ftp.cc.uoc.gr
rfc6759
This is a purely informative rendering of an RFC that includes verified errata. This rendering may not be used as a reference.

The following 'Verified' errata have been incorporated in this document: EID 3909, EID 3910, EID 3911
Internet Engineering Task Force (IETF)                         B. Claise
Request for Comments: 6759                                     P. Aitken
Category: Informational                                     N. Ben-Dvora
ISSN: 2070-1721                                      Cisco Systems, Inc.
                                                           November 2012


           Cisco Systems Export of Application Information in
                   IP Flow Information Export (IPFIX)

Abstract

   This document specifies a Cisco Systems extension to the IPFIX
   information model specified in RFC 5102 to export application
   information.

Status of This Memo

   This document is not an Internet Standards Track specification; it is
   published for informational purposes.

   This document is a product of the Internet Engineering Task Force
   (IETF).  It represents the consensus of the IETF community.  It has
   received public review and has been approved for publication by the
   Internet Engineering Steering Group (IESG).  Not all documents
   approved by the IESG are a candidate for any level of Internet
   Standard; see Section 2 of RFC 5741.

   Information about the current status of this document, any errata,
   and how to provide feedback on it may be obtained at
   http://www.rfc-editor.org/info/rfc6759.

Copyright Notice

   Copyright (c) 2012 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

   This document is subject to BCP 78 and the IETF Trust's Legal
   Provisions Relating to IETF Documents
   (http://trustee.ietf.org/license-info) in effect on the date of
   publication of this document.  Please review these documents
   carefully, as they describe your rights and restrictions with respect
   to this document.  Code Components extracted from this document must
   include Simplified BSD License text as described in Section 4.e of
   the Trust Legal Provisions and are provided without warranty as
   described in the Simplified BSD License.

Table of Contents

   1. Introduction ....................................................3
      1.1. Application Information Use Cases ..........................5
      1.2. Conventions Used in This Document ..........................5
   2. IPFIX Documents Overview ........................................5
   3. Terminology .....................................................6
      3.1. New Terminology ............................................6
   4. applicationId Information Element Specification .................6
      4.1. Existing Classification Engine IDs .........................7
      4.2. Selector ID Length per Classification ID ..................11
      4.3. Application Name Options Template Record ..................12
      4.4. Resolving IANA L4 Port Discrepancies ......................13
   5. Grouping Applications with Attributes ..........................13
      5.1. Options Template Record for Attribute Values ..............15
   6. Application ID Examples ........................................15
      6.1. Example 1: Layer 2 Protocol ...............................15
      6.2. Example 2: Standardized IANA Layer 3 Protocol .............16
      6.3. Example 3: Proprietary Layer 3 Protocol ...................17
      6.4. Example 4: Standardized IANA Layer 4 Port .................18
      6.5. Example 5: Layer 7 Application ............................19
      6.6. Example 6: Layer 7 Application with Private
           Enterprise Number (PEN) ...................................21
      6.7. Example: Port Obfuscation .................................22
      6.8. Example: Application Name Mapping Options Template ........23
      6.9. Example: Attributes Values Options Template Record ........24
   7. IANA Considerations ............................................25
      7.1. New Information Elements ..................................25
           7.1.1. applicationDescription .............................25
           7.1.2. applicationId ......................................26
           7.1.3. applicationName ....................................26
           7.1.4. classificationEngineId .............................26
           7.1.5. applicationCategoryName ............................29
           7.1.6. applicationSubCategoryName .........................29
           7.1.7. applicationGroupName ...............................29
           7.1.8. p2pTechnology ......................................29
           7.1.9. tunnelTechnology ...................................30
           7.1.10. encryptedTechnology ...............................30
      7.2. Classification Engine ID Registry .........................30
   8. Security Considerations ........................................30
   9. References .....................................................31
      9.1. Normative References ......................................31
      9.2. Informative References ....................................32
   10. Acknowledgements ..............................................33
   Appendix A. Additions to XML Specification of IPFIX Information
               (Non-normative) .......................................34
   Appendix B. Port Collisions Tables (Non-normative) ................39
   Appendix C. Application Registry Example (Non-normative) ..........43

List of Figures

   Figure 1: applicationId Information Element .......................7
   Figure 2: Selector ID Encoding ...................................12

List of Tables

   Table 1: Existing Classification Engine IDs .......................7
   Table 2: Selector ID Default Length per Classification
            Engine ID ...............................................11
   Table 3: Application ID Static Attributes ........................13
   Table 4: Different Protocols on UDP and TCP ......................39
   Table 5: Different Protocols on SCTP and TCP .....................40

1.  Introduction

   Today, service providers and network administrators are looking for
   visibility into the packet content rather than just the packet
   header.  Some network devices' Metering Processes inspect the packet
   content and identify the applications that are utilizing the network
   traffic.  Applications in this context are defined as networking
   protocols used by networking processes that exchange packets between
   them (such as web applications, peer-to-peer applications, file
   transfer, e-mail applications, etc.).  Applications can be further
   characterized by other criteria, some of which are application
   specific.  Examples include: web application to a specific domain,
   per-user specific traffic, a video application with a specific codec,
   etc.

   The application identification is based on several different methods
   or even a combination of methods:

   1. L2 (Layer 2) protocols (such as ARP (Address Resolution Protocol),
      PPP (Point-to-Point Protocol), LLDP (Link Layer Discovery
      Protocol))

   2. IP protocols (such as ICMP (Internet Control Message Protocol),
      IGMP (Internet Group Management Protocol), GRE (Generic Routing
      Encapsulation)

   3. TCP or UDP ports (such as HTTP, Telnet, FTP)

   4. Application layer header (of the application to be identified)

   5. Packet data content

   6. Packets and traffic behavior

   The exact application identification methods are part of the Metering
   Process internals that aim to provide an accurate identification and
   minimize false identification.  This task requires a sophisticated
   Metering Process since the protocols do not behave in a standard
   manner.

   1. Applications use port obfuscation where the application runs on a
      different port than the IANA assigned one.  For example, an HTTP
      server might run on TCP port 23 (assigned to telnet in
      [IANA-PORTS]).

   2. IANA port registries do not accurately reflect how certain ports
      are "commonly" used today.  Some ports are reserved, but the
      application either never became prevalent or is not in use today.

   3. The application behavior and identification logic become more and
      more complex.

   For that reason, such Metering Processes usually detect applications
   based on multiple mechanisms in parallel.  Detection based only on
   port matching might wrongly identify the application.  If the
   Metering Process is capable of detecting applications more
   accurately, it is considered to be stronger and more accurate.

   Similarly, a reporting mechanism that uses L4 port based applications
   only, such as L4:<known port>, would have similar issues.  The
   reporting system should be capable of reporting the applications
   classified using all types of mechanisms.  In particular,
   applications that do not have any IANA port definition.  While a
   mechanism to export application information should be defined, the L4
   port being used must be exported using the destination port
   (destinationTransportPort at [IANA-IPFIX]) in the corresponding IPFIX
   record.

   Applications could be identified at different OSI layers, from layer
   2 to layer 7.  For example, the Link Layer Distribution Protocol
   (LLDP) [LLDP] can be identified in layer 2, ICMP can be identified in
   layer 3 [IANA-PROTO], HTTP can be identified in layer 4 [IANA-PORTS],
   and Webex can be identified in layer 7.

   While an ideal solution would be an IANA registry for applications
   above (or inside the payload of) the well-known ports [IANA-PORTS],
   this solution is not always possible.  Indeed, the specifications for
   some applications embedded in the payload are not available.  Some
   reverse engineering as well as a ubiquitous language for application
   identification would be required conditions to be able to manage an
   IANA registry for these types of applications.  Clearly, these are
   blocking factors.

   This document specifies the Cisco Systems application information
   encoding (as described in Section 4) to export the application
   information with the IPFIX protocol [RFC5101].  However, the layer 7
   application registry values are out of scope of this document.

