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rfc:rfc2863

Network Working Group K. McCloghrie Request for Comments: 2863 Cisco Systems Obsoletes: 2233 F. Kastenholz Category: Standards Track Argon Networks

                                                             June 2000
                      The Interfaces Group MIB

Status of this Memo

 This document specifies an Internet standards track protocol for the
 Internet community, and requests discussion and suggestions for
 improvements.  Please refer to the current edition of the "Internet
 Official Protocol Standards" (STD 1) for the standardization state
 and status of this protocol.  Distribution of this memo is unlimited.

Copyright Notice

 Copyright (C) The Internet Society (2000).  All Rights Reserved.

Table of Contents

 1 Introduction .................................................    2
 2 The SNMP Network Management Framework ........................    2
 3 Experience with the Interfaces Group .........................    3
 3.1 Clarifications/Revisions ...................................    4
 3.1.1 Interface Sub-Layers .....................................    4
 3.1.2 Guidance on Defining Sub-layers ..........................    7
 3.1.3 Virtual Circuits .........................................    8
 3.1.4 Bit, Character, and Fixed-Length Interfaces ..............    8
 3.1.5 Interface Numbering ......................................   10
 3.1.6 Counter Size .............................................   14
 3.1.7 Interface Speed ..........................................   16
 3.1.8 Multicast/Broadcast Counters .............................   17
 3.1.9 Trap Enable ..............................................   17
 3.1.10 Addition of New ifType values ...........................   18
 3.1.11 InterfaceIndex Textual Convention .......................   18
 3.1.12 New states for IfOperStatus .............................   18
 3.1.13 IfAdminStatus and IfOperStatus ..........................   19
 3.1.14 IfOperStatus in an Interface Stack ......................   21
 3.1.15 Traps ...................................................   21
 3.1.16 ifSpecific ..............................................   23
 3.1.17 Creation/Deletion of Interfaces .........................   23
 3.1.18 All Values Must be Known ................................   24
 4 Media-Specific MIB Applicability .............................   24
 5 Overview .....................................................   25
 6 Interfaces Group Definitions .................................   26

McCloghrie & Kastenholz Standards Track [Page 1] RFC 2863 The Interfaces Group MIB June 2000

 7 Acknowledgements .............................................   64
 8 References ...................................................   64
 9 Security Considerations ......................................   66
 10 Authors' Addresses ..........................................   67
 11 Changes from RFC 2233 .......................................   67
 12 Notice on Intellectual Property .............................   68
 13 Full Copyright Statement ....................................   69

1. Introduction

 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 managed objects used for managing Network
 Interfaces.  This memo discusses the 'interfaces' group of MIB-II
 [17], especially the experience gained from the definition of
 numerous media-specific MIB modules for use in conjunction with the '
 interfaces' group for managing various sub-layers beneath the
 internetwork-layer.  It specifies clarifications to, and extensions
 of, the architectural issues within the MIB-II model of the '
 interfaces' group.  This memo obsoletes RFC 2233, the previous
 version of the Interfaces Group MIB.
 The key words "MUST" and "MUST NOT" in this document are to be
 interpreted as described in RFC 2119 [16].

2. The SNMP Network Management Framework

 The SNMP Management Framework presently consists of five major
 components:
    o  An overall architecture, described in RFC 2571 [1].
    o  Mechanisms for describing and naming objects and events for the
       purpose of management.  The first version of this Structure of
       Management Information (SMI) is called SMIv1 and described in
       STD 16, RFC 1155 [2], STD 16, RFC 1212 [3] and RFC 1215 [4].
       The second version, called SMIv2, is described in STD 58, which
       consists of RFC 2578 [5], RFC 2579 [6] and RFC 2580 [7].
    o  Message protocols for transferring management information.  The
       first version of the SNMP message protocol is called SNMPv1 and
       described in STD 15, RFC 1157 [8].  A second version of the
       SNMP message protocol, which is not an Internet standards track
       protocol, is called SNMPv2c and described in RFC 1901 [9] and
       RFC 1906 [10].  The third version of the message protocol is
       called SNMPv3 and described in RFC 1906 [10], RFC 2572 [11] and
       RFC 2574 [12].

