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Versions: 00 01 02 03 04 05 06 07 08 09 RFC 5476

   PSAMP working group
   Internet Draft                                EDITOR:     B. Claise
   draft-ietf-psamp-protocol-00.txt                       Cisco Systems
   Expires: April 2003                                     Otcober 2003
 
 
 
              Packet Sampling (PSAMP) Protocol Specifications
 
 
 
 Status of this Memo
 
   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 export of packet information from a
   PSAMP exporting process to a PSAMP colleting process. For export of
   packet information the IP Flow Information eXport (IPFIX) protocol
   is used. It is shown that The IPFIX protocol is well suited for this
   purpose, because the IPFIX architecture matches the PSAMP
   architecture very well and the means provided by the IPFIX protocol
   are sufficient. The document specifies in detail how the IPFIX
   protocol is used for PSAMP export of packet information.
 
  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.
 
 
 
 
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                 PSAMP Protocol Specifications            October 2003
 
 
  Table of Contents
 
     1. Open Issues.................................................2
     2. Introduction................................................2
     3. Terminology.................................................3
     4. Relationship between PSAMP and IPFIX........................3
      4.1 IPFIX Overview............................................3
      4.2 IPFIX and PSAMP Differences and Similarities..............4
     4.2.1  Export Point of View....................................4
     4.2.2  Information Model Point of View.........................4
     5. Using IPFIX for PSAMP.......................................5
      5.1 High Level View of the Integration........................5
      5.2 Partial or Entire IPFIX Protocol Specifications Support...6
     6. PSAMP Requirements versus the IPFIX Solution................6
      6.1 IPFIX Solution for the PSAMP Requirements.................7
     7. Low Level View of the Integration...........................9
      7.1 Sampling Case, PSAMP Base Level of Functionality..........9
     7.1.1  Example................................................10
      7.2 Sampling Case............................................10
     7.2.1  Example................................................11
      7.3 Filtering Case...........................................11
     7.3.1  Example................................................11
     8. Security Considerations....................................12
     9. References.................................................12
     10. Acknowledgments...........................................12
     11. AuthorsÆ Addresses........................................13
 
 
 1. Open Issues
 
   This section covers the open issues, still to be resolved/updated in
   this draft:
   - For section 6 "PSAMP requirements versus the IPFIX solution",
   check if there are any other requirements in the [PSAMP-FRAMEWORK].
 
 2. Introduction
 
   The packet sampling (PSAMP) Working Group and the IP flow
   information export (IPFIX) Working Group both aim at standardizing
   technology for observing traffic from network devices and for
   exporting some part of the observation. Also, both Working Groups
   consider packet sampling as a component of their technology. While
   for the IPFIX Working Group packet sampling is just one out of many
   components considered, it is the focus of the PSAMP Working Group.
 
   The PSAMP Working Group has agreed to use the IPFIX reporting
   protocol if it's suitable for the PSAMP requirements. Therefore, a
 
 
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   detailed analysis on the IPFIX protocol needs to be done and if
   IPFIX is not suitable, then the reason should be stated exactly.
 
   This document evaluates if the IPFIX protocol specifications could
   fit the export format requirements for PSAMP device, how PSAMP could
   use the IPFIX protocol, and whether the part of or the full IPFIX
   protocol specifications are actually required. As we will conclude
   that the IPFIX protocol is suitable as export protocol for PSAMP,
   this document finally specifies in details how to use IPFIX.
 
 3. Terminology
 
   To be copied in from [PSAMP-FRAMEWORK4].
 
 4. Relationship between PSAMP and IPFIX
 
 4.1 IPFIX Overview
 
   The output of the IPFIX working group relevant for this draft, is
   structured into three documents:
      - IP flow information architecture [IPFIX-ARCH]
      - IPFIX Protocol Specifications [IPFIX-PROTO]
      - IP flow information export information model [IPFIX-INFO]
 
   This table will help summarizing the IPFIX protocol specifications
   [IPFIX-PROTO].
 
