IPFIX working group Internet Draft EDITOR: B. Claise draft-ietf-ipfix-protocol-07.txt Cisco Systems Expires: June 2005 December 2004 IPFIX Protocol Specification Status of this Memo By submitting this Internet-Draft, each author represents that any applicable patent or other IPR claims of which he or she is aware have been or will be disclosed, and any of which he or she becomes aware will be disclosed, in accordance with Section 6 of RFC 3668. This document is an Internet-Draft and is in full conformance with all provisions of Section 10 of RFC2026. 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 obsolete by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress." The list of current Internet-Drafts can be accessed at http://www.ietf.org/ietf/1id-abstracts.txt The list of Internet-Draft Shadow Directories can be accessed at http://www.ietf.org/shadow.html Abstract This document specifies the IPFIX protocol that provides network operators with access to IP flow information. In order to export IP flow information to the IPFIX collecting process, a common method of representing the flow data and a standard means of communicating them from an exporter to a collector is required. This document describes how the IPFIX flow record data, options record data and Claise, et. al Standard Track [Page 1]
IPFIX Protocol Specification December 2004 templates are carried over a congestion-aware transport protocol from an IPFIX exporting process to an IPFIX collecting process. 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. Table of Contents 1. Points of Discussion.........................................4 2. Introduction.................................................5 2.1 IPFIX Documents Overview...................................6 3. Terminology..................................................6 3.1 Terminology Summary Table.................................11 4. Criteria for Flow Expiration and Export.....................12 4.1 Flow Expiration...........................................12 4.2 Flow Export...............................................12 5. Message Format..............................................13 6. IPFIX Message Format........................................15 6.1 Header Format.............................................15 6.2 Field Type Format.........................................16 6.3 Template Set Format.......................................17 6.4 Data Set Format...........................................19 6.5 Options Template Set......................................21 6.5.1 Scope..................................................21 6.5.2 Options Template Set Format............................22 6.5.3 Options Data Record Format.............................24 7. Specific Reporting Requirements.............................26 7.1 The Metering Process Statistics Option Template...........26 7.2 The Metering Process Reliability Statistics Option Template27 7.3 The Exporting Process Reliability Statistics Option Template28 7.4 The Flow Keys Option Template.............................28 8. "Export Time" Computation and Flow Record Time..............29 8.1 Microsecond Precision.....................................29 8.2 Millisecond Precision.....................................30 8.3 Nanosecond Precision......................................31 8.4 Multiple Precisions.......................................31 9. Linkage with the Information Model..........................31 9.1 Reduced Size Encoding of Integer Types....................31 10. Variable Length Information Element........................32 11. Template Management........................................33 12. The Collecting Process's Side..............................36 13. Transport Protocol.........................................38 13.1 Transport Compliance and Transport Usage.................38 13.2 TCP......................................................39 13.2.1 Congestion Avoidance...................................39 Claise, et. al Standard Track [Page 2]
IPFIX Protocol Specification December 2004 13.2.2 Reliability............................................39 13.2.3 MTU....................................................39 13.2.4 Exporting Process......................................39 13.2.4.1 Connection Establishment..............................39 13.2.4.2 Connection Release....................................40 13.2.4.3 IPFIX Message Encoding................................40 13.2.5 Template Management....................................40 13.2.6 Fail-over..............................................41 13.3 SCTP.....................................................41 13.3.1 Congestion Avoidance...................................41 13.3.2 Reliability............................................41 13.3.3 MTU....................................................42 13.3.4 Exporting Process......................................42 13.3.4.1 Association Establishment.............................42 13.3.4.2 Association Shutdown..................................42 13.3.4.3 Source ID.............................................43 13.3.4.4 Stream................................................43 13.3.4.5 Template Management...................................44 13.3.5 Collecting Process.....................................44 13.3.6 Failover...............................................44 13.4 UDP......................................................44 13.4.1 Congestion Avoidance...................................44 13.4.2 Reliability............................................44 13.4.3 MTU....................................................45 13.4.4 Port Numbers...........................................45 13.4.5 Exporting Process......................................45 13.4.6 Template Management....................................45 13.4.7 Collecting Process.....................................46 13.4.8 Failover...............................................47 14. Security Considerations....................................47 14.1 IPsec Usage..............................................47 14.1.1 Selectors..............................................48 14.1.2 Mode...................................................48 14.1.3 Key Management.........................................48 14.1.4 Security Policy........................................48 14.1.5 Authentication.........................................48 14.1.6 Availability...........................................49 14.2 TLS Usage................................................49 14.3 Protection against DoS attacks...........................49 14.4 When IPsec or TLS is not an option.......................50 14.5 Logging an IPFIX Attack..................................50 15. IANA Considerations........................................51 15.1 Numbers used in the Protocol.............................51 15.2 Numbers used in the Information Model....................51 16. Examples...................................................52 16.1 Message Header Example...................................52 16.2 Template Set Examples....................................53 16.2.1 Template Set using IETF specified Information Elements53 Claise, et. al Standard Track [Page 3]
IPFIX Protocol Specification December 2004 16.2.2 Template Set using Enterprise Specific Information Elements 53 16.3 Data Set Example.........................................54 16.4 Options Template Set Examples............................55 16.4.1 Options Template Set using IETF specified Information Elements 55 16.4.2 Options Template Set using Enterprise Specific Information Elements...........................................56 16.4.3 Options Template Set using an Enterprise Specific scope57 16.5 Data Set with Options Data Records Example...............57 17. References.................................................58 17.1 Normative References.....................................58 17.2 Informative References...................................59 18. Acknowledgments............................................60 1. Points of Discussion This section covers the open issues, still to be resolved/updated in this draft. Note that the issues starting with PROTO-31 have been added to this draft version. PROTO-23: Finalize the time details. The time-related Information Elements are not defined in [IPFIX-INFO]. We agree that the definition of timer semantics should be moved to the info model document (see the http://ipfix.doit.wisc.edu/archive/2588.html email thread). Now we need: - to insert some new text in the section 9 of this document - to insert the timing Information Element in [IFPIX-INFO] Note: see http://ipfix.doit.wisc.edu/archive/2580.html for a way to improve the timing-related Information Elements. PROTO-30: review RFC 3917, to see if we miss any requirements PROTO-34: Need a security expert to review the security section: - [TBD] in the security section - [EDITOR NOTE: the security section may need be adapted to the revised transport section], [XXX-REFERENCE] - [XXX-SCTP-BLIND-SPOOFING-REFERENCE] not defined - TCP Security 1. Handshake: should we introduce a handshake sequence at the start of the connection? A simple ASCII-based handshake could be used to request TLS. 2. It would make sense to add TLS support even in the absence of a handshake. It would be the responsibility of the Claise, et. al Standard Track [Page 4]
IPFIX Protocol Specification December 2004 collector (connection initiator) to know whether TLS setup is required. PROTO-38: [IPFIX-INFO] consistency issue: - the ipfixOption, time, droppedFUPacketCount, droppedFUByteCount, droppedFlows, keyList, timeFirstFUDropped, timeLastFUDropped, droppedFAPacketCount, droppedFAByteCount, timeFirstFADropped, timeLastFADropped, and Exporter ID, Source ID Information Elements are not used in this document but not yet specified in [IPFIX-INFO]. - Review the Options Template example once the Source ID is defined as an information element (currently the ID 141 is used) PROTO-44: UDP, TCP, and SCTP ports XXXX should be replaced once assigned by IANA. Proposal: 4739 PROTO-46: TCP section update, waiting text for Simon Leinen. See the thread starting with http://ipfix.doit.wisc.edu/archive/2569.html PROTO-47: Some ææEDITORÆS NOTEÆÆ in the draft. PROTO-48: Should the ææsequence numberÆÆ be improved to contains the number of flow records, like proposed in http://ipfix.doit.wisc.edu/archive/2587.html? 2. Introduction A data network with IP traffic, primarily consists of IP Flows passing through the network elements of the network. It is often interesting, useful or even a requirement to have access to information about these flows that pass through the network elements for administrative or other purposes. The IPFIX collecting process should be able to receive the flow information passing through multiple network elements within the data network. This requires uniformity in the method of representing the flow information and the means of communicating the flows from the network elements to the collection point. This document specifies the protocol to achieve these aforementioned requirements. This document specifies in detail the representation of different flows, the additional data required for flow interpretation, packet format, transport mechanisms used, security concerns, etc. Claise, et. al Standard Track [Page 5]
IPFIX Protocol Specification December 2004 2.1 IPFIX Documents Overview The IPFIX protocol 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 [IPFIX-ARCH], per the requirements defined in [IPFIX-REQ]. This document specifies how IPFIX flow record data, options record data, and templates are carried via a congestion- aware transport protocol from IPFIX exporting process to IPFIX collecting process. IPFIX has a formal description of IPFIX information elements (fields), their name, type and additional semantic information, as specified in [IPFIX-INFO]. Finally [IPFIX- AS] describes what type of applications can use the IPFIX protocol and how they can use the information provided. It furthermore shows how the IPFIX framework relates to other architectures and frameworks. 3. Terminology The definitions of the basic terms like IP Traffic Flow, Exporting Process, Collecting Process, Observation Points, etc. are semantically identical with that found in the IPFIX requirements document [IPFIX-REQ]. Some of the terms have been expanded for more clarity when defining the protocol. Additional terms required for the protocol has also been defined. Definitions in this document and in [IPFIX-ARCH] are equivalent, except that definitions which are only relevant to the IPFIX protocol only appear here. Should there be any apparent discrepancy in definitions between these two documents, the definitions defined in this document take precedence. The terminology summary table in Section 3.1 gives a quick overview of the relationships between some of the different terms defined. Observation Point An Observation Point is a location in the network where IP packets can be observed. Examples include: a line to which a probe is attached, a shared medium, such as an Ethernet-based LAN, a single port of a router, or a set of interfaces (physical or logical) of a router. Note that one Observation Point may be a superset of several other Observation Points. For example, one Observation Point can be Claise, et. al Standard Track [Page 6]