McCloghrie & Kastenholz Standards Track [Page 2] RFC 2863 The Interfaces Group MIB June 2000

    o  Protocol operations for accessing management information.  The
       first set of protocol operations and associated PDU formats is
       described in STD 15, RFC 1157 [8].  A second set of protocol
       operations and associated PDU formats is described in RFC 1905
       [13].
    o  A set of fundamental applications described in RFC 2573 [14]
       and the view-based access control mechanism described in RFC
       2575 [15].
 A more detailed introduction to the current SNMP Management Framework
 can be found in RFC 2570 [22].
 Managed objects are accessed via a virtual information store, termed
 the Management Information Base or MIB.  Objects in the MIB are
 defined using the mechanisms defined in the SMI.
 This memo specifies a MIB module that is compliant to the SMIv2.  A
 MIB conforming to the SMIv1 can be produced through the appropriate
 translations.  The resulting translated MIB must be semantically
 equivalent, except where objects or events are omitted because no
 translation is possible (e.g., use of Counter64).  Some machine
 readable information in SMIv2 will be converted into textual
 descriptions in SMIv1 during the translation process.  However, this
 loss of machine readable information is not considered to change the
 semantics of the MIB.

3. Experience with the Interfaces Group

 One of the strengths of internetwork-layer protocols such as IP [18]
 is that they are designed to run over any network interface.  In
 achieving this, IP considers any and all protocols it runs over as a
 single "network interface" layer.  A similar view is taken by other
 internetwork-layer protocols.  This concept is represented in MIB-II
 by the 'interfaces' group which defines a generic set of managed
 objects such that any network interface can be managed in an
 interface-independent manner through these managed objects.  The '
 interfaces' group provides the means for additional managed objects
 specific to particular types of network interface (e.g., a specific
 medium such as Ethernet) to be defined as extensions to the '
 interfaces' group for media-specific management.  Since the
 standardization of MIB-II, many such media-specific MIB modules have
 been defined.
 Experience in defining these media-specific MIB modules has shown
 that the model defined by MIB-II is too simplistic and/or static for
 some types of media-specific management.  As a result, some of these
 media-specific MIB modules assume an evolution or loosening of the

McCloghrie & Kastenholz Standards Track [Page 3] RFC 2863 The Interfaces Group MIB June 2000

 model.  This memo documents and standardizes that evolution of the
 model and fills in the gaps caused by that evolution.  This memo also
 incorporates the interfaces group extensions documented in RFC 1229
 [19].

3.1. Clarifications/Revisions

 There are several areas for which experience has indicated that
 clarification, revision, or extension of the model would be helpful.
 The following sections discuss the changes in the interfaces group
 adopted by this memo in each of these areas.
 In some sections, one or more paragraphs contain discussion of
 rejected alternatives to the model adopted in this memo.  Readers not
 familiar with the MIB-II model and not interested in the rationale
 behind the new model may want to skip these paragraphs.

3.1.1. Interface Sub-Layers

 Experience in defining media-specific management information has
 shown the need to distinguish between the multiple sub-layers beneath
 the internetwork-layer.  In addition, there is a need to manage these
 sub-layers in devices (e.g., MAC-layer bridges) which are unaware of
 which, if any, internetwork protocols run over these sub-layers.  As
 such, a model of having a single conceptual row in the interfaces
 table (MIB-II's ifTable) represent a whole interface underneath the
 internetwork-layer, and having a single associated media-specific MIB
 module (referenced via the ifType object) is too simplistic.  A
 further problem arises with the value of the ifType object which has
 enumerated values for each type of interface.
 Consider, for example, an interface with PPP running over an HDLC
 link which uses a RS232-like connector.  Each of these sub-layers has
 its own media-specific MIB module.  If all of this is represented by
 a single conceptual row in the ifTable, then an enumerated value for
 ifType is needed for that specific combination which maps to the
 specific combination of media-specific MIBs.  Furthermore, such a
 model still lacks a method to describe the relationship of all the
 sub-layers of the MIB stack.
 An associated problem is that of upward and downward multiplexing of
 the sub-layers.  An example of upward multiplexing is MLP (Multi-
 Link-Procedure) which provides load-sharing over several serial lines
 by appearing as a single point-to-point link to the sub-layer(s)
 above.  An example of downward multiplexing would be several
 instances of PPP, each framed within a separate X.25 virtual circuit,