        FlowSet        Template  Record        Data Record
  +----------------------------------------------------------------+
  |                  |                    |  Flow Data Record(s)   |
  | Data FlowSet     |          /         |          or            |
  |                  |                    | Options Data Record(s) |
  +----------------------------------------------------------------+
  | Template FlowSet | Template Record(s) |           /            |
  +----------------------------------------------------------------+
  | Options Template | Options Template   |           /            |
  | FlowSet          | Record(s)          |                        |
  +----------------------------------------------------------------+
 
   A Data FlowSet is composed of an Options Data Record(s) or Flow Data
   Record(s); no Template Record is included.
   The Flow Data Record is linked to a Template Record, and the Options
   Data Record is linked to an Options Template Record.
 
 
 
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   A Template FlowSet is composed of Template Record(s); no Flow or
   Options Data Record is included.
 
   An Options Template FlowSet is composed of Options Template
   Record(s); no Flow or Options Data Record is included. The Options
   Template Record (and its corresponding Options Data Record) is used
   to supply information about the metering process configuration or
   specific data, rather than supplying information about IP flows.
   The Options Data Records are sent on a regular basis, but not with
   every Flow Data Record.
 
 4.2 IPFIX and PSAMP Differences and Similarities
 
   IPFIX achieves data reduction by aggregating per-packet IP layer
   information into flow records. IPFIX produces and exports flow
   records containing information per flow. This information is created
   based on the observation of a potentially large number of packets.
   In contrast, PSAMP achieves data reduction by reducing the packet
   population via sampling. PSAMP generates and exports information per
   packet. For more details please see the [PSAMP-FRAMEWORK] and
   [PSAMP-SAMPLE-TECH].
 
 
 4.2.1   Export Point of View
 
   From a pure export point of view, IPFIX will not distinguish a flow
   record composed of several packets aggregated together, from a flow
   record composed of a single packet.
 
   As a conclusion, the PSAMP export can be seen as special IPFIX flow
   record containing information about a single packet.
 
   PSAMP doesn't have the notion of flow. But in order to avoid any
   duplication in the terminology and as a consequence a redefinition
   of the IPFIX protocol specifications, the IPFIX terminology [IPFIX-
   PROTO] is kept unchanged, even if some obvious pointers to the
   notion of flow is made. For example: Flow Data Record, FlowSet,
   etc...
 
 4.2.2    Information Model Point of View
 
   On one hand, the IPFIX export probably contains data types like
   source IP address, destination IP address, ToS, etc. Refer to
 
 
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   [IPFIX-INFO] for more details. On the other hand, the PSAMP export
   contains only the packet fragment in the base level of
   functionality. Refer to [PSAMP-INFO] for more details.
 
   As the templates are flexible, IPFIX will not distinguish from a
   export point of view a flow record composed of several data types,
   from a flow record composed of just a few data types (for example:
   the packet fragment and the selector ID).
 
   The information model data types exported in an IPFIX device and a
   PSAMP device are not completely different but most of the time
   overlapping. Note that, according to [PSAMP-FRAMEWORK] section 5.2
   "Recommended Contents for Packet Reports", the PSAMP reporting
   process SHOULD also report fields relating to the protocols used in
   the packets, to the packet treatment and to the selection state
   associated with the packet.
 
   Thus the PSAMP reporting process will not limit itself to the export
   the data types defined in [PSAMP-INFO], and can benefit from the
   data types already defined in [IPFIX-INFO].
 
   From the IPFIX point of view, the new PSAMP information model will
   augment the data types that could be exported; for example, the hash
   value, the selector ID or the packet-sampled. If a IPFIX metering
   process create some flow records by sampling some packets, and if
   both the IPFIX and PSAMP specifications are implemented on the
   device, the IPFIX flow records could be augmented with extra data
   types like the selector ID, the selector ID parameters, etc.
 