IPFIX Protocol Specification December 2004 an entire line card. This would be the superset of the individual Observation Points at the line card's interfaces. Observation Domain An Observation Domain is the largest set of Observation Points for which Flow information can be aggregated by a Metering Process. Each Observation Domain presents itself using a unique ID to the Collecting Process to identify the IPFIX Messages it generates. For example, a router line card may be an observation domain if it is composed of several interfaces: each of which is an Observation Point. Every Observation Point is associated with an Observation Domain. IP Traffic Flow or Flow There are several definitions of the term 'flow' being used by the Internet community. Within the context of IPFIX we use the following definition: A Flow is defined as a set of IP packets passing an Observation Point in the network during a certain time interval. All packets belonging to a particular Flow have a set of common properties. Each property is defined as the result of applying a function to the values of: 1. one or more packet header field (e.g. destination IP address), transport header field (e.g. destination port number), or application header field (e.g. RTP header fields [RFC1889]) 2. one or more characteristics of the packet itself (e.g. number of MPLS labels, etc...) 3. one or more of fields derived from packet treatment (e.g. next hop IP address, the output interface, etc...) A packet is defined to belong to a Flow if it completely satisfies all the defined properties of the Flow. This definition covers the range from a Flow containing all packets observed at a network interface to a Flow consisting of just a single packet between two applications. It includes packets selected by a sampling mechanism. Claise, et. al Standard Track [Page 7]
IPFIX Protocol Specification December 2004 Flow Key Each of the fields which 1. Belong to the packet header (e.g. destination IP address) 2. Are a property of the packet itself (e.g. packet length) 3. Are derived from packet treatment (e.g. AS number) and which are used to define a Flow are termed Flow Keys. Flow Record A Flow Record contains information about a specific Flow that was observed at an Observation Point. A Flow Record contains measured properties of the Flow (e.g. the total number of bytes of all packets of the Flow) and usually characteristic properties of the Flow (e.g. source IP address). Metering Process The Metering Process generates Flow Records. Input to the process are packet headers observed at an Observation Point and packet treatment at the Observation Point (for example the selected output interface). The Metering Process consists of a set of functions that includes packet header capturing, timestamping, sampling, classifying, and maintaining Flow Records. The maintenance of Flow Records may include creating new records, updating existing ones, computing Flow statistics, deriving further Flow properties, detecting Flow expiration, passing Flow Records to the Exporting Process, and deleting Flow Records. Exporting Process The Exporting Process sends Flow Records to one or more Collecting Processes. The Flow Records are generated by one or more Metering Processes. Claise, et. al Standard Track [Page 8]
IPFIX Protocol Specification December 2004 IPFIX Device An IPFIX Device hosts at least one Observation Point, a Metering Process and an Exporting Process. Typically, corresponding Observation Point(s), Metering Process(es) and Exporting Process(es) are co-located at such a device, for example at a router. Exporter A device which hosts one or more Exporting Processes is termed an Exporter. Collecting Process A Collecting Process receives Flow Records from one or more Exporting Processes. The Collecting Process might process or store received Flow Records, but such actions are out of scope for this document. Collector A device which hosts one or more Collecting Processes is termed a Collector. Template Template is an ordered sequence of pairs (<type,length>), used to completely identify the structure and semantics of a particular information that needs to be communicated from the IPFIX Device to the Collector. Each Template is uniquely identifiable by means of a Template ID. IPFIX Message An IPFIX Message is a message originating at the Exporting Process that carries the IPFIX records of this Exporting Process and whose destination is the Collecting Process. An IPFIX Message is encapsulated within a transport layer. Message Header Claise, et. al Standard Track [Page 9]
IPFIX Protocol Specification December 2004 The Message Header is the first part of an IPFIX Message, which provides basic information about the message such as the IPFIX version, length of the message, message sequence number, etc. Template Record A Template Record defines the structure and interpretation of fields in a Flow Data Record. Flow Data Record A Flow Data Record is a data record that contains values of the Flow parameters corresponding to a Template Record. Options Template Record An Options Template Record defines the structure and interpretation of fields in an Options Data Record, including defining how to scope the applicability of the Options Data Record. Options Data Record The Options Data Record is a data record that contains values and scope information of the Flow measurement parameters, corresponding to an Options Template Record. Set Set is a generic term for a collection of records that have a similar structure. In an IPFIX Message, one or more Sets follow the Message Header. There are three different types of Sets: Template Set, Options Template Set, and Data Set. Template Set A Template Set is a collection of one or more Template Records that have been grouped together in an IPFIX Message. Options Template Set Claise, et. al Standard Track [Page 10]
IPFIX Protocol Specification December 2004 An Options Template Set is a collection of one or more Options Template Records that have been grouped together in an IPFIX Message. Data Set A Data Set is one or more records, of the same type, that are grouped together in an IPFIX Message. Each record is either a Flow Data Record or an Options Data Record previously defined by a Template Record or an Options Template Record. Information Element An Information Element is a protocol and encoding independent description of an attribute which may appear in an IPFIX Flow Record. The IPFIX information model [IPFIX-INFO] defines the base set of Information Elements for IPFIX. The type associated with an Information Element indicates constraints on what it may contain and also determine the valid encoding mechanisms for use in IPFIX. 3.1 Terminology Summary Table +------------------+---------------------------------------------+ | | Contents | | +--------------------+------------------------+ | Set | Template Record | data record | +------------------+--------------------+------------------------+ | | | Flow Data Record(s) | | Data Set | / | or | | | | Options Data Record(s) | +------------------+--------------------+------------------------+ | Template Set | Template Record(s) | / | +------------------+--------------------+------------------------+ | Options Template | Options Template | / | | Set | Record(s) | | +------------------+--------------------+------------------------+ Figure A: Terminology Summary Table A Data Set is composed of an Options Data Record(s) or Flow Data Record(s). No Template Record is included. A Template Record defines the Flow Data Record, and an Options Template Record defines the Options Data Record. Claise, et. al Standard Track [Page 11]
IPFIX Protocol Specification December 2004 A Template Set is composed of Template Record(s). No Flow or Options Data Record is included. An Options Template Set is composed of Options Template Record(s). No Flow or Options Data Record is included. 4. Criteria for Flow Expiration and Export 4.1 Flow Expiration A Flow is considered as expired under the following conditions: 1. If the Metering Process can deduce the end of a Flow, that Flow Record should be exported when the end of the Flow is detected. For example, a Flow generated by TCP [TCP] traffic where the FIN or RST bits indicate the end of the Flow Record. 2. If no packets belonging to the Flow have been observed for a certain period of time. This time period should be configurable at the Metering Process, with a minimum value of 0 seconds for immediate expiration. Note that a zero timeout would report a Flow as a sequence of single-packet Flows. 3. If the IPFIX Device experiences resource constraints, a Flow Record may be prematurely expired (e.g. lack of memory to store Flow Records). 4. For long-running Flows, the Metering Process should expire the Flow Record on a regular basis or based on some expiration policy. This periodicity or expiration policy should be configurable at the Metering Process. When the Record of a long-running Flow is expired, that Flow Record may still be maintained by the Metering Process so that, for further observed packets of the same Flow Record, the Metering Process does not need to create a new Flow Record. 4.2 Flow Export The Exporting Process decides when and whether to export an expired Flow. A Flow can be exported because it expired due to the reasons mentioned in Flow Expiration section. For example: the Exporting Process exports a portion of the expired Flows every 'x' seconds. Claise, et. al Standard Track [Page 12]
IPFIX Protocol Specification December 2004 For long-lasting Flows, the Exporting Process should export the Flow Records on a regular basis or based on some export policy. This periodicity or export policy should be configurable at the Metering Process. 5. Message Format An IPFIX Message consists of a Message Header followed by one or more Sets. The Sets can be any of the possible three types: Template, Data, or Options Template. The format of the IPFIX Message is shown in Figure B. +--------+-------------------------------------------+ | | +----------+ +---------+ +----------+ | |Message | | Template | | Data | | Options | | | Header | | Set | | Set | | Template | ... | | | | | | | | Set | | | | +----------+ +---------+ +----------+ | +--------+-------------------------------------------+ Figure B: IPFIX Message format A Set ID is used to distinguish the different types of Sets. Set IDs lower than 256 are reserved for special Sets, such as the Template Set (ID 2) and the Options Template Set (ID 3). The Data Sets have a Set ID greater than 255. The Set ID value of 0 and 1 are not used for historical reasons [NETFLOW9]. The format of the Template, Data, and Options Template Sets will be discussed later in this document. The Exporter MUST code all binary integers of the Message Header and the different Sets in network byte order (also known as the big-endian byte ordering). Following are some examples of IPFIX Messages: 1. An IPFIX Message consisting of interleaved Template, Data, and Options Template Sets-A newly created Template is exported as soon as possible. So if there is already an IPFIX Message with a Data Set that is being prepared for export, the Template and Option Sets are also interleaved with this information, subject to availability of space. Claise, et. al Standard Track [Page 13]
IPFIX Protocol Specification December 2004 +--------+--------------------------------------------------------+ | | +----------+ +---------+ +-----------+ +---------+ | |Message | | Template | | Data | | Options | | Data | | | Header | | Set | | Set | ... | Template | | Set | | | | | | | | | Set | | | | | | +----------+ +---------+ +-----------+ +---------+ | +--------+--------------------------------------------------------+ Figure C: IPFIX Message example 1 2. An IPFIX Message consisting entirely of Data Sets-After the appropriate Template Records have been defined and transmitted to the Collecting Process, the majority of IPFIX Messages consist solely of Data Sets. +--------+----------------------------------------------+ | | +---------+ +---------+ +---------+ | |Message | | Data | ... | Data | ... | Data | | | Header | | Set | ... | Set | ... | Set | | | | +---------+ +---------+ +---------+ | +--------+----------------------------------------------+ Figure D: IPFIX Message example 2 3. An IPFIX Message consisting entirely of Template and Options Template Sets-When UDP is used as the transport protocol, Templates Sets and Option Template Sets MUST be sent periodically to help ensure that the Collecting Process has the correct Template Records and Options Template Records when the corresponding Flow Data Records are received. +--------+-------------------------------------------------+ | | +----------+ +----------+ +----------+ | |Message | | Template | | Template | | Options | | | Header | | Set | ... | Set | ... | Template | | | | | | | | | Set | | | | +----------+ +----------+ +----------+ | +--------+-------------------------------------------------+ Figure E: IPFIX Message example 3 Claise, et. al Standard Track [Page 14]
