Network Working Group T. Dietz, Ed.
Internet-Draft NEC Europe Ltd.
Intended status: Standards Track B. Claise
Expires: December 31, 2012 Cisco Systems, Inc.
J. Quittek
NEC Europe Ltd.
July 2012

Definitions of Managed Objects for Packet Sampling

Abstract

This memo defines a portion of the Management Information Base (MIB) for use with network management protocols in the Internet community. In particular, it describes extensions to the IPFIX SELECTOR MIB module. For IPFIX implementations that use packet Sampling (PSAMP) techniques, this memo defines the PSAMP MIB module containing managed objects for providing information on applied packet selection functions and their parameters.

Status of this Memo

This Internet-Draft is submitted in full conformance with the provisions of BCP 78 and BCP 79.

Internet-Drafts are working documents of the Internet Engineering Task Force (IETF). Note that other groups may also distribute working documents as Internet-Drafts. The list of current Internet- Drafts is at http://datatracker.ietf.org/drafts/current/.

Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress."

This Internet-Draft will expire on December 31, 2012.

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. The Internet-Standard Management Framework

For a detailed overview of the documents that describe the current Internet-Standard Management Framework, please refer to section 7 of RFC 3410 [RFC3410].

Managed objects are accessed via a virtual information store, termed the Management Information Base or MIB. MIB objects are generally accessed through the Simple Network Management Protocol (SNMP). Objects in the MIB are defined using the mechanisms defined in the Structure of Management Information (SMI). This memo specifies a MIB module that is compliant to the SMIv2, which is described in STD 58, RFC 2578 [RFC2578], STD 58, RFC 2579 [RFC2579] and STD 58,RFC 2580 [RFC2580].

2. Introduction

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

This document is a product of the IP Flow Information eXport (IPFIX) working group. Work on this document was started in the Packet Sampling (PSAMP) Working Group (WG) and moved to the IPFIX WG when the PSAMP WG was concluded.

Its purpose is to define managed objects for monitoring PSAMP Devices performing packet selection by Sampling and Filtering as described in [RFC5475].

It is assumed that packet Sampling is performed according to the framework defined in [RFC5474].

Managed objects in the PSAMP MIB module are defined as an extension of the IPFIX MIB and IPFIX SELECTOR MIB modules [RFC6615]. Since the IPFIX MIB module is only for monitoring the same holds true for the PSAMP MIB module defined in this document. The definition of objects is in line with the PSAMP information model [RFC5477].

Section 3 gives an overview of the PSAMP documents, while section 4 refers to the related IPFIX documents. Section 5 describes the structure of the PSAMP MIB module and section 6 contains the formal definition. Security issues are discussed in section 7.

3. PSAMP Documents Overview

[RFC5474]: "A Framework for Packet Selection and Reporting" describes the PSAMP framework for network elements to select subsets of packets by statistical and other methods, and to export a stream of reports on the selected packets to a Collector.

[RFC5475]: "Sampling and Filtering Techniques for IP Packet Selection" describes the set of packet selection techniques supported by PSAMP.

[RFC5476]: "Packet Sampling (PSAMP) Protocol Specifications" specifies the export of packet information from a PSAMP Exporting Process to a PSAMP Collecting Process.

[RFC5477]: "Information Model for Packet Sampling Exports" defines an information and data model for PSAMP.

This document: "Definitions of Managed Objects for Packet Sampling" describes the PSAMP Management Information Base.

4. Related IPFIX Documents

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

[RFC5101]: The protocol document "Specification of the IP Flow Information Export (IPFIX) Protocol for the Exchange of IP Traffic Flow Information" specifies how IPFIX Data Records and Templates are carried via a congestion-aware transport protocol from IPFIX Exporting Processes to IPFIX Collecting Processes. It also specifies the data types used in the PSAMP MIB module and their encoding.

[RFC6615]: The IPFIX MIB "Definitions of Managed Objects for IP Flow Information Export" is the basis for this document because it extends the IPFIX SELECTOR MIB module defined there.

5. Structure of the PSAMP MIB module

The IPFIX MIB module defined in [RFC6615] has the concept of a packet Selection Process containing a set of Selector function instances. Selection Processes and functions are referenced in the ipfixSelectionProcessTable of the IPFIX MIB module. The ipfixSelectionProcessTable identifies an instance of a Selector function by an OID. The OID points to an object that describes the Selector function. For simple Selector functions without parameters, the OID refers to an object which contains only one additional object indicating the current availability of the function. For functions which have one or more parameters the object has a subtree that in addition to an availability object contains a table with a conceptual column for each parameter. Entries (conceptual rows) in this table represent different combinations of parameter values for instances of the Selector function.

The object ipfixSelectorFunctions in the IPFIX SELECTOR MIB module serves as the root for objects that describe instances of packet Selector functions. The IPFIX SELECTOR MIB module is a very small module which is defined in [RFC6615]. The top level OIDs of the parameter trees located beneath ipfixSelectorFunctions are maintained by IANA. In the IPFIX SELECTOR MIB module as defined by [RFC6615] the object ipfixSelectorFunctions contains just a single trivial packet Selector function called ipfixFuncSelectAll that selects every packet and has no parameter:

ipfixSelectorMIB
+- ipfixSelectorObjects(1)
   +- ipfixSelectorFunctions(1)
      +- ipfixFuncSelectAll(1)
         +- ipfixFuncSelectAllAvail(1)
       

The PSAMP MIB module defined in this document registers additional toplevel OIDs for the parameter subtrees of its Selector functions in the IPFIX-SELECTOR-MIB Function subregistry according to the procedures defined in [RFC6615]. It introduces six new subtrees beneath ipfixSelectorFunctions. Each of them describes a packet Selector function with one or more parameters. Naming and ordering of objects is fully in line with the guidelines given in section 6.1 of [RFC6615]. All functions and their parameters are already listed in the overview of functions given by the table in section 8.2.1 of [RFC5477].