McCloghrie & Kastenholz Standards Track [Page 4] RFC 2863 The Interfaces Group MIB June 2000

 all of which run over one fractional T1 channel, concurrently with
 other uses of the T1 link.  The MIB structure must allow these sorts
 of relationships to be described.
 Several solutions for representing multiple sub-layers were rejected.
 One was to retain the concept of one conceptual row for all the sub-
 layers of an interface and have each media-specific MIB module
 identify its "superior" and "subordinate" sub-layers through OBJECT
 IDENTIFIER "pointers".  This scheme would have several drawbacks: the
 superior/subordinate pointers would be contained in the media-
 specific MIB modules; thus, a manager could not learn the structure
 of an interface without inspecting multiple pointers in different MIB
 modules; this would be overly complex and only possible if the
 manager had knowledge of all the relevant media-specific MIB modules;
 MIB modules would all need to be retrofitted with these new
 "pointers"; this scheme would not adequately address the problem of
 upward and downward multiplexing; and finally, enumerated values of
 ifType would be needed for each combination of sub-layers.  Another
 rejected solution also retained the concept of one conceptual row for
 all the sub-layers of an interface but had a new separate MIB table
 to identify the "superior" and "subordinate" sub-layers and to
 contain OBJECT IDENTIFIER "pointers" to the media-specific MIB module
 for each sub-layer.  Effectively, one conceptual row in the ifTable
 would represent each combination of sub-layers between the
 internetwork-layer and the wire.  While this scheme has fewer
 drawbacks, it still would not support downward multiplexing, such as
 PPP over MLP: observe that MLP makes two (or more) serial lines
 appear to the layers above as a single physical interface, and thus
 PPP over MLP should appear to the internetwork-layer as a single
 interface; in contrast, this scheme would result in two (or more)
 conceptual rows in the ifTable, both of which the internetwork-layer
 would run over.  This scheme would also require enumerated values of
 ifType for each combination of sub-layers.
 The solution adopted by this memo is to have an individual conceptual
 row in the ifTable to represent each sub-layer, and have a new
 separate MIB table (the ifStackTable, see section 6 below) to
 identify the "superior" and "subordinate" sub-layers through INTEGER
 "pointers" to the appropriate conceptual rows in the ifTable.  This
 solution supports both upward and downward multiplexing, allows the
 IANAifType to Media-Specific MIB mapping to identify the media-
 specific MIB module for that sub-layer, such that the new table need
 only be referenced to obtain information about layering, and it only
 requires enumerated values of ifType for each sub-layer, not for
 combinations of them.  However, it does require that the descriptions
 of some objects in the ifTable (specifically, ifType, ifPhysAddress,
 ifInUcastPkts, and ifOutUcastPkts) be generalized so as to apply to
 any sub-layer (rather than only to a sub-layer immediately beneath

McCloghrie & Kastenholz Standards Track [Page 5] RFC 2863 The Interfaces Group MIB June 2000

 the network layer as previously), plus some (specifically, ifSpeed)
 which need to have appropriate values identified for use when a
 generalized definition does not apply to a particular sub-layer.
 In addition, this adopted solution makes no requirement that a
 device, in which a sub-layer is instrumented by a conceptual row of
 the ifTable, be aware of whether an internetwork protocol runs on top
 of (i.e., at some layer above) that sub-layer.  In fact, the counters
 of packets received on an interface are defined as counting the
 number "delivered to a higher-layer protocol".  This meaning of
 "higher-layer" includes:
 (1)   Delivery to a forwarding module which accepts
       packets/frames/octets and forwards them on at the same protocol
       layer.  For example, for the purposes of this definition, the
       forwarding module of a MAC-layer bridge is considered as a
       "higher-layer" to the MAC-layer of each port on the bridge.
 (2)   Delivery to a higher sub-layer within a interface stack.  For
       example, for the purposes of this definition, if a PPP module
       operated directly over a serial interface, the PPP module would
       be considered the higher sub-layer to the serial interface.
 (3)   Delivery to a higher protocol layer which does not do packet
       forwarding for sub-layers that are "at the top of" the
       interface stack.  For example, for the purposes of this
       definition, the local IP module would be considered the higher
       layer to a SLIP serial interface.
 Similarly, for output, the counters of packets transmitted out an
 interface are defined as counting the number "that higher-level
 protocols requested to be transmitted".  This meaning of "higher-
 layer" includes:
 (1)   A forwarding module, at the same protocol layer, which
       transmits packets/frames/octets that were received on an
       different interface.  For example, for the purposes of this
       definition, the forwarding module of a MAC-layer bridge is
       considered as a "higher-layer" to the MAC-layer of each port on
       the bridge.
 (2)   The next higher sub-layer within an interface stack.  For
       example, for the purposes of this definition, if a PPP module
       operated directly over a serial interface, the PPP module would
       be a "higher layer" to the serial interface.