IPFIX Protocol Specification December 2004 6. IPFIX Message Format 6.1 Header Format The format of the IPFIX Message Header format is shown in Figure F. 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Version Number | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Export Time | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Sequence Number | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Source ID | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure F: IPFIX Message Header format Message Header Field Descriptions Version Version of Flow Record format exported in this message. The value of this field is 0x000a for the current version. Length Total Length is the length of the IPFIX Message, measured in octets, including message Header and Set(s). Export Time Time in seconds since 0000 UTC 1970, at which the IPFIX Message Header leaves the Exporter. Sequence Number Incremental sequence counter modulo 2exp32 of all IPFIX Messages sent on this stream from the current Observation Domain by the Exporting Process. This value SHOULD be used by the Collecting Process to identify whether any IPFIX Messages have been missed. Source ID Claise, et. al Standard Track [Page 15]
IPFIX Protocol Specification December 2004 A 32-bit value that identifies the Exporter Process Observation Domain. Collecting Process SHOULD use the combination of the source IP address and the Source ID field to separate different export streams originating from the same Exporting Process. 6.2 Field Type Format Vendors need the ability to define proprietary Information Elements, because, for example, they are delivering pre-standards product, or the Information Element is in some way commercially sensitive. This section describes the Field Type format for both IETF specified Information Elements [IPFIX-INFO] and Enterprise Specific Information Elements, both the Template Set and the Option Template Set. The Field Ids used to identify Information Elements are represented by the Field Type. When the Enterprise Field Type bit is set to 0, the corresponding Field Type will report an IETF specified Information Elements. When the Enterprise Field Type bit is set to 1, the corresponding Field Type will report an Enterprise Specific Information Element. An example of this is shown in section 16. The Field Type format is shown in Figure G. 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |E| Field Type | Field Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Enterprise Number | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure G: Field Type format Where: E Enterprise Field Type. This is the first bit of the Field Type. If this bit is zero, the Field Type identifies an IETF specified Information Element, and the four octet Enterprise Number field MUST NOT be present. If this bit is one, the Claise, et. al Standard Track [Page 16]
IPFIX Protocol Specification December 2004 Field Type identifies an Enterprise Specific Information Element, and the Enterprise Number filed MUST be present. Field Type A numeric value that represents the type of the field. Refer to [IPFIX-INFO]. Field Length The length of the corresponding Field Type, in bytes. Refer to [IPFIX-INFO]. Enterprise Number IANA enterprise number [PEN] of the authority defining the Field Type in this Template Record. 6.3 Template Set Format One of the essential elements in the IPFIX format is the Template Set. Templates greatly enhance the flexibility of the Flow Record format because they allow the Collecting Process to process Flow Records without necessarily knowing the interpretation of all the data in the Flow Record. A Template Set MAY exclusively contain IETF defined Field Types. A Template Set MAY contain Enterprise Specific Information Elements from one or more vendors. The format of the Template Set is shown in Figure H. 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 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Template ID 256 | Field Count 1 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Field Type 1.1 | Field Length 1.1 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Enterprise Number 1.1 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Field Type 1.2 | Field Length 1.2 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | ... | ... | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Field Type 1.N | Field Length 1.N | Claise, et. al Standard Track [Page 17]
IPFIX Protocol Specification December 2004 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Enterprise Number 1.N | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Template ID 257 | Field Count 2 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Field Type 2.1 | Field Length 2.1 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Field Type 2.2 | Field Length 2.2 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Enterprise Number 2.2 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | ... | ... | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Field Type 2.M | Field Length 2.M | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Enterprise Number 2.M | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Padding (opt) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure H: Template Set Format Field Types 1.2 and 2.1 are defined by the IETF (bit 0 = 0) and therefore do not need and Enterprise Number to identify them. The Template Set Field Definitions are as follows: Set ID Set ID value of 2 is reserved for the Template Set. Length Total length of this Set. Because an individual Template Set MAY contain multiple Template Records, the Length value MUST be used to determine the position of the next Set record, which could be any type of Set. Length is the sum of the lengths of the Set ID, the Length itself, and all Template Records within this Set. Template ID Each of the newly generated Template Records is given a unique Template ID. This uniqueness is local to the Observation Domain that generated the Template ID. Claise, et. al Standard Track [Page 18]
IPFIX Protocol Specification December 2004 Template IDs 0-255 are reserved for Template Sets, Options Sets, and other reserved Sets yet to be created. Template IDs of Data Sets are numbered from 256 to 65535. Field Count Number of fields in this Template Record. Because a Template Set usually contains multiple Template Records, this field allows the Collecting Process to determine the end of the current Template Record and the start of the next. Field Type A numeric value that represents the type of the field. Refer to [IPFIX-INFO]. Field Length The length of the corresponding Field Type, in bytes. Refer to [IPFIX-INFO]. Enterprise Number IANA enterprise number [PEN] of the authority defining the Field Type. Padding The Exporting Process MAY insert some padding bytes, so that the subsequent Set starts at an aligned boundary. Padding MUST be composed of zero (0) bytes. The padding length MUST be shorter than any allowable Template Record in this Template Set. It is important to note that the Length field includes the padding bytes. Because Template Sets are always 4-byte aligned by definition padding is only needed in case of other alignments e.g. on 8-byte boundaries. The Set ID value of 0 and 1 are not used for historical reasons [NETFLOW9]. 6.4 Data Set Format The format of the Data Set is shown in Figure I. 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Claise, et. al Standard Track [Page 19]
IPFIX Protocol Specification December 2004 | Set ID = Template ID | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Record 1 - Field Value 1 | Record 1 - Field Value 2 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Record 1 - Field Value 3 | ... | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Record 2 - Field Value 1 | Record 2 - Field Value 2 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Record 2 - Field Value 3 | ... | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Record 3 - Field Value 1 | ... | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | ... | Padding (opt) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure I: Data Set Format Note that not all Field Values do necessarily have a length of 16 bit. Data Set Field Descriptions are as follows: Set ID = Template ID Each Data Set is associated with a Set ID. The Set ID maps to a (previously generated) Template ID. The Collecting Process MUST use the Set ID to find the corresponding Template Record and decode the Flow Records from the Set. Length The length of this Set. Length is the sum total of lengths of Set ID, Length itself, all Flow Records within this Set, and the padding bytes, if any. Record N - Field Value M The remainder of the Data Set is a collection of Flow Data Record(s), each containing a set of Field Types and values. The Type and Length of the fields have been previously defined in the Template Record referenced by the Set ID or Template ID. Padding Claise, et. al Standard Track [Page 20]
IPFIX Protocol Specification December 2004 The Exporting Process MAY insert some padding bytes, so that the subsequent Set starts at an aligned boundary. Padding MUST be composed of zero (0) bytes. The padding length MUST be shorter than any allowable Flow Data Record in this Data Set. It is important to note that the Length field includes the padding bytes. Interpretation of the Data Set format can be done only if the Template Set corresponding to the Template ID is available at the Collecting Process. 6.5 Options Template Set The Options Template Record (and its corresponding Options Data Record) is used to supply information about the Metering Process configuration or Metering Process specific data, rather than supplying information about IP Flows. For example, the Options Template Set can report the sample rate of a specific interface, if sampling is supported, along with the sampling method used. 6.5.1 Scope The Options Template Set gives the Exporter the ability to provide additional information to the Collector which would not be possible with only Flow Records. The scope, which is only available in the Options Template Set, gives the context of the reported Information Elements. One Options Template Set example is the "Metering Process statistics", which reports the statistics for the Observation Domain, which is defined as the scope. Another example is the "Template configuration", which reports the configuration sampling parameter(s) for the template, which is defined as the scope. Multiple scope fields MAY be present in the Options Template Set, in which, the composite scope is the combination of the scopes. For example, if the two scopes are defined as "cache" and "template", the combined scope is this template in this cache. The order of the scope, as defined in the Options Template Set, is in this case irrelevant. However, if the order of the scopes fields in the Option Template Set is relevant, the order of the scope fields MUST be used. For example, if the first scope defines the filtering function, while the second scope defines the sampling function, the Claise, et. al Standard Track [Page 21]
IPFIX Protocol Specification December 2004 order of the scope is important. Applying first the sampling function, followed by the filtering function, would lead to potential different Flow Records than applying first the filtering function, followed by the filtering function. In this case, the Collector deduces the function order by looking at the order of the scope in the Options Template Set. Finally, note that the scope length MAY NOT be zero. 6.5.2 Options Template Set Format An Options Template MAY exclusively contain IETF defined Field Types. An Options Template MAY contain Enterprise Specific Information Elements from multiple vendors. An Options Template MAY contain IETF defined Field Types and Enterprise Specific Information Elements. The format of the Options Template Set is shown in Figure J. 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 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Template ID | Field Count | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Scope Field Count | Scope 1 Field Type | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Scope 1 Field Length | Scope 2 Field Type | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Scope 2 Field Length | ... | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | ... | Scope N Field Type | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Scope N Field Length | Scope N Entreprise Number ... +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ ... Scope N Enterprise Number | Option 1 Field Type | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Option 1 Field Length | Option 1 Entreprise Number ... +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ ... Option 1 Enterprise Number | ... | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | ... | Option M Field Type | Claise, et. al Standard Track [Page 22]
IPFIX Protocol Specification December 2004 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Option M Field Length | Padding (opt) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure J: Option Template Set Format The Options Template Set Field Definitions are as follows: Set ID = 3 A Set ID value of 3 is reserved for the Options Template. Length Total length of this Set, including the padding bytes, if any. Each Options Template Set MAY contain multiple Options Template Records. Thus, the Length value MUST be used to determine the position of the next Set record, which could be either a Template Set or Data Set. Length is the sum total of lengths of Set ID, the Length itself, and all Options Template Records within this Set Template ID. Template ID Template ID of this Options Template. This value is greater than 255. Field Count Number of all fields in this Option Template Record, including the Scope Fields. Because a Option Template Set usually contains multiple Template Records, this field allows the Collecting Process to determine the end of the current Option Template Record and the start of the next. Scope Field Count Number of scope fields in this Option Template Record. Scope Field Type A numeric value that represents the type of the field. Refer to [IPFIX-INFO]. Scope Field Length The length (in bytes) of the Scope field, as it would appear in an Options Data Record. Claise, et. al Standard Track [Page 23]