5.1. Textual Conventions

The PSAMP MIB module imports two textual conventions which define data types used in this MIB module from other MIB modules. The Unsigned64TC data type is imported from the APPLICATION MIB module [RFC2564] and the Float64TC data type is imported from the FLOAT-TC-MIB module [RFC6340]. Those data types are defined according to [RFC5101]. Those data types are not an integral part of [RFC2578] but are needed to define objects in this MIB module that conform to the Information Elements defined for those objects in [RFC5477].

The Unsigned64TC textual convention describes an unsigned integer of 64 bits. It is imported from the APPLICATION MIB module. The Float64TC textual convention describes the format that is used for 64 bit floating point numbers.

5.2. Packet Selection Functions

In general, different packet Selector functions have different parameters. The PSAMP MIB module contains six objects with subtrees that provide information on parameters of function instances of different Selector functions. All objects are named and structured according to section 8.2.1 of [RFC5477]:

ipfixSelectorFunctions(1)
+-- psampSampCountBased(2)
+- -psampSampTimeBased(3)
+-- psampSampRandOutOfN(4)
+-- psampSampUniProb(5)
+-- psampFiltPropMatch(6)
+-- psampFiltHash(7)
     

Indexing of these functions in the PSAMP MIB module starts with index (2). The function ipfixFuncSelectAll with index (1) is already defined in the IPFIX SELECTOR MIB module as shown above.

The object tree for each of these functions is described below. Semantics of all functions and their parameters are described in detail in [RFC5475]. More information on the Selector Reports can also be found in section 6.5.2 of [RFC5476].

5.2.1. Systematic Count-based Sampling

The first Selector function is systematic count-based Sampling. Its availability is indicated by object psampSampCountBasedAvail. The function has two parameters: psampSampCountBasedInterval and psampSampCountBasedSpace. Different combination of values of these parameters for different instances of the Selector function are represented by different conceptual rows in table psampSampCountBasedParamSetEntry:

psampSampCountBased(2)
+-- psampSampCountBasedAvail(1)
+-- psampSampCountBasedParamSetTable(2)
   +-- psampSampCountBasedParamSetEntry(1) [psampSampCountBasedIndex]
      +-- psampSampCountBasedIndex(1)
      +-- psampSampCountBasedInterval(2)
      +-- psampSampCountBasedSpace(3)
         

5.2.2. Systematic Time-based Sampling

The second Selector function is systematic time-based Sampling. The structure of the sub-tree for this function is similar to the psampSampCountBased sub-tree. Parameters are psampSampTimeBasedInterval and psampSampTimeBasedSpace. They appear to be the same as for count based Sampling, but their data types are different because they indicate time values instead of numbers of packets:

psampSampTimeBased(3)
+-- psampSampTimeBasedAvail(1)
+-- psampSampTimeBasedParamSetTable(2)
   +-- psampSampTimeBasedParamSetEntry(1) [psampSampTimeBasedIndex]
      +-- psampSampTimeBasedIndex(1)
      +-- psampSampTimeBasedInterval(2)
      +-- psampSampTimeBasedSpace(3)
         

5.2.3. Random n-out-of-N Sampling

The third Selector function is random n-out-of-N Sampling. Parameters are psampSampRandOutOfNSize and psampSampRandOutOfNPopulation:

psampSampRandOutOfN(4)
+-- psampSampRandOutOfNAvail(1)
+-- psampSampRandOutOfNParamSetTable(2)
   +-- psampSampRandOutOfNParamSetEntry(1) [psampSampRandOutOfNIndex]
      +-- psampSampRandOutOfNIndex(1)
      +-- psampSampRandOutOfNSize(2)
      +-- psampSampRandOutOfNPopulation(3)
         

5.2.4. Uniform Probabilistic Sampling

The fourth Selector function is uniform probabilistic Sampling. It has just a single parameter called psampSampUniProbProbability:

psampSampUniProb(5)
+-- psampSampUniProbAvail(1)
+-- psampSampUniProbParamSetTable(2)
   +-- psampSampUniProbParamSetEntry(1) [psampSampUniProbIndex]
      +-- psampSampUniProbIndex(1)
      +-- psampSampUniProbProbability(2)
         

5.2.5. Property Match Filtering

The fifth Selector function is property match Filtering. For this Selector function there is a broad variety of possible parameters that could be used. But as stated in section 8.2.1 of [RFC5477] there are no agreed parameters specified and the sub-tree for this function only contains an object indicating the availability of this function. Parameters cannot be retrieved via the PSAMP MIB module:

psampFiltPropMatch(6)
+-- psampFiltPropMatchAvail(1)
         

5.2.6. Hash-based Filtering

The sixth Selector function is hash-based Filtering. The object psampFiltHashFunction is an enumeration that specifies the kind of hash function that is applied. These hash function have quite a number of parameters and the actual number may vary with the choice of the hash function applied. The common parameter set for all hash-based Filtering functions contains 7 parameters: psampFiltHashInitializerValue, psampFiltHashIpPayloadOffset, psampFiltHashIpPayloadSize, psampFiltHashSelectedRangeMin, psampFiltHashSelectedRangeMax, psampFiltHashOutputRangeMin, and psampFiltHashOutputRangeMax.

psampFiltHash(7)
+-- psampFiltHashAvail(1)
+-- psampFiltHashCapabilities(2)
+-- psampFiltHashParamSetTable(3)
   +-- psampFiltHashParamSetEntry(1) [psampFiltHashIndex]
      +-- psampFiltHashIndex(1)
      +-- psampFiltHashFunction(2)
      +-- psampFiltHashInitializerValue(3)
      +-- psampFiltHashIpPayloadOffset(4)
      +-- psampFiltHashIpPayloadSize(5)
      +-- psampFiltHashSelectedRangeMin(6)
      +-- psampFiltHashSelectedRangeMax(7)
      +-- psampFiltHashOutputRangeMin(8)
      +-- psampFiltHashOutputRangeMax(9)
         

Further parameters depend on the applied hash function and are not specified within the PSAMP MIB module.

