RFC 6615
Definitions of Managed Objects for IP Flow Information Export
Internet Engineering Task Force (IETF) T. Dietz, Ed. Request for Comments: 6615 NEC Europe Ltd. Obsoletes: 5815 A. Kobayashi Category: Standards Track NTT PF Labs ISSN: 2070-1721 B. Claise Cisco Systems, Inc. G. Muenz Technische Universitaet Muenchen June 2012 Definitions of Managed Objects for IP Flow Information ExportAbstract
This document defines managed objects for IP Flow Information eXport (IPFIX). These objects provide information for monitoring IPFIX Exporters and IPFIX Collectors, including basic configuration information. Status of This Memo This is an Internet Standards Track document. 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). Further information on Internet Standards is available in 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/rfc6615. Copyright Notice Copyright (c) 2012 IETF Trust and the persons identified as the document authors. All rights reserved. This document is subject to BCP 78 and the IETF Trust's Legal Provisions Relating to IETF Documents (http://trustee.ietf.org/license-info) in effect on the date of publication of this document. Please review these documents carefully, as they describe your rights and restrictions with respect to this document. Code Components extracted from this document must include Simplified BSD License text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as described in the Simplified BSD License.
Table of Contents
1. Introduction ....................................................3 2. IPFIX Documents Overview ........................................3 3. The Internet-Standard Management Framework ......................4 4. Terminology .....................................................4 5. Structure of the IPFIX MIB ......................................4 5.1. The Transport Session Table ................................4 5.2. The Template Table .........................................7 5.3. The Template Definition Table ..............................9 5.4. The Export Table ..........................................11 5.5. The Metering Process Table ................................13 5.6. The Observation Point Table ...............................14 5.7. The Selection Process Table ...............................15 5.8. The Statistical Tables ....................................16 5.8.1. The Transport Session Statistical Table ............16 5.8.2. The Template Statistical Table .....................16 5.8.3. The Metering Process Statistical Table .............16 5.8.4. The Selection Process Statistical Table ............16 6. Structure of the IPFIX SELECTOR MIB ............................16 6.1. The Selector Functions ....................................17 7. Relationship to Other MIB Modules ..............................19 7.1. Relationship to the ENTITY MIB and Interfaces MIB .........19 7.2. MIB Modules Required for IMPORTS ..........................19 8. MIB Definitions ................................................20 8.1. IPFIX MIB Definition ......................................20 8.2. IPFIX SELECTOR MIB Definition .............................56 9. Security Considerations ........................................60 10. IANA Considerations ...........................................61 11. Acknowledgments ...............................................62 12. References ....................................................62 12.1. Normative References .....................................62 12.2. Informative References ...................................63
1. Introduction
This document defines two MIB modules for monitoring IP Flow Information eXport (IPFIX) Devices, including Exporters and Collectors. While most of the objects defined by the IPFIX MIB module must be implemented, some objects may be implemented corresponding to the functionality implemented in the equipment. Since the IPFIX architecture [RFC5470] foresees the possibility of using Filtering and/or Sampling functions to reduce the data volume, this document also provides the IPFIX SELECTOR MIB module, which contains the standardized selection methods and is controlled by IANA. The full configuration of the IPFIX Metering Process is out of the scope of these MIB modules. 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].2. IPFIX Documents Overview
The IPFIX protocol provides network administrators with access to IP Flow information. The architecture for the export of measured IP Flow information out of an IPFIX Exporting Process to a Collecting Process is defined in [RFC5470], per the requirements defined in [RFC3917]. The protocol document [RFC5101] 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 name, type, and additional semantic information -- as specified in [RFC5102]. Finally, [RFC5472] describes what type of applications can use the IPFIX protocol and how they can use the information provided. It furthermore shows how the IPFIX framework relates to other architectures and frameworks. It is assumed that Flow metering, export, and collection are performed according to the IPFIX architecture defined in [RFC5470]. The monitored configuration parameters of the export and collection of Flow Templates and Data Records are modeled according to [RFC5101]. Packet selection methods that may be optionally used by the IPFIX Metering Process are not considered in this MIB document. They are defined in the Packet Sampling (PSAMP) framework [RFC5474] and Sampling techniques [RFC5475] documents. Nevertheless, the basis for defining Sampling and Filtering functions is given with the IPFIX SELECTOR MIB module. Since the PSAMP export protocol [RFC5476] is based on the IPFIX protocol, the Sampling and Filtering functions can be added to the IPFIX SELECTOR MIB module as needed.