1.1.  Application Information Use Cases

   There are several use cases for application information:

   1. Application Visibility

      This is one of the main cases for using application information.
      Network administrators are using application visibility to
      understand the main network consumers, network trends, and user
      behavior.

   2. Security Functions

      Application knowledge is sometimes used in security functions in
      order to provide comprehensive functions such as Application-based
      firewall, URL filtering, parental control, intrusion detection,
      etc.

   All of the above use cases require exporting application information
   to provide the network function itself or to log the network function
   operation.

1.2.  Conventions Used in This Document

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
   document are to be interpreted as described in RFC 2119 [RFC2119].

2.  IPFIX Documents Overview

   The IPFIX protocol [RFC5101] provides network administrators with
   access to IP Flow information.

   The architecture for the export of measured IP Flow information out
   of an IPFIX Exporting Process to a Collecting Process is defined in
   the IPFIX Architecture [RFC5470], per the requirements defined in RFC
   3917 [RFC3917].

   The IPFIX Architecture [RFC5470] specifies how IPFIX Data Records and
   Templates are carried via a congestion-aware transport protocol from
   IPFIX Exporting Processes to IPFIX Collecting Processes.

   IPFIX has a formal description of IPFIX Information Elements, their
   names, types, and additional semantic information, as specified in
   the IPFIX information model [RFC5102].

   In order to gain a level of confidence in the IPFIX implementation,
   probe the conformity and robustness, and allow interoperability, the
   Guidelines for IPFIX Testing [RFC5471] presents a list of tests for
   implementers of compliant Exporting Processes and Collecting
   Processes.

   The Bidirectional Flow Export [RFC5103] specifies a method for
   exporting bidirectional flow (biflow) information using the IPFIX
   protocol, representing each biflow using a single Flow Record.

   "Reducing Redundancy in IP Flow Information Export (IPFIX) and Packet
   Sampling (PSAMP) Reports" [RFC5473] specifies a bandwidth-saving
   method for exporting Flow or packet information, by separating
   information common to several Flow Records from information specific
   to an individual Flow Record: common Flow information is exported
   only once.

3.  Terminology

   IPFIX-specific terminology used in this document is defined in
   Section 2 of the IPFIX protocol specification [RFC5101].  As in
   [RFC5101], these IPFIX-specific terms have the first letter of a word
   capitalized when used in this document.

3.1.  New Terminology

   Application ID

      A unique identifier for an application.

   When an application is detected, the most granular application is
   encoded in the Application ID.

4.  applicationId Information Element Specification

   This document specifies the applicationId Information Element, which
   is a single field composed of two parts:

   1. 8 bits of Classification Engine ID.  The Classification Engine can
      be considered as a specific registry for application assignments.

   2. n bits of Selector ID.  The Selector ID length varies depending on
      the Classification Engine ID.

    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
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   | Class. Eng. ID|         Selector ID  ...                      |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                             ...                               |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

             Figure 1: applicationId Information Element

   Classification Engine ID

      A unique identifier for the engine that determined the Selector
      ID.  Thus, the Classification Engine ID defines the context for
      the Selector ID.

   Selector ID

      A unique identifier of the application for a specific
      Classification Engine ID.  Note that the Selector ID length varies
      depending on the Classification Engine ID.

   The Selector ID term is a similar concept to the selectorId
   Information Element, specified in the PSAMP Protocol
   [RFC5476][RFC5477].

4.1.  Existing Classification Engine IDs

   The following Classification Engine IDs have been allocated:

   Name         Value  Description

                0      Invalid.

   IANA-L3      1      The Assigned Internet Protocol
                       Number (layer 3 (L3)) is exported
                       in the Selector ID.
                       See [IANA-PROTO].

   PANA-L3      2      Proprietary layer 3 definition.
                       An enterprise can export its own
                       layer 3 protocol numbers.  The
                       Selector ID has a global
                       significance for all devices from
                       the same enterprise.

   IANA-L4      3      The IANA layer 4 (L4) well-known
                       port number is exported in the
                       Selector ID.  See [IANA-PORTS].
                       Note: as an IPFIX flow is
                       unidirectional, it contains the
                       destination port.

   PANA-L4      4      Proprietary layer 4 definition.
                       An enterprise can export its own
                       layer 4 port numbers.  The
                       Selector ID has global
                       significance for devices from the
                       same enterprise.  Example: IPFIX was
                       pre-assigned the port 4739 using the IANA
                       early allocation process [RFC4020] years
                       before the document was published as an RFC.
                       While waiting for the RFC and its associated
                       IANA registration, Selector ID 4739
                       was used with this PANA-L4.

                5      Reserved.

   USER-        6      The Selector ID represents
   Defined             applications defined by the user
                       (using CLI, GUI, etc.) based on
                       the methods described in Section
                       1.  The Selector ID has a local
                       significance per device.

                7      Reserved.

                8      Reserved.

                9      Reserved.

                10     Reserved.

                11     Reserved.

   PANA-L2      12     Proprietary layer 2 (L2)
                       definition.  An enterprise can
                       export its own layer 2
                       identifiers.  The Selector ID
                       represents the enterprise's
                       unique global layer 2
                       applications.  The Selector ID has
                       a global significance for all

                       devices from the same enterprise.
                       Examples include Cisco Subnetwork
                       Access Protocol (SNAP).

   PANA-L7      13     Proprietary layer 7 definition.
                       The Selector ID represents the
                       enterprise's unique global ID for
                       layer 7 applications.  The
                       Selector ID has a global
                       significance for all devices from
                       the same enterprise.  This
                       Classification Engine ID is used
                       when the application registry is
                       owned by the Exporter
                       manufacturer (referred to as the
                       "enterprise" in this document).

                14     Reserved.

                15     Reserved.

                16     Reserved.

                17     Reserved.

   ETHERTYPE    18     The Selector ID represents the
                       well-known Ethertype.  See
                       [ETHERTYPE].

   LLC          19     The Selector ID represents the
                       well-known IEEE 802.2 Link Layer
                       Control (LLC) Destination Service
                       Access Point (DSAP).  See [LLC].


   PANA-L7-     20     Proprietary layer 7 definition,
   PEN                 including a Private Enterprise
                       Number (PEN) [IANA-PEN] to identify
                       that the application registry
                       being used is not owned by the
                       Exporter manufacturer or to
                       identify the original
                       enterprise in the case of a
                       mediator or 3rd party device.  The
                       Selector ID represents the
                       enterprise unique global ID for
                       the layer 7 applications.  The

                       Selector ID has a global
                       significance for all devices from
                       the same enterprise.

                21 to
                 255   Available (255 is the maximum
                       Engine ID)

       Table 1: Existing Classification Engine IDs

   "PANA = Proprietary Assigned Number Authority".  In other words, an
   enterprise specific version of IANA for internal IDs.

   The PANA-L7 Classification Engine ID SHOULD be used when the
   application registry is owned by the Exporter manufacturer.  Even if
   the application registry is owned by the Exporter manufacturer, the
   PANA-L7-PEN MAY be used, specifying the manufacturer.

   For example, if Exporter A (from enterprise-A) wants to export its
   enterprise-A L7 registry, then it uses the PANA-L7 Classification
   Engine ID.  If Exporter B (from enterprise-B) wants to export its
   enterprise-B L7 registry, then it also uses the PANA-L7
   Classification Engine ID.

   The mechanism for the Collector to know about the Exporter PEN is out
   of scope of this document.  Possible tracks are SNMP polling, an
   Options Template exporting the privateEnterpriseNumber Information
   Element [IANA-IPFIX], hardcoded value, etc.

   An Exporter may classify the application according to another
   vendor's application registry.  For example, an IPFIX Mediator
   [RFC6183] may need to re-export applications received from different
   Exporters using different PANA-L7 application registries.  For
   example, if Exporter C (from enterprise-C) wants to reuse enterprise-
   D's application registry, then it uses PANA-L7-PEN with enterprise-
   D's PEN.