McCloghrie & Kastenholz Standards Track [Page 6] RFC 2863 The Interfaces Group MIB June 2000

 (3)   For sub-layers that are "at the top of" the interface stack, a
       higher element in the network protocol stack.  For example, for
       the purposes of this definition, the local IP module would be
       considered the higher layer to an Ethernet interface.

3.1.2. Guidance on Defining Sub-layers

 The designer of a media-specific MIB must decide whether to divide
 the interface into sub-layers or not, and if so, how to make the
 divisions.  The following guidance is offered to assist the media-
 specific MIB designer in these decisions.
 In general, the number of entries in the ifTable should be kept to
 the minimum required for network management.  In particular, a group
 of related interfaces should be treated as a single interface with
 one entry in the ifTable providing that:
 (1)   None of the group of interfaces performs multiplexing for any
       other interface in the agent,
 (2)   There is a meaningful and useful way for all of the ifTable's
       information (e.g., the counters, and the status variables), and
       all of the ifTable's capabilities (e.g., write access to
       ifAdminStatus), to apply to the group of interfaces as a whole.
 Under these circumstances, there should be one entry in the ifTable
 for such a group of interfaces, and any internal structure which
 needs to be represented to network management should be captured in a
 MIB module specific to the particular type of interface.
 Note that application of bullet 2 above to the ifTable's ifType
 object requires that there is a meaningful media-specific MIB and a
 meaningful ifType value which apply to the group of interfaces as a
 whole.  For example, it is not appropriate to treat an HDLC sub-layer
 and an RS-232 sub-layer as a single ifTable entry when the media-
 specific MIBs and the ifType values for HDLC and RS-232 are separate
 (rather than combined).
 Subject to the above, it is appropriate to assign an ifIndex value to
 any interface that can occur in an interface stack (in the
 ifStackTable) where the bottom of the stack is a physical interface
 (ifConnectorPresent has the value 'true') and there is a layer-3 or
 other application that "points down" to the top of this stack.  An
 example of an application that points down to the top of the stack is
 the Character MIB [21].

McCloghrie & Kastenholz Standards Track [Page 7] RFC 2863 The Interfaces Group MIB June 2000

 Note that the sub-layers of an interface on one device will sometimes
 be different from the sub-layers of the interconnected interface of
 another device; for example, for a frame-relay DTE interface
 connected a frameRelayService interface, the inter-connected DTE and
 DCE interfaces have different ifType values and media-specific MIBs.
 These guidelines are just that, guidelines.  The designer of a
 media-specific MIB is free to lay out the MIB in whatever SMI
 conformant manner is desired.  However, in doing so, the media-
 specific MIB MUST completely specify the sub-layering model used for
 the MIB, and provide the assumptions, reasoning, and rationale used
 to develop that model.

3.1.3. Virtual Circuits

 Several of the sub-layers for which media-specific MIB modules have
 been defined are connection oriented (e.g., Frame Relay, X.25).
 Experience has shown that each effort to define such a MIB module
 revisits the question of whether separate conceptual rows in the
 ifTable are needed for each virtual circuit.  Most, if not all, of
 these efforts to date have decided to have all virtual circuits
 reference a single conceptual row in the ifTable.
 This memo strongly recommends that connection-oriented sub-layers do
 not have a conceptual row in the ifTable for each virtual circuit.
 This avoids the proliferation of conceptual rows, especially those
 which have considerable redundant information.  (Note, as a
 comparison, that connection-less sub-layers do not have conceptual
 rows for each remote address.)  There may, however, be circumstances
 under which it is appropriate for a virtual circuit of a connection-
 oriented sub-layer to have its own conceptual row in the ifTable; an
 example of this might be PPP over an X.25 virtual circuit.  The MIB
 in section 6 of this memo supports such circumstances.
 If a media-specific MIB wishes to assign an entry in the ifTable to
 each virtual circuit, the MIB designer must present the rationale for
 this decision in the media-specific MIB's specification.

3.1.4. Bit, Character, and Fixed-Length Interfaces

 RS-232 is an example of a character-oriented sub-layer over which
 (e.g., through use of PPP) IP datagrams can be sent.  Due to the
 packet-based nature of many of the objects in the ifTable, experience
 has shown that it is not appropriate to have a character-oriented
 sub-layer represented by a whole conceptual row in the ifTable.