3. 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 MIB modules that are compliant to the SMIv2, which is described in STD 58, RFC 2578 [RFC2578], STD 58, RFC 2579 [RFC2579] and STD 58, RFC 2580 [RFC2580].4. Terminology
The definitions of basic terms such as IP Traffic Flow, Exporting Process, Collecting Process, Observation Points, etc. can be found in the IPFIX protocol document [RFC5101].5. Structure of the IPFIX MIB
The IPFIX MIB module consists of seven main tables: the Transport Session table, the Template table and the corresponding Template Definition table, the Export table, the Metering Process table, the Observation Point table, and the Selection Process table. Since the IPFIX architecture [RFC5470] foresees the possibility of using Filtering and/or Sampling functions to reduce the data volume, the IPFIX MIB module provides the basic objects for these functions with the Selection Process table. The IPFIX SELECTOR MIB module, defined in the next section, provides the standard Filtering and Sampling functions that can be referenced in the ipfixSelectionProcessTable. All remaining objects contain statistical values for the different tables contained in the MIB module. The following subsections describe all tables in the IPFIX MIB module.5.1. The Transport Session Table
The Transport Session is the basis of the MIB module. The Transport Session table (ipfixTransportSessionTable) contains all Transport Sessions between the Exporter and Collector. The table specifies the transport layer protocol of the Transport Session and, depending on that protocol, further parameters for the Transport Session. In the case of UDP and TCP, these are the source and destination address as
well as the source and destination port. For the Stream Control Transmission Protocol (SCTP), the table contains ipfixTransportSessionSctpAssocId, which is the index for the SCTP association in the SCTP MIB module [RFC3873]. The mode of operation of the device, i.e., whether the Transport Session is used for collecting or exporting, is given in the ipfixTransportSessionDeviceMode object. Further on, the table contains the configured refresh parameters for Templates and Options Templates that are used across unreliable connections such as UDP. Finally, the IPFIX version that is exported or collected by this Transport Session and a status of the Transport Session are given in the table. To illustrate the use of this table, let us assume the following scenario: we have an Exporter on IP address 192.0.2.22 and a Collector on IP address 192.0.2.37. The Exporter uses TCP to export Templates and Data Records. The same Exporter also exports, with UDP, to a Collector with the IP address of 192.0.2.44. This would lead to the following Transport Session table on the Exporter:
ipfixTransportSessionTable (1)
|
+- ipfixTransportSessionEntry (1)
|
+- index (5) (ipfixTransportSessionIndex)
| +- ipfixTransportSessionIndex (1) = 5
| +- ipfixTransportSessionProtocol (2) = 6 (TCP)
| +- ipfixTransportSessionSourceAddressType (3) = 1 (ipv4)
| +- ipfixTransportSessionSourceAddress (4) = 192.0.2.22
| +- ipfixTransportSessionDestinationAddressType (5) = 1 (ipv4)
| +- ipfixTransportSessionDestinationAddress (6) = 192.0.2.37
| +- ipfixTransportSessionSourcePort (7) = 7653
| +- ipfixTransportSessionDestinationPort (8) = 4739
| +- ipfixTransportSessionSctpAssocId (9) = 0
| +- ipfixTransportSessionDeviceMode (10) = exporting(1)
| +- ipfixTransportSessionTemplateRefreshTimeout (11) = 0
| +- ipfixTransportSessionOptionsTemplateRefreshTimeout (12) = 0
| +- ipfixTransportSessionTemplateRefreshPacket (13) = 0
| +- ipfixTransportSessionOptionsTemplateRefreshPacket (14) = 0
| +- ipfixTransportSessionIpfixVersion (15) = 10
| +- ipfixTransportSessionStatus (16) = 2 (active)
.
