.4.2. subTemplateList The subTemplateList Information Element represents a list of zero or more instances of Template data. Because the Template Record referenced by a subTemplateList Information Element can itself contain other subTemplateList Information Elements, and because these Template Record references are part of the Information Elements content in the Data Record, it is possible to represent complex hierarchical data structures. The following diagram shows how a subTemplateList Information Element is encoded within a Data Record: 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Template ID | SubTemplateList Content | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | ... | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure E: subTemplateList Encoding Template ID The Template ID is the ID of the template used to encode and decode the SubTemplateList Content. SubTemplateList Content The SubTemplateList Content consists of zero or more instances of Data Records corresponding to the Template ID. A Collecting Process decodes the Data Records until no further data remains. A record count is not included but can be derived when the subTemplateList is decoded. Encoding and decoding are performed recursively if the specified Template Expires April 15, 2010 [Page 18] Internet-Draft October 2009 itself contains Structured Data Information Elements as described here. Note that, if a subTemplateList has zero elements, the encoded data contains just the Template ID; the SubTemplateList Content is empty. If the subTemplateList is encoded as a Variable-Length Information Element in less than 255 octets, it is encoded with the Length per section 7 of [RFC5101] as follows: 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Length (< 255)| subTemplateList Information Element | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | ... continuing as needed | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure F: Variable-Length subTemplateList Information Element Encoding (Length < 255 octets) If the subTemplateList is encoded as a Variable-Length Information Element in 255 or more octets, it is encoded with the Length per section 7 of [RFC5101] as follows: 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | 255 | Length (0 to 65535) | ... | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | ... SubTemplateList continuing as needed | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure G: Variable-Length subTemplateList Information Element Encoding (Length 0 to 65535 octets) 4.4.3. subTemplateMultiList Whereas each top-level element in a subTemplateList Information Element corresponds with a single Template ID and therefore has the same data type, sometimes it is useful for a list to contain elements of more than one data type. To support this case, each top-level element in a subTemplateMultiList Information Element carries a Template ID and Length. The following diagram shows how Expires April 15, 2010 [Page 19] Internet-Draft October 2009 a subTemplateMultiList Information Element is encoded within a Data Record. Note that the subTemplateMultiList encoding is consistent with Set Header specified in [RFC5101]. 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Element 1 Template Id | Element 1 Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Element 1 Content ... | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | ... | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Element 2 Template Id | Element 2 Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Element 2 content ... | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | ... | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Element N Template Id | Element N Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Element N content ... | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure H: subTemplateMultiList Encoding Element Length The total length of the Element encoding, including the 2 bytes for the Template Id and the 2 bytes for the Element Length field itself. Element Template ID Unlike the subTemplateList Information Element, each list element contains an Element Length and Element Template ID which specifies the encoding of the following Element Content. Element Content The Element Content consists of zero or more instances of Data Records corresponding to the Element Template ID. A Collecting Process decodes the Data Records until no further data remains. A record count is not included but can be derived when the Element Content is decoded. Encoding and decoding are performed recursively if the specified Template Expires April 15, 2010 [Page 20] Internet-Draft October 2009 itself contains Structured Data Information Elements as described here. In the exceptional case of zero instances in the subTemplateMultiList, no data is encoded and the Length is set to zero. If the subTemplateMultiList is encoded as a Variable-Length Information Element in less than 255 octets, it is encoded with the Length per section 7 of [RFC5101] as follows: 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Length (< 255)| subTemplateMultiList Information Element | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | ... continuing as needed | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure I: Variable-Length subTemplateMultiList Information Element Encoding (Length < 255 octets) If the subTemplateMultiList is encoded as a Variable-Length Information Element in 255 or more octets, it is encoded with the Length per section 7 of [RFC5101] as follows: 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | 255 | Length (0 to 65535) | IE | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | ... continuing as needed | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure J: Variable-Length subTemplateMultiList Information Element Encoding (Length 0 to 65535 octets) 5. Structured Data Format 5.1. Length Encoding Considerations The new Structured Data Information Elements represent a list that potentially carries complex hierarchical and repeated data. In Expires April 15, 2010 [Page 21] Internet-Draft October 2009 the normal case where the number and length of elements can vary from record to record, these Information Elements are encoded as variable-length Information Elements as described in section 7 of [RFC5101]. Because of the complex and repeated nature of the data, it is potentially difficult for the Exporting Process to efficiently know in advance the exact encoding size; as a result, data may be recursively encoded starting at a fixed offset, with the final length only known and filled in afterwards. Therefore, the three-byte length encoding is RECOMMENDED for variable-length information elements in all Template Records containing a Structured Data Information Element, even if the encoded length can be less than 255 bytes, because the starting offset of the data is known in advance. An Exporting Process MUST take care when encoding such data to not exceed the maximum allowed length of an IPFIX Message, 65535 bytes, respecting the IPFIX specifications [RFC5101] that imposes: "The IPFIX Message Header 16-bit Length field limits the length of an IPFIX Message to 65535 octets, including the header". 5.2. Recursive Structured Data It is possible to define recursive relationships between IPFIX structured data instances, for example when representing a tree structure. The simplest case of this might be a basicList where each element is itself a basicList, or a subTemplateList where one of the fields of the referenced template is itself a subTemplateList referencing the same Template. When encoding recursively-defined structured data, each leaf element of the encoded structure MUST be terminated with a zero-length element. This implies that variable-length encoding as described in section 7 of [RFC5101] MUST be used when such a recursive relationship exists. Also, the Exporting Process MUST take care that, when encoding recursively-defined structured data, to not exceed the maximum allowed length of an IPFIX Message (as noted in Length Encoding Considerations). 