6. Definitions

PSAMP-MIB DEFINITIONS ::= BEGIN

IMPORTS
    MODULE-IDENTITY, OBJECT-TYPE, Integer32, Unsigned32, mib-2
        FROM SNMPv2-SMI                  -- RFC2578
    TruthValue
        FROM SNMPv2-TC                   -- RFC2579
    MODULE-COMPLIANCE, OBJECT-GROUP
        FROM SNMPv2-CONF                 -- RFC2580
    Unsigned64TC
        FROM APPLICATION-MIB             -- RFC2564
    Float64TC
        FROM FLOAT-TC-MIB                -- RFC6340
    ipfixSelectorFunctions
        FROM IPFIX-SELECTOR-MIB;         -- RFC6615

psampMIB MODULE-IDENTITY
    LAST-UPDATED "201207051200Z"         -- 05 July 2012
    ORGANIZATION "IETF IPFIX Working Group"
    CONTACT-INFO
        "WG charter:
          http://www.ietf.org/html.charters/ipfix-charter.html

        Mailing Lists:
          General Discussion: ipfix@ietf.org
          To Subscribe: http://www1.ietf.org/mailman/listinfo/ipfix
          Archive:
      http://www1.ietf.org/mail-archive/web/ipfix/current/index.html

        Editor:
          Thomas Dietz
          NEC Europe Ltd.
          NEC Laboratories Europe
          Network Research Division
          Kurfuersten-Anlage 36
          69115 Heidelberg
          Germany
          Phone: +49 6221 4342-128
          Email: Thomas.Dietz@neclab.eu

          Benoit Claise
          Cisco Systems, Inc.
          De Kleetlaan 6a b1
          Degem 1831
          Belgium
          Phone:  +32 2 704 5622
          Email: bclaise@cisco.com

          Juergen Quittek
          NEC Europe Ltd.
          NEC Laboratories Europe
          Network Research Division
          Kurfuersten-Anlage 36
          69115 Heidelberg
          Germany
          Phone: +49 6221 4342-115
          Email: quittek@neclab.eu"
        DESCRIPTION
        "The PSAMP MIB defines managed objects for packet sampling
        and filtering.
        These objects provide information about managed nodes
        supporting packet sampling, including packet sampling
        capabilities, configuration and statistics.
        The PSAMP MIB module registers additional toplevel OIDs for
        the parameter subtrees of its Selector functions in the
        IPFIX-SELECTOR-MIB Function subregistry according to the
        procedures defined in RFC 6615.

        Copyright (c) 2012 IETF Trust and the persons identified as
        the document authors.  All rights reserved. This version
        of this MIB module is part of RFC yyyy; see the RFC itself
        for full legal notices"
-- RFC Ed.: replace yyyy with actual RFC number & remove this notice
     --  Revision history

     REVISION     "201207051200Z"         -- 05 July 2012
     DESCRIPTION
         "Initial version, published as RFC yyyy."
-- RFC Ed.: replace yyyy with actual RFC number & remove this notice

    ::= { mib-2 xxx }
-- RFC Ed.: replace xxx which is to be assigned by IANA & remove
-- this notice.

-- Top level structure of the MIB

psampObjects     OBJECT IDENTIFIER ::= { psampMIB 1 }
psampConformance OBJECT IDENTIFIER ::= { psampMIB 2 }


--==================================================================
-- Packet selection sampling methods group of objects
--==================================================================

--==================================================================
--* Method 1: Systematic count-based Sampling
--==================================================================

-- Reference: RFC5475, Section 5.1, RFC5476 Section 6.5.2.1 and
--            RFC5477, Section 8.2
psampSampCountBased OBJECT IDENTIFIER
    ::= { ipfixSelectorFunctions 2 }

psampSampCountBasedAvail OBJECT-TYPE
    SYNTAX      TruthValue
    MAX-ACCESS  read-only
    STATUS      current
    DESCRIPTION
        "This object indicates the availability of systematic
        count-based sampling at the managed node.
         
        A Selector may be unavailable if it is implemented but
        currently disabled due to e.g., administrative reasons, lack
        of resources or similar."
    ::= { psampSampCountBased 1 }

-- Parameter Set Table +++++++++++++++++++++++++++++++++++++++++++++

psampSampCountBasedParamSetTable OBJECT-TYPE
    SYNTAX      SEQUENCE OF
                PsampSampCountBasedParamSetEntry
    MAX-ACCESS  not-accessible
    STATUS      current
    DESCRIPTION
        "This table lists configurations of systematic count-based
        packet sampling.  A parameter set describing a
        configuration contains two parameters: the sampling
        interval length and space."
    ::= { psampSampCountBased 2 }

psampSampCountBasedParamSetEntry OBJECT-TYPE
    SYNTAX      PsampSampCountBasedParamSetEntry
    MAX-ACCESS  not-accessible
    STATUS      current
    DESCRIPTION
        "Defines an entry in the psampSampCountBasedParamSetTable."
    INDEX { psampSampCountBasedIndex }
    ::= { psampSampCountBasedParamSetTable 1 }