.
.
+- index (11) (ipfixTransportSessionIndex)
+- ipfixTransportSessionIndex (1) = 11
+- ipfixTransportSessionProtocol (2) = 17 (UDP)
+- ipfixTransportSessionSourceAddressType (3) = 1 (ipv4)
+- ipfixTransportSessionSourceAddress (4) = 192.0.2.22
+- ipfixTransportSessionDestinationAddressType (5) = 1 (ipv4)
+- ipfixTransportSessionDestinationAddress (6) = 192.0.2.44
+- ipfixTransportSessionSourcePort (7) = 14287
+- ipfixTransportSessionDestinationPort (8) = 4739
+- ipfixTransportSessionSctpAssocId (9) = 0
+- ipfixTransportSessionDeviceMode (10) = exporting(1)
+- ipfixTransportSessionTemplateRefreshTimeout (11) = 100
+- ipfixTransportSessionOptionsTemplateRefreshTimeout (12)
| = 100
+- ipfixTransportSessionTemplateRefreshPacket (13) = 10
+- ipfixTransportSessionOptionsTemplateRefreshPacket (14) = 10
+- ipfixTransportSessionIpfixVersion (15) = 10
+- ipfixTransportSessionStatus (16) = 2 (active)
The values in parentheses are the OID numbers. The Collectors would
then have the same entry, except that the index would most likely
differ and the ipfixTransportSessionDeviceMode value would be
collecting(2).
5.2. The Template Table
The Template table lists all Templates (including Options Templates) that are sent (by an Exporter) or received (by a Collector). The (Options) Templates are unique per Observation Domain and per Transport Session. Note that the Transport Session also gives the device mode, i.e., Exporter or Collector. Thus, the table is indexed by o the Transport Session Index (ipfixTransportSessionIndex) and o the Observation Domain ID (ipfixTemplateObservationDomainId). It contains the Set ID and an access time denoting the time when the (Options) Template was last sent or received. To resume the above example, the Exporter may want to export a Template and an Options Template for each Transport Session defined above. This leads to the following Template table, which defines the Template and Options Template:
ipfixTemplateTable (3)
|
+- ipfixTemplateEntry (1)
|
+- index (5) (ipfixTransportSessionIndex)
| +- index (3) (ipfixTemplateObservationDomainId)
| + index (257) (ipfixTemplateId)
| | +- ipfixTemplateObservationDomainId (1) = 3
| | +- ipfixTemplateId (2) = 257
| | +- ipfixTemplateSetId (3) = 2
| | +- ipfixTemplateAccessTime (4)
| | = 2008-7-1,12:49:11.2,+2:0
| |
| + index (264) (ipfixTemplateId)
| +- ipfixTemplateObservationDomainId (1) = 3
| +- ipfixTemplateId (2) = 264
| +- ipfixTemplateSetId (3) = 3
| +- ipfixTemplateAccessTime (4)
. = 2008-7-1,12:47:04.8,+2:0
.
.
.
+- index (11) (ipfixTransportSessionIndex)
+- index (3) (ipfixTemplateObservationDomainId)
+ index (273) (ipfixTemplateId)
| +- ipfixTemplateObservationDomainId (1) = 3
| +- ipfixTemplateId (2) = 273
| +- ipfixTemplateSetId (3) = 2
| +- ipfixTemplateAccessTime (4)
| = 2008-7-1,12:49:11.2,+2:0
|
+ index (289) (ipfixTemplateId)
+- ipfixTemplateObservationDomainId (1) = 3
+- ipfixTemplateId (2) = 289
+- ipfixTemplateSetId (3) = 3
+- ipfixTemplateAccessTime (4)
= 2008-7-1,12:47:04.8,+2:0
We assume that the Transport Session that is stored with index 5 in
the Transport Session table of the Exporter is stored with index 17
in the Transport Session table of the (corresponding) Collector.