   When reporting application information from multiple Exporters from
   different enterprises (different PENs), the PANA-L7-PEN
   Classification Engine MUST be used in exported Flow Records, which
   allows the original enterprise ID to be reported.  The ID of the
   enterprise that defined the Application ID is identified by the
   enterprise's PEN.  For example, an IPFIX Mediator aggregates traffic
   from some Exporters which report enterprise-E applications and other
   Exporters that report enterprise-F applications.

   An example is displayed in Section 6.6.

   Note that the PANA-L7 Classification Engine ID is also used for
   resolving IANA L4 port Discrepancies (see Section 4.4).

   The list in Table 1 is maintained by IANA thanks to the registry
   within the classificationEngineId Information Element.  See the IANA
   Considerations section.  The Classification Engine ID is part of the
   Application ID encoding, so the classificationEngineId Information
   Element is currently not required by the specifications in this
   document.  However, this Information Element was created for
   completeness, as it was anticipated that this Information Element
   will be required in the future.

4.2.  Selector ID Length per Classification ID

   As the Selector ID part of the Application ID is variable based on
   the Classification Engine ID value, the applicationId SHOULD be
   encoded in a variable-length Information Element [RFC5101] for IPFIX
   export.

   The following table displays the Selector ID default length for the
   different Classification Engine IDs.

      Classification               Selector ID default
      Engine ID Name               length (in bytes)

      IANA-L3                      1

      PANA-L3                      1

      IANA-L4                      2

      PANA-L4                      2

      USER-Defined                 3

      PANA-L2                      5

      PANA-L7                      3

      ETHERTYPE                    2

      LLC                          1

      PANA-L7-PEN                  3 (*)

               Table 2: Selector ID Default Length
                  per Classification Engine ID

   (*) There are an extra 4 bytes for the PEN.  However, the PEN is not
   considered part of the Selector ID.

   If a legacy protocol such as NetFlow version 9 [RFC3954] is used, and
   this protocol doesn't support variable-length Information Elements,
   then either multiple Template Records (one per applicationId length),
   or a single Template Record corresponding to the maximum sized
   applicationId MUST be used.

   Application IDs MAY be encoded in a smaller number of bytes,
   following the same rules as for IPFIX Reduced Size Encoding
   [RFC5101].

   Application IDs MAY be encoded with a larger length.  For example, a
   normal IANA L3 protocol encoding would take 2 bytes since the
   Selector ID represents the protocol field from the IP header encoded
   in one byte.  However, an IANA L3 protocol encoding may be encoded
   with 3 bytes.  In this case, the Selector ID value MUST always be
   encoded in the least significant bits as shown in Figure 2.

    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
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    |Class. Eng. ID |zero-valued upper-bits ... Selector ID         |
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

                    Figure 2: Selector ID Encoding

4.3.  Application Name Options Template Record

   For Classification Engines that specify locally unique Application
   IDs (which means unique per engine and per router), an Options
   Template Record (see [RFC5101]) MUST be used to export the
   correspondence between the Application ID, the Application Name, and
   the Application Description.

   For Classification Engines that specify globally unique Application
   IDs, an Options Template Record MAY be used to export the
   correspondence between the Application ID, the Application Name and
   the Application Description, unless the mapping is hardcoded in the
   Collector, or known out of band (for example, by polling a MIB).

   An example Options Template is shown in Section 6.8.

   Enterprises may assign company-wide Application ID values for the
   PANA-L7 Classification Engine.  In this case, a possible optimization
   for the Collector is to keep the mappings between the Application IDs
   and the Application Names per enterprise, as opposed to per Exporter.

4.4.  Resolving IANA L4 Port Discrepancies

   Even though IANA L4 ports usually point to the same protocols for
   both UDP, TCP or other transport types, there are some exceptions, as
   mentioned in Appendix B.

   Instead of imposing the transport protocol (UDP/TCP/SCTP/etc.) in the
   scope of the "Application Name Options Template Record" (Section 6.8)
   for all applications (in addition to having the transport protocol as
   a key-field in the Flow Record definition), the convention is that
   the L4 application is always TCP related.  So, whenever the Collector
   has a conflict in looking up IANA, it would choose the TCP choice.
   As a result, the UDP L4 applications from Table 3 and the SCTP L4
   applications from Table 4 are assigned in the PANA_L7 Application ID
   range, i.e., under Classification Engine ID 13.

   Currently, there are no discrepancies between the well-known ports
   for TCP and the Datagram Congestion Control Protocol (DCCP).

5.  Grouping Applications with Attributes

   Due to the high number of different Application IDs, Application IDs
   MAY be categorized into groups.  This offers the benefits of easier
   reporting and action, such as QoS policies.  Indeed, most
   applications with the same characteristics should be treated the same
   way; for example, all video traffic.

   Attributes are statically assigned per Application ID and are
   independent of the traffic.  The attributes are listed below:

      Name                   Description

      Category               An attribute that provides a first-
                             level categorization for each
                             Application ID.  Examples include
                             browsing, email, file-sharing,
                             gaming, instant messaging, voice-
                             and-video, etc.
                             The category attribute is encoded by
                             the applicationCategoryName
                             Information Element.

      Sub-Category           An attribute that provides a second-
                             level categorization for each
                             Application ID.  Examples include
                             backup-systems, client-server,
                             database, routing-protocol, etc.
                             The sub-category attribute is

                             encoded by the
                             applicationSubCategoryName
                             Information Element.

      Application-           An attribute that groups multiple
      Group                  Application IDs that belong to the
                             same networking application.  For
                             example, the ftp-group contains
                             ftp-data (port 20), ftp (port 20),
                             ni-ftp (port 47), sftp (port 115),
                             bftp (port 152), ftp-agent(port
                             574), ftps-data (port 989).  The
                             application-group attribute is
                             encoded by the applicationGroupName
                             Information Element.

      P2P-Technology         Specifies if the Application ID is
                             based on peer-to-peer technology.
                             The P2P-technology attribute is
                             encoded by the p2pTechnology
                             Information Element.

      Tunnel-                Specifies if the Application ID is
      Technology             used as a tunnel technology.  The
                             tunnel-technology attribute is
                             encoded by the tunnelTechnology
                             Information Element.

      Encrypted              Specifies if the Application ID is
                             an encrypted networking protocol.
                             The encrypted attribute is encoded
                             by the encryptedTechnology
                             Information Element.

          Table 3: Application ID Static Attributes

   Every application is assigned to one applicationCategoryName, one
   applicationSubCategoryName, one applicationGroupName, and it has one
   p2pTechnology, one tunnelTechnology, and one encryptedTechnology.
   These new Information Elements are specified in the IANA
   Considerations section (Section 7.1).

   Maintaining the attribute values in IANA seems impossible to realize.
   Therefore, the attribute values per application are enterprise
   specific.

5.1.  Options Template Record for Attribute Values

   An Options Template Record (see [RFC5101]) SHOULD be used to export
   the correspondence between each Application ID and its related
   Attribute values.  An alternative way for the Collecting Process to
   learn the correspondence is to populate these mappings out of band,
   for example, by loading a CSV file containing the correspondence
   table.

   The Attributes Option Template contains the application ID as a scope
   field, followed by the applicationCategoryName, the
   applicationSubCategoryName, the applicationGroupName, the
   p2pTechnology, the tunnelTechnology, and the encryptedTechnology
   Information Elements.

   A list of attributes may conveniently be exported using a
   subTemplateList per [RFC6313].

   An example is given in Section 6.9.

6.  Application ID Examples

   The following examples are created solely for the purpose of
   illustrating how the extensions proposed in this document are
   encoded.

6.1.  Example 1: Layer 2 Protocol

   The list of Classification Engine IDs in Table 1 shows that the layer
   2 Classification Engine IDs are 12 (PANA-L2), 18, (ETHERTYPE) and 19
   (LLC).