IPFIX Protocol Specification December 2004 Scope N Enterprise Number IANA enterprise number [PEN] of the authority defining Scope N Field Type. This is 4 bytes long. Option Field Type A numeric value that represents the type of field. Refer to [IPFIX-INFO]. Option Field Length The length of the corresponding Option Field Type, in bytes. Refer to [IPFIX-INFO]. Option M Enterprise Number IANA enterprise number [PEN] of the authority defining the Option M Field Type. This is 4 bytes long. Padding The Exporting Process MAY insert some padding bytes, so that the subsequent Set starts at an aligned boundary. Padding MUST be composed of zero (0) bytes. The padding length MUST be shorter than any allowable Options Template Record in this Options Template Set. It is important to note that the Length field includes the padding bytes. The Set ID value of 0 and 1 are not used for historical reasons [NETFLOW9]. 6.5.3 Options Data Record Format The Options Data Records are sent in Data Sets. The format of the Data Set, containing Options Data Records, is shown in Figure K. 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 = Template ID | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Record 1 - Scope 1 Value | Record 1 - Scope 2 Value | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | ... |Record 1 - Option Field 1 Value| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Claise, et. al Standard Track [Page 24]
IPFIX Protocol Specification December 2004 |Record 1 - Option Field 2 Value| ... | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Record 2 - Scope 1 Value | Record 2 - Scope 2 Value | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | ... |Record 2 - Option Field 1 Value| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |Record 2 - Option Field 2 Value| ... | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Record 3 - Scope 1 Value | Record 3 - Scope 2 Value | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | ... |Record 3 - Option Field 1 Value| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |Record 3 - Option Field 2 Value| ... | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | ... | Padding (opt) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure K: Data Set format, containing Options Data Records Options Data Records of the Data Set Field Descriptions Set ID = Template ID A Set ID precedes each group of Options Data Records within a Data Set. The Set ID maps to a previously generated Template ID corresponding to this Options Template Record. The Collecting Process MUST use the Set ID to map the appropriate type and length to any field values that follow. Length The length of this Set. Length is the sum of the lengths of the Set ID, Length itself, all the Options Data Records within this Set, and the padding bytes, if any. Record N - Option Field M Value The remainder of the Data Set is a collection of Flow Records, each containing a set of Scope and Field Values. The type and length of the fields were previously defined in the Options Template Record referenced by the Set ID or Template ID. Padding Claise, et. al Standard Track [Page 25]
IPFIX Protocol Specification December 2004 The Exporting Process MAY insert some padding bytes, so that the subsequent Set starts at an aligned boundary. Padding MUST be composed of zero (0) bytes. The padding length MUST be shorter than any allowable Options Data Record in this Data Set. It is important to note that the Length field includes the padding bytes. The Data Set format can be interpreted only if the Options Template Set corresponding to the Template ID is available at the Collecting Process. 7. Specific Reporting Requirements Some specific Options Templates and Options Templates Records are necessary to provide extra information about the Flow Records and about the Metering Process. The ipfixOption Field [IPFIX-INFO], always included in these specific Options Templates, defines the type of information sent in the Option Template / Option Template Record pair. For example, if the ipfixOption [IPFIX-INFO] value is METER_STATS, then the Option Template will specify information about the Metering Process statistics. The Option Template and Option Template Records defined in these sub-sections are not mandatory to implement as they impose some constraints about the Metering Process implementation: this document specifies the protocol to export the records, not the Metering Process implementation. However, if the specific Option Templates are implemented, they should ideally be implemented as specified in these sub-sections. In any case, if the ipfixOption Information Element is present, it MUST always be the first Information Element in the Option Template so that the Collector can quickly determine which specific Option Template Record is received. The minimum set of Information Elements is always specified in these Specific IPFIX Options Templates. Nevertheless, extra Information Elements may be used in these specific Options Templates. 7.1 The Metering Process Statistics Option Template Claise, et. al Standard Track [Page 26]
IPFIX Protocol Specification December 2004 The Metering Process Statistics Option Template specifies the Metering Process Statistics. It contains the following Information Elements [IPFIX-INFO]: ipfixOption The value is METERING_STATS exportedOctetCount The number of all octets reported by the Exporting Process to the Collecting Process. exportedPacketCount The number of all packets reported by the exporting process to the Collecting Process. exportedFlowCount The number of all flows records reported by the Exporting Process to the Collecting Process. time The time at which the record was generated The Exporting Process should export the Metering Process Statistics Option Template Record on a regular basis or based on some export policy. This periodicity or export policy should be configurable. The Metering Process Statistics Option Template could be extended with other Information Elements. The Scope Field specified in the Metering Process Statistics Option Template Record is the Source ID. 7.2 The Metering Process Reliability Statistics Option Template The Metering Process Reliability Option Template specifies information about lack of reliability in the Metering process. It contains the following Information Elements [IPFIX-INFO]: ipfixOption The value is METERING_RELIABILITY_STATS droppedFUPacketCount Packets dropped by Metering Process droppedFUOctetCount Bytes dropped by Metering Process timeFirstFUDropped Time of the first packet dropped at the Specified scope ID timeLastFUDropped Time of the last packet dropped at the Specified scope ID time The time at which the record was generated The Exporting Process should export the Metering Process Reliability Statistics Option Template Record on a regular basis or based on Claise, et. al Standard Track [Page 27]
IPFIX Protocol Specification December 2004 some export policy. This periodicity or export policy should be configurable. The Metering Process Reliability Statistics Option Template could be extended with other Information Elements. The Scope Field specified in the Metering Process Reliability Statistics Option Template Record is the Source ID. 7.3 The Exporting Process Reliability Statistics Option Template The Exporting Process Reliability Option Template specifies information about lack of reliability in the Exporting process. It contains the following Information Elements [IPFIX-INFO]: ipfixOption The value is EXPORTING_RELIABILITY_STATS droppedFlows Number of flow records not exported (due to resources starvation at Exporting Process or due to some flow records export policies) droppedFAPacketCount Packets in the dropped flows droppedFAByteCount Bytes in the dropped flows timeFirstFADropped Time of the first packet within the dropped flows timeLastFADropped Time of the last packet within the dropped flows time The time at which the record was generated The Exporting Process should export the Exporting Process Reliability Statistics Option Template Record on a regular basis or based on some export policy. This periodicity or export policy should be configurable. The Exporting Process Reliability Statistics Option Template could be extended with other Information Elements. The Scope Field specified in the Exporter Reliability Statistics Option Template Record is the Exporter ID. 7.4 The Flow Keys Option Template The Flow Keys Option Template specifies the flow keys used by the Metering Process for the Template ID definition. It contains the following Information Elements [IPFIX-INFO]: Claise, et. al Standard Track [Page 28]
IPFIX Protocol Specification December 2004 ipfixOption The value is FLOW_KEY keyList Bitmap with the positions of the flow keys in the template time The time at which the record was generated The Scope Field specified in the Flow Keys Option Template Record is the Template ID with which the flow keys are associated. 8. "Export Time" Computation and Flow Record Time 8.1 Microsecond Precision For a Data Set with Flow Records requiring microsecond precision, the IPFIX Message Header "Export Time" field MUST be calculated so that each Flow Records flowStartUsec [IPFIX-INFO] and flowEndUsec [IPFIX-INFO] would contain a 32 bit signed microsecond offset from the "Export Time" base timestamp. Hereafter some pseudo code to calculate the Export Time in one pass, which would return an absolute duration of 35 minutes for all Flow Records contained in the Data Set. Flow Records MUST be exported in different IPFIX Message Header if the absolute durations can not fit in those 35 minutes. // pseudo code for microsecond offset in IPFIX encoded Flow Records. // struct flow{ uint32 tv_sec; uint32 tv_usec; uint32 numbytes; ... // other Information Elements... }; struct flow flowtable [MAX_TABLE_SIZE]; int lastflowindex = -1; writeflows() { if (lastflowindex < 0) return; // simply take the second field from the first available flow // and make this the base time for this collection of flows. uint32 base_sec = flowtable[0].tv_sec; Claise, et. al Standard Track [Page 29]
IPFIX Protocol Specification December 2004 writeheaderToSocket(base_sec); // put 32-bit second value in header for (int i=0; i<=lastflowindex; i++){ int32 offset = (flowtable[i].tv_sec - base_sec) * 1000000 + flowtable[i].tv_usec; writeint32ToSocket(offset); // put the 32-bit time offset in the record. // write other Information Elements... } } A two pass approach calculation for the optimum (center) "Export Time" base timestamp would allow an absolute duration of 71 minutes for all Flow Records contained in the Data Set. The two pass approach MAY be used. The "Export Time" base timestamp calculation requires that at the IPFIX Message Header exporting time the Exporting Process MUST run down the list of Flow Records in the Data Set message and adjust the Flow start and Flow end timestamps. 8.2 Millisecond Precision For a Data Set with Flow Records requiring a millisecond precision, the same principles as in section 9.1 "Microsecond Precision" will be used. The only difference will be that the Flow start and the Flow end SHOULD now be represented respectively by the flowStartMsec [IPFIX- INFO] and flowEndMsec [IPFIX-INFO]. As a consequence of the millisecond precision, the absolute duration of all Flow Records is now of about 49 days. The Export header "Export Time" base time SHOULD be calculated with the algorithm described in the Section 9.1 "Microsecond Precision". In order to reduce the load on the Exporter, the Export header "Export Time" MAY be the time in seconds since 0000 UTC 1970 at which the IPFIX Message Header leaves the Exporter and not the calculated optimum value anymore as described in section 9.1 "Microsecond Precision". Alternatively, for a Data Set with Flow Records requiring a millisecond precision, the microsecond mechanism as described in section 9.1 MAY be used as such. The Flow Record MAY use the flowStartUsec [IPFIX-INFO] and flowEndUsec [IPFIX-INFO] rounded at a millisecond precision. Claise, et. al Standard Track [Page 30]