Then, the Template table would look as follows:
ipfixTemplateTable (3)
|
+- ipfixTemplateEntry (1)
|
+- index (17) (ipfixTransportSessionIndex)
+- index (3) (ipfixTemplateObservationDomainId)
+ index (257) (ipfixTemplateId)
| +- ipfixTemplateObservationDomainId (1) = 3
| +- ipfixTemplateId (2) = 257
| +- ipfixTemplateSetId (3) = 2
| +- ipfixTemplateAccessTime (4)
| = 2008-7-1,12:49:11.8,+2:0
|
+ index (264) (ipfixTemplateId)
+- ipfixTemplateObservationDomainId (1) = 3
+- ipfixTemplateId (2) = 264
+- ipfixTemplateSetId (3) = 3
+- ipfixTemplateAccessTime (4)
= 2008-7-1,12:47:05.3,+2:0
The table on the second Collector would be analogous to the one shown
above.
5.3. The Template Definition Table
The Template Definition table lists all the Information Elements
contained in a Template or Options Template. Therefore, it has the
same indexes as the corresponding Template table plus the Template
ID. Its own index denotes the order of the Information Element
inside the Template. Besides the Information Element ID and the
length of the encoded value, the table contains the enterprise number
for enterprise-specific Information Elements and flags for each
Information Element. The flags indicate whether the Information
Element is used for scoping or as a Flow Key.
To resume the above example again, the Exporter is configured to
export the octets received and dropped at the Observation Point since
the last export of these values. In addition, it exports the start
and end time of the Flow relative to the timestamp contained in the
IPFIX header. This leads to the following Template Definition table
on the Exporter:
ipfixTemplateDefinitionTable (4)
|
+- ipfixTemplateDefinitionEntry (1)
|
+- index (5) (ipfixTransportSessionIndex)
+- index (3) (ipfixTemplateObservationDomainId)
+ index (257) (ipfixTemplateId)
+- index (1) (ipfixTemplateDefinitionIndex)
| +- ipfixTemplateDefinitionIndex (1) = 1
| +- ipfixTemplateDefinitionIeId (2) = 158
| | (flowStartDeltaMicroseconds)
| +- ipfixTemplateDefinitionIeLength (3) = 4
| +- ipfixTemplateDefinitionEnterpriseNumber (4) = 0
| +- ipfixTemplateDefinitionFlags (5) = 0
|
+- index (2) (ipfixTemplateDefinitionIndex)
| +- ipfixTemplateDefinitionIndex (1) = 2
| +- ipfixTemplateDefinitionIeId (2) = 159
| | (flowEndDeltaMicroseconds)
| +- ipfixTemplateDefinitionIeLength (3) = 4
| +- ipfixTemplateDefinitionEnterpriseNumber (4) = 0
| +- ipfixTemplateDefinitionFlags (5) = 0
|
+- index (3) (ipfixTemplateDefinitionIndex)
| +- ipfixTemplateDefinitionIndex (1) = 3
| +- ipfixTemplateDefinitionIeId (2) = 1
| | (octetDeltaCount)
| +- ipfixTemplateDefinitionIeLength (3) = 8
| +- ipfixTemplateDefinitionEnterpriseNumber (4) = 0
| +- ipfixTemplateDefinitionFlags (5) = 0
|
+- index (4) (ipfixTemplateDefinitionIndex)
+- ipfixTemplateDefinitionIndex (1) = 4
+- ipfixTemplateDefinitionIeId (2) = 132
| (droppedOctetDeltaCount)
+- ipfixTemplateDefinitionIeLength (3) = 8
+- ipfixTemplateDefinitionEnterpriseNumber (4) = 0
+- ipfixTemplateDefinitionFlags (5) = 0
The corresponding table entry on the Collector is the same, except
that it would have another ipfixTransportSessionIndex, e.g., 17 as in
the previous example.
