Internet Engineering Task Force (IETF)
Request for Comments: 6759
Category: Informational
ISSN: 2070-1721
B. Claise
P. Aitken
N. Ben-Dvora
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 © 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))
  1. IP protocols (such as ICMP (Internet Control Message Protocol), IGMP (Internet Group Management Protocol), GRE (Generic Routing Encapsulation)
  1. TCP or UDP ports (such as HTTP, Telnet, FTP)
  1. Application layer header (of the application to be identified)
  1. Packet data content
  1. 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]).
  1. 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.
  1. 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.

  1. 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.
  1. 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.

  1. applicationName.
  1. 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.
  1. 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.
  1. 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.

  1. applicationCategoryName.
  1. applicationSubCategoryName.
  1. applicationGroupName
  1. p2pTechnology
  1. tunnelTechnology
  1. 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.

  1. 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.
  1. Reserved
  1. 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.
  1. Reserved
  1. Reserved
  1. Reserved
  1. Reserved
  1. 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).
  1. Reserved
  1. Reserved
  1. Reserved
  1. Reserved
  1. ETHERTYPE: The Selector ID represents the well- known Ethertype. See [ETHERTYPE].
  1. LLC: The Selector ID represents the well-known IEEE 802.2 Link Layer Control (LLC) Destination Service Access Point (DSAP). See [LLC].
  1. 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 }.
   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 }.
   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 }.
   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.
  1. Reserved
  1. 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.
  1. Reserved
  1. Reserved
  1. Reserved
  1. Reserved
  1. Reserved
  1. 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).
  1. Reserved
  1. Reserved
  1. Reserved
  1. Reserved
  1. ETHERTYPE: The Selector ID represents the well-known Ethertype. See [ETHERTYPE].
  1. 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