   As the PSAMP information model is basically an extension to the
   IPFIX information model, a formal process must be in place for the
   addition of data types. The draft draft-bryant-ipfix-vendor-ie-00.tx
   (not yet out) discusses some possibilities.
 
 5. Using IPFIX for PSAMP
 
 5.1 High Level View of the Integration
 
   The Template Record in the Template FlowSet is used to describe the
   different PSAMP data types that will be exported to the Collector.
   The Collector decodes the Template FlowSet and knows which data
   types to expect when it receives the Flow Data Records in the Data
   FlowSet, i.e. the PSAMP Packet Reports. Typically, in the base level
 
 
 
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   of the PSAMP functionality, the Template FlowSet will contain the
   input sequence number, the packet fragment (some number of
   contiguous bytes from the start of the packet) and the selector ID.
 
   The Options Template Record in the Options Template FlowSet is used
   to describe the different PSAMP data types that concern the metering
   process itself: sampling and/or filtering functions, plus the
   associated parameters. The Collector decodes the Options Template
   FlowSet and knows which data types to expect when it receives the
   Options Data Records in the Data FlowSet, i.e. the PSAMP Report
   Interpretation. Typically, the Options Template would contain the
   Selector ID, the sampling or filtering functions, and the sampling
   or filtering associated parameters.
 
 5.2 Partial or Entire IPFIX Protocol Specifications Support
 
   The "High level view of the integration" section 5.1 concludes that
   PSAMP requires all the different possibilities of the IPFIX protocol
   specifications [IPFIX-PROTO]. That is the 3 types of FlowSet (Data
   FlowSet, Template FlowSet and Options Templates FlowSet), the 2
   types of Templates Records (Template Record and Options Template
   Record), and the 2 types of Data Record (Flow Data Record, Options
   Data Record), as described again in the table below.
 
        FlowSet        Template  Record        Data Record
  +----------------------------------------------------------------+
  |                  |                    |  Flow Data Record(s)   |
  | Data FlowSet     |          /         |          or            |
  |                  |                    | Options Data Record(s) |
  +----------------------------------------------------------------+
  | Template FlowSet | Template Record(s) |           /            |
  +----------------------------------------------------------------+
  | Options Template | Options Template   |           /            |
  | FlowSet          | Record(s)          |                        |
  +----------------------------------------------------------------+
 
   As a consequence, PSAMP can't rely on a subset of the IPFIX protocol
   specifications are described in [IPFIX-PROTO]. The entire IPFIX
   protocol specifications MUST be implemented for the PSAMP export.
 
 6. PSAMP Requirements versus the IPFIX Solution
 
 
 
 
 
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   [PSAMP-FRAMEWORK] describes some requirements that affect directly
   the export protocol. Refer to the following sections:
   section 3.2 "Reporting Process Requirements"
   section 3.3 "Exporting Process Requirements"
   section 5 "Reporting Process"
 
   [PSAMP-FRAMEWORK] also describes in the section 3.1 one requirement
   that, if not directly related to the export protocol, will put some
   constraints on it:
       Selection Process Requirements:
       - Parallel Measurements: multiple independent measurement
       processes at the same entity."
 
   [PSAMP-FRAMEWORK] finally describes in the section 5 some
   requirements regarding the reporting process. This series of
   requirements specifies the different data types that MUST and SHOULD
   reported to the collector. Nevertheless IPFIX, being a generic
   export protocol, can export any data types as long as there are
   described in the information model. So these requirements are mainly
   targeted for the [PSAMP-INFO] document.
 
 6.1 IPFIX Solution for the PSAMP Requirements
 
   Let's address the PSAMP requirements one by one.
 
   * Parallel Measurements: multiple independent measurement processes
   at the same entity. Refer to [PSAMP-FRAMEWORK] section 3.1 "Selection
   Process Requirements".
 