   From the Ethertype list, LLDP [LLDP] has the Selector ID value
   0x88CC, so 35020 in decimal:

   NAME    Selector ID
   LLDP    35020

   So, in the case of LLDP, the Classification Engine ID is 18 (LLC)
   while the Selector ID has the value 35020.

   Per Section 4, the applicationId Information Element is a single
   field composed of 8 bits of Classification Engine ID, followed by n
   bits of Selector ID.  From Table 2, the Selector ID length n is 2 for
   the ETHERTYPE Engine ID.

   Therefore, the Application ID is encoded as:

       0                   1                   2
       0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |       18      |             35020             |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   So the Application ID has the decimal value of 1214668.  The format
   '18..35020' is used for simplicity in the examples below, to clearly
   express that two components of the Application ID.

   The Exporting Process creates a Template Record with a few
   Information Elements: amongst other things, the Application ID.  For
   example:

   - applicationId (key field)
   - octetTotalCount (non-key field)

   For example, a Flow Record corresponding to the above Template Record
   may contain:

       { applicationId='18..35020',
         octetTotalCount=123456 }

   The Collector has all the required information to determine that the
   application is LLDP, because the Application ID uses a global and
   well-known registry, i.e., the Ethertype.  The Collector can
   determine which application is represented by the Application ID by
   loading the registry out of band.

6.2.  Example 2: Standardized IANA Layer 3 Protocol

   From the list of Classification Engine IDs in Table 1, the IANA layer
   3 Classification Engine ID (IANA-L3) is 1.  From Table 2 the Selector
   ID length is 1 for the IANA-L3 Engine ID.

   From the list of IANA layer 3 protocols (see [IANA-PROTO]), ICMP has
   the value 1:

   Decimal    Keyword    Protocol                   Reference
   1          ICMP       Internet Control           [RFC792]
                          Message

   So, in the case of the standardized IANA layer 3 protocol ICMP, the
   Classification Engine ID is 1, and the Selector ID has the value of
   1.

   Therefore, the Application ID is encoded as:

       0                   1
       0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |       1       |       1       |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   So, the Application ID has the value of 257.  The format '1..1'  is
   used for simplicity in the examples below.

   The Exporting Process creates a Template Record with a few
   Information Elements: amongst other things, the Application ID.  For
   example:

   - sourceIPv4Address (key field)
   - destinationIPv4Address (key field)
   - ipDiffServCodePoint (key field)
   - applicationId (key field)
   - octetTotalCount (non-key field)

   For example, a Flow Record corresponding to the above Template Record
   may contain:

       { sourceIPv4Address=192.0.2.1,
         destinationIPv4Address=192.0.2.2,
         ipDiffServCodePoint=0,
         applicationId='1..1',
         octetTotalCount=123456 }

   The Collector has all the required information to determine that the
   application is ICMP, because the Application ID uses a global and
   well-known registry, i.e., the IANA L3 protocol number.

6.3.  Example 3: Proprietary Layer 3 Protocol

   Assume that an enterprise has specified a new layer 3 protocol called
   "foo".

   From the list of Classification Engine IDs in Table 1, the
   proprietary layer 3 Classification Engine ID (PANA-L3) is 2.  From
   Table 2 the Selector ID length is 1 for the PANA-L3 Engine ID.

   A global registry within the enterprise specifies that the "foo"
   protocol has the value 90:

   Protocol    Protocol ID
   foo         90

   So, in the case of the layer 3 protocol foo specified by this
   enterprise, the Classification Engine ID is 2, and the Selector ID
   has the value of 90.

   Therefore, the Application ID is encoded as:

       0                   1
       0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |       2       |       90      |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   So the Application ID has the value of 602.  The format '2..90' is
   used for simplicity in the examples below.

   The Exporting Process creates a Template Record with a few
   Information Elements: amongst other things, the Application ID.  For
   example:

   - sourceIPv4Address (key field)
   - destinationIPv4Address (key field)
   - ipDiffServCodePoint (key field)
   - applicationId (key field)
   - octetTotalCount (non-key field)

   For example, a Flow Record corresponding to the above Template Record
   may contain:

       { sourceIPv4Address=192.0.2.1,
         destinationIPv4Address=192.0.2.2,
         ipDiffServCodePoint=0,
         applicationId='2..90',
         octetTotalCount=123456 }

   Along with this Flow Record, a new Options Template Record would be
   exported, as shown in Section 6.8.

6.4.  Example 4: Standardized IANA Layer 4 Port

   From the list of Classification Engine IDs in Table 1, the IANA layer
   4 Classification Engine ID (IANA-L4) is 3.  From Table 2 the Selector
   ID length is 2 for the IANA-L4 Engine ID.

   From the list of IANA layer 4 ports (see [IANA-PORTS]), SNMP has the
   value 161:

   Keyword    Decimal    Description
   snmp       161/tcp    SNMP
   snmp       161/udp    SNMP

   So, in the case of the standardized IANA layer 4 SNMP port, the
   Classification Engine ID is 3, and the Selector ID has the value of
   161.

   Therefore, the Application ID is encoded as:

       0                   1
       0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |       3       |              161              |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   So the Application ID has the value of 196769.  The format '3..161'
   is used for simplicity in the examples below.

   The Exporting Process creates a Template Record with a few
   Information Elements: amongst other things, the Application ID.  For
   example:

   - sourceIPv4Address (key field)
   - destinationIPv4Address (key field)
   - protocol (key field)
   - ipDiffServCodePoint (key field)
   - applicationId (key field)
   - octetTotalCount (non-key field)

   For example, a Flow Record corresponding to the above Template Record
   may contain:

       { sourceIPv4Address=192.0.2.1,
         destinationIPv4Address=192.0.2.2,
         protocol=17, ipDiffServCodePoint=0,
         applicationId='3..161',
         octetTotalCount=123456 }

   The Collector has all the required information to determine that the
   application is SNMP, because the Application ID uses a global and
   well-known registry, i.e., the IANA L4 protocol number.

6.5.  Example 5: Layer 7 Application

   In this example, the Metering Process has observed some Webex
   traffic.

   From the list of Classification Engine IDs in Table 1, the layer 7
   unique Classification Engine ID (PANA-L7) is 13.  From Table 2 the
   Selector ID length is 3 for the PANA-L7 Engine ID.

   Suppose that the Metering Process returns the ID 10000 for Webex
   traffic.

   So, in the case of this Webex application, the Classification Engine
   ID is 13 and the Selector ID has the value of 10000.

   Therefore, the Application ID is encoded as:

    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
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    |      13       |                     10000                     |
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   So the Application ID has the value of 218113808.  The format
   '13..10000' is used for simplicity in the examples below.

   The Exporting Process creates a Template Record with a few
   Information Elements: amongst other things, the Application ID.  For
   example:

   - sourceIPv4Address (key field)
   - destinationIPv4Address (key field)
   - ipDiffServCodePoint (key field)
   - applicationId (key field)
   - octetTotalCount (non-key field)

   For example, a Flow Record corresponding to the above Template Record
   may contain:

       { sourceIPv4Address=192.0.2.1,
         destinationIPv4Address=192.0.2.2,
         ipDiffServCodePoint=0,
         applicationId='13..10000',
         octetTotalCount=123456 }

   The 10000 value is globally unique for the enterprise, so that the
   Collector can determine which application is represented by the
   Application ID by loading the registry out of band.

   Along with this Flow Record, a new Options Template Record would be
   exported, as shown in Section 6.8.

6.6.  Example 6: Layer 7 Application with Private Enterprise Number
      (PEN)

   In this example, the layer 7 Webex traffic from Example 5 above have
   been classified by enterprise X.  The exported records have been
   received by enterprise Y's mediation device, which wishes to forward
   them to a top-level Collector.