5.4. The Export Table
On Exporters, the Export table (ipfixExportTable) can be used to support features like failover, load-balancing, duplicate export to several Collectors, etc. The table has three indexes that link an entry with o the Metering Process table (ipfixMeteringProcessCacheId; see below) and o the Transport Session table (ipfixTransportSessionIndex). Those entries with the same ipfixExportIndex and the same ipfixMeteringProcessCacheId define a Transport Session group. The member type for each group member describes its functionality. All Transport Sessions referenced in this table MUST have a ipfixTransportSessionDeviceMode value of exporting(1). If the Exporter does not use Transport Session grouping, then each ipfixExportIndex contains a single ipfixMeteringProcessCacheId, and thus a single Transport Session (ipfixTransportSessionIndex); this session MUST have a member type value of primary(1). For failover, a Transport Session group can contain one Transport Session with member type primary(1) and several Transport Sessions with type secondary(2). Entries with other member types are not allowed for that type of group. For load-balancing or parallel export, all Transport Sessions in the group MUST have the same member type -- either loadBalancing(4) or parallel(3). The algorithms used for failover or load-balancing are out of the scope of this document. To continue the example, we assume that the Exporter uses the two connections shown in the examples above as one primary Transport Session protected by a secondary Transport Session. The Exporter then has the following entries in the ipfixExportTable:
ipfixExportTable (5)
|
+- ipfixExportEntry (1)
|
+- index (7) (ipfixExportIndex)
| +- index (9) (ipfixMeteringProcessCacheId)
| | +- index (5) (ipfixTransportSessionIndex)
| | +- ipfixExportIndex (1) = 7
| | +- ipfixExportMemberType (2) = 1 (primary)
| |
| +- index (11) (ipfixTransportSessionIndex)
| +- ipfixExportIndex (1) = 7
| +- ipfixExportMemberType (2) = 2 (secondary)
|
+- index (8) (ipfixExportIndex)
+- index (9) (ipfixMeteringProcessCacheId)
+- index (5) (ipfixTransportSessionIndex)
| +- ipfixExportIndex (1) = 8
| +- ipfixExportMemberType (2) = 2 (secondary)
+- index (11) (ipfixTransportSessionIndex)
+- ipfixExportIndex (1) = 8
+- ipfixExportMemberType (2) = 1 (primary)
The example shows that the Exporter uses the Metering Process cache
(index (9)), explained below, to export IPFIX Data Records for
Transport Sessions 5 and 11. Templates 257 and 264 defined above are
exported within Transport Session 5 as primary, while the secondary
Transport Session is 11. Templates 273 and 289 are exported within
Transport Session 11 as primary, while the secondary Transport
Session is 5.
Here are the steps required by a manager in order to understand what
the backups are (if any) for Template Records exported from a
specific Exporter to a specific Collector:
1. Look up the Collector IP address in the
ipfixTransportSessionDestinationAddress object (in the
ipfixTransportSessionTable).
2. From the same row, double-check the Exporter IP address in the
ipfixTransportSessionSourceAddress object.
3. From the same row, write down the ipfixTransportSessionIndex
value.
4. Use that ipfixTransportSessionIndex value in the
ipfixTemplateTable and look up the pairs of
(ipfixTemplateObservationDomainId, ipfixTemplateId). From there,
the manager deduces the Template Record(s) (ipfixTemplateId),
exported from the Observation Domain(s)
(ipfixTemplateObservationDomainId) on the tracked Exporter
(ipfixTransportSessionSourceAddress) to the tracked Collector
(ipfixTransportSessionDestinationAddress).
5. Reusing the same ipfixTransportSessionIndex in the
ipfixExportTable, look in the table for a value of
ipfixExportMemberType that equals "primary". Note that there
could be multiple entries for which the ipfixExportMemberType
equals "primary" in the ipfixExportTable, so multiple iterations
might be required until the correct value of
ipfixTransportSessionIndex is found.
6. From the same row, write down the ipfixExportIndex value.
7. In the ipfixExportTable, under the same three index values
(ipfixExportIndex, ipfixMeteringProcessCacheId, and
ipfixTransportSessionIndex), look up the entries for which
ipfixExportMemberType is different than "primary". Write down
the associated ipfixTransportSessionIndex value.
8. From the ipfixTransportSessionTable, look up the Transport
Session details for this ipfixTransportSessionIndex value -- for
example, the secondary Collector IP address and port
(ipfixTransportSessionDestinationAddress and
ipfixTransportSessionSourcePort).