PsampSampCountBasedParamSetEntry ::=
    SEQUENCE {
        psampSampCountBasedIndex     Integer32,
        psampSampCountBasedInterval  Unsigned32,
        psampSampCountBasedSpace     Unsigned32
    }

psampSampCountBasedIndex OBJECT-TYPE
    SYNTAX      Integer32 (1..2147483647)
    MAX-ACCESS  not-accessible
    STATUS      current
    DESCRIPTION
        "The index of this parameter set in the
        psampSampCountBasedParamSetTable. It is used in the
        object ipfixSelectionProcessSelectorFunction entries of
        the ipfixSelectionProcessTable in the IPFIX-MIB as reference
        to this parameter set."
    ::= { psampSampCountBasedParamSetEntry 1 }

psampSampCountBasedInterval OBJECT-TYPE
    SYNTAX      Unsigned32
    UNITS       "packets"
    MAX-ACCESS  read-only
    STATUS      current
    DESCRIPTION
        "This object specifies the number of packets that are
        consecutively sampled.  A value of 100 means that 100
        consecutive packets are sampled."
    REFERENCE
        "RFC5475, Section 5.1 and RFC5477, Section 8.2"
    ::= { psampSampCountBasedParamSetEntry 2 }

psampSampCountBasedSpace OBJECT-TYPE
    SYNTAX      Unsigned32
    UNITS       "packets"
    MAX-ACCESS  read-only
    STATUS      current
    DESCRIPTION
        "This object specifies the number of packets between two
        psampSampCountBasedInterval's.  A value of 100 means that
        the next interval starts 100 packets (which are not sampled)
        after the current psampSampCountBasedInterval is over."
    REFERENCE
        "RFC5475, Section 5.1 and RFC5477, Section 8.2"
    ::= { psampSampCountBasedParamSetEntry 3 }

--==================================================================
--* Method 2: Systematic time-based Sampling
--==================================================================

-- Reference: RFC5475, Section 5.1, RFC5476 Section 6.5.2.2 and
--            RFC5477, Section 8.2
psampSampTimeBased OBJECT IDENTIFIER
    ::= { ipfixSelectorFunctions 3 }

psampSampTimeBasedAvail OBJECT-TYPE
    SYNTAX      TruthValue
    MAX-ACCESS  read-only
    STATUS      current
    DESCRIPTION
        "This object indicates the availability of systematic
        time-based sampling at the managed node.
         
        A Selector may be unavailable if it is implemented but
        currently disabled due to e.g., administrative reasons, lack
        of resources or similar."
    ::= { psampSampTimeBased 1 }

-- Parameter Set Table +++++++++++++++++++++++++++++++++++++++++++++

psampSampTimeBasedParamSetTable OBJECT-TYPE
    SYNTAX      SEQUENCE OF
                PsampSampTimeBasedParamSetEntry
    MAX-ACCESS  not-accessible
    STATUS      current
    DESCRIPTION
        "This table lists configurations of systematic time-based
        packet sampling. A parameter set describing a configuration
        contains two parameters: the sampling interval length and
        the space."
    ::= { psampSampTimeBased 2 }

psampSampTimeBasedParamSetEntry OBJECT-TYPE
    SYNTAX      PsampSampTimeBasedParamSetEntry
    MAX-ACCESS  not-accessible
    STATUS      current
    DESCRIPTION
        "Defines an entry in the psampSampTimeBasedParamSetTable."
    INDEX { psampSampTimeBasedIndex }
    ::= { psampSampTimeBasedParamSetTable 1 }

PsampSampTimeBasedParamSetEntry ::=
    SEQUENCE {
        psampSampTimeBasedIndex     Integer32,
        psampSampTimeBasedInterval  Unsigned32,
        psampSampTimeBasedSpace     Unsigned32
    }

psampSampTimeBasedIndex OBJECT-TYPE
    SYNTAX      Integer32 (1..2147483647)
    MAX-ACCESS  not-accessible
    STATUS      current
    DESCRIPTION
        "The index of this parameter set in the
        psampSampTimeBasedParamSetTable. It is used in the
        object ipfixSelectionProcessSelectorFunction entries of
        the ipfixSelectionProcessTable in the IPFIX-MIB as reference
        to this parameter set."
    ::= { psampSampTimeBasedParamSetEntry 1 }

psampSampTimeBasedInterval OBJECT-TYPE
    SYNTAX      Unsigned32
    UNITS       "microseconds"
    MAX-ACCESS  read-only
    STATUS      current
    DESCRIPTION
        "This object specifies the time interval in microseconds
        during which all arriving packets are sampled."
    REFERENCE
        "RFC5475, Section 5.1 and RFC5477, Section 8.2"
    ::= { psampSampTimeBasedParamSetEntry 2 }

psampSampTimeBasedSpace OBJECT-TYPE
    SYNTAX      Unsigned32
    UNITS       "microseconds"
    MAX-ACCESS  read-only
    STATUS      current
    DESCRIPTION
        "This object specifies the time interval in microseconds
        between two psampSampTimeBasedInterval's.  A value of 100
        means that the next interval starts 100 microseconds (during
        which no packets are sampled) after the current
        psampSampTimeBasedInterval is over."
    REFERENCE
        "RFC5475, Section 5.1 and RFC5477, Section 8.2"
    ::= { psampSampTimeBasedParamSetEntry 3 }

--==================================================================
--* Method 3: Random n-out-of-N Sampling
--==================================================================

-- Reference: RFC5475, Section 5.2.1, RFC5476 Section 6.5.2.3 and
--            RFC5477, Section 8.2
psampSampRandOutOfN OBJECT IDENTIFIER
    ::= { ipfixSelectorFunctions 4 }

psampSampRandOutOfNAvail OBJECT-TYPE
    SYNTAX      TruthValue
    MAX-ACCESS  read-only
    STATUS      current
    DESCRIPTION
        "This object indicates the availability of random n-out-of-N
        sampling at the managed node.
         