   In order for the top-level Collector to know that the records were
   classified by enterprise X, the enterprise Y mediation device must
   report the records using the PANA-L7-PEN Classification Engine ID
   with enterprise X's Private Enterprise Number.

   The PANA-L7-PEN Classification Engine ID is 20, and enterprise X's
   Selector ID for Webex traffic has the value of 10000.  From Table 2
   the Selector ID length is 3 for the PANA-L7-PEN Engine ID.

   Therefore, the Application ID is encoded as:

    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
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    |      20       |               enterprise ID = X            ...|
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    |...Ent.ID.contd|                     10000                     |
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   The format '20..X..10000' is used for simplicity in the examples
   below.

   The Exporting Process creates a Template Record with a few
   Information Elements: amongst other things, the Application ID.  For
   example:

   - sourceIPv4Address (key field)
   - destinationIPv4Address (key field)
   - ipDiffServCodePoint (key field)
   - applicationId (key field)
   - octetTotalCount (non-key field)

   For example, a Flow Record corresponding to the above Template Record
   may contain:

       { sourceIPv4Address=192.0.2.1,
         destinationIPv4Address=192.0.2.2,
         ipDiffServCodePoint=0,
         applicationId='20..X..10000',
         octetTotalCount=123456 }

   The 10000 value is globally unique for enterprise X, so that the
   Collector can determine which application is represented by the
   Application ID by loading the registry out of band.

   Along with this Flow Record, a new Options Template Record would be
   exported, as shown in Section 6.8.

6.7.  Example: Port Obfuscation

   For example, an HTTP server might run on a TCP port 23 (assigned to
   telnet in [IANA-PORTS]).  If the Metering Process is capable of
   detecting HTTP in the same case, the Application ID representation
   must contain HTTP.  However, if the reporting application wants to
   determine whether or not the default HTTP port 80 or 8080 was used,
   the transport ports (sourceTransportPort and destinationTransportPort
   at [IANA-IPFIX]) must also be exported in the corresponding IPFIX
   record.

   In the case of a standardized IANA layer 4 port, the Classification
   Engine ID (PANA-L4) is 3, and the Selector ID has the value of 80 for
   HTTP (see [IANA-PORTS]).  From Table 2 the Selector ID length is 2
   for the PANA-L4 Engine ID.

   Therefore, the Application ID is encoded as:

       0                   1                   2
       0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |       3       |             80                |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   The Exporting Process creates a Template Record with a few
   Information Elements: amongst other things, the Application ID.  For
   example:

   - sourceIPv4Address (key field)
   - destinationIPv4Address (key field)
   - protocol (key field)
   - destinationTransportPort (key field)
   - applicationId (key field)
   - octetTotalCount (non-key field)

   For example, a Flow Record corresponding to the above
   Template Record may contain:

       { sourceIPv4Address=192.0.2.1,
         destinationIPv4Address=192.0.2.2,
         protocol=17,
         destinationTransportPort=23,
         applicationId='3..80',
         octetTotalCount=123456 }

   The Collector has all the required information to determine that the
   application is HTTP, but runs on port 23.

6.8.  Example: Application Name Mapping Options Template

   Along with the Flow Records shown in the above examples, a new
   Options Template Record should be exported to express the Application
   Name and Application Description associated with each Application ID.

   The Options Template Record contains the following Information
   Elements:

   1. Scope = applicationId.

          From RFC 5101: The scope, which is only available
          in the Options Template Set, gives the context of
          the reported Information Elements in the Data
          Records.

   2. applicationName.

   3. applicationDescription.

   The Options Data Record associated with the examples above
   would contain, for example:

       { scope=applicationId='2..90',
         applicationName="foo",
         applicationDescription="The foo protocol",

         scope=applicationId='13..10000',
         applicationName="webex",
         applicationDescription="Webex application" }

         scope=applicationId='20..X..10000',
         applicationName="webex",
         applicationDescription="Webex application" }

   When combined with the example Flow Records above, these Options
   Template Records tell the Collector:

   1. A flow of 123456 bytes exists from sourceIPv4Address 192.0.2.1 to
      destinationIPv4address 192.0.2.2 with an applicationId of
      '12..90', which maps to the "foo" application.

   2. A flow of 123456 bytes exists from sourceIPv4Address 192.0.2.1 to
      destinationIPv4address 192.0.2.2 with an Application ID of
      '13..10000', which maps to the "Webex" application.

   3. A flow of 123456 bytes exists from sourceIPv4Address 192.0.2.1 to
      destinationIPv4address 192.0.2.2 with an Application ID of
      '20..PEN..10000', which maps to the "Webex" application, according
      to the application registry from the enterprise X.

6.9.  Example: Attributes Values Options Template Record

   Along with the Flow Records shown in the above examples, a new
   Options Template Record is exported to express the values of the
   different attributes related to the Application IDs.

   The Options Template Record would contain the following Information
   Elements:

   1. Scope = applicationId.

      From RFC 5101: The scope, which is only available in the Options
      Template Set, gives the context of the reported Information
      Elements in the Data Records.

   2. applicationCategoryName.

   3. applicationSubCategoryName.

   4. applicationGroupName

   5. p2pTechnology

   6. tunnelTechnology

   7. encryptedTechnology

   The Options Data Record associated with the examples above would
   contain, for example:

       { scope=applicationId='2..90',
         applicationCategoryName="foo-category",
         applicationSubCategoryName="foo-subcategory",
         applicationGroupName="foo-group",
         p2pTechnology=NO
         tunnelTechnology=YES
         encryptedTechnology=NO

   When combined with the example Flow Records above, these Options
   Template Records tell the Collector:

   A flow of 123456 bytes exists from sourceIPv4Address 192.0.2.1 to
   destinationIPv4address 192.0.2.2 with a DSCP value of 0 and an
   applicationId of '12..90', which maps to the "foo" application.  This
   application can be characterized by the relevant attributes values.

7.  IANA Considerations

7.1.  New Information Elements

   This document specifies 10 new IPFIX Information Elements:
   applicationDescription, applicationId, applicationName,
   classificationEngineId, applicationCategoryName,
   applicationSubCategoryName, applicationGroupName, p2pTechnology,
   tunnelTechnology, and encryptedTechnology.

   The new Information Elements listed below have been added to the
   IPFIX Information Element registry at [IANA-IPFIX].

7.1.1.  applicationDescription

   Name: applicationDescription
   Description:
     Specifies the description of an application.
   Abstract Data Type: string
   Data Type Semantics:
   ElementId: 94
   Status: current

7.1.2.  applicationId

   Name: applicationId
   Description:
     Specifies an Application ID.
   Abstract Data Type: octetArray
   Data Type Semantics: identifier
   Reference: See Section 4 of [RFC6759]
   for the applicationId Information Element Specification.
   ElementId: 95
   Status: current

7.1.3.  applicationName

   Name: applicationName
   Description:
     Specifies the name of an application.
   Abstract Data Type: string
   Data Type Semantics:
   ElementId: 96
   Status: current

7.1.4.  classificationEngineId

   Name: classificationEngineId
   Description:
    A unique identifier for the engine that determined the
    Selector ID.  Thus, the Classification Engine ID defines
    the context for the Selector ID.  The Classification
    Engine can be considered as a specific registry for
    application assignments.

    Initial values for this field are listed below.  Further
    values may be assigned by IANA in the Classification
    Engine IDs registry per Section 7.2.

         0 Invalid.

         1 IANA-L3: The Assigned Internet Protocol Number
           (layer 3 (L3)) is exported in the Selector ID.  See
           http://www.iana.org/assignments/protocol-numbers.

         2 PANA-L3: Proprietary layer 3 definition.  An
           enterprise can export its own layer 3 protocol
           numbers.  The Selector ID has a global significance
           for all devices from the same enterprise.

         3 IANA-L4: The IANA layer 4 (L4) well-known port
           number is exported in the Selector ID.  See [IANA-PORTS].
           Note: as an IPFIX flow is unidirectional,
           it contains the destination port.