5.3. Structured Data Information Elements Applicability in Options Template Sets Structured Data Information Elements MAY be used in Options Template Sets. Expires April 15, 2010 [Page 22] Internet-Draft October 2009 As an example, consider a mediation function that must aggregate Data Records from multiple Observation Point types: Router 1, (interface 1) Router 2, (line card A) Router 3, (line card B) Router 4, (line card C, interface 2) In order to encode the PSAMP Selection Sequence Report Interpretation [RFC5476], the mediation function must express this combination of Observation Points as a single new Observation Point. Recall from [RFC5476] that the PSAMP Selection Sequence Report Interpretation consists of the following fields: Scope: selectionSequenceId Non-Scope: one Information Element mapping the Observation Point selectorId (one or more) Without structured data, there is clearly no way to express the complex aggregated Observation Point as "one Information Element mapping the Observation Point". However, the desired result may be easily achieved using the structured data types. Refer to Section 8.4. "Encoding an Options Template Set using Structured Data" for an encoding example related to this case study. Regarding the scope in the Options Template Record, the IPFIX specification [RFC5101] mentions that "The IPFIX protocol doesn't prevent the use of any Information Elements for scope". Therefore, a Structured Data Information Element MAY be used as scope in an Options Template Set. Extending the previous example, the mediation function could export a given name for this complex aggregated Observation Point: Scope: Aggregated Observation Point (Structured Data) Non-Scope: a new Information Element containing the name 5.4. Usage Guidelines for Equivalent Data Representations Because basicList, subTemplateList, and subTemplateMultiList are all lists, in several cases there is more than one way to represent what is effectively the same data structure. However, in some cases, one approach has an advantage over the other e.g. Expires April 15, 2010 [Page 23] Internet-Draft October 2009 more compact, uses fewer resources, etc., and is therefore preferred over an alternate representation. A subTemplateList can represent the same simple list of single- value Information Elements as a basicList, if the Template referenced by the subTemplateList contains only one single-valued Information Element. Although the encoding is more compact than a basicList by two bytes, using a subTemplateList in this case requires a new Template per list element. The basicList requires no additional Template and is therefore RECOMMENDED in this case. Although a subTemplateMultiList with one Element can represent the contents of a subTemplateList, the subTemplateMultiList carries two additional bytes (Element Length). It is also potentially useful to a Collecting Process to know in advance that a subTemplateList directly indicates that list element types are consistent. The subTemplateList Information Element is therefore RECOMMENDED in this case. Similarly, although a basicList of single-element subTemplateList Information Elements can represent the same mixed-type content as a subTemplateMultiList, a basicList instance carries four additional bytes (Element Length and Field ID), so the subTemplateMultiList is more compact and is therefore RECOMMENDED in this case. The basicList is best suited for exporting recurrence of a single Information Element. Note that the referenced Information Element(s) in the Structured Data Information Elements can be taken from the IPFIX information model [RFC5102], the PSAMP information model [RFC5477], or any of the Information Elements defined in the IANA IPFIX registry. 5.5. Padding The Exporting Process MAY insert some padding octets in structured data field values in a Data Record by including the 'paddingOctets' Information Element as described in [RFC5101] section 3.3.1, "Set Format". The paddingOctets Information Element can be included in a Template Record referenced by Structured Data Information Element for this purpose. Expires April 15, 2010 [Page 24] Internet-Draft October 2009 6. Template Management This section introduces some more specific Template Management and Template Withdrawal Message-related specifications compared to the IPFIX protocol specification [RFC5101]. First of all, the Template ID uniqueness is unchanged compared to [RFC5101]; the uniqueness is local to the Transport Session and Observation Domain that generated the Template ID. In other words, the Set ID used to export the Template Record does not influence the Template ID uniqueness. While [RFC5101] mentions that: "If an Information Element is required more than once in a Template, the different occurrences of this Information Element SHOULD follow the logical order of their treatments by the Metering Process.", this rule MAY not be followed for the Structured Data Information Elements. As specified in [RFC5101], Templates that are not used anymore SHOULD be deleted. Before reusing a Template ID, the Template MUST be deleted. In order to delete an allocated Template, the Template is withdrawn through the use of a Template Withdrawal Message. 7. The Collecting Process's Side This section introduces some more specific specifications to the Collection Process compared to section 9 in the IPFIX Protocol [RFC5101]. As described in [RFC5101], a Collecting Process MUST note the Information Element identifier of any Information Element that it does not understand and MAY discard that Information Element from the Flow Record. Therefore a Collection Process that does not support the extension specified in this document can ignore the Structured Data Information Elements in a Data Record, or it can ignore Data Records containing these new Structured Data Information Elements while continuing to process other Data Records. 8. Structured Data Encoding Examples The following examples are created solely for the purpose of illustrating how the extensions proposed in this document are encoded. Expires April 15, 2010 [Page 25] Internet-Draft October 2009 8.1. Encoding BasicList Consider encoding a multicast flow containing the following data: --------------------------------------------------------------- Ingress If | Source IP | Destination IP | Egress Interfaces --------------------------------------------------------------- 9 192.0.2.201 233.252.0.1 1, 4, 8 --------------------------------------------------------------- Template Record for the multicast Flows, with the Template ID 258: 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Set ID = 2 | Length = 24 octets | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Template ID = 258 | Field Count = 4 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0| ingressInterface = 10 | Field Length = 4 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0| sourceIPv4Address = 8 | Field Length = 4 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0| DestinationIPv4Address = 12 | Field Length = 4 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0| basicList = XXX | Field Length = 0xFFFF | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure K: Encoding basicList, Template Record The list of outgoing interfaces is represented as a basicList, the Length of the list is chosen to be encoded in three bytes even though it may be less than 255 octets. The Data Set is represented as follows: 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Set ID = 258 | Length = 35 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | ingressInterface = 9 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Expires April 15, 2010 [Page 26] Internet-Draft October 2009 | sourceIPv4Address = 192.0.2.201 