5.5. The Metering Process Table
The Metering Process, as defined in [RFC5101], consists of a set of
functions. Maintaining the Flow Records is one of them. This
function is responsible for passing the Flow Records to the Exporting
Process and also for detecting Flow expiration. The Flow Records
that are maintained by the Metering Process can be grouped by the
Observation Points at which they are observed. The instance that
maintains such a group of Flow Records is a kind of cache. For this
reason, the Metering Process table (ipfixMeteringProcessTable) is
indexed by cache IDs (ipfixMeteringProcessCacheId). Each cache can
be maintained by a separate instance of the Metering Process. To
specify the Observation Point(s) where the Flow Records are gathered,
the ipfixMeteringProcessObservationPointGroupRef may contain an
ipfixObservationPointGroupId from the Observation Point table
(ipfixObservationPointTable), which is described in the next
subsection. If an Observation Point is not specified for the Flow
Records, the ipfixMeteringProcessObservationPointGroupRef MUST be
zero(0). The timeouts (ipfixMeteringProcessCacheActiveTimeout and
ipfixMeteringProcessCacheIdleTimeout) specify when Flows are expired.
ipfixMeteringProcessTable (6)
|
+- ipfixMeteringProcessEntry (1)
|
+- index (9) (ipfixMeteringProcessCacheId)
+- ipfixMeteringProcessCacheId (1) = 9
+- ipfixMeteringProcessObservationPointGroupRef (2) = 17
+- ipfixMeteringProcessCacheActiveTimeout (3) = 100
+- ipfixMeteringProcessCacheIdleTimeout (4) = 100
5.6. The Observation Point Table
The Observation Point table (ipfixObservationPointTable) groups
Observation Points with the ipfixObservationPointGroupId. Each entry
contains the Observation Domain ID in which the Observation Point is
located and a reference to the ENTITY MIB module [RFC4133] or the
Interfaces MIB module [RFC2863]. The objects in the ENTITY MIB
module referenced by ipfixObservationPointPhysicalEntity, or the
objects in the Interfaces MIB module referenced by
ipfixObservationPointPhysicalInterface, denote the Observation Point.
At least one reference for the objects
ipfixObservationPointPhysicalEntity or
ipfixObservationPointPhysicalInterface MUST exist for a valid
Observation Point entry. If a reference to the Observation Point is
given in both object ipfixObservationPointPhysicalEntity and
ipfixObservationPointPhysicalInterface, then both MUST point to the
same physical interface. However, if one of two references
(ipfixObservationPointPhysicalEntity or
ipfixObservationPointPhysicalInterface) cannot be given, its
reference MUST be 0. In addition, a direction can be given to render
more specifically which Flow to monitor.
ipfixObservationPointTable (7)
|
+- ipfixObservationPointEntry (1)
|
+- index (17) (ipfixObservationPointGroupId)
+- index (1) (ipfixObservationPointIndex)
| +- ipfixObservationPointGroupId (1) = 17
| +- ipfixObservationPointIndex (2) = 1
| +- ipfixObservationPointObservationDomainId (3) = 3
| +- ipfixObservationPointPhysicalEntity (4) = 6
| +- ipfixObservationPointPhysicalInterface(5) = 0
| +- ipfixObservationPointPhysicalEntityDirection (6)
= 3 (both)
|
+- index (2) (ipfixObservationPointIndex)
+- ipfixObservationPointGroupId (1) = 17
+- ipfixObservationPointIndex (2) = 2
+- ipfixObservationPointObservationDomainId (3) = 3
+- ipfixObservationPointPhysicalEntity (4) = 0
+- ipfixObservationPointPhysicalInterface (5) = 0
+- ipfixObservationPointPhysicalEntityDirection (6)
= 1 (ingress)
5.7. The Selection Process Table
This table supports the usage of Filtering and Sampling functions, as
described in [RFC5470]. It contains lists of functions per Metering
Process cache (ipfixMeteringProcessCacheId). The selection process
index ipfixSelectionProcessIndex forms groups of selection methods
that are applied to an observed packet stream. The selection process
selector index (ipfixSelectionProcessSelectorIndex) indicates the
order in which the functions are applied to the packets observed at
the Observation Points associated with the Metering Process cache.