         4 PANA-L4: Proprietary layer 4 definition.  An
           enterprise can export its own layer 4 port
           numbers.  The Selector ID has global significance
           for devices from the same enterprise.  Example:
           IPFIX was pre-assigned port 4739 using the IANA
           early allocation process [RFC4020] years before the
           document was published as an RFC.  While waiting for
           the RFC and it associated IANA registration,
           Selector ID 4739 was used with this PANA-L4.

         5 Reserved

         6 USER-Defined: The Selector ID represents
           applications defined by the user (using CLI, GUI,
           etc.) based on the methods described in Section 2.
           The Selector ID has a local significance per
           device.

         7 Reserved

         8 Reserved

         9 Reserved

        10 Reserved

        11 Reserved

        12 PANA-L2: Proprietary layer 2 (L2) definition.  An
           enterprise can export its own layer 2 identifiers.
           The Selector ID represents the enterprise's unique
           global layer 2 applications.  The Selector ID has a
           global significance for all devices from the same
           enterprise.  Examples include the Cisco Subnetwork
           Access Protocol (SNAP).

        13 PANA-L7: Proprietary layer 7 definition.  The
           Selector ID represents the enterprise's unique
           global ID for layer 7 applications.  The
           Selector ID has a global significance for all
           devices from the same enterprise.  This
           Classification Engine ID is used when the
           application registry is owned by the Exporter
           manufacturer (referred to as the "enterprise" in
           this document).

        14 Reserved

        15 Reserved

        16 Reserved

        17 Reserved

        18 ETHERTYPE: The Selector ID represents the well-
           known Ethertype.  See [ETHERTYPE].

        19 LLC: The Selector ID represents the well-known
           IEEE 802.2 Link Layer Control (LLC) Destination
           Service Access Point (DSAP).  See [LLC].

        20 PANA-L7-PEN: Proprietary layer 7 definition,
           including a Private Enterprise Number (PEN) [IANA-PEN]
           to identify that the application registry being
           used is not owned by the Exporter manufacturer or to
           identify the original enterprise in the case of a
           mediator or 3rd party device.  The Selector ID represents
           the enterprise unique global ID for layer 7
           applications.  The Selector ID has a global
           significance for all devices from the same
           enterprise.

        Some values (5, 7, 8, 9, 10, 11, 14, 15, 16, and 17),
        are reserved to be compliant with existing
        implementations already using the
        classificationEngineId.

   Abstract Data Type: unsigned8
   Data Type Semantics: identifier
   ElementId: 101
   Status: current

7.1.5.  applicationCategoryName

    Name: applicationCategoryName
    Description:
     An attribute that provides a first-level categorization for
     each Application Id.
    Abstract Data Type: string
    Data Type Semantics:
    ElementId: 372
    Status: current

7.1.6.  applicationSubCategoryName

   Name: applicationSubCategoryName
   Description:
    An attribute that provides a second-level categorization
    for each Application Id.
   Abstract Data Type: string
   Data Type Semantics:
   ElementId: 373
   Status: current

7.1.7.  applicationGroupName

   Name: applicationGroupName
   Description:
    An attribute that groups multiple Application IDs that
    belong to the same networking application.
   Abstract Data Type: string
   Data Type Semantics:
   ElementId: 374
   Status: current

7.1.8.  p2pTechnology

   Name: p2pTechnology
      Description: 
    Specifies if the Application ID is based on peer-to-peer
    technology.  Possible values are { "yes", "y", 1 },
    { "no", "n", 2 }, and { "unassigned", "u", 0 }.

    Note that 0, 1, and 2 above are integer values; as UTF-8 
    characters they are U+0000(NUL), U+0001(SOH), and U+0002(STX). 
    WARNING: the overloading of a string value with an integer 
    representation that can take the value 0 requires careful 
    handling on collectors and exporters which use this value
    to signify the end of a string.
EID 3909 (Verified) is as follows:

Section: 7.1.8

Original Text:

   Description:
    Specifies if the Application ID is based on peer-to-peer
    technology.  Possible values are { "yes", "y", 1 },
    { "no", "n", 2 }, and { "unassigned", "u", 0 }.

Corrected Text:

   Description:
    Specifies if the Application ID is based on peer-to-peer
    technology.  Possible values are { "yes", "y", 1 },
    { "no", "n", 2 }, and { "unassigned", "u", 0 }.

    Note that 0, 1, and 2 above are integer values; as UTF-8 
    characters they are U+0000(NUL), U+0001(SOH), and U+0002(STX). 
    WARNING: the overloading of a string value with an integer 
    representation that can take the value 0 requires careful 
    handling on collectors and exporters which use this value
    to signify the end of a string.
Notes:
Added clarifying text. The difference between a quoted and unquoted
digit (1 vs "1") is extremely subtle and easily missed.

See, for example,
http://www.ietf.org/mail-archive/web/ipfix/current/msg07151.html.
Abstract Data Type: string Data Type Semantics: ElementId: 288 Status: current 7.1.9. tunnelTechnology Name: tunnelTechnology Description: Specifies if the Application ID is used as a tunnel technology. Possible values are { "yes", "y", 1 }, { "no", "n", 2 }, and { "unassigned", "u", 0 }. Note that 0, 1, and 2 above are integer values; as UTF-8 characters they are U+0000(NUL), U+0001(SOH), and U+0002(STX). WARNING: the overloading of a string value with an integer representation that can take the value 0 requires careful handling on collectors and exporters which use this value to signify the end of a string.
EID 3910 (Verified) is as follows:

Section: 7.1.9

Original Text:

   Description:
     Specifies if the Application ID is used as a tunnel technology.
     Possible values are { "yes", "y", 1 }, { "no", "n", 2 },
     and { "unassigned", "u", 0 }.

Corrected Text:

   Description:
     Specifies if the Application ID is used as a tunnel technology.
     Possible values are { "yes", "y", 1 }, { "no", "n", 2 },
     and { "unassigned", "u", 0 }.
 
     Note that 0, 1, and 2 above are integer values; as UTF-8 
     characters they are U+0000(NUL), U+0001(SOH), and U+0002(STX). 
     WARNING: the overloading of a string value with an integer 
     representation that can take the value 0 requires careful 
     handling on collectors and exporters which use this value
     to signify the end of a string.
Notes:
Added clarifying text. The difference between a quoted and unquoted
digit (1 vs "1") is extremely subtle and easily missed.

See, for example,
http://www.ietf.org/mail-archive/web/ipfix/current/msg07151.html.
Abstract Data Type: string Data Type Semantics: ElementId: 289 Status: current 7.1.10. encryptedTechnology Name: encryptedTechnology Description: Specifies if the Application ID is an encrypted networking protocol. Possible values are { "yes", "y", 1 }, { "no", "n", 2 }, and { "unassigned", "u", 0 }. Note that 0, 1, and 2 above are integer values; as UTF-8 characters they are U+0000(NUL), U+0001(SOH), and U+0002(STX). WARNING: the overloading of a string value with an integer representation that can take the value 0 requires careful handling on collectors and exporters which use this value to signify the end of a string.
EID 3911 (Verified) is as follows:

Section: 7.1.10

Original Text:

   Description:
    Specifies if the Application ID is an encrypted networking
    protocol.  Possible values are { "yes", "y", 1 },
    { "no", "n", 2 }, and { "unassigned", "u", 0 }.

Corrected Text:

   Description:
    Specifies if the Application ID is an encrypted networking
    protocol.  Possible values are { "yes", "y", 1 },
    { "no", "n", 2 }, and { "unassigned", "u", 0 }.

    Note that 0, 1, and 2 above are integer values; as UTF-8 
    characters they are U+0000(NUL), U+0001(SOH), and U+0002(STX). 
    WARNING: the overloading of a string value with an integer 
    representation that can take the value 0 requires careful 
    handling on collectors and exporters which use this value
    to signify the end of a string.
Notes:
Added clarifying text. The difference between a quoted and unquoted
digit (1 vs "1") is extremely subtle and easily missed.