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | DestinationIPv4Address = 233.252.0.1 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | 255 | List Length = 16 |egressInterface| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |... Field Id=14| egressInterf. Field Length = 4|egressInterface| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | ... value 1 = 1 |egressInterface| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | ... value 2 = 4 |egressInterface| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | ... value 3 = 8 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure L: Encoding basicList, Data Record 8.2. Encoding subTemplateList As explained in section 3.2. , multiple pairs of (observationTimeMicroseconds, digestHashValue) must be collected from two different Observation Points to compute passively the one-way delay across the network. This data can be exported with an optimized Flow Record that consists of the following attributes: 5 tuple observationTimeMicroseconds 1, digestHashValue 1 observationTimeMicroseconds 2, digestHashValue 2 observationTimeMicroseconds 3, digestHashValue 3 ... , ... A subTemplateList is best suited for exporting the list of (observationTimeMicroseconds, digestHashValue). For illustration purposes, the number of elements in the list is 5, in practice, it could be more. ------------------------------------------------------------------ srcIP | dstIP | src | dst |proto| one-way delay | | Port | Port | | metrics ------------------------------------------------------------------ 192.0.2.1 192.0.2.105 1025 80 6 Time1, 0x0x91230613 Time2, 0x0x91230650 Time3, 0x0x91230725 Expires April 15, 2010 [Page 27] Internet-Draft October 2009 Time4, 0x0x91230844 Time5, 0x0x91230978 ------------------------------------------------------------------ The following Template is defined for exporting the one-way delay metrics: 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Set ID = 2 | Length = 16 octets | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Template ID = 259 | Field Count = 2 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0| observationTimeMicroSec=324 | Field Length = 8 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0| digestHashValue = 326 | Field Length = 4 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure M: Encoding subTemplateList, Template for One-Way Delay Metrics The Template Record for the Optimized Flow Record is as follows: 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Set ID = 2 | Length = 32 octets | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Template ID = 260 | Field Count = 6 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0| sourceIPv4Address = 8 | Field Length = 4 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0| destinationIPv4Address = 12 | Field Length = 4 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0| sourceTransportPort = 7 | Field Length = 2 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0| destinationTransportPort= 11| Field Length = 2 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0| protocolIdentifier = 4 | Field Length = 1 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0| subTemplateList = YYY | Field Length = 0xFFFF | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure N: Encoding subTemplateList, Template Record Expires April 15, 2010 [Page 28] Internet-Draft October 2009 The list of (observationTimeMicroseconds, digestHashValue) is exported as a subTemplateList. The Length of the subTemplatelist is chosen to be encoded in three bytes even though it may be less than 255 octets. The Data Record is represented as follows: 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Set ID = 260 | Length = 82 octets | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | sourceIPv4Address = 192.0.2.1 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | destinationIPV4Address = 192.0.2.105 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | sourceTransportPort = 1025 | destinationTransportPort = 80 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Protocol = 6 | 255 | one-way metrics list len = 62 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Template ID=259 | octets 1-2 of TimeValue1 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | ... octets 3-6 of TimeValue1 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | ... octets 7-8 of TimeValue1 | digestHashValue 1 = | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | ... 0x0x91230613 | octets 1-2 of TimeValue2 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | ... octets 3-6 of TimeValue2 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | ... octets 7-8 of TimeValue2 | digestHashValue 2 = | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | ... 0x0x91230650 | octets 1-2 of TimeValue3 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | ... octets 3-6 of TimeValue3 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | ... octets 7-8 of TimeValue3 | digestHashValue 3 = | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | ... 0x0x91230725 | octets 1-2 of TimeValue4 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | ... octets 3-6 of TimeValue4 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | ... octets 7-8 of TimeValue4 | digestHashValue 4 = | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | ... 0x0x91230844 | octets 1-2 of TimeValue5 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | ... octets 3-6 of TimeValue5 | Expires April 15, 2010 [Page 29] Internet-Draft October 2009 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | ... octets 7-8 of TimeValue5 | digestHashValue 5 = | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | ... 0x0x91230978 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure O: Encoding subTemplateList, Data Set 8.3. Encoding subTemplateMultiList As explained in section 4.4.3. , a subTemplateMultiList is used to export a list of mixed-type content where each top level element corresponds to a different Template Record. To illustrate this, consider the Flow Record with the following attributes: 5 tuple (Flow Keys), octetCount, packetCount attributes for classification selectorId, selectorAlgorithm attributes for sampling selectorId, selectorAlgorithm, samplingPacketInterval, samplingPacketSpace This example demonstrates that the Selector Report Interpretation [RFC5476] can be encoded with the subTemplateMultiList. More specifically, the example describes Property Match Filtering Selector Report Interpretation [RFC5476] used for classification purposes, and the Systemic Count-Based Sampling as described in Section 6.5.2.1 of [RFC5476]. Some traffic will be filtered according to match properties configured, some will be sampled, some will be filtered and sampled, and some will not be filtered or be sampled. A subTemplateMultiList is best suited for exporting this variable data. A Template is defined for classification attributes and another Template is defined for sampling attributes. A Flow Record can contain data corresponding to either of the Templates, both or none. Expires April 15, 2010 [Page 30] Internet-Draft October 2009 Consider the example below where the following Flow Record contains both classification and sampling attributes. Key attributes of the Flow Record: ------------------------------------------------------------------ srcIP | dstIP | src | dst |proto|octetCount|packet | | Port | Port | | |Count ------------------------------------------------------------------ 192.0.2.1 192.0.2.105 1025 80 6 108000 120 ------------------------------------------------------------------ Classification attributes: ------------------------------------------- selectorId | selectorAlgorithm ------------------------------------------- 100 5 (Property Match Filtering) ------------------------------------------- Sampling attributes: For Systemic Count-Based Sampling as defined in Section 6.5.2.1 of [RFC5476] the required algorithm-specific