        A Selector may be unavailable if it is implemented but
        currently disabled due to e.g., administrative reasons, lack
        of resources or similar."
    ::= { psampSampRandOutOfN 1 }

-- Parameter Set Table +++++++++++++++++++++++++++++++++++++++++++++

psampSampRandOutOfNParamSetTable OBJECT-TYPE
    SYNTAX      SEQUENCE OF
                PsampSampRandOutOfNParamSetEntry
    MAX-ACCESS  not-accessible
    STATUS      current
    DESCRIPTION
        "This table lists configurations of random n-out-of-N
        sampling.  A parameter set describing a configuration
        contains two parameters, the sampling size and the
        parent population."
    ::= { psampSampRandOutOfN 2 }

psampSampRandOutOfNParamSetEntry OBJECT-TYPE
    SYNTAX      PsampSampRandOutOfNParamSetEntry
    MAX-ACCESS  not-accessible
    STATUS      current
    DESCRIPTION
        "Defines an entry in the psampSampRandOutOfNParamSetTable."
    INDEX { psampSampRandOutOfNIndex }
    ::= { psampSampRandOutOfNParamSetTable 1 }

PsampSampRandOutOfNParamSetEntry ::=
    SEQUENCE {
        psampSampRandOutOfNIndex        Integer32,
        psampSampRandOutOfNSize Unsigned32,
        psampSampRandOutOfNPopulation   Unsigned32
    }

psampSampRandOutOfNIndex OBJECT-TYPE
    SYNTAX      Integer32 (1..2147483647)
    MAX-ACCESS  not-accessible
    STATUS      current
    DESCRIPTION
        "The index of this parameter set in the
        psampSampRandOutOfNParamSetTable.  It is used in the
        object ipfixSelectionProcessSelectorFunction entries of
        the ipfixSelectionProcessTable in the IPFIX-MIB as reference
        to this parameter set."
    ::= { psampSampRandOutOfNParamSetEntry 1 }

psampSampRandOutOfNSize OBJECT-TYPE
    SYNTAX      Unsigned32
    UNITS       "packets"
    MAX-ACCESS  read-only
    STATUS      current
    DESCRIPTION
        "This object specifies the number of elements taken from the
        parent Population specified in
        psampSampRandOutOfNPopulation."
    REFERENCE
        "RFC5475, Section 5.2.1 and RFC5477, Section 8.2"
    ::= { psampSampRandOutOfNParamSetEntry 2 }

psampSampRandOutOfNPopulation OBJECT-TYPE
    SYNTAX      Unsigned32
    UNITS       "packets"
    MAX-ACCESS  read-only
    STATUS      current
    DESCRIPTION
        "This object specifies the number of elements in the parent
        Population."
    REFERENCE
        "RFC5475, Section 5.2.1 and RFC5477, Section 8.2"
    ::= { psampSampRandOutOfNParamSetEntry 3 }

--==================================================================
--* Method 4: Uniform probabilistic Sampling
--==================================================================

-- Reference: RFC5475, Section 5.2.2, RFC5476 Section 6.5.2.4 and
--            RFC5477, Section 8.2
psampSampUniProb OBJECT IDENTIFIER ::= { ipfixSelectorFunctions 5 }

psampSampUniProbAvail OBJECT-TYPE
    SYNTAX      TruthValue
    MAX-ACCESS  read-only
    STATUS      current
    DESCRIPTION
        "This object indicates the availability of random uniform
        probabilistic sampling at the managed node.
         
        A Selector may be unavailable if it is implemented but
        currently disabled due to e.g., administrative reasons, lack
        of resources or similar."
    ::= { psampSampUniProb 1 }

-- Parameter Set Table +++++++++++++++++++++++++++++++++++++++++++++

-- Reference: RFC5475, Section 5.2.2.1 and RFC5477, Section 8.2
psampSampUniProbParamSetTable OBJECT-TYPE
    SYNTAX      SEQUENCE OF
                PsampSampUniProbParamSetEntry
    MAX-ACCESS  not-accessible
    STATUS      current
    DESCRIPTION
        "This table lists configurations of random probabilistic
        sampling.  A parameter set describing a configuration
        contains a single parameter only: the sampling probability."
    ::= { psampSampUniProb 2 }

psampSampUniProbParamSetEntry OBJECT-TYPE
    SYNTAX      PsampSampUniProbParamSetEntry
    MAX-ACCESS  not-accessible
    STATUS      current
    DESCRIPTION
        "Defines an entry in the psampSampUniProbParamSetTable."
    INDEX { psampSampUniProbIndex }
    ::= { psampSampUniProbParamSetTable 1 }

PsampSampUniProbParamSetEntry ::=
    SEQUENCE {
        psampSampUniProbIndex       Integer32,
        psampSampUniProbProbability Float64TC
    }

psampSampUniProbIndex OBJECT-TYPE
    SYNTAX      Integer32 (1..2147483647)
    MAX-ACCESS  not-accessible
    STATUS      current
    DESCRIPTION
        "The index of this parameter set in the
        psampSampUniProbParamSetTable.  It is used in the
        object ipfixSelectionProcessSelectorFunction entries of
        the ipfixSelectionProcessTable in the IPFIX-MIB as reference
        to this parameter set."
    ::= { psampSampUniProbParamSetEntry 1 }

psampSampUniProbProbability OBJECT-TYPE
    SYNTAX      Float64TC
    MAX-ACCESS  read-only
    STATUS      current
    DESCRIPTION
        "This object specifies the probability that a packet is
        sampled, expressed as a value between 0 and 1.  The
        probability is equal for every packet.  A value of 0 means
        no packet is sampled since the probability is 0. A value
        of 1 means all packets are sampled since the
        probability is 1. NaN (not a number) and infinity MUST NOT
        be used."
    REFERENCE
        "RFC5475, Section 5.2.2.1 and RFC5477, Section 8.2"
    ::= { psampSampUniProbParamSetEntry 2 }