McCloghrie & Kastenholz Standards Track [Page 8] RFC 2863 The Interfaces Group MIB June 2000

 Experience has also shown that it is sometimes desirable to have some
 management information for bit-oriented interfaces, which are
 similarly difficult to represent by a whole conceptual row in the
 ifTable.  For example, to manage the channels of a DS1 circuit, where
 only some of the channels are carrying packet-based data.
 A further complication is that some subnetwork technologies transmit
 data in fixed length transmission units.  One example of such a
 technology is cell relay, and in particular Asynchronous Transfer
 Mode (ATM), which transmits data in fixed-length cells.  Representing
 such a interface as a packet-based interface produces redundant
 objects if the relationship between the number of packets and the
 number of octets in either direction is fixed by the size of the
 transmission unit (e.g., the size of a cell).
 About half the objects in the ifTable are applicable to every type of
 interface: packet-oriented, character-oriented, and bit-oriented.  Of
 the other half, two are applicable to both character-oriented and
 packet-oriented interfaces, and the rest are applicable only to
 packet-oriented interfaces.  Thus, while it is desirable for
 consistency to be able to represent any/all types of interfaces in
 the ifTable, it is not possible to implement the full ifTable for
 bit- and character-oriented sub-layers.
 A rejected solution to this problem would be to split the ifTable
 into two (or more) new MIB tables, one of which would contain objects
 that are relevant only to packet-oriented interfaces (e.g., PPP), and
 another that may be used by all interfaces.  This is highly
 undesirable since it would require changes in every agent
 implementing the ifTable (i.e., just about every existing SNMP
 agent).
 The solution adopted in this memo builds upon the fact that
 compliance statements in SMIv2 (in contrast to SMIv1) refer to object
 groups, where object groups are explicitly defined by listing the
 objects they contain.  Thus, with SMIv2, multiple compliance
 statements can be specified, one for all interfaces and additional
 ones for specific types of interfaces.  The separate compliance
 statements can be based on separate object groups, where the object
 group for all interfaces can contain only those objects from the
 ifTable which are appropriate for every type of interfaces.  Using
 this solution, every sub-layer can have its own conceptual row in the
 ifTable.
 Thus, section 6 of this memo contains definitions of the objects of
 the existing 'interfaces' group of MIB-II, in a manner which is both
 SNMPv2-compliant and semantically-equivalent to the existing MIB-II
 definitions.  With equivalent semantics, and with the BER ("on the

McCloghrie & Kastenholz Standards Track [Page 9] RFC 2863 The Interfaces Group MIB June 2000

 wire") encodings unchanged, these definitions retain the same OBJECT
 IDENTIFIER values as assigned by MIB-II.  Thus, in general, no
 rewrite of existing agents which conform to MIB-II and the
 ifExtensions MIB is required.
 In addition, this memo defines several object groups for the purposes
 of defining which objects apply to which types of interface:
 (1)   the ifGeneralInformationGroup.  This group contains those
       objects applicable to all types of network interfaces,
       including bit-oriented interfaces.
 (2)   the ifPacketGroup.  This group contains those objects
       applicable to packet-oriented network interfaces.
 (3)   the ifFixedLengthGroup.  This group contains the objects
       applicable not only to character-oriented interfaces, such as
       RS-232, but also to those subnetwork technologies, such as
       cell-relay/ATM, which transmit data in fixed length
       transmission units.  As well as the octet counters, there are
       also a few other counters (e.g., the error counters) which are
       useful for this type of interface, but are currently defined as
       being packet-oriented.  To accommodate this, the definitions of
       these counters are generalized to apply to character-oriented
       interfaces and fixed-length-transmission interfaces.
 It should be noted that the octet counters in the ifTable aggregate
 octet counts for unicast and non-unicast packets into a single octet
 counter per direction (received/transmitted).  Thus, with the above
 definition of fixed-length-transmission interfaces, where such
 interfaces which support non-unicast packets, separate counts of
 unicast and multicast/broadcast transmissions can only be maintained
 in a media-specific MIB module.

3.1.5. Interface Numbering

 MIB-II defines an object, ifNumber, whose value represents:
    "The number of network interfaces (regardless of their
    current state) present on this system."
 Each interface is identified by a unique value of the ifIndex object,
 and the description of ifIndex constrains its value as follows:
    "Its value ranges between 1 and the value of ifNumber.  The
    value for each interface must remain constant at least from
    one re-initialization of the entity's network management
    system to the next re-initialization."