Information Elements are: samplingPacketInterval: number of packets selected in a row samplingPacketSpace: number of packets between selections Example of a simple 1 out-of 100 systematic count-based Selector definition, where the samplingPacketInterval is 1 and the samplingPacketSpace is 99. -------------------------------------------------------------- selectorId | selectorAlgorithm | sampling | sampling | | Packet | Packet | | Interval | Space -------------------------------------------------------------- 15 1 (Count-Based Sampling) 1 99 -------------------------------------------------------------- To represent the Flow Record, the following Template Records are defined: Expires April 15, 2010 [Page 31] Internet-Draft October 2009 Template for classification attributes: 261 Template for sampling attributes: 262 Template for Flow Record: 263 Flow record (263) | (sourceIPv4Address) | (destinationIPv4Address) | (sourceTransportPort) | (destinationTransportPort) | (protocolIdentifier) | (octetTotalCount) | (packetTotalCount) | +------ classification attributes (261) | (selectorId) | (selectorAlgorithm) | +------ sampling attributes (262) | (selectorId) | (selectorAlgorithm) | (samplingPacketInterval) | (samplingPacketSpace) The following Template Record is defined for classification attributes: 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Set ID = 2 | Length = 16 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Template ID = 261 | Field Count = 2 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0| selectorId = 302 | Field Length = 4 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0| selectorAlgorithm = 304 | Field Length = 1 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure P: Encoding subTemplateMultiList, Template for Classification Attributes The Template for sampling attributes is defined as follows: 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 Expires April 15, 2010 [Page 32] Internet-Draft October 2009 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Set ID = 2 | Length = 24 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Template ID = 262 | Field Count = 4 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0| selectorId = 302 | Field Length = 4 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0| selectorAlgorithm = 304 | Field Length = 1 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0| samplingPacketInteval = 305 | Field Length = 1 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0| samplingPacketSpace = 306 | Field Length = 1 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure Q: Encoding subTemplateMultiList, Template for Sampling Attributes Note that while samplingPacketInterval and samplingPacketSpace are defined as unsigned32, they are compressed down to 1 octet here as allowed by Reduced Size Encoding in section 6.2 of the IPFIX protocol specifications [RFC5101]. Template for the Flow Record is defined as shown below: 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Set ID = 2 | Length = 40 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Template ID = 263 | Field Count = 8 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0| sourceIPv4Address = 8 | Field Length = 4 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0| destinationIPv4Address = 12 | Field Length = 4 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0| sourceTransportPort = 7 | Field Length = 2 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0| destinationTransportPort=11 | Field Length = 2 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0| protocolIdentifier = 4 | Field Length = 1 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0| octetTotalCount = 85 | Field Length = 4 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0| packetTotalCount = 86 | Field Length = 4 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Expires April 15, 2010 [Page 33] Internet-Draft October 2009 |0| subTemplateMultiList = ZZZ | Field Length = 0XFFFF | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure R: Encoding subTemplateMultiList, Template for Flow Record A subTemplateMultiList is used to export the classification and sampling attributes. The Length of the subTemplateMultilist is chosen to be encoded in three bytes even though it may be less than 255 octets. The Data Record is encoded as follows: 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Set ID = 263 | Length = 48 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | sourceIPv4Address = 192.0.2.1 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | destinationIPv4Address = 192.0.2.105 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | sourceTransportPort = 1025 | destinationTransportPort = 80 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | protocol = 6 | octetTotalCount = 108000 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | ... | packetTotalCount = 120 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | ... | 255 | Attributes List Length = 20 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Classify Template ID = 261 | Classif. Attributes Length = 9| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | selectorId = 100 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |selectorAlg = 5| Sampling Template ID = 262 |Sampling Attr.| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Length = 11 | selectorId = 15 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | ... |selectorAlg = 1| Interval = 1 | Space = 99 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure S: Encoding subTemplateMultiList, Data Set Expires April 15, 2010 [Page 34] Internet-Draft October 2009 8.4. Encoding an Options Template Set using Structured Data As described in section 5.3. , consider a mediation function that must aggregate Data Records from multiple different Observation Points. Say Observation Point 1 consists of one or more interfaces, Observation Points 2 and 3 consist of one or more line cards, and Observation Point 4 consists of one or more interfaces and one or more line cards. Without the support for structured data, a template would have to be defined for every possible combination to interpret the data corresponding to each of the Observation Points. However, with the support for structured data, a basicList can be used to encode the list of interfaces and another basicList can be used to encode the list of line cards. For the sake of simplicity, each Observation Point shown below has an or or . This can very well be extended to include a list of interfaces and a list of linecards using basicLists as explained above. Observation Point 1: Router 1, (interface 1) Observation Point 2: Router 2, (line card A) Observation Point 3: Router 3, (line card B) Observation Point 4: Router 4, (line card C, interface 2) The mediation function wishes to express this as a single Observation Point, in order to encode the PSAMP Selection Sequence Report Interpretation (SSRI). Recall from [RFC5476] that the PSAMP Selection Sequence Report Interpretation consists of the following fields: Scope: selectionSequenceId Non-Scope: one Information Element mapping the Observation Point selectorId (one or more) For example, the Observation Point detailed above may be encoded in a PSAMP Selection Sequence Report Interpretation as shown below: Selection Sequence 7 (Filter->Sampling): observation point: subTemplateMultiList. Router 1, (interface 1) Router 2, (line card A) Expires April 15, 2010 [Page 35] Internet-Draft October 2009 Router 3, (line card B) Router 4, (line card C, interface 2) selectorId: 5 (Filter, match IPV4SourceAddress 192.0.2.1) selectorId: 10 (Sampler, Random 1 out-of ten) The following Templates are defined to represent the PSAMP SSRI: Template for representing PSAMP SSRI: 264 Template for representing interface: 265 Template for representing linecard: 266 Template for representing linecard and interface: 267 PSAMP SSRI (264) | (SelectionSequenceId) | +--- Observation Point 1 (265) | (Interface Id) | +--- Observation Point 2 and 3 (266) | (line card) | +--- Observation Point 4 (267) | (line card) | (Interface Id) | | (selectorId 1) | (selectorId 2) Figure T: PSAMP SSRI to be encoded 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Set ID = 3 | Length = 26 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Template ID = 264 | Field Count = 4 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Scope Field Count = 1 |0| selectionSequenceId = 301 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Scope 1 Length = 4 |0| subTemplateMultiList = ZZZ | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Field Length = 0xFFFF |0| selectorId = 302 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Field Length = 4 |0| selectorId = 302 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Expires April 15, 2010 [Page 36] Internet-Draft October 2009 | Field Length = 4 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure U: Options Template Record for PSAMP SSRI using subTemplateMultiList The subTemplateMultiList is used to encode the list of Observation Points. 