The selection methods are applied in increasing order; i.e.,
selection methods with a lower ipfixSelectionProcessSelectorIndex are
applied first. The functions are referenced by object identifiers
pointing to each function with its parameters. If the selection
method does not use parameters, then it MUST point to the root of the
function subtree (see also Section 6). If the function uses
parameters, then it MUST point to an entry in the parameter table of
the selection method. If no Filtering or Sampling function is used
for a Metering Process, then an entry for the Metering Process SHOULD
be created that points to the Select All function
(ipfixFuncSelectAll).
5.8. The Statistical Tables
Statistical tables that augment the ipfixTransportSessionTable, ipfixTemplateTable, ipfixMeteringProcessTable, and ipfixSelectionProcessTable have been defined. All the statistical tables contain a discontinuity object that holds a timestamp denoting the time when a discontinuity event occurred, in order to notify the management system that the counters contained in those tables might not be continuous anymore.5.8.1. The Transport Session Statistical Table
The Transport Session Statistical table (ipfixTransportSessionStatsTable) augments the ipfixTransportSessionTable with statistical values. It contains the rate (in bytes per second) at which it receives or sends out IPFIX Messages; the number of bytes, packets, messages, Records, Templates, and Options Templates received or sent; and the number of messages that were discarded.5.8.2. The Template Statistical Table
This table contains a statistical value for each Template. It augments the Template table (ipfixTemplateTable) and specifies the number of Data Records exported or collected for the Template.5.8.3. The Metering Process Statistical Table
This table augments the Metering Process table (ipfixMeteringProcessTable). It contains the statistical values for the exported Data Records and the number of unused cache entries.5.8.4. The Selection Process Statistical Table
This table augments the Selection Process table (ipfixSelectionProcessTable) and introduces two generic statistical values: the number of packets observed and the number of packets dropped by the selection method.6. Structure of the IPFIX SELECTOR MIB
The IPFIX SELECTOR MIB module defined in this section provides the standard Filtering and Sampling functions that can be referenced in the ipfixSelectionProcessTable. All standard Filtering and Sampling functions MUST be registered in the subtree under object ipfixSelectorFunctions (iso.org.dod.internet.mgmt.mib-2. ipfixSelectorMIB.ipfixSelectorObjects.ipfixSelectorFunctions, or 1.3.6.1.2.1.194.1.1). The top-level OIDs in the subtree under object
ipfixSelectorFunctions MUST be registered in a sub-registry maintained by IANA at http://www.iana.org/assignments/smi-numbers. The first entry in this subtree is the Select All function (ipfixFuncSelectAll), defined in this document as {ipfixSelectorFunctions 1}. New Selector Functions MUST be registered at IANA and are subject to Expert Review [RFC5226], i.e., review by one of a group of experts designated by an IETF Area Director. The group of experts MUST check the requested MIB objects for completeness and accuracy of the description. Requests for MIB objects that duplicate the functionality of existing objects SHOULD be declined. The smallest available OID SHOULD be assigned to new MIB objects. The specification of new MIB objects SHOULD follow the structure specified in Section 6.1 and MUST be published using a well- established and persistent publication medium. The experts will initially be drawn from the Working Group Chairs and document editors of the IPFIX and PSAMP Working Groups.6.1. The Selector Functions
The following figure shows what the MIB tree usually should look like. It already contains ipfixFuncSelectAll. The subtree in ipfixFuncF2 gives the basic structure that all selection methods SHOULD follow. ipfixSelectorFunctions | +- ipfixFuncSelectAll | | | +- ipfixFuncSelectAllAvail (is the function available?) | +- ipfixFuncF2 | | | +- ipfixFuncF2Avail (is the function F2 available?) | | | +- ipfixFuncF2Parameters (a table with parameters) ... | +- ipfixFuncFn... The selection method SHOULD be designed as a MIB subtree introduced by an object with the name ipfixFunc appended by a function name. The objects in this subtree SHOULD be prefixed by this name. If the function is named Fx, then we would start a subtree with an OID named ipfixFuncFx. This subtree should contain an object ipfixFuncFxAvail that has the type TruthValue. If a selection method takes parameters, the MIB should contain a table named
ipfixFuncFxParameters, which should contain all the parameters that
the selection method specifies. An entry in this table will be
referenced by the IPFIX MIB module if the selection method with the
parameters is used.