McCloghrie & Kastenholz Standards Track [Page 10] RFC 2863 The Interfaces Group MIB June 2000

 This constancy requirement on the value of ifIndex for a particular
 interface is vital for efficient management.  However, an increasing
 number of devices allow for the dynamic addition/removal of network
 interfaces.  One example of this is a dynamic ability to configure
 the use of SLIP/PPP over a character-oriented port.  For such dynamic
 additions/removals, the combination of the constancy requirement and
 the restriction that the value of ifIndex is less than ifNumber is
 problematic.
 Redefining ifNumber to be the largest value of ifIndex was rejected
 since it would not help.  Such a re-definition would require ifNumber
 to be deprecated and the utility of the redefined object would be
 questionable.  Alternatively, ifNumber could be deprecated and not
 replaced.  However, the deprecation of ifNumber would require a
 change to that portion of ifIndex's definition which refers to
 ifNumber.  So, since the definition of ifIndex must be changed anyway
 in order to solve the problem, changes to ifNumber do not benefit the
 solution.
 The solution adopted in this memo is just to delete the requirement
 that the value of ifIndex must be less than the value of ifNumber,
 and to retain ifNumber with its current definition.  This is a minor
 change in the semantics of ifIndex; however, all existing agent
 implementations conform to this new definition, and in the interests
 of not requiring changes to existing agent implementations and to the
 many existing media-specific MIBs, this memo assumes that this change
 does not require ifIndex to be deprecated.  Experience indicates that
 this assumption does "break" a few management applications, but this
 is considered preferable to breaking all agent implementations.
 This solution also results in the possibility of "holes" in the
 ifTable, i.e., the ifIndex values of conceptual rows in the ifTable
 are not necessarily contiguous, but SNMP's GetNext (and GetBulk)
 operation easily deals with such holes.  The value of ifNumber still
 represents the number of conceptual rows, which increases/decreases
 as new interfaces are dynamically added/removed.
 The requirement for constancy (between re-initializations) of an
 interface's ifIndex value is met by requiring that after an interface
 is dynamically removed, its ifIndex value is not re-used by a
 *different* dynamically added interface until after the following
 re-initialization of the network management system.  This avoids the
 need for assignment (in advance) of ifIndex values for all possible
 interfaces that might be added dynamically.  The exact meaning of a
 "different" interface is hard to define, and there will be gray
 areas.  Any firm definition in this document would likely turn out to
 be inadequate.  Instead, implementors must choose what it means in
 their particular situation, subject to the following rules:

McCloghrie & Kastenholz Standards Track [Page 11] RFC 2863 The Interfaces Group MIB June 2000

 (1)   a previously-unused value of ifIndex must be assigned to a
       dynamically added interface if an agent has no knowledge of
       whether the interface is the "same" or "different" to a
       previously incarnated interface.
 (2)   a management station, not noticing that an interface has gone
       away and another has come into existence, must not be confused
       when calculating the difference between the counter values
       retrieved on successive polls for a particular ifIndex value.
 When the new interface is the same as an old interface, but a
 discontinuity in the value of the interface's counters cannot be
 avoided, the ifTable has (until now) required that a new ifIndex
 value be assigned to the returning interface.  That is, either all
 counter values have had to be retained during the absence of an
 interface in order to use the same ifIndex value on that interface's
 return, or else a new ifIndex value has had to be assigned to the
 returning interface.  Both alternatives have proved to be burdensome
 to some implementations:
 (1)   maintaining the counter values may not be possible (e.g., if
       they are maintained on removable hardware),
 (2)   using a new ifIndex value presents extra work for management
       applications.  While the potential need for such extra work is
       unavoidable on agent re-initializations, it is desirable to
       avoid it between re-initializations.
 To address this, a new object, ifCounterDiscontinuityTime, has been
 defined to record the time of the last discontinuity in an
 interface's counters.  By monitoring the value of this new object, a
 management application can now detect counter discontinuities without
 the ifIndex value of the interface being changed.  Thus, an agent
 which implements this new object should, when a new interface is the
 same as an old interface, retain that interface's ifIndex value and
 update if necessary the interface's value of
 ifCounterDiscontinuityTime.  With this new object, a management
 application must, when calculating differences between counter values
 retrieved on successive polls, discard any calculated difference for
 which the value of