--==================================================================
-- Packet selection filtering methods group of objects
--==================================================================

--==================================================================
--* Method 5: Property Match filtering
--==================================================================

-- Reserves Method 5 (see RFC5475, Section 6.1, RFC5476
-- Section 6.5.2.5 and RFC5477)
psampFiltPropMatch OBJECT IDENTIFIER
    ::= { ipfixSelectorFunctions 6 }

psampFiltPropMatchAvail OBJECT-TYPE
    SYNTAX      TruthValue
    MAX-ACCESS  read-only
    STATUS      current
    DESCRIPTION
        "This object indicates the availability of property match
        filtering at the managed node.
         
        A Selector may be unavailable if it is implemented but
        currently disabled due to e.g., administrative reasons, lack
        of resources or similar."
    ::= { psampFiltPropMatch 1 }

--==================================================================
--* Method 6: Hash filtering
--==================================================================

-- Reference: RFC5475, Section 6.2, RFC5476 Section 6.5.2.6 and
--            RFC5477, Section 8.3
psampFiltHash OBJECT IDENTIFIER ::= { ipfixSelectorFunctions 7 }

psampFiltHashAvail OBJECT-TYPE
    SYNTAX      TruthValue
    MAX-ACCESS  read-only
    STATUS      current
    DESCRIPTION
        "This object indicates the availability of hash filtering
        at the managed node.
         
        A Selector may be unavailable if it is implemented but
        currently disabled due to e.g., administrative reasons, lack
        of resources or similar."
    ::= { psampFiltHash 1 }

psampFiltHashCapabilities OBJECT IDENTIFIER
    ::= { psampFiltHash 2 }

-- Parameter Set Table +++++++++++++++++++++++++++++++++++++++++++++

-- Reference: RFC5475, Sections 6.2, 3.8, and 7.1
psampFiltHashParamSetTable OBJECT-TYPE
    SYNTAX      SEQUENCE OF
                PsampFiltHashParamSetEntry
    MAX-ACCESS  not-accessible
    STATUS      current
    DESCRIPTION
        "This table lists configurations of hash filtering. A
        parameter set describing a configuration contains eight
        parameters describing the hash function."
    ::= { psampFiltHash 3 }

psampFiltHashParamSetEntry OBJECT-TYPE
    SYNTAX      PsampFiltHashParamSetEntry
    MAX-ACCESS  not-accessible
    STATUS      current
    DESCRIPTION
        "Defines an entry in the psampFiltHashParamSetTable."
    INDEX { psampFiltHashIndex }
    ::= { psampFiltHashParamSetTable 1 }

PsampFiltHashParamSetEntry ::=
    SEQUENCE {
        psampFiltHashIndex            Integer32,
        psampFiltHashFunction         INTEGER,
        psampFiltHashInitializerValue Unsigned64TC,
        psampFiltHashIpPayloadOffset  Unsigned64TC,
        psampFiltHashIpPayloadSize    Unsigned64TC,
        psampFiltHashSelectedRangeMin Unsigned64TC,
        psampFiltHashSelectedRangeMax Unsigned64TC,
        psampFiltHashOutputRangeMin   Unsigned64TC,
        psampFiltHashOutputRangeMax   Unsigned64TC
    }

psampFiltHashIndex OBJECT-TYPE
    SYNTAX      Integer32 (1..2147483647)
    MAX-ACCESS  not-accessible
    STATUS      current
    DESCRIPTION
        "The index of this parameter set in the
        psampFiltHashParamSetTable. It is used in the
        object ipfixSelectionProcessSelectorFunction entries of
        the ipfixSelectionProcessTable in the IPFIX-MIB as reference
        to this parameter set."
    ::= { psampFiltHashParamSetEntry 1 }

psampFiltHashFunction OBJECT-TYPE
    SYNTAX      INTEGER {
                    crc32(1),
                    ipsx(2),
                    bob(3)
                }
    MAX-ACCESS  read-only
    STATUS      current
    DESCRIPTION
        "The Hash Function used by this filter. The PSAMP-MIB
        defines the following Hash Functions:
        
        crc32(1): The CRC32 Hash Function as defined in RFC1141.
        
        ipsx(2): The IPSX Hash Function as described in RFC5475
            appendix A.1.
        
        bob(3): The BOB Hash Function as described in RFC5475
            appendix A.2.
        "
    REFERENCE
        "RFC5475, Section 6.2 and Appendixes A.1 and A.2.
         RFC1141."
    ::= { psampFiltHashParamSetEntry 2 }

psampFiltHashInitializerValue OBJECT-TYPE
    SYNTAX      Unsigned64TC
    MAX-ACCESS  read-only
    STATUS      current
    DESCRIPTION
        "This object specifies the initializer value to the hash
        function."
    REFERENCE
        "RFC5475, Sections 6.2, 3.8, and 7.1"
    ::= { psampFiltHashParamSetEntry 3 }

psampFiltHashIpPayloadOffset OBJECT-TYPE
    SYNTAX      Unsigned64TC
    MAX-ACCESS  read-only
    STATUS      current
    DESCRIPTION
        "This object specifies the IP payload offset used by a
        Hash-based Selection Selector."
    REFERENCE
        "RFC5475, Sections 6.2, 3.8, and 7.1"
    ::= { psampFiltHashParamSetEntry 4 }