   This requirement is addressed by exporting the Selector ID data type
   in every packet report, so part of every Flow Data Records. Note that
   without this requirement, exporting the Scope [IPFIX-PROTO] part of
   every single packet report could have been sufficient.
 
   * Transparency: allow transparent interpretation of measurements as
   communicated by PSAMP reporting, without any need to obtain
   additional information concerning the observed packet stream. Refer
   to [PSAMP-FRAMEWORK] section 3.2 "Reporting Process Requirements".
 
   This requirement is addressed by exporting the Selector ID in every
   Flow Data Records (packet report) and exporting the associated
   SAMPLING_ALGORITHM and SAMPLING PARAMETERS in the Options Data Record
 
 
 
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   (packet interpretation). So the all the metering process parameters
   are linked to the Flow Data Records.
 
   * Robustness to Information Loss: allow robust interpretation of
   measurements with respect to reports missing due to data loss, e.g.
   in transport, or within the measurement, reporting or exporting
   processes. Inclusion in reporting of information that enables the
   accuracy of measurements to be determined. Refer to [PSAMP-FRAMEWORK]
   section 3.2 "Reporting Process Requirements".
 
   An Options Templates MUST be sent on regular basis. This Options
   Template contains for example the total number of packet report
   exported from the PSAMP device, the total number of packet observed,
   etc... Thus the Collector can compare the number of packet report
   received per selector ID with the number actually metered and/or
   sent. In case of discrepancy, a new sampling rate could be computed.
 
   * Faithfulness: all reported quantities that relate to the packet
   treatment MUST reflect the router state and configuration encountered
   by the packet at the time it is received by the measurement process.
   Refer to [PSAMP-FRAMEWORK] section 3.2 "Reporting Process
   Requirements".
 
   This requirement doesn't concern the export protocol itself but the
   metering process, even if described in the "Reporting Process
   Requirements" section.
 
   * Privacy: selection of the content of packet reports will be
   cognizant of privacy and anonymity issues while being responsive to
   the needs of measurement applications, and in accordance with RFC
   2804. Full packet capture of arbitrary packet streams is explicitly
   out of scope. Refer to [PSAMP-FRAMEWORK] section 3.2 "Reporting
   Process Requirements".
 
   This requirement doesn't concern the export protocol itself, even if
   described in the "Reporting Process Requirements" section.
 
   * Timeliness: reports on selected packets MUST be made available to
   the collector quickly enough to support near real time applications.
   Specifically, any report on a packet MUST be dispatched within 1
   second of the time of receipt of the packet by the measurement
   process. Refer to [PSAMP-FRAMEWORK] section 3.3 "Export Process
   Requirements".
 
 
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   The IPFIX protocol specifications [IPFIX-PROTO] describe an
   inactivity timeout for the flow expiration. This inactivity timeout
   is configurable, with a minimum value of 0 for immediate expiration.
   Note that this minimum value of 0 will force every single Flow Data
   Record to contain information about a single packet and not an
   aggregation of packets.
 
   * Congestion Avoidance: export of a report stream across a network
   MUST be congestion avoiding in compliance with RFC 2914. Refer to
   [PSAMP-FRAMEWORK] section 3.3 "Export Process Requirements".
 
   IPFIX, by its charter, MUST also respect this requirement.
 
   * Secure Export:
       - confidentiality: the option to encrypt exported data MUST be
       provided.
       - integrity: alterations in transit to exported data MUST be
       detectable at the collector
       - authenticity: authenticity of exported data MUST be verifiable
       by the collector in order to detect forged data.
 
   The motivation here is the same as for security in IPFIX export.
   Refer to [PSAMP-FRAMEWORK] section 3.3 "Export Process
   Requirements".
 