IPFIX Protocol Specification December 2004 8.3 Nanosecond Precision For a Data Set with Flow Records requiring a nanosecond precision, all Flow Records will contain Flow start flowStartNsec [IPFIX-INFO] and flowEndNsec [IPFIX-INFO]. The Export header "Export Time" will be of no use on the Collector side in this case as the flowStartNsec [IPFIX-INFO] and flowEndNsec [IPFIX-INFO] both have a nanosecond precision already. Both flowStartNsec [IPFIX-INFO] and flowEndNsec [IPFIX-INFO] use the NTP time format which is represented as a 64- bit value which contains a 32-bit specification of seconds since 1900 and a 32-bit "fraction" field. Refer to the NTP specification, RFC1305, section 3.1 "Data Formats". 8.4 Multiple Precisions When Flow Records requiring different precisions must be exported, the Exporting Process SHOULD split the Flow Records in different Data Set according to the precision: millisecond, microsecond or nanosecond. 9. Linkage with the Information Model The Information Elements [IPFIX-INFO] MUST be sent in canonical format in network byte order. 9.1 Reduced Size Encoding of Integer Types Information Elements containing integer types in the information model MAY be encoded using fewer bytes than those implied by their type in the information model definition [IPFIX-INFO], based on the assumption that the smaller type is sufficient to carry any value the Exporter may need to deliver. This reduces the network bandwidth requirement between the Exporter and the Collector. Note that the Information Elements definition [IPFIX-INFO] will always define the maximum encoding size. For instance the information model [IPFIX-INFO] defines byteCount as an unsignedLong type, which would require 64-bits. However if the Exporter will never locally encounter the need to send a value larger than 4294967295, it may chose to send the value instead as an unsignedInt. For example, a core router would require an unsignedLong byteCount while an unsignedInt might be sufficient for an access router. Claise, et. al Standard Track [Page 31]
IPFIX Protocol Specification December 2004 This behavior is indicated by the Exporter by specifying a type size smaller than that associated with the assigned type of the field. In the example above the Exporter would place a length of 4 versus 8 in the template. If reduced sizing is used, it MUST be applied only to following integer types: unsignedLong, long, unsignedInt, int, unsignedShort, short. In each case the downcasting MUST be to a smaller integer type. The same signed versus unsigned properties MUST be preserved. Specifically unsignedLong may be downcast to unsignedInt, unsignedShort or unsignedByte. A long may be downcast to an int, a short or a byte. The other downcasts follow the same pattern. 10. Variable Length Information Element The IPFIX template mechanism is optimized for fixed length Information Elements [IPFIX-INFO]. Where an Information Element has a variable length the following mechanism MUST used to carry the length information, for both the IETF and proprietary Information Elements. In the Template Set the length is recorded as 65535. This reserved length value notifies the Collecting Process that length of the Information Element will be carried in the Information Element content itself. In most cases the length of the Information Element will be less than 256 bytes. The following length encoding mechanism optimizes the overhead of carrying the Information Element length in this majority case. If the length of the Information Element is less than 255 bytes, the length is carried in the first byte of the Information Element, as shown on Figure L. 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)| Information element | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | ... continuing as needed | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure L: Variable Length Information Element (length < 255 bytes) Claise, et. al Standard Track [Page 32]
IPFIX Protocol Specification December 2004 If the length of the Information Element is greater or equal than 255 bytes, the first byte of the Information Element is 255, and the length is carried in the second and third bytes of the Information Element, as shown in Figure M. 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 (255 to 65535) | IE | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | ... continuing as needed | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure M: Variable Length Information Element (length 255 to 65535) bytes 11. Template Management This section describes Template management when using SCTP and SCTP- PR as the transport protocol. Any necessary changes to Template management specifically related to TCP or UDP transport protocols are specified in section 13. The Exporting Process assigns and maintains the Template IDs for the ExporterÆs Observations Domains. A newly created Template Record is assigned an unused Template ID by the Exporting Process. Templates Sets and Option Template Sets MUST be only sent once on SCTP stream zero with full reliability. As such, the Collecting Process MUST store the Template Record information for the duration of the association so that it can interpret the corresponding Flow Data Records that are received in subsequent Data Sets. New Template Records SHOULD be transmitted as soon as they are created. The Exporting Process MAY transmit the Template Set and Options Template in advance of any Data Sets that use that (Options) Template ID, to ensure that the Collector has the Template Record before receiving the first Flow or Options Data Record. Flow and Options Data Records that correspond to a Template Record MAY appear in the same and/or subsequent IPFIX Message(s). Claise, et. al Standard Track [Page 33]
IPFIX Protocol Specification December 2004 A Template ID MUST be unique per Observation Domain. Different Observation Domains from the same Exporter may use the same Template ID value to refer to different Templates. Disused Templates SHOULD be deleted. Prior to reuse a Template ID the disused Template MUST be deleted. In order to delete an allocated Template, the Template is withdrawn through the use of a Template Withdraw Message. The Template Withdraw Message MUST not be sent until sufficient time has elapsed to allow the Collecting Process to receive and process the last data record using this Template information. The Template ID from a withdrawn Template MUST NOT be reused until sufficient time has elapsed to allow for the Collecting Process to receive and process the Template withdraw message. A Template Withdraw Message is Template Record for that Template ID with a Field Count of 0. The format of the Template Withdrawal Message is shown in figure O. 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 or 3) | Length = 8 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Template ID | Field Count = 0 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure O: Template Withdrawal Message format The Set ID field MUST contain the value 2 for Template Set withdrawal, and the value 3 for Options Template Set. Multiple Template ID MAY be withdrawn with a single Template Withdrawal Message: in that case, padding MAY be used. The Template Withdraw Message withdraws the Template ID for the Source ID specified in the IPFIX Message header. If the measurement parameters change, the Template MUST be withdrawn using a Template Withdraw Message or an unused Template ID MUST be used. Examples of the measurement changes are: a new sampling rate, a new flow expiration process, a new filtering definition, etc. If a Claise, et. al Standard Track [Page 34]
IPFIX Protocol Specification December 2004 Template is changed, a Template Withdraw Message MUST be sent to delete the Template. If the Exporting Process restarts, the SCTP association MUST be shutdown and restarted. When the Exporting Process restarts, all Template assignments are lost and Template IDs MUST be re-assigned. If the Metering Process restarts, the Exporting Process MUST either reuse the previously assigned Template ID for each Template, or it MUST withdraw the previously issued Template IDs by sending Template Withdraw Message(s) before reusing them. A Template Withdrawal Message to withdraw all Data Templates for the Source ID specified in the IPFIX message header MAY be used. Its format is shown in figure P. A Template Withdrawal Message to withdraw all Options Templates for the Source ID specified in the IPFIX message header MAY be used. Its format is shown in figure Q. 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 = 8 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Template ID = 2 | Field Count = 0 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure P: All Data Templates Withdrawal Message format 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 = 8 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Template ID = 3 | Field Count = 0 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure Q: All Options Templates Withdrawal Message format When the SCTP association restarts, the Exporting Process MUST resend all the Template Records. The Exporting Process MUST NOT transmit IPFIX Messages with more than one Source ID value inside any single stream. More that one (Option) Template Set MAY be sent in an IPFIX Message. Claise, et. al Standard Track [Page 35]
IPFIX Protocol Specification December 2004 12. The Collecting Process's Side This section describes the Collecting Process when using SCTP and SCTP-PR as the transport protocol. Any necessary changes to the Collecting Process specifically related to TCP or UDP transport protocols are specified in section 13. The Collecting Process SHOULD listen for a new association request from the Exporting Process. The Exporting Process will request a number of streams to use for export. A Collecting Process MUST support at least two inbound streams per association. An Exporting Process MAY ask for and support more than two streams. The Collecting Process MUST verify that only one Source ID value is used inside each stream. If the Collecting Process detects that more than one Source ID has been received within a stream, it MUST discard the IPFIX Message, reset the SCTP association, and SHOULD log the error If the Collecting Process receives a malformed IPFIX Message, it MUST reset the SCTP association, discard the IPFIX Message, and SHOULD log the error. Templates Sets and Option Template Sets are only sent once. The Collecting Process MUST store the Template Record information for the duration of the association so that it can interpret the corresponding Flow Data Records that are received in subsequent Data Sets. Template IDs are unique per Exporting Process and per Observation Domain. If the Collecting Process receives a Template which has already been received but which has not previously been withdrawn (i.e. a Template Record from the same Exporter Observation Domain with the same Template ID), then the Collecting Process MUST shutdown the association. When an SCTP association is closed, the Collecting Process MUST discard all templates received over that association and stop decoding IPFIX Messages that use those templates. The Collecting Process normally receives Template Records from the Exporting Process, before receiving Flow or Options Data Records. Claise, et. al Standard Track [Page 36]
IPFIX Protocol Specification December 2004 The Flow Data Records (or Options Data Records) are then decoded and stored by the Collector. If the Template Records have not been received at the time Flow Data Records (or Options Data Records) are received, the Collecting Process MAY store the Flow Data Records (or Options Data Records) for a short period of time and decode them after the Template Records are received. A Collecting Process MUST NOT assume that the Data Set and the associated Template Set (or Options Template Set) are exported in the same IPFIX Message. The Collecting Process MUST note the Field ID of any Information Element that it does not understand and MAY discard that Information Element from the Flow Record. The Collecting Process MUST note the size and position of any Vendor Specified Information Element that it does not understand and discard that Information Element from the Flow Record. More that one (Options) Template Set MAY be received in an IPFIX Message. The Collector MUST accept padding in Flow Data Records, Options Data Records and Template Records. The IPFIX protocol has a Sequence Number field in the Export header which increases with each IPFIX Message. A Collector may detect out of sequence, dropped, or duplicate IPFIX Messages by tracking the Sequence Number. EDITORÆS NOTE: THIS MIGHT CHANGE IF THE SEQUENCE NUMBER IS PER STREAM AND IF THIS IS THE NUMBER OF FLOW RECORDS. A collector SHOULD provide a logging mechanism for tracking out of sequence IPFIX Messages. Such out of sequence IPFIX Messages may be due to Exporter resource exhaustion where it can not transmit messages at their creation rate, an Exporting Process reset, congestion on the network link between the Exporter and Collector, Collector resource exhaustion where it can not process the IPFIX Messages at their arrival rate, out of order packet reception, duplicate packet reception, or an attacker injecting false messages. If a Collecting Process receives a Template Withdraw Message, the Collecting Process MUST delete the corresponding Template Record associated with the specific Exporter and specific Observation Domain, and stop decoding IPFIX Messages that use those Templates. A Collecting Process that receives IPFIX Messages from several Observation Domains from the same Exporter MUST be aware that the Claise, et. al Standard Track [Page 37]