To illustrate the structure defined above, the following contains an
example of a function MyFunc that holds three integer parameters
Param1, Param2, and Param3. In the example, there are currently two
instances of the parameter sets, defined with indexes 1 and 4.
ipfixSelectorFunctions (1)
|
+- ipfixFuncMyFunc (?)
|
+- ipfixFuncMyFuncAvail (1) = true
+- ipfixFuncMyFuncParameters (2)
|
+- ipfixFuncMyFuncParametersEntry (1)
|
+- index (1) (ipfixFuncMyFuncParametersIndex)
| +- ipfixFuncMyFuncParam1 (1) = 47
| +- ipfixFuncMyFuncParam2 (2) = -128
| +- ipfixFuncMyFuncParam3 (3) = 19
|
+- index(4) (ipfixFuncMyFuncParametersIndex)
+- ipfixFuncMyFuncParam1 (1) = 19
+- ipfixFuncMyFuncParam2 (2) = -1
+- ipfixFuncMyFuncParam3 (3) = 728
If the function defined above is referenced in the IPFIX MIB module,
the ipfixSelectionProcessTable would look as follows:
ipfixSelectionProcessTable (8)
|
+- ipfixSelectionProcessEntry (1)
|
+- index (9) (ipfixMeteringProcessCacheId)
+- index (1) (ipfixSelectionProcessIndex)
+- index (1) (ipfixSelectionProcessSelectorIndex)
| +- ipfixSelectionProcessSelectorFunction (3)
| = ipfixSelectorFunctions.?.2.1.4
+- index (2) (ipfixSelectionProcessSelectorIndex)
+- ipfixSelectionProcessSelectorFunction (3)
= ipfixSelectorFunctions.?.2.1.1
This means that for the ipfixMeteringProcessCacheId(9), a Selection Process with index 1 is created that applies the same function two times but with different parameter sets. First, the function MyFunc is applied with the parameters of the set with index 4, and then with the parameters of the set with index 1.7. Relationship to Other MIB Modules
Besides the usual imports from the SNMP Standards [RFC2578], [RFC2579], and [RFC2580], the IPFIX MIB module references the ENTITY MIB module [RFC4133] and the Interfaces MIB module [RFC2863].7.1. Relationship to the ENTITY MIB and Interfaces MIB
The Observation Point table (ipfixObservationPointTable) contains a reference to the ENTITY MIB module [RFC4133] (ipfixObservationPointPhysicalEntity) and a reference to the Interfaces MIB module [RFC2863] (ipfixObservationPointPhysicalInterface). If the implementers of the IPFIX MIB module want to specify the physical entity where Flows are observed, then they SHOULD also implement the ENTITY MIB and/or the Interfaces MIB module. The implementation of the ENTITY MIB and/or the Interfaces MIB module is OPTIONAL. If one of them is not implemented, then all values of the respective column ipfixObservationPointPhysicalEntity or ipfixObservationPointPhysicalInterface in the Observation Point table are zero and the values of the ipfixObservationPointPhysicalEntityDirection columns are unknown(0), if none of them are defined.7.2. MIB Modules Required for IMPORTS
The IPFIX MIB module requires the modules SNMPv2-SMI [RFC2578], SNMPv2-TC [RFC2579], and SNMPv2-CONF [RFC2580]. Further on, it imports the textual conventions InetAddressType and InetAddress from the INET ADDRESS MIB module [RFC4001]. The IPFIX SELECTOR MIB module also requires the modules SNMPv2-SMI [RFC2578], SNMPv2-TC [RFC2579], and SNMPv2-CONF [RFC2580].
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