 7. Low Level View of the Integration
 
 7.1 Sampling Case, PSAMP Base Level of Functionality
 
   EDITORÆS NOTE: LET'S ASSUME THAT THE [PSAMP-INFO] DEFINES THE
   FOLLOWING DATA TYPES
        SEQUENCE-NUMBER: the input sequence number,
        PACKET-SAMPLE: some number of contiguous bytes from the start
        of the packet
        SELECTOR-ID:
        SAMPLING-ALGORITHM:
        SAMPLING-PARAMETER1, SAMPLING-PARAMETERS2, ETC...
 
   As described in the section 5.1 "Mandatory Contents of Packet
   Reports" of [PSAMP-FRAMEWORK], the packet reports must contain:
   - the input sequence number(s), denoted the SEQUENCE-NUMBER in
   [PSAMP-INFO]
 
 
 
 
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   - some number of contiguous bytes from the start of the packet,
   denoted the PACKET-SAMPLE in [PSAMP-INFO].
   Thus the Template FlowSet defines a Template Record composed of
   SEQUENCE-NUMBER, PACKET-SAMPLE and SELECTOR-ID.
 
   The report interpretation must contain:
   - the sampling algorithm, denoted SAMPLING-ALGORITHM in [PSAMP-INFO]
   - the sampling parameters denoted SAMPLING-PARAMETER1, SAMPLING-
   PARAMETER2, etc... in [PSAMP-INFO]
   The Options Template FlowSet defines a Options Template Record
   composed of SELECTOR-ID, SAMPLING-ALGORITHM, SAMPLING-PARAMETERS.
 
   Finally the Data FlowSet is used to export the Flow Data Record(s)
   containing the real values of SEQUENCE-NUMBER, PACKET-SAMPLE and
   SELECTOR-ID. The Data FlowSet is also used to export the
   Options Data Record(s) containing the real values of SELECTOR-ID,
   SAMPLING-ALGORITHM, SAMPLING-PARAMETERS.
 
   By means of the SELECTOR-ID, the Collector can link any Flow Data
   Record to the corresponding Options Data Record. That is, any Flow
   Data Record to the metering process funtion and parameters.
 
 7.1.1    Example
 
   EDITORÆS THIS MUST BE A FULL EXAMPLE LIKE IN SECTION 13 OF [IPFIX-
   PROTO].
   THE [PSAMP-INFO] MUST BE FIRST PUBLISHED.
 
 7.2 Sampling Case
 
   The PSAMP reporting process SHOULD also report fields relating to
   the protocols used in the packets, to the packet treatment and to
   the selection state associated with the packet, as specified in
   [PSAMP-FRAMEWORK] section 5.2 "Recommended Contents for Packet
   Reports".
 
   Let's take the same example as in the section 7.1, but let's add the
   export of the destination BGP Autonomous System (AS) [1771] and of
   the input interface
 
   The packet reports MUST contain:
   - the input sequence number(s), denoted the SEQUENCE-NUMBER in
   [PSAMP-INFO]
 
 
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   - some number of contiguous bytes from the start of the packet,
   denoted the PACKET-SAMPLE in [PSAMP-INFO]
   - the destination BGP AS , denoted destinationAS in [IPFIX-INFO]
   - the input interface, denoted ingressPort in [IPFIX-INFO]
   Thus the Template FlowSet defines a Template Record composed of
   SEQUENCE-NUMBER, PACKET-SAMPLE and SELECTOR-ID, destinationAS and
   ingressPort.
 
   The report interpretation will remain unchanged and must contain:
   - the sampling algorithm, denoted SAMPLING-ALGORITHM in [PSAMP-INFO]
   - the sampling parameters denoted SAMPLING-PARAMETER1, SAMPLING-
   PARAMETER2, etc... in [PSAMP-INFO]
   The Options Template FlowSet is used to define this template
   composed of SELECTOR-ID, SAMPLING-ALGORITHM, SAMPLING-PARAMETERS.
 
   Finally Data FlowSet is used to export the Flow Data Record(s)
   containing the real values of SEQUENCE-NUMBER, PACKET-SAMPLE and
   SELECTOR-ID, destinationAS and ingressPort. The Data FlowSet is also
   used to export the Options Data Record(s) containing the real values
   of SELECTOR-ID, SAMPLING-ALGORITHM, SAMPLING-PARAMETERS.
 