IPFIX Protocol Specification December 2004 uniqueness of the Template ID is not guaranteed across Observation Domains. IPFIX Messages with a Source ID of zero MUST be discarded by the Collecting Process. 13. Transport Protocol The IPFIX Protocol Specification has been designed to be transport protocol independent. Note that the Exporter can export to multiple Collecting Processes, using independent transport protocols. The IPFIX Message Header 16-bit LENGTH field limits the length of a IPFIX Message to 65536 octets including the header. A Collecting Process MUST be able to handle IPFIX Message lengths of up to 65536 octets. 13.1 Transport Compliance and Transport Usage We need to differentiate between what must be implemented (so that operators can interoperably deploy compliant implementations from different vendors) and what should or could be used in various operational environments. We must also make sure that ALL implementations can operate in a congestion-aware and congestion avoiding mode. SCTP [RFC2960] and SCTP-PR [RFC3758] MUST be implemented by all compliant implementations. UDP [UDP] MAY also be implemented by compliant implementations. TCP [TCP] MAY also be implemented by compliant implementations. SCTP-PR SHOULD be used in deployments where Exporters and Collectors are communicating over links that are susceptible to congestion. SCTP-PR is capable of providing any required degree of reliability. TCP MAY be used in deployments where Exporters and Collectors communicate over links that are susceptible to congestion, but SCTP- PR is preferred, due to its ability to limit back pressure on Exporters and its message versus stream orientation. UDP MAY be used although it is not a congestion aware protocol. However, the IPFIX traffic between Exporter and Collector MUST remain wholly within the administrative domains of the operators. Claise, et. al Standard Track [Page 38]
IPFIX Protocol Specification December 2004 13.2 TCP This section describes how IPFIX can be transported over TCP [TCP]. 13.2.1 Congestion Avoidance TCP will detect congestion in the end-to-end path between the IPFIX Exporting Process and the IPFIX Collecting Process, and limit the transfer rate accordingly. When an IPFIX Exporting Process has records to export, but detects that transmission by TCP is temporarily impossible, it can either wait until sending is possible again, or it can decide to drop the record. In the latter case, the dropped export data MUST be accounted for, so that the amount of dropped export data can be reported. 13.2.2 Reliability TCP provides an intrinsically reliable delivery service from the IPFIX Exporting Process to the IPFIX Collecting Process. 13.2.3 MTU TCP provides the required IPFIX Message fragmentation service based on path MTU discovery. 13.2.4 Exporting Process The following sections describe how an IPFIX-over-TCP connection is created, how IPFIX data is transferred over it, and how a connection is to be terminated. 13.2.4.1 Connection Establishment The IPFIX Exporting Process initiates a TCP connection to the IPFIX Collecting Process. By default, the Collecting Process listens for connections on TCP port XXXX (to be assigned by IANA). It MUST be possible to configure both the Exporting and Collecting Processes to use a different TCP port. An Exporting Process MAY support more than one active connection to different Collecting Processes (including the case of different Collecting Processes on the same host). Claise, et. al Standard Track [Page 39]
IPFIX Protocol Specification December 2004 13.2.4.2 Connection Release When an Exporting Process has no more IPFIX Messages to send, it SHOULD close the TCP connection. When a Collecting Process no longer wants to receive IPFIX messages, it SHOULD close the TCP connection, but SHOULD continue to receive and process IPFIX messages until the Exporting Process has closed its end. When an Collecting Process detects that the TCP connection to the Exporting Process is abnormally terminated, it MUST continue to listen for a new connection. When an Exporting Process detects that the TCP connection is abnormally terminated, it SHOULD try to re-establish the connection. Connection timeouts SHOULD be configurable. 13.2.4.3 IPFIX Message Encoding TCP provides message boundary marking marking mechanism. When IPFIX Message are sent over a TCP connection, the LENGTH field in the IPFIX Message header defines the end of each message and the start of the next message. If an Exporting Process exports data from multiple Observation Domains, it should be careful to choose the IPFIX Message lengths appropriately to avoid head-of-line blocking between different Observation Domains. 13.2.5 Template Management New Template Records SHOULD be transmitted as soon as they are created on the Metering Process, and preferably before any associated Flow or Options Data Record is transmitted. The Collecting Process SHOULD accept Flow and Options Data Records without the associated Template Record. A Collecting Process MUST record all Template and Option Template Records for the duration of the connection, as an Exporting Process is not required to re-export Template Records. Claise, et. al Standard Track [Page 40]
IPFIX Protocol Specification December 2004 13.2.6 Fail-over If the Collecting Process does not acknowledge the attempt by the Exporting Process to establish a connection, the Exporting Process should retry. The retry schedule SHOULD be configurable. In the default configuration, an Exporting Process MUST NOT attempt to establish a connection more frequently than once per minute. The Exporter MAY log an alarm if the time to establish the association exceeds a specified threshold. If Collecting Process fail-over is supported by the Exporting Process a second TCP connection MAY be opened in advance. 13.3 SCTP This section describes how IPFIX can be transported over SCTP [RFC2960] using the PR-SCTP [RFC3758] extension. 13.3.1 Congestion Avoidance The SCTP transport protocol provides the required level of congestion avoidance by design. SCTP will detect congestion in the end-to-end path between the IPFIX Exporting Process and the IPFIX Collecting Process, and limit the transfer rate accordingly. When an IPFIX Exporting Process has records to export, but detects that transmission by SCTP is temporarily impossible, it can either wait until sending is possible again, or it can decide to drop the record. In the latter case, the dropped export data MUST be accounted for, so that the amount of dropped export data can be reported. 13.3.2 Reliability The SCTP transport protocol is by default reliable, but has the capability to operate in unreliable and partially reliable modes [RFC3758]. Using reliable SCTP streams (referred to hereafter as "streams") for the IPFIX export is not in itself a guarantee that all data records are delivered. If there is congestion on the link from the Claise, et. al Standard Track [Page 41]
IPFIX Protocol Specification December 2004 Exporting Process to the Collecting Process, or if a significant number of retransmissions are required, the send queues on the Exporting Process may fill up: the Exporting Process MAY either suspend export or discard IPFIX Messages. If data records are discarded the sequence numbers used for export MUST reflect the loss of data. 13.3.3 MTU SCTP provides the required IPFIX Message fragmentation service based on path MTU discovery. 13.3.4 Exporting Process 13.3.4.1 Association Establishment The IPFIX Exporting Process SHOULD initiate an SCTP association with the IPFIX Collecting Process. By default, the Collecting Process listens for connections on SCTP port XXXX (to be assigned by IANA). It MUST be possible to configure both the Exporting and Collecting Processes to use a different SCTP port. The Exporting Process MAY establish more than one associations (connection "bundle" in SCTP terminology) to the Collecting Process. An Exporting Process MAY support more than one active association to different Collecting Processes (including the case of different Collecting Processes on the same host). 13.3.4.2 Association Shutdown When an Exporting Process has no more IPFIX Messages to send, it SHOULD shutdown the SCTP association. When a Collecting Process no longer wants to receive IPFIX Messages, it SHOULD shutdown its end of the association. The Collecting Process SHOULD continue to receive and process IPFIX Messages until the Exporting Process has closed its end. When a Collecting Process detects that the SCTP association has been abnormally terminated, it MUST continue to listen for a new association establishment. Claise, et. al Standard Track [Page 42]
IPFIX Protocol Specification December 2004 When an Exporting Process detects that the SCTP association to the Collecting Process is abnormally terminated, it SHOULD try to re- establish the association. Association timeouts SHOULD be configurable. 13.3.4.3 Source ID The IPFIX Message MUST contain a Message Header, which includes a Source ID. The Exporting Process uses the Source ID to uniquely identify to the Collecting Process the Observation Domain that metered the Flows. 13.3.4.4 Stream An Exporting Process MUST request at least two outbound streams per association. The first stream (referred to as stream zero in the rest of this document), is used to send the Template Set and the Options Template Set. Stream zero MUST be fully reliable. Data Sets MUST NOT be sent on stream zero. Depending on the application requirement, the Exporting Process selects the mode (unreliable, partially reliable, or fully reliable mode) of the stream, used to send the Data Sets. Unreliable mode MAY be used where the application does not require reliable transmission and the use of a retransmission queue is impractical. An Exporter MAY use multiple streams to export Data Sets, in some cases different applications will have different requirements in terms of reliability. In such a case, the Observation Domain MUST use the same Source ID value on all of the multiple streams it uses. Data Sets from multiple Observation Domains MUST NOT be transmitted over the same stream; the Collecting Process should however verify that the Source ID values are the expected values. When Data Sets are exported over a partially reliable stream, they SHOULD be marked for retransmission as long as there is room in the SCTP send queues. However during times of congestion or other retransmission events, if the queue overflows, the oldest data record that has been transmitted and marked as partially reliable should be freed and marked to be skipped per the PR-SCTP [RFC3758] Claise, et. al Standard Track [Page 43]
IPFIX Protocol Specification December 2004 specification. The freed buffer space should then be re-used for the new Data Sets being exported. 13.3.4.5 Template Management When the transport protocol is SCTP the default Template Management described in Section 12 is used. 13.3.5 Collecting Process When the transport protocol is SCTP, the default Collector processing described in Section 13 is used. 13.3.6 Failover If the Collecting Process does not acknowledge the attempt by the Exporting Process to establish an association it will retry using the SCTP exponential backoff feature. The Exporter MAY log an alarm if the time to establish the association exceeds a specified threshold. If Collecting Process failover is supported by the Exporting Process a second SCTP association MAY be opened in advance. 13.4 UDP This section describes how IPFIX can be transported over UDP [RFC768] 13.4.1 Congestion Avoidance UDP has no integral congestion avoidance mechanism. Its use over congestion sensitive network paths is therefore deprecated. UDP MAY be used in deployments where Exporters and Collectors always communicate over dedicated links that are not susceptible to congestion. 13.4.2 Reliability UDP is not a reliable transport protocol, and cannot guarantee delivery of messages. IPFIX Messages sent from the Exporting Process to the Collecting Process using UDP may therefore be lost. Claise, et. al Standard Track [Page 44]
IPFIX Protocol Specification December 2004 UDP MUST NOT be used unless the application can tolerate some loss of Messages. The Collecting Process could deduce the loss and reordering of IPFIX Messages by looking at the discontinuities in the IPFIX Message sequence number. These conditions SHOULD be logged. Templates sent from the Exporting Process to the Collecting Process using UDP as a transport MUST be resent at regular intervals in case previous copies were lost. Implementations MAY send templates using a reliable transport protocol, and send IPFIX Flow and Option Data Records using UDP as the transport protocol. 13.4.3 MTU The maximum size of exported messages MUST be configured such that the total packet size does not exceed the path MTU. 13.4.4 Port Numbers By default, the Collecting Process listens on the UDP port XXXX (to be assigned by IANA). It MUST be possible to configure both the Exporting and Collecting Processes to use a different UDP port. 13.4.5 Exporting Process The Exporting Process MAY duplicate the IPFIX Message to the several Collecting Process. 13.4.6 Template Management When IPFIX uses UDP as the transport protocol, Template Sets and Option Template Sets MUST be re-sent at regular intervals. The frequency of (Options) Template transmission MUST be configurable. New Template Records SHOULD be transmitted as soon as they are created, and SHOULD be transmitted before any associated Data Record is transmitted. In the event of configuration changes, the Exporting Process SHOULD send the new template definitions at an accelerated rate. In such a case, it MAY transmit the changed Template Record(s) and Options Template Record(s), without any data, in advance to help ensure that Claise, et. al Standard Track [Page 45]