See, for example,
http://www.ietf.org/mail-archive/web/ipfix/current/msg07151.html.
Abstract Data Type: string Data Type Semantics: ElementId: 290 Status: current 7.2. Classification Engine ID Registry The Information Element #101, named classificationEngineId, carries information about the context for the Selector ID, and can be considered as a specific registry for application assignments. For ensuring extensibility of this information, IANA has created a new registry for Classification Engine IDs and filled it with the initial list from the description Information Element #101, classificationEngineId, along with their respective default lengths (Table 2 in this document). New assignments for Classification Engine IDs will be administered by IANA through Expert Review [RFC5226], i.e., review by one of a group of experts designated by an IETF Area Director. The group of experts must double-check the new definitions with already defined Classification Engine IDs for completeness, accuracy, and redundancy. The specification of Classification Engine IDs MUST be published using a well-established and persistent publication medium. 8. Security Considerations The same security considerations as for the IPFIX protocol [RFC5101] apply. The IPFIX extension specified in this memo allows to identify what applications are used on the network. Consequently, it is possible to identify what applications are being used by the users, potentially threatening the privacy of those users, if not handled with great care. As mentioned in Section 1.1, the application knowledge is useful in security based applications. Security applications may impose supplementary requirements on the export of application information, and these need to be examined on a case by case basis. 9. References 9.1. Normative References [ETHERTYPE] IEEE, <http://standards.ieee.org/develop/regauth/ ethertype/eth.txt>. [IANA-PEN] IANA, "PRIVATE ENTERPRISE NUMBERS", <http://www.iana.org/assignments/enterprise-numbers>. [IANA-PORTS] IANA, "Service Name and Transport Protocol Port Number Registry", <http://www.iana.org/assignments/port-numbers>. [IANA-PROTO] IANA, "Protocol Numbers", <http://www.iana.org/assignments/protocol-numbers>. [LLC] IEEE, "LOGICAL LINK CONTROL (LLC) PUBLIC LISTING", <http://standards.ieee.org /develop/regauth/llc /public.html>. [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. [RFC5101] Claise, B., Ed., "Specification of the IP Flow Information Export (IPFIX) Protocol for the Exchange of IP Traffic Flow Information", RFC 5101, January 2008. [RFC5102] Quittek, J., Bryant, S., Claise, B., Aitken, P., and J. Meyer, "Information Model for IP Flow Information Export", RFC 5102, January 2008. [RFC5226] Narten, T. and H. Alvestrand, "Guidelines for Writing an IANA Considerations Section in RFCs", BCP 26, RFC 5226, May 2008. 9.2. Informative References [CISCO-APPLICATION-REGISTRY] Cisco, "Application Registry", <http://www.cisco.com/go/application_registry>. [IANA-IPFIX] IANA, "IP Flow Information Export (IPFIX) Entities", <http://www.iana.org/assignments/ipfix>. [LLDP] IEEE, Std 802.1AB-2005, "Standard for Local and metropolitan area networks - Station and Media Access Control Connectivity Discovery", IEEE Std 802.1AB-2005 IEEE Std, 2005. [RFC792] Postel, J., "Internet Control Message Protocol", STD 5, RFC 792, September 1981. [RFC3917] Quittek, J., Zseby, T., Claise, B., and S. Zander, "Requirements for IP Flow Information Export (IPFIX)", RFC 3917, October 2004. [RFC3954] Claise, B., Ed., "Cisco Systems NetFlow Services Export Version 9", RFC 3954, October 2004. [RFC4020] Kompella, K. and A. Zinin, "Early IANA Allocation of Standards Track Code Points", BCP 100, RFC 4020, February 2005. [RFC5103] Trammell, B. and E. Boschi, "Bidirectional Flow Export Using IP Flow Information Export (IPFIX)", RFC 5103, January 2008. [RFC5470] Sadasivan, G., Brownlee, N., Claise, B., and J. Quittek, "Architecture for IP Flow Information Export", RFC 5470, March 2009. [RFC5471] Schmoll, C., Aitken, P., and B. Claise, "Guidelines for IP Flow Information Export (IPFIX) Testing", RFC 5471, March 2009. [RFC5473] Boschi, E., Mark, L., and B. Claise, "Reducing Redundancy in IP Flow Information Export (IPFIX) and Packet Sampling (PSAMP) Reports", RFC 5473, March 2009. [RFC5476] Claise, B., Ed., Johnson, A., and J. Quittek, "Packet Sampling (PSAMP) Protocol Specifications", RFC 5476, March 2009. [RFC5477] Dietz, T., Claise, B., Aitken, P., Dressler, F., and G. Carle, "Information Model for Packet Sampling Exports", RFC 5477, March 2009. [RFC5353] Xie, Q., Stewart, R., Stillman, M., Tuexen, M., and A. Silverton, "Endpoint Handlespace Redundancy Protocol (ENRP)", RFC 5353, September 2008. [RFC5811] Hadi Salim, J. and K. Ogawa, "SCTP-Based Transport Mapping Layer (TML) for the Forwarding and Control Element Separation (ForCES) Protocol", RFC 5811, March 2010. [RFC6183] Kobayashi, A., Claise, B., Muenz, G., and K. Ishibashi, "IP Flow Information Export (IPFIX) Mediation: Framework", RFC 6183, April 2011. [RFC6313] Claise, B., Dhandapani, G., Aitken, P., and S. Yates, "Export of Structured Data in IP Flow Information Export (IPFIX)", RFC 6313, July 2011. 10. Acknowledgements The authors would like to thank their many colleagues across Cisco Systems who made this work possible. Specifically, Patrick Wildi for his time and expertise. Appendix A. Additions to XML Specification of IPFIX Information Elements (Non-normative) This appendix contains additions to the machine-readable description of the IPFIX information model coded in XML in Appendix A and Appendix B in [RFC5102]. Note that this appendix is of informational nature, while the text in Section 7 (generated from this appendix) is normative. The following field definitions are appended to the IPFIX information model in Appendix A of [RFC5102]. <field name="applicationDescription" dataType="string" group="application" elementId="94" applicability="all" status="current"> <description> <paragraph> Specifies the description of an application. </paragraph> </description> </field> <field name="applicationId" dataType="octetArray" group="application" dataTypeSemantics="identifier" elementId="95" applicability="all" status="current"> <description> <paragraph> Specifies an Application ID. </paragraph> </description> <reference> <paragraph> See Section 4 of [RFC6759] for the applicationId Information Element Specification. </paragraph> </reference> </field> <field name="applicationName" dataType="string" group="application" elementId="96" applicability="all" status="current"> <description> <paragraph> Specifies the name of an application. </paragraph> </description> </field> <field name="classificationEngineId" dataType="unsigned8" group="application" dataTypeSemantics="identifier" elementId="101" applicability="all" status="current"> <description> <paragraph> 0 Invalid. 1 IANA-L3: The Assigned Internet Protocol Number (layer 3 (L3)) is exported in the Selector ID. See http://www.iana.org/assignments/protocol- numbers. 2 PANA-L3: Proprietary layer 3 definition. An enterprise can export its own layer 3 protocol numbers. The Selector ID has a global significance for all devices from the same enterprise. 3 IANA-L4: The IANA layer 4 (L4) well-known port number is exported in the Selector ID. See [IANA-PORTS]. Note: as an IPFIX flow is unidirectional, it contains the destination port. 4 PANA-L4: Proprietary layer 4 definition. An enterprise can export its own layer 4 port numbers. The Selector ID has global significance for devices from the same enterprise. Example: IPFIX was pre-assigned port 4739 using the IANA early allocation process [RFC4020] years before the document was published as an RFC. While waiting for the RFC and its associated IANA registration, Selector ID 4739 was used with this PANA-L4. 