psampFiltHashIpPayloadSize OBJECT-TYPE
    SYNTAX      Unsigned64TC
    MAX-ACCESS  read-only
    STATUS      current
    DESCRIPTION
        "This object specifies the IP payload size used by a
        Hash-based Selection Selector."
    REFERENCE
        "RFC5475, Sections 6.2, 3.8, and 7.1"
    ::= { psampFiltHashParamSetEntry 5 }

psampFiltHashSelectedRangeMin OBJECT-TYPE
    SYNTAX      Unsigned64TC
    MAX-ACCESS  read-only
    STATUS      current
    DESCRIPTION
        "This object specifies the value for the beginning of a hash
        function's selected range."
    REFERENCE
        "RFC5475, Sections 6.2, 3.8, and 7.1"
    ::= { psampFiltHashParamSetEntry 6 }

psampFiltHashSelectedRangeMax OBJECT-TYPE
    SYNTAX      Unsigned64TC
    MAX-ACCESS  read-only
    STATUS      current
    DESCRIPTION
        "This object specifies the value for the end of a hash
        function's selected range."
    REFERENCE
        "RFC5475, Sections 6.2, 3.8, and 7.1"
    ::= { psampFiltHashParamSetEntry 7 }

psampFiltHashOutputRangeMin OBJECT-TYPE
    SYNTAX      Unsigned64TC
    MAX-ACCESS  read-only
    STATUS      current
    DESCRIPTION
        "This object specifies the value for the beginning of a hash
        function's potential output range."
    REFERENCE
        "RFC5475, Sections 6.2, 3.8, and 7.1"
    ::= { psampFiltHashParamSetEntry 8 }

psampFiltHashOutputRangeMax OBJECT-TYPE
    SYNTAX      Unsigned64TC
    MAX-ACCESS  read-only
    STATUS      current
    DESCRIPTION
        "This object specifies the value for the end of a hash
        function's potential output range."
    REFERENCE
        "RFC5475, Sections 6.2, 3.8, and 7.1"
    ::= { psampFiltHashParamSetEntry 9 }

--==================================================================
-- Conformance information
--==================================================================

psampCompliances OBJECT IDENTIFIER ::= { psampConformance 1 }
psampGroups      OBJECT IDENTIFIER ::= { psampConformance 2 }

--==================================================================
-- Compliance statements
--==================================================================

psampCompliance MODULE-COMPLIANCE
    STATUS  current
    DESCRIPTION
        "The implementation of all objects is optional and depends
        on the implementation of the corresponding functionality in
        the equipment."
    MODULE  -- this module
        GROUP psampGroupSampCountBased
        DESCRIPTION
            "These objects must be implemented if systematic
            count-based sampling is implemented in the equipment."
        GROUP psampGroupSampTimeBased
        DESCRIPTION
            "These objects must be implemented if systematic
            time-based sampling is implemented in the equipment."
        GROUP psampGroupSampRandOutOfN
        DESCRIPTION
            "These objects must be implemented if random n-out-of-N
            sampling is implemented in the equipment."
        GROUP psampGroupSampUniProb
        DESCRIPTION
            "These objects must be implemented if uniform
            probabilistic sampling is implemented in the equipment."
        GROUP psampGroupFiltPropMatch
        DESCRIPTION
            "These objects must be implemented if the property match
            filtering is implemented in the equipment."
        GROUP psampGroupFiltHash
        DESCRIPTION
            "These objects must be implemented if hash filtering
            is implemented in the equipment."
    ::= { psampCompliances 1 }

--==================================================================
-- MIB groupings
--==================================================================

psampGroupSampCountBased OBJECT-GROUP
    OBJECTS {
              psampSampCountBasedAvail,
              psampSampCountBasedInterval,
              psampSampCountBasedSpace
            }
    STATUS  current
    DESCRIPTION
        "These objects are needed if count based sampling is
        implemented."
    ::= { psampGroups 1 }

psampGroupSampTimeBased OBJECT-GROUP
    OBJECTS {
              psampSampTimeBasedAvail,
              psampSampTimeBasedInterval,
              psampSampTimeBasedSpace
            }
    STATUS  current
    DESCRIPTION
        "These objects are needed if time based sampling is
        implemented."
    ::= { psampGroups 2 }

psampGroupSampRandOutOfN OBJECT-GROUP
    OBJECTS {
              psampSampRandOutOfNAvail,
              psampSampRandOutOfNSize,
              psampSampRandOutOfNPopulation
            }
    STATUS  current
    DESCRIPTION
        "These objects are needed if random n-out-of-N sampling is
        implemented."
    ::= { psampGroups 3 }

psampGroupSampUniProb OBJECT-GROUP
    OBJECTS {
              psampSampUniProbAvail,
              psampSampUniProbProbability
            }
    STATUS  current
    DESCRIPTION
        "These objects are needed if uniform probabilistic sampling
        is implemented."
    ::= { psampGroups 4 }

psampGroupFiltPropMatch OBJECT-GROUP
    OBJECTS {
              psampFiltPropMatchAvail
            }
    STATUS  current
    DESCRIPTION
        "These objects are needed if property match filtering is
        implemented."
    ::= { psampGroups 5 }

psampGroupFiltHash OBJECT-GROUP
    OBJECTS {
              psampFiltHashAvail,
              psampFiltHashFunction,
              psampFiltHashInitializerValue,
              psampFiltHashIpPayloadOffset,
              psampFiltHashIpPayloadSize,
              psampFiltHashSelectedRangeMin,
              psampFiltHashSelectedRangeMax,
              psampFiltHashOutputRangeMin,
              psampFiltHashOutputRangeMax
            }
    STATUS  current
    DESCRIPTION
        "These objects are needed if hash filtering is implemented."
    ::= { psampGroups 6 }

END

7. Security Considerations

There are no management objects defined in this MIB module that have a MAX-ACCESS clause of read-write and/or read-create. So, if this MIB module is implemented correctly, then there is no risk that an intruder can alter or create any management objects of this MIB module via direct SNMP SET operations.