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Set ID = 2 | Length = 12 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Template ID = 265 | Field Count = 1 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0| ingressInterface = 10 | Field Length = 4 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure V: PSAMP SSRI, Template Record for interface 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Set ID = 2 | Length = 12 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Template ID = 266 | Field Count = 1 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0| lineCardId = 141 | Field Length = 4 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure W: PSAMP SSRI, Template Record for linecard 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Set ID = 2 | Length = 16 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Template ID = 267 | Field Count = 2 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0| lineCardId = 141 | Field Length = 4 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0| ingressInterface = 10 | Field Length = 4 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Expires April 15, 2010 [Page 37] Internet-Draft October 2009 Figure X: PSAMP SSRI, Template Record for linecard and interface 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Set ID = 264 | Length = 51 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | selectionSequenceId = 7 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | 255 | Observation Point List Len=32 | OP1_Template | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |... ID = 265 | OP1 Length = 8 | ingress ... | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | ... Interface = 1 | OP2,3 Template| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |... ID = 266 | OP2,3 Length = 12 |lineCardId=A...| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | ...lineCardId = A |lineCardId=B...| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | ...lineCardId = B |OP4 Template...| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |... ID = 267 | OP4 Length = 12 |lineCardId=C...| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | ...lineCardId = C | ingress ... | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | ...Interface = 2 |selectorID ... | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | selectorId = 5 |selectorID ... | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | selectorId = 10 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure Y: Example of a PSAMP SSRI Data Record, Encoded using a subTemplateMultiList Note that the Data Record above contains multiple instances of Template 266 to represent Observation Point 2 (line card A) and Observation Point 3 (line card B). Instead, if a single Observation Point had both line card A and line card B, a basicList would be used to represent the list of line cards. Expires April 15, 2010 [Page 38] Internet-Draft October 2009 9. Relationship with the Other IFPIX Documents 9.1. Relationship with Reducing Redundancy "Reducing Redundancy in IP Flow Information Export (IPFIX) and Packet Sampling (PSAMP) Reports" [RFC5473] describes a bandwidth saving method for exporting Flow or packet information using the IP Flow Information eXport (IPFIX) protocol. It defines the commonPropertiesID Information Element for exporting Common Properties. 9.1.1. Encoding Structured Data Element using Common Properties. When Structured Data Information Elements contain repeated elements, these elements may be replaced with a commonPropertiesID Information Element as specified in [RFC5473]. The replaced elements may include the basicList, subTemplateList and subTemplateMultiList Information Elements. This technique might help reducing the bandwidth requirements for the export. However, a detailed analysis of the gain has not been done; refer to Section 8.3 "Efficiency Gain" [RFC5473] for further considerations. 9.1.2. Encoding Common Properties elements With Structured Data Element. Structured Data Information Element MAY be used to define a list of commonPropertiesID, as a replacement for the specifications in [RFC5473]. Indeed, the example in figures 1 and 2 of [RFC5473] can be encoded with the specifications in this document. +----------------+-------------+---------------------------+ | sourceAddressA | sourcePortA | | +----------------+-------------+---------------------------+ | sourceAddressA | sourcePortA | | +----------------+-------------+---------------------------+ | sourceAddressA | sourcePortA | | +----------------+-------------+---------------------------+ Expires April 15, 2010 [Page 39] Internet-Draft October 2009 | sourceAddressA | sourcePortA | | +----------------+-------------+---------------------------+ | ... | ... | ... | +----------------+-------------+---------------------------+ Figure Z: Common and Specific Properties Exported Together [RFC5473] +------------------------+-----------------+-------------+ | index for properties A | sourceAddressA | sourcePortA | +------------------------+-----------------+-------------+ | ... | ... | ... | +------------------------+-----------------+-------------+ +------------------------+---------------------------+ | index for properties A | | +------------------------+---------------------------+ | index for properties A | | +------------------------+---------------------------+ | index for properties A | | +------------------------+---------------------------+ | index for properties A | | +------------------------+---------------------------+ Figure ZA: Common and Specific Properties Exported Separately according to [RFC5473] +----------------+-------------+---------------------------+ | sourceAddressA | sourcePortA | | +----------------+-------------+---------------------------+ | | +---------------------------+ | | +---------------------------+ | | +---------------------------+ | ... | +---------------------------+ Figure ZB: Common and Specific Properties Exported with Structured Data Information Element The example in figure ZB could be encoded with a basicList if the represents a single Information Element, Expires April 15, 2010 [Page 40] Internet-Draft October 2009 with a subTemplateList if the represents a Template Record, or with a subTemplateMultiList if the is composed of different Template Records. Using Structured Data Information Elements as a replacement for the techniques specified in "Reducing Redundancy in IP Flow Information Export (IPFIX) and Packet Sampling (PSAMP) Reports" [RFC5473] offers the advantage that a single Template Record is defined. Hence the Collectors job in term of Template management and combining Template/Options Template Records is simplified. However, it must be noted that using Structured Data Information Elements as a replacement for the techniques specified in "Reducing Redundancy in IP Flow Information Export (IPFIX) and Packet Sampling (PSAMP) Reports" only applies to simplified cases. For example, the "Multiple Data Reduction" (section 7.1 [RFC5473]) might be too complex to encode with Structured Data Information Elements. 