IPFIX Protocol Specification December 2004 the Collector will have the correct template information before receiving the first data. If the Option Template scope is defined in another Template, then both Templates SHOULD be sent in the same IPFIX Message. For example: if a Flow Key Option Template (see section 8.3) is sent in an Option Template, then the associated Template SHOULD be sent in the same IPFIX Message. Note that following a configuration change a new Template ID should be used and the old Template ID SHOULD NOT be reused until its lifetime has expired. Template Withdraw Messages SHOULD NOT be sent over UDP. 13.4.7 Collecting Process The Collecting Process SHOULD accept Flow and Options Data Records without the associated Template Record. If the Template Records have not been received at the time Flow Data Records (or Options Data Records) are received, the Collecting Process SHOULD store the Flow Data Records (or Options Data Records) for a short period of time and decode them after the (Options) Template Records are received. The short period of time MUST be lower than the Template lifetime. The lifetime of a template at the Collecting Process is limited to a fixed refresh timeout. The Collecting Process MUST associate a lifetime with each Template received via UDP. Templates not refreshed by the Exporting Process within the timeout are expired at the Collecting Process. If the template is not refreshed by the Exporting Process before that lifetime has expired, the Collecting Process MUST discard the Template, and any current and future associated Flow or Option Data Records. The Collecting Process MUST NOT decode any further Flow or Option Data Records which are associated with that expired Template. At any given time the Collecting Process SHOULD maintain the following for all the current Template Records and Options Template Records: <Exporting Process, Observation Domain, Template ID, Template Definition, Last Received>. Claise, et. al Standard Track [Page 46]
IPFIX Protocol Specification December 2004 13.4.8 Failover Because UDP is not a connection oriented protocol, the Exporting Process is unable to determine from the transport protocol that the Collecting Process is no longer able to receive the IFPIX Messages. Therefore, it can not invoke a failover mechanism. However, the Exporting Process MAY duplicate the IPFIX Message to several Collecting Processes. 14. Security Considerations Because IPFIX can be used to collect billing information and network forensics, confusing or blinding IPFIX must be seen as a prime objective during a sophisticated network attack. If an attacker is in a position to inject false messages into an IPFIX Message stream this will allow them to send forged Flow Data Records, Options Data Records, or Templates. Forged Templates may impair the Collectors ability to process any further Flow Records. Forged Flow Records would have a direct effect on the application using the Flows, for example a billing system may generate incorrect billing information. Forged options may be able to alter the meaning of Flow Records, for example if the sample rate is changed. The IPFIX Messages themselves may contain information of value to an attacker, and thus care must be taken to confine their visibility to authorized users. IPFIX Messages can be secured using IPsec. Alternatively if IPFIX runs on top of SCTP or TCP, TLS [TLS] can be used. When an Information Element containing end-user payload information is exported, it SHOULD be transmitted to the Collecting Process using a means that secures its contents against eavesdropping. Suitable mechanisms include the use of either a direct point-to- point connection or the use of an encryption mechanism. It is the responsibility of the Collecting Process to provide a satisfactory degree of security for this collected data, including, if necessary, anonymization of any reported data. 14.1 IPsec Usage To secure messages between the Exporter and the Collector an IPFIX Claise, et. al Standard Track [Page 47]
IPFIX Protocol Specification December 2004 implementation MAY use IPsec. To ensure interworking between Exporters and Collectors from different vendors, the following IPsec profile MUST be supported. This profile is derived from [USEIPSEC]. 14.1.1 Selectors IPFIX runs between manually configured pairs of hosts on the following transport ports (TBD). The appropriate selector would be Exporter-Collector pairs and port number. Note that, if the Exporter is a router, a non-interface ("loopback") address should be used. 14.1.2 Mode IPsec MUST be run in transport mode. The AH and ESP MUST be supported by an IPFIX implementation of IPsec. The Authentication Header (AH) [RFC2402] MUST be used if authentication is required. The Security Protocol (ESP) [RFC2406] must be used if there is a threat to the IPFIX Message content, or if that content is confidential. Normally in situations where the ESP was required the AH would also be required. If ESP only is used, the sender's IP address MUST be checked against the IP address asserted in the key management exchange. 14.1.3 Key Management In many networks, manual key management will be sufficient, and this reduces the complexity of the Exporter, albeit at a cost of greater configuration complexity. Manual key management MUST be supported. If a replay attack is considered likely, an automated key management such as IKE [IKE] key management system SHOULD be used. 14.1.4 Security Policy Connections should be accepted only from the designated peer. 14.1.5 Authentication Claise, et. al Standard Track [Page 48]
IPFIX Protocol Specification December 2004 Given the number of IPFIX capable Exporters that are likely to be deployed by large ISPs, there will be circumstances where shared key mechanisms are not adequate. Where an automated key management system is used, certificate-based IKE SHOULD be supported. 14.1.6 Availability It is accepted that IPsec will not be universally available in IPFIX Exporters, and that where it is available, there may be issues of throughput, which may itself raise security issues. In such circumstances the other security measures described in this document provide some threat mitigation. 14.2 TLS Usage The IPFIX Exporter initiating a connection acts as a TLS client according to [TLS], and an IPFIX Collector that accepts a connection acts as a TLS server. If mutual authentication is required the IPFIX Device acting as TLS server MUST request a certificate from the IPFIX Device acting as TLS client, and the IPFIX Device acting as TLS client MUST be prepared to supply a certificate on request. 14.3 Protection against DoS attacks An attacker may directly mount a DoS attack by generating large amounts of traffic. If TCP is used for transport, then the Flow to the Collector would back off due to congestion and eventually stall, blinding the IPFIX system. An attack could then proceed without further observation. SCTP-PR will have a different pathology under such an attack. Stale data at the head of the queue will get flushed giving some visibility of the attack. In case of UDP, IPFIX would reduce to some sort of sampling, meaning that some forensics may be left. To avoid blinding of the IPFIX system some mechanism for service differentiation can be used to prioritize IPFIX traffic over user traffic. An alternative is to use a dedicated network for the transport of IPFIX Messages. By sending the IPFIX Messages over a dedicated network, IPFIX Message loss induced by user traffic congestion is minimized. However an attacker may trigger the generation of excessive IPFIX Messages, and to avoid information loss during such an attack the IPFIX network must be adequately sized. Claise, et. al Standard Track [Page 49]
IPFIX Protocol Specification December 2004 14.4 When IPsec or TLS is not an option The use of IPsec or TLS might not be an option because of performance issues. Without IPsec or TLS an IPFIX entity has no means to authenticate an IPFIX entity other than the Source IP address. Useful protection is gained by allocating Exporter and Collector IP addresses from ranges that are excluded from use by user traffic and preventing spoofing attacks by proper ingress filtering. Where large numbers of Exporters, proxies and Collectors are used in a network, it may be tempting for the administrator to not impose source IP address restrictions but this leaves a proxy or Collector open to the reception of invalid information. Using an open proxy or Collector is therefore discouraged. If IP address spoofing can not be prevented some level of protection against an insertion attack is required. With a modern implementation of TCP with good ISN randomization [XXX-REFERENCE] or SCTP insertion such attacks are difficult without the ability to snoop the packet Flow [XXX-SCTP-BLIND-SPOOFING-REFERENCE]. UDP is vulnerable to insertion attacks, however, randomization of the IPFIX Sequence Number might mitigate this problem. In all these cases, the Sequence Number space is relatively small giving only limited protection. Therefore a 64 bit cookie [L2TPv3] SHOULD be included as an element within all messages. The use of a dedicated network prevents IPFIX Messages from being inspected by an attacker. 14.5 Logging an IPFIX Attack A Collector may detect problems by tracking the IPFIX Sequence Number and therefore SHOULD provide a logging mechanism for tracking out of sequence messages. Such out of sequence messages may not only be caused by network congestion or Exporter/Collector resource exhaustion but also by an attacker injecting false messages. Note that an attacker may be able to exploit the behavior of the Collector when it receives an out of sequence message. For example a Collector that simply reset the expected Sequence Number upon receipt of a later message would easily be temporarily blinded by Claise, et. al Standard Track [Page 50]
IPFIX Protocol Specification December 2004 deliberately injecting messages with a much larger Sequence Number. [EDITOR NOTE: the security section may need be adapted to the revised transport section] 15. IANA Considerations The IPFIX Protocol, as set out in this document, has two sets of assigned numbers. Considerations for assigning them are discussed in this section, using the example policies as set out in the "Guidelines for IANA Considerations" document IANA-RFC [RFC2434]. 15.1 Numbers used in the Protocol IPFIX Messages use two fields with assigned values. These are the IPFIX Version Number, indicating which version of the IPFIX Protocol was used to export an IPFIX Message, and the IPFIX Set ID, indicating the type for each set of information within an IPFIX Message. Changes in either IPFIX Version Number or IPFIX Set ID assignments require an IETF Consensus, i.e. they are to be made via RFCs approved by the IESG. 15.2 Numbers used in the Information Model Fields of the IPFIX protocol carry information about traffic measurement. They are modeled as elements of the IPFIX information model [IPFIX-INFO]. Each Information Element describes a field which may appear in an IPFIX Message. Within an IPFIX Message the field type is indicated by its Field Type. New assignments for IPFIX Field Types will be administered by IANA, on First Come First Serve basis [RFC 2434] , subject to Expert Review [RFC 2434], i.e. review by one of a group of experts designated by an IETF Operations and Management Area Director. The group of experts must double check the Information Elements definitions for completeness, accuracy and redundancy with already defined Information Elements. Those experts will initially be drawn from the Working Group Chairs and document editors of the IPFIX and PSAMP Working Groups. The IANA assignments for IPFIX Field Types will range from 128 to 32767; the values below 128 are reserved or Claise, et. al Standard Track [Page 51]
IPFIX Protocol Specification December 2004 assigned already; the values ranging from 32768 to 65535 are allocated for private use by vendors. 16. Examples Let's consider the example of an IPFIX Message composed of a Template Set, a Data Set (which contains three Flow Data Records), an Options Template Set and a Data Set (which contains 2 Options Data Records). IPFIX Message: +--------+---------------------------------------------. . . | | +--------------+ +-----------------------+ |Message | | Template | | Data | | Header | | Set | | Set | . . . | | | (1 Template) | | (3 Flow Data Records) | | | +--------------+ +-----------------------+ +--------+---------------------------------------------. . . . . .+-------------------------------------------------+ +------------------+ +--------------------------+ | | Options | | Data | | . . .| Template Set | | Set | | | (1 Template) | | (2 Options Data Records) | | +------------------+ +--------------------------+ | . . .--------------------------------------------------+ 16.1 Message Header Example The Message Header is composed of: 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Version = 0x000a | Length = 152 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Export Time | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Sequence Number | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Source ID | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Claise, et. al Standard Track [Page 52]