All tables in this MIB module may be considered sensitive or vulnerable in some network environments because objects in the tables may reveal information about the network infrastructure and device configuration. It is thus important to control even GET and/or NOTIFY access to these objects and possibly to even encrypt the values of these objects when sending them over the network via SNMP.

SNMP versions prior to SNMPv3 did not include adequate security. Even if the network itself is secure (for example by using IPsec), there is no control as to who on the secure network is allowed to access and GET/SET (read/change/create/delete) the objects in this MIB module.

It is RECOMMENDED that implementers consider the security features provided by the SNMPv3 framework (see [RFC3410], section 8), including full support for the SNMPv3 cryptographic mechanisms (for authentication and privacy).

Further, deployment of SNMP versions prior to SNMPv3 is NOT RECOMMENDED. Instead, it is RECOMMENDED to deploy SNMPv3 and to enable cryptographic security. It is then a customer/operator responsibility to ensure that the SNMP entity giving access to an instance of this MIB module is properly configured to give access to the objects only to those principals (users) who have legitimate rights to GET or SET (change/create/delete) them.

8. IANA Considerations

The MIB module in this document uses the following IANA-assigned OBJECT IDENTIFIER values recorded in the SMI Numbers registry:

        Descriptor             OBJECT IDENTIFIER value
        ----------             -----------------------
        psampMIB               { mib-2 xxx }
      
Decimal Name                Description                      Reference
------- ------------------- -------------------------------- ---------
2       psampSampCountBased Systematic Count-based Sampling  [RFCyyyy]
3       psampSampTimeBased  Systematic Time-based Sampling   [RFCyyyy]
4       psampSampRandOutOfN Random n-out-of-N Sampling       [RFCyyyy]
5       psampSampUniProb    Universal Probabilistic Sampling [RFCyyyy]
6       psampFiltPropMatch  Property Match Filtering         [RFCyyyy]
7       psampFiltHash       Hash-based Filtering             [RFCyyyy]
      

Further on, IANA will register the following toplevel OIDs in the IPFIX-SELECTOR-MIB Functions sub-registry at http://www.iana.org/assignments/smi-numbers according to the procedures set forth in [RFC6615]:

Editor's Note (to be removed prior to publication): the IANA is requested to assign a value for "xxx" under the 'mib-2' subtree and to record the assignment in the SMI Numbers registry. When the assignment has been made, the RFC Editor is asked to replace "xxx" (here and in the MIB module) with the assigned value and to remove this note. The RFC editor is also asked to replace "yyyy" in this document and the MIB module by the number of the RFC when the assignment has been made.

9. Acknowledgment

This document is a product of the PSAMP and IPFIX working groups. The authors would like to thank the following persons: Paul Aitken for his detailed review, Dan Romascanu and the MIB doctors, and many more, for the technical reviews and feedback.

10. References

10.1. Normative References

[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC2578] McCloghrie, K., Perkins, D. and J. Schoenwaelder, "Structure of Management Information Version 2 (SMIv2)", STD 58, RFC 2578, April 1999.
[RFC2579] McCloghrie, K., Perkins, D. and J. Schoenwaelder, "Textual Conventions for SMIv2", STD 58, RFC 2579, April 1999.
[RFC2580] McCloghrie, K., Perkins, D. and J. Schoenwaelder, "Conformance Statements for SMIv2", STD 58, RFC 2580, April 1999.
[RFC2564] Kalbfleisch, C., Krupczak, C., Presuhn, R. and J. Saperia, "Application Management MIB", RFC 2564, May 1999.
[RFC5101] Claise, B., "Specification of the IP Flow Information Export (IPFIX) Protocol for the Exchange of IP Traffic Flow Information", RFC 5101, January 2008.
[RFC5477] Dietz, T., Claise, B., Aitken, P., Dressler, F. and G. Carle, "Information Model for Packet Sampling Exports", RFC 5477, March 2009.
[RFC6615] Dietz, T., Kobayashi, A., Claise, B. and G. Muenz, "Definitions of Managed Objects for IP Flow Information Export", RFC 6615, June 2012.
[RFC6340] Presuhn, R., "Textual Conventions for the Representation of Floating-Point Numbers", RFC 6340, August 2011.

10.2. Informative References

[RFC3410] Case, J., Mundy, R., Partain, D. and B. Stewart, "Introduction and Applicability Statements for Internet-Standard Management Framework", RFC 3410, December 2002.
[RFC5474] Duffield, N., Chiou, D., Claise, B., Greenberg, A., Grossglauser, M. and J. Rexford, "A Framework for Packet Selection and Reporting", RFC 5474, March 2009.
[RFC5475] Zseby, T., Molina, M., Duffield, N., Niccolini, S. and F. Raspall, "Sampling and Filtering Techniques for IP Packet Selection", RFC 5475, March 2009.
[RFC5476] Claise, B., Johnson, A. and J. Quittek, "Packet Sampling (PSAMP) Protocol Specifications", RFC 5476, March 2009.

Authors' Addresses

Thomas Dietz editor NEC Europe Ltd. NEC Laboratories Europe Kurfuersten-Anlage 36 Heidelberg, 69115 DE Phone: +49 6221 4342-128 EMail: dietz@neclab.eu
Benoit Claise Cisco Systems, Inc. De Kleetlaan 6a b1 Degem, 1831 BE Phone: +32 2 704 5622 EMail: bclaise@cisco.com
J├╝rgen Quittek NEC Europe Ltd. NEC Laboratories Europe Kurfuersten-Anlage 36 Heidelberg, 69115 DE Phone: +49 6221 4342-115 EMail: quittek@neclab.eu