9.2. Relationship with Guidelines for IPFIX Testing [RFC5471] presents a list of tests for implementers of IP Flow Information eXport (IPFIX) compliant Exporting Processes and Collecting Processes. Although [RFC5471] doesn't define any structured data element specific tests, the Structured Data Information Elements can be used in many of the [RFC5471] tests. The [RFC5471] series of test could be useful because the document specifies that every Information Element type should be tested. However, not all cases from this document are tested in [RFC5471]. The following sections are especially noteworthy: . 3.2.1. Transmission of Template with fixed size Information Elements - each data type should be used in at least one test. The new data types specified in section 4.1. should be included in this test. Expires April 15, 2010 [Page 41] Internet-Draft October 2009 . 3.2.2. Transmission of Template with variable length Information Elements - this test should be expanded to include Data Records containing variable length basicList, subTemplateList, and subTemplateMultiList Information Elements. . 3.3.1. Enterprise-specific Information Elements - this test should include the export of basicList, subTemplateList, and subTemplateMultiList Information Elements containing Enterprise-specific Information Elements. e.g., see the example in figure B. . 3.3.3. Multiple instances of the same Information Element in one Template - this test should verify that multiple instances of the basicList, subTemplateList and subTemplateMultiList Information Elements are accepted. . 3.5 Stress/Load tests - since the structured data types defined here allow modeling of complex data structures, they may be useful for stress testing both Exporting Processes and Collecting Processes. 9.3. Relationship with Bidirectional Flow Export [RFC5103] describes a method for exporting bidirectional flow information, and defines the biflowDirection Information Element for this purpose. [RFC5103] Biflows may be encoded in a subTemplateList or subTemplateMultiList. The basicList requires recurrence of a single element, so is not suitable for Biflows. Encoding Biflows with subTemplateList or subTemplateMultiList provides a more logical division of the information in both directions, although this encoding incurs a small additional bandwidth penalty. Expires April 15, 2010 [Page 42] Internet-Draft October 2009 An example of Biflow encoding using Structure Data Information Elements and comparison with the [RFC5103] Biflow encoding is shown in Appendix B. 9.4. Relationship with IPFIX Mediation Function The Structured Data Information Elements would be beneficial for the export of aggregated Data Records in mediation function, as it was demonstrated with the example of the aggregated Observation Point in section 5.3. 10. IANA Considerations This document specifies several new IPFIX abstract data types, a new IPFIX Data Type Semantic, and several new Information Elements. These require the creation of two new IPFIX registries and updating the existing IPFIX Information Element registry as detailed below. 10.1. New Abstract Data Types Section 4.1. of this document specifies several new IPFIX abstract data types. Per section 6 of the IPFIX information model [RFC5102], new abstract data types can be added to the IPFIX information model. This requires creation of a new IPFIX "abstract data types" registry at http://www.iana.org/assignments/ipfix. This registry should include all the abstract data types from section 3.1 of [RFC5102]. Abstract data types to be added to the IPFIX "abstract data types" registry are listed below. 10.1.1. basicList The type "basicList" represents a list of any Information Element used for single-valued data types. Expires April 15, 2010 [Page 43] Internet-Draft October 2009 10.1.2. subTemplateList The type "subTemplateList" represents a list of a structured data type, where the data type of each list element is the same and corresponds with a single Template Record. 10.1.3. subTemplateMultiList The type "subTemplateMultiList" represents a list of structured data types, where the data types of the list elements can be different and correspond with different template definitions. 10.2. New Data Type Semantics Section 4.2. of this document specifies a new IPFIX Data Type Semantic. Per section 3.2 of the IPFIX information model [RFC5102], new data type semantics can be added to the IPFIX information model. This requires creation of a new IPFIX "data types semantics" registry at http://www.iana.org/assignments/ipfix. This registry should include all the data type semantics from section 3.2 of [RFC5102]. Data type semantics to be added to the IPFIX "data types semantics" registry are listed below. 10.2.1. list A list is a structured data type, being composed of a sequence of elements e.g. Information Element, Template Record, etc. 10.3. New Information Elements Section 4.3. of this document specifies several new Information Elements which are to be created in the IPFIX Information Element registry located at http://www.iana.org/assignments/ipfix. New Information Elements to be added to the IPFIX Information Element registry are listed below. 10.3.1. basicList Name: basicList Description: Specifies a generic Information Element with a basicList abstract Expires April 15, 2010 [Page 44] Internet-Draft October 2009 data type. For example, list of port numbers, list of interface indexes, etc. Abstract Data Type: basicList Data Type Semantics: list ElementId: XXX (to be specified) Status: current 10.3.2. subTemplateList Name: subTemplateList Description: Specifies a generic Information Element with a subTemplateList abstract data type. Abstract Data Type: subTemplateList Data Type Semantics: list ElementId: YYY (to be specified) Status: current 10.3.3. subTemplateMultiList Name: subTemplateMultiList Description: Specifies a generic Information Element with a subTemplateMultiList abstract data type. Abstract Data Type: subTemplateMultiList Data Type Semantics: list ElementId: ZZZ (to be specified) Status: current 11. Security Considerations The same security considerations as for the IPFIX Protocol [RFC5101] apply. 12. References 12.1. Normative References [RFC2119] S. Bradner, Key words for use in RFCs to Indicate Requirement Levels, BCP 14, RFC 2119, March 1997. [RFC5101] Claise, B., Ed., "Specification of the IP Flow Information Export (IPFIX) Protocol for the Exchange of IP Traffic Flow Information", RFC 5101, January 2008. Expires April 15, 2010 [Page 45] Internet-Draft October 2009 [RFC5102] Quittek, J., Bryant, S., Claise, B., Aitken, P., and J. Meyer, "Information Model for IP Flow Information Export", RFC 5102, January 2008. 12.2. Informative References [RFC3917] Quittek, J., Zseby, T., Claise, B., and S. Zander, Requirements for IP Flow Information Export, RFC 3917, October 2004. [RFC5103] Trammell, B., and E. Boschi, "Bidirectional Flow Export Using IP Flow Information Export (IPFIX)", RFC 5103, January 2008. [RFC5470] Sadasivan, G., Brownlee, N., Claise, B., and J. Quittek, "Architecture for IP Flow Information Export", RFC 5470, March 2009. [RFC5471] Schmoll, C., Aitken, P., and B. Claise, "Guidelines for IP Flow Information Export (IPFIX) Testing", RFC 5471, March 2009. [RFC5472] Zseby, T., Boschi, E., Brownlee, N., and B. Claise, "IP Flow Information Export (IPFIX) Applicability", RFC 5472, March 2009. [RFC5473] Boschi, E., Mark, L., and B. Claise, "Reducing Redundancy in IP Flow Information Export (IPFIX) and Packet Sampling (PSAMP) Reports", RFC 5473, March 2009. [RFC5475] Zseby, T., Molina, M., Duffield, N., Niccolini, S., and F. Raspall, "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. [RFC5477] Dietz, T., Claise, B., Aitken, P., Dressler, F., and G. Carle, "Information Model for Packet Sampling Exports", RFC 5477, March 2009. Expires April 15, 2010 [Page 46] Internet-Draft October 2009 13. Acknowledgement The authors would like to thank Zhipu Jin, Nagaraj Varadharajan, Brian Trammel, and Atsushi Kobayashi for their feedback. 