   As a consequence, the collector can link any Flow Data Record to the
   sampling algorithm and sampling parameters, by means of the
   SELECTOR-ID value.
 
 
 7.2.1    Example
 
   EDITORÆS NOTE: THIS MUST BE A FULL EXAMPLE LIKE IN SECTION 13 OF
   [IPFIX-PROTO]. THE [PSAMP-INFO] MUST BE FIRST PUBLISHED.
 
 7.3 Filtering Case
 
   EDITORÆS NOTE: ACTUALLY THE EXAMPLE WILL BE QUITE SIMILAR TO 7.1 AND
   7.2 BUT WILL DEPEND A LOT ON HOW WE WILL DEFINE THE FILTERING IN
   [IPFIX-INFO].
 
 
 7.3.1    Example
 
   EDITORÆS NOTE:  THIS MUST BE A FULL EXAMPLE LIKE IN SECTION 13 OF
   [IPFIX-PROTO]. THE [PSAMP-INFO] MUST BE FIRST PUBLISHED.
 
 
 
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 8. Security Considerations
 
   As IPFIX has been selected as the PSAMP export protocol and as the
   PSAMP security requirements are not stricter than the IPFIX security
   requirements, refer to the IPFIX export protocol [IPFIX-PROTO] for
   the security considerations.
 
 9. References
 
   [PSAMP-FRAMEWORK] N. Duffield, D. Chiou, B. Claise, A. Greenber, M.
   Grossglauser "A Framework for Passive Packet Measurement" draft-
   ietf-psamp-framework-03.txt
 
   [PSAMP-FRAMEWORK4] N. Duffield, D. Chiou, B. Claise, A. Greenber, M.
   Grossglauser "A Framework for Passive Packet Measurement" draft-
   ietf-psamp-framework-04.txt
 
   [PSAMP-SAMPLE-TECH] T. Zseby, M. Molina, F. Raspall, N. Duffield
   "Sampling and Filtering Techniques for IP Packet Selection" draft-
   ietf-psamp-sample-tech-02.txt
 
   [PSAMP-MIB] T. Dietz, D. Romascanu, B. Claise "Definitions of
   Managed Objects for Packet Sampling" draft-ietf-psamp-mib-00.txt
 
   [PSAMP-INFO] T. Dietz, F. Dressler, G. Carle, B. Claise,
   "Information Model for Packet Sampling Exports", draft-ietf-psamp-
   info-00.txt
 
   [IPFIX-ARCH] G. Sadasivan, N. Brownlee "Architecture Model for IP
   Flow Information Export" draft-ietf-ipfix-arch-01.txt", June 2003
 
   [IPFIX-INFO] P. Calato, J. Meyer, J. Quittek, "Information Model for
   IP Flow Information Export" draft-ietf-ipfix-info-01, August 2003
 
   [IPFIX-PROTO] B. Claise, M. Fullmer, P. Calato, R. Penno, "IPFIX
   Protocol Specifications", draft-ietf-ipfix-protocol-00.txt, June
   2003
 
   [RFC1771]   Y. Rekhter, T. Li, "A Border Gateway Protocol 4 (BGP-
   4)", RFC 1771, March 1995.
 
 10. Acknowledgments
 
   To be completed.
 
 
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 11. AuthorsÆ Addresses
 
   Benoit Claise
   Cisco Systems
   De Kleetlaan 6a b1
   1831 Diegem
   Belgium
   Phone: +32 2 704 5622
   E-mail: bclaise@cisco.com
 
   Juergen Quittek
   NEC Europe Ltd.
   Network Laboratories
   Kurfuersten-Anlage 36
   69115 Heidelberg
   Germany
   Phone: +49 6221 90511-15
   Email: quittek@ccrle.nec.de
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
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