5 Reserved 6 USER-Defined: The Selector ID represents applications defined by the user (using CLI, GUI, etc.) based on the methods described in Section 2. The Selector ID has a local significance per device. 7 Reserved 8 Reserved 9 Reserved 10 Reserved 11 Reserved 12 PANA-L2: Proprietary layer 2 (L2) definition. An enterprise can export its own layer 2 identifiers. The Selector ID represents the enterprise's unique global layer 2 applications. The Selector ID has a global significance for all devices from the same enterprise. Examples include the Cisco Subnetwork Access Protocol (SNAP). 13 PANA-L7: Proprietary layer 7 definition. The Selector ID represents the enterprise's unique global ID for layer 7 applications. The Selector ID has a global significance for all devices from the same enterprise. This Classification Engine ID is used when the application registry is owned by the Exporter manufacturer (referred to as the "enterprise" in this document). 14 Reserved 15 Reserved 16 Reserved 17 Reserved 18 ETHERTYPE: The Selector ID represents the well-known Ethertype. See [ETHERTYPE]. 19 LLC: The Selector ID represents the well-known IEEE 802.2 Link Layer Control (LLC) Destination Service Access Point (DSAP). See [LLC]. 20 PANA-L7-PEN: Proprietary layer 7 definition, including a Private Enterprise Number (PEN) [IANA-PEN] to identify that the application registry being used is not owned by the Exporter manufacturer or to identify the original enterprise in the case of a mediator or 3rd party device. The Selector ID represents the enterprise unique global ID for layer 7 applications. The Selector ID has a global significance for all devices from the same enterprise. </paragraph> </description> </field> <field name="applicationCategoryName" dataType="string" group="application" elementId="372" applicability="all" status="current"> <description> <paragraph> An attribute that provides a first-level categorization for each Application Id. </paragraph> </description> </field> <field name="applicationSubCategoryName" dataType="string" group="application" elementId="373" applicability="all" status="current"> <description> <paragraph> An attribute that provides a second-level categorization for each Application ID. </paragraph> </description> </field> <field name="applicationGroupName" dataType="string" group="application" elementId="374" applicability="all" status="current"> <description> <paragraph> An attribute that groups multiple Application IDs that belong to the same networking application. </paragraph> </description> </field> <field name="p2pTechnology" dataType="string" group="application" elementId="288" applicability="all" status="current"> <description> <paragraph> Specifies if the Application ID is based on peer- to-peer technology. Possible values are { "yes", "y", 1 }, { "no", "n", 2 }, and { "unassigned", "u", 0 }. </paragraph> </description> </field> <field name="tunnelTechnology" dataType="string" group="application" elementId="289" applicability="all" status="current"> <description> <paragraph> Specifies if the Application ID is used as a tunnel technology. Possible values are { "yes", "y", 1 }, { "no", "n", 2 }, and { "unassigned", "u", 0 }. </paragraph> </description> </field> <field name="encryptedTechnology" dataType="string" group="application" elementId="290" applicability="all" status="current"> <description> <paragraph> Specifies if the Application ID is an encrypted networking protocol. Possible values are { "yes", "y", 1 }, { "no", "n", 2 }, and { "unassigned", "u", 0 }. </paragraph> </description> </field> Appendix B. Port Collisions Tables (Non-normative) The following table lists the 10 ports that have different protocols assigned for TCP and UDP (at the time of writing this document): exec 512/tcp remote process execution; authentication performed using passwords and UNIX login names comsat/biff 512/udp used by mail system to notify users of new mail received; currently receives messages only from processes on the same machine login 513/tcp remote login a la telnet; automatic authentication performed based on priviledged [sic] port numbers and distributed data bases which identify "authentication domains" who 513/udp maintains data bases showing who's logged in to machines on a local net and the load average of the machine shell 514/tcp cmd like exec, but automatic authentication is performed as for login server syslog 514/udp oob-ws-https 664/tcp DMTF out-of-band secure web services management protocol Jim Davis <jim.davis@wbemsolutions.com> asf-secure-rmcp 664/udp ASF Secure Remote Management and Control Protocol rfile 750/tcp kerberos-iv 750/udp kerberos version iv submit 773/tcp notify 773/udp rpasswd 774/tcp acmaint_dbd 774/udp entomb 775/tcp acmaint_transd 775/udp busboy 998/tcp puparp 998/udp garcon 999/tcp applix 999/udp Applix ac Table 4: Different Protocols on UDP and TCP The following table lists the 19 ports that have different protocols assigned for TCP and SCTP (at the time of writing this document): # 3097/tcp Reserved itu-bicc-stc 3097/sctp ITU-T Q.1902.1/Q.2150.3 Greg Sidebottom <gregside@home.com> # 5090/tcp <not assigned> car 5090/sctp Candidate AR # 5091/tcp <not assigned> cxtp 5091/sctp Context Transfer Protocol # 6704/tcp Reserved frc-hp 6704/sctp ForCES HP (High Priority) channel [RFC5811] # 6705/tcp Reserved frc-mp 6705/sctp ForCES MP (Medium Priority) channel [RFC5811] # 6706/tcp Reserved frc-lp 6706/sctp ForCES LP (Low Priority) channel [RFC5811] # 9082/tcp <not assigned> lcs-ap 9082/sctp LCS Application Protocol Kimmo Kymalainen <kimmo.kymalainen@etsi.org> # 9902/tcp <not assigned> enrp-sctp-tls 9902/sctp enrp/tls server channel [RFC5353] # 11997/tcp <not assigned> # 11998/tcp <not assigned> # 11999/tcp <not assigned> wmereceiving 11997/sctp WorldMailExpress wmedistribution 11998/sctp WorldMailExpress wmereporting 11999/sctp WorldMailExpress Greg Foutz <gregf@adminovation.com> # 25471/tcp <not assigned> rna 25471/sctp RNSAP User Adaptation for Iurh Dario S. Tonesi <dario.tonesi@nsn.com> 07 February 2011 # 29118/tcp Reserved sgsap 29118/sctp SGsAP in 3GPP # 29168/tcp Reserved sbcap 29168/sctp SBcAP in 3GPP # 29169/tcp <not assigned> iuhsctpassoc 29169/sctp HNBAP and RUA Common Association John Meredith <John.Meredith@etsi.org> 08 September 2009 # 36412/tcp <not assigned> s1-control 36412/sctp S1-Control Plane (3GPP) Kimmo Kymalainen <kimmo.kymalainen@etsi.org> 01 September 2009 # 36422/tcp <not assigned> x2-control 36422/sctp X2-Control Plane (3GPP) Kimmo Kymalainen <kimmo.kymalainen@etsi.org> 01 September 2009 # 36443/tcp <not assigned> m2ap 36443/sctp M2 Application Part Dario S. Tonesi <dario.tonesi@nsn.com> 07 February 2011 # 36444/tcp <not assigned> m3ap 36444/sctp M3 Application Part Dario S. Tonesi <dario.tonesi@nsn.com> 07 February 2011 Table 5: Different Protocols on SCTP and TCP Appendix C. Application Registry Example (Non-normative) A reference to the Cisco Systems assigned numbers for the Application ID and the different attribute assignments can be found at [CISCO-APPLICATION-REGISTRY]. Authors' Addresses Benoit Claise Cisco Systems, Inc. De Kleetlaan 6a b1 Diegem 1813 Belgium Phone: +32 2 704 5622 EMail: bclaise@cisco.com Paul Aitken Cisco Systems, Inc. 96 Commercial Quay Commercial Street Edinburgh, EH6 6LX United Kingdom Phone: +44 131 561 3616 EMail: paitken@cisco.com Nir Ben-Dvora Cisco Systems, Inc. 32 HaMelacha St., P.O. Box 8735, I.Z.Sapir South Netanya, 42504 Israel Phone: +972 9 892 7187 EMail: nirbd@cisco.com