14. Authors' Addresses Benoit Claise Cisco Systems Inc. De Kleetlaan 6a b1 Diegem 1813 Belgium Phone: +32 2 704 5622 EMail: bclaise@cisco.com Gowri Dhandapani Cisco Systems Inc. 13615 Dulles Technology Drive Herndon, Virigina 20171 United States Phone: +1 408 853 0480 EMail: gowri@cisco.com Stan Yates Cisco Systems Inc. 7100-8 Kit Creek Road PO Box 14987 Research Triangle Park North Carolina, 27709-4987 United States Phone: +1 919 392 8044 EMail: syates@cisco.com Paul Aitken Cisco Systems (Scotland) Ltd. 96 Commercial Quay Commercial Street Edinburgh, EH6 6LX, United Kingdom Expires April 15, 2010 [Page 47] Internet-Draft October 2009 Phone: +44 131 561 3616 EMail: paitken@cisco.com Appendix A. XML Specification of IPFIX Information Elements and Abstract Data Types Represents a list of zero or more instances of any single Information Element, primarily used for single-valued data types. For example, a list of port numbers, list of interface indexes, list of AS in a BGP AS-PATH, etc. Represents a list of zero or more instances of a structured data type, where the data type of each list element is the same and corresponds with a single Template Record. For example, a structured data type composed of multiple pairs of ("MPLS label stack entry position", "MPLS label stack value"), a structured data type composed of performance metrics, a structured data type composed of multiple pairs of IP address, etc. Expires April 15, 2010 [Page 48] Internet-Draft October 2009 Represents a list of zero or more instances of structured data types, where the data type of each list element can be different and corresponds with different template definitions. For example, a structured data type composed of multiple access-list entries, where entries can be composed of different criteria types. Represents a list of zero or more instances of any single Information Element, primarily used for single-valued data types. For example, a list of port numbers, list of interface indexes, list of AS in a BGP AS-PATH, etc. Represents a list of zero or more instances of a structured data type, where the data type of each list element is the same and corresponds with a single Template Record. For example, a structured data type composed of multiple pairs of ("MPLS label stack entry position", "MPLS label stack value"), a structured data type composed of performance metrics, a Expires April 15, 2010 [Page 49] Internet-Draft October 2009 structured data type composed of multiple pairs of IP address, etc. Represents a list of zero or more instances of structured data types, where the data type of each list element can be different and corresponds with different template definitions. For example, a structured data type composed of multiple access-list entries, where entries can be composed of different criteria types. Represents an arbitrary-length sequence of structured data elements, either composed of regular Information Elements or composed of data conforming to a Template Record. Appendix B. Example of Biflow Encoding using Structured Data Information Elements Referring to [RFC5103] figure 1, a Biflow consists of two parts: some "key" fields such as src/dst information (IP addresses, ports), followed by a set of forward/reverse pairs. Then looking at [RFC5103] figure 7, we see that the Reverse PEN Expires April 15, 2010 [Page 50] Internet-Draft October 2009 is repeated many times to indicate fields which were observed in the reverse direction. Clearly that repetition is wasteful. Looking back at [RFC5103] figure 1, it's clear that the encoding can use a Template Record consisting of the Flow Keys followed by a subTemplateList consisting of two elements: one for the forward direction, the other for the reverse direction. The subTemplateList uses a single Template Record to describe the fields in both lists since they are a set of forward/reverse pairs. Uniflow Uniflow +-------+-------+-----------------+ +-------+-------+-----------------+ | src A | dst B | counters/values | | src B | dst A | counters/values | +-------+-------+-----------------+ +-------+-------+-----------------+ | | | | V V V V +-------+-------+---------------------+---------------------+ | src A | dst B | fwd counters/values | rev counters/values | +-------+-------+---------------------+---------------------+ | | | V V V key fields fwd element rev element Figure B0: Using a subTemplateList to represent a Biflow. The following example shows the example from Appendix A of [RFC5103] encoded using a subTemplateList: 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Set ID = 2 | Length = 24 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Template ID = 268 | Field Count = 4 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0| flowDirection 61 | Field Length = 1 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0| flowStartSeconds 150 | Field Length = 4 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0| octetTotalCount 85 | Field Length = 4 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0| packetTotalCount 86 | Field Length = 4 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Expires April 15, 2010 [Page 51] Internet-Draft October 2009 Figure B1: Template for the Biflow Fields 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Set ID = 2 | Length = 32 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Template ID = 269 | Field Count = 6 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0| sourceIPv4Address 8 | Field Length = 4 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0| destinationIPv4Address 12 | Field Length = 4 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0| sourceTransportPort 7 | Field Length = 2 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0| destinationTransportPort 11 | Field Length = 2 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0| protocolIdentifier 4 | Field Length = 1 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0| subTemplateList = YYY | Field Length = 28 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure B2: Template for the Key Fields The Template Record includes a subTemplateList for encoding the BiFlow fields for the forward and reverse direction. Note that the subTemplateList is encoded using Fixed Length, as shown in the above template definition. Also, note that the overall template size is 24 + 32 = 56 octets, compared with 64 octets in the [RFC5103] example - so a small saving is achieved. 