IPFIX Protocol Specification December 2004 16.2 Template Set Examples 16.2.1 Template Set using IETF specified Information Elements We want to report the following Field Types: - The source IP address (IPv4), so the length is 4 - The destination IP address (IPv4), so the length is 4 - The next-hop IP address (IPv4), so the length is 4 - The number of bytes of the Flow - The number of packets of the Flow Therefore, the Template Set will be composed of the following: 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 = 28 bytes | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Template ID 256 | Field Count = 5 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | IP_SRC_ADDR = 0x0008 | Field Length = 4 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | IP_DST_ADDR = 0x000C | Field Length = 4 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | IP_NEXT_HOP = 0x000F | Field Length = 4 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | IN_PKTS = 0x0002 | Field Length = 4 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | IN_BYTES = 0x0001 | Field Length = 4 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 16.2.2 Template Set using Enterprise Specific Information Elements We want to report the following Field Types: - The source IP address (IPv4), so the length is 4 - The destination IP address (IPv4), so the length is 4 - An Enterprise Specific Field representing proprietary information, with a type of 0x000F and a length of 4 - The number of bytes of the Flow - The number of packets of the Flow Therefore, the Template Set will be composed of the following: Claise, et. al Standard Track [Page 53]
IPFIX Protocol Specification December 2004 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 = 28 bytes | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Template ID 256 | Field Count = 5 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | IP_SRC_ADDR = 0x0008 | Field Length = 4 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | IP_DST_ADDR = 0x000C | Field Length = 4 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |1| Enterprise Field Type=0x000F| Field Length = 4 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Enterprise number | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | IN_PKTS = 0x0002 | Field Length = 4 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | IN_BYTES = 0x0001 | Field Length = 4 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 16.3 Data Set Example In this example, we report the following three Flow Records: Src IP addr. | Dst IP addr. | Next Hop addr. | Packet | Bytes | | | Number | Number ------------------------------------------------------------------ 192.168.1.12 | 192.168.2.254 | 192.168.1.1 | 5009 | 5344385 192.168.1.27 | 192.168.2.23 | 192.168.1.2 | 748 | 388934 192.168.1.56 | 192.168.2.65 | 192.168.1.3 | 5 | 6534 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 = 256 | Length = 64 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | 192.168.1.12 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | 192.168.2.254 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | 192.168.1.1 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | 5009 | Claise, et. al Standard Track [Page 54]
IPFIX Protocol Specification December 2004 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | 5344385 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | 192.168.1.27 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | 192.168.2.23 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | 192.168.1.2 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | 748 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | 388934 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | 192.168.1.56 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | 192.168.2.65 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | 192.168.1.3 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | 5 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | 6534 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Note that padding is not necessary in this example. 16.4 Options Template Set Examples 16.4.1 Options Template Set using IETF specified Information Elements Per line card (the router being composed of two line cards), we want to report the following Field Types: - Total number of IPFIX Messages - Total number of exported Flows Each line card is characterized by an unique Observation Domain, represented by the unique Source ID Information Elements [IPFIX- INFO]. As a consequence, the Scope Field is the Source ID Information Element. Therefore, the Options Template Set will be: 0 1 2 3 Claise, et. al Standard Track [Page 55]
IPFIX Protocol Specification December 2004 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 = 24 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Template ID 257 | Field Count = 3 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Scope Field Count = 1 | Scope 1 Field Type = 141 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Scope 1 Field Length = 4 | TOTAL_EXP_PKTS_SENT = 41 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Field Length = 4 | TOTAL_FLOWS_EXP = 42 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Field Length = 4 | Padding | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 16.4.2 Options Template Set using Enterprise Specific Information Elements Per line card (the router being composed of two line cards), we want to report the following Field Types: - Total number of IPFIX Messages - An Enterprise Specific number of exported Flows, with a type of 42 and a length of 4 Each line card is characterized by an unique Observation Domain, represented by the unique Source ID Information Elements [IPFIX- INFO]. As a consequence, the Scope Field is the Source ID Information Element. The format of the Options Template Set 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 = 3 | Length = 24 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Template ID 257 | Field Count = 3 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Scope Field Count = 1 | Scope 1 Field Type = 141 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Scope 1 Field Length = 4 | TOTAL_EXP_PKTS_SENT = 41 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Field Length = 4 |1| Enterprise Field Type = 42 | Claise, et. al Standard Track [Page 56]
IPFIX Protocol Specification December 2004 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Field Length = 4 | Enterprise number ... +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ ... Enterprise number | Padding | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 16.4.3 Options Template Set using an Enterprise Specific scope In this example, we want to export the same information as in the example in section 16.4.2: - Total number of IPFIX Messages - Total number of exported Flows But this time, the information pertains to a proprietary scope, identified by Enterprise Specific Information Element number 123. The format of the Options Template Set is now 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 = 3 | Length = 28 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Template ID 257 | Field Count = 3 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Scope Field Count = 1 |1| Scope 1 Field Type = 123 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Enterprise Number | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Scope 1 Field Length = 4 | TOTAL_EXP_PKTS_SENT = 41 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Field Length = 4 | TOTAL_FLOWS_EXP = 42 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Field Length = 4 | Padding | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 16.5 Data Set with Options Data Records Example In this example, we report the following two Options Data Records: Line Card ID | IPFIX Message | Exported Flow Records ------------------------------------------------------------------ Line Card 1 (SourceID=1) | 345 | 10201 Line Card 2 (SourceID=2) | 690 | 20402 Claise, et. al Standard Track [Page 57]
IPFIX Protocol Specification December 2004 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 = 257 | Length = 20 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | 1 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | 345 | 10201 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | 2 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | 690 | 20402 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 17. References 17.1 Normative References [IPFIX-ARCH] Sadasivan, G, Brownlee, N. "Architecture Model for IP Flow Information Export" draft-ietf-ipfix-arch-02.txt", October 2003 [IPFIX-INFO] Calato, P, Meyer, J, Quittek, J, "Information Model for IP Flow Information Export" draft-ietf-ipfix-info-02, November 2003 [UDP] Postel, J., "User Datagram Protocol" RFC 768, August 1980 [TCP] "TRANSMISSION CONTROL PROTOCOL DARPA INTERNET PROGRAM PROTOCOL SPECIFICATION" RFC 793, September 1981 [RFC1889] Schulzrinne, H., Casner, S., Frederick, R., Jacobson, V., "RTP: A Transport Protocol for Real-Time Applications ", RFC 1889, January 1996 [RFC2434] Alvestrand, H. and T. Narten, "Guidelines for Writing an IANA Considerations Section in RFCs", RFC 2434, October 1998. [RFC2402] Kent, S., Atkinson, R., "IP Authentication Header ", RFC 2402, November 1998 [RFC2406] Kent, S., Atkinson, R., "IP Encapsulating Security Payload (ESP)", RFC 2406, November 1998 Claise, et. al Standard Track [Page 58]
IPFIX Protocol Specification December 2004 [RFC2960] Stewart, R. (ed.) "Stream Control Transmission Protocol", RFC 2960, October 2000 [RFC3758] Stewart, R., Ramalho, M., Xie, Q., Tuexen, M., Conrad, P. "Stream Control Transmission Protocol (SCTP) Partial Reliability Extension", RFC 3758, May 2004 17.2 Informative References [IPFIX-REQ] Quittek, J, Zseby, T, Claise, B, Zander, S, "Requirements for IP Flow Information Export" draft-ietf-ipfix-reqs- 15.txt, June 2003 [IPFIX-AS] Zseby, T, Penno, R, Brownlee, N, Claise, B, "IPFIX Applicability", draft-ietf-ipfix-as-01.txt, October 2003 [IPFIX-EVAL] Leinen, S, "Evaluation of Candidate Protocols for IP Flow Information Export (IPFIX)", draft-leinen-ipfix-eval-contrib- 02.txt, January 2003 [NETFLOW9] Claise, B, et al "Cisco Systems NetFlow Services Export Version 9", draft-claise-netflow-9-07.txt, December 2003 [PEN] IANA Private Enterprise Numbers registry http://www.iana.org/assignments/enterprise-numbers [USEIPSEC] S. Bellovin, Guidelines for Mandating the Use of IPsec, draft-bellovin-useipsec-02.txt, October 2003, work in progress. [IKE] Harkins, D. and D. Carrel, "The Internet Key Exchange (IKE)", RFC 2409, November 1998. [TLS] Dierks, T. and C. Allen, "The TLS Protocol Version 1.0", RFC 2246, January 1999. [L2TPv3] J. Lau et al. Layer Two Tunneling Protocol (Version 3) draft-ietf-l2tpext-l2tp-base-11.txt, October 2003, work in progress. [XXX-REFERENCE] [XXX-SCTP-BLIND-SPOOFING-REFERENCE] Claise, et. al Standard Track [Page 59]
IPFIX Protocol Specification December 2004 18. Acknowledgments We would like to thank the following persons: Juergen Quittek for the coordination job; Nevil Brownlee and Dave Plonka for the thorough reviews; Randall Stewart and Peter Lei for their SCTP expertise; Martin Djernaes for the first essay on the SCTP section; Simon Leinen for the first essay on the TCP section Sebastian Zander, Jeff Meyer, Maurizio Molina, Carter Bullard, Tal Givoly, and many more, for the technical feedback. Authors Addresses Benoit Claise Cisco Systems De Kleetlaan 6a b1 1831 Diegem Belgium Phone: +32 2 704 5622 E-mail: bclaise@cisco.com Stewart Bryant Cisco Systems, Inc. 250, Longwater, Green Park, Reading, RG2 6GB, United Kingdom Phone: +44 (0)20 8824-8828 Email: stbryant@cisco.com Ganesh Sadasivan Cisco Systems, Inc. 170 W. Tasman Dr. San Jose, CA 95134 USA Phone: +1 (408) 527-0251 Email: gsadasiv@cisco.com Mark Fullmer OARnet 2455 North Star Rd. Columbus, Ohio 43221 Phone: +1 (614) 728-8100 Claise, et. al Standard Track [Page 60]
IPFIX Protocol Specification December 2004 Email: maf@eng.oar.net Intellectual Property Statement The IETF takes no position regarding the validity or scope of any Intellectual Property Rights or other rights that might be claimed to pertain to the implementation or use of the technology described in this document or the extent to which any license under such rights might or might not be available; nor does it represent that it has made any independent effort to identify any such rights. Information on the procedures with respect to rights in RFC documents can be found in BCP 78 and BCP 79. Copies of IPR disclosures made to the IETF Secretariat and any assurances of licenses to be made available, or the result of an attempt made to obtain a general license or permission for the use of such proprietary rights by implementers or users of this specification can be obtained from the IETF on-line IPR repository at http://www.ietf.org/ipr. The IETF invites any interested party to bring to its attention any copyrights, patents or patent applications, or other proprietary rights that may cover technology that may be required to implement this standard. Please address the information to the IETF at ietf- ipr@ietf.org. The IETF has been notified of intellectual property rights claimed in regard to some or all of the specification contained in this document. For more information consult the online list of claimed rights. Disclaimer of Validity This document and the information contained herein are provided on an "AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY AND THE INTERNET ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. Copyright Statement Claise, et. al Standard Track [Page 61]
IPFIX Protocol Specification December 2004 Copyright (C) The Internet Society (2004). This document is subject to the rights, licenses and restrictions contained in BCP 78, and except as set forth therein, the authors retain all their rights. Claise, et. al Standard Track [Page 62]