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Set ID = 269 | Length = 45 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | sourceIPv4Address = 192.0.2.2 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | destinationIPv4Address = 192.0.2.3 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | sourceTransportPort = 32770 | destinationTransportPort = 80 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Expires April 15, 2010 [Page 52] Internet-Draft October 2009 | protocol = 6 | Template ID = 268 | dir = forward | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | flowStartSeconds = 2006-02-01 17:00:00 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | octetTotalCount = 18000 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | packetTotalCount = 65 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | dir = reverse | flowStartSeconds = 2006-02-01 17:00:01 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | ... | octetTotalCount = 128000 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | ... | packetTotalCount = 110 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | ... | +-+-+-+-+-+-+-+-+ Figure B3: Biflow Data Set Encoded using Structured Data Note that the Data Set length is 45, compared with 41 in RFC5103. The four additional octets are due to the inclusion of the 16-bit Template ID and two, 8-bit direction indicators. Clearly structured data offers an alternative way to encode Biflows. Although this may not be best suited if the number of elements is small as in this example, it does offer a more robust and scalable solution if multiple elements need to be encoded. Appendix C. Encoding IPS Alert using Structured Data Information Elements In this section, a contrived example of an IPS alert is used to demonstrate how complex data and multiple levels of hierarchy can be encoded using Structured Data Information Elements. An IPS alert consists of the following mandatory attributes: signatureId, protocolIdentifier and riskRating. It can also contain zero or more participants, each participant can contain zero or more attackers and zero or more targets. An attacker contains the attributes sourceIPv4Address and applicationId and a target contains the attribute destinationIPv4Address and zero or more occurrences of the attribute applicationId. Note that the signatureId and riskRating Information Element fields are created for these examples only; the Field IDs are Expires April 15, 2010 [Page 53] Internet-Draft October 2009 shown as N/A. The signatureId helps to uniquely identify the IPS signature that triggered the alert. The riskRating identifies the potential risk, on a scale of 0-100 (100 being most serious), of the traffic that triggered the alert. Consider the following contrived example of an IPS alert. The participant can contain attackers and targets in any order and the sequence conveys some information to the Collector and needs to be preserved. In the example below, we have attacker1 A1, target T1 and attacker A2 and this is encoded as a subTemplateMultiList. ------------------------------------------------------------------ | | | participant sigId |protocol| risk | attacker | target | Id | Rating | IP | appId | IP | appId(s) ------------------------------------------------------------------ 1003 17 10 192.0.2.3 103 192.0.2.103 3001, 3002 192.0.2.4 104 ------------------------------------------------------------------ Where attacker A1 is: (IP, appID)=(192.0.2.3, 103) Where attacker A2 is: (IP, appID)=(192.0.2.4, 104) Where target T1 is: (IP, appID)= (192.0.2.103, (3001, 3002)) To represent an alert, the following Templates are defined: Template for target (270) Template for attacker (271) Template for participant (272) Template for alert (273) alert (273) | (signatureId) | (protocolIdentifier) | (riskRating) | +------- participant (272) | +------- attacker (271) | (sourceIPv4Address) | (applicationId) | +------- target (270) | (destinationIPv4Address) | (list of applicationId) Expires April 15, 2010 [Page 54] Internet-Draft October 2009 Note that the attackers are always composed of a single applicationId, while the targets typically have multiple applicationId. Template Record for target, with the Template ID 270: 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Set ID = 2 | Length = 16 octets | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Template ID = 270 | Field Count = 2 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0| destinationIPv4Address = 12 | Field Length = 4 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0| basicList = XXX | Field Length = 0xFFFF | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure C0: Encoding IPS Alert, Template for Target The list of applicationId in the target Template Record is represented as a basicList. Template Record for attacker, with the Template ID 271: 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Set ID = 2 | Length = 16 octets | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Template ID = 271 | Field Count = 2 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0| sourceIPv4Address = 8 | Field Length = 4 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0| applicationId = 95 | Field Length = 4 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure C1: Encoding IPS Alert, Template for Attacker Template Record for participant, with the Template ID 272: 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Set ID = 2 | Length = 12 octets | Expires April 15, 2010 [Page 55] Internet-Draft October 2009 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Template ID = 272 | Field Count = 1 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0| subTemplateMultiList = ZZZ | Field Length = 0xFFFF | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure C2: Encoding IPS Alert, Template for Participant The Template Record for the participant has one subTemplateMultiList Information Element, which is a list that can include attackers and targets repeated in any order. Template Record for IPS alert, with the Template ID 273: 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Set ID = 2 | Length = 24 octets | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Template ID = 273 | Field Count = 4 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0| signatureId = N/A | Field Length = 2 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0| protocolIdentifier = 4 | Field Length = 1 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0| riskRating = N/A | Field Length = 1 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0| subTemplateList = YYY | Field Length = 0xFFFF | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure C3: Encoding IPS Alert, Template for IPS Alert The subTemplateList in the alert Template Record contains a list of participants. For the sake of simplicity, only one participant is shown in the Data Set. Note that a subTemplateList is used to encode the list of participants. Each participant contains the list of attackers and targets encoded using a subTemplateMultiList and a target contains a basicList for encoding the list of applications. The Length of basicList, subTemplateList and subTemplateMultiList are encoded in three bytes even though it may be less than 255 octets. Expires April 15, 2010 [Page 56] Internet-Draft October 2009 The Data Set is represented as follows: 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Set ID = 273 | Length = 63 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | signatureId = 1003 | protocolId=17 | riskRating=10 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | 255 |participant List Length = 52 |participant ...| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |Template ID=272| 255 |subTemplateMultiList Length=47 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | attacker1 Template ID = 271 | attacker1 Length = 12 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | attacker1 sourceIPv4Address = 192.0.2.3 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | attacker1 applicationId = 103 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | target1 Template ID = 270 | Target1 Length = 23 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | target1 destinationIPv4Address = 192.0.2.103 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | 255 | target1 appId List Length=12 |target1 appId..| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Field ID = 95 | target1 appId Field ID Len = 4|target1 appId =| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | ... 3001 |target1 appId =| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | ... 3002 | attacker2 ...| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |Template ID=271| attacker2 Length = 12 | attacker2 ...| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | ... sourceIPv4Address = 192.0.2.4 | attacker2 ...| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | ... applicationId = 104 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure C4: Encoding IPS Alert, Data Set Expires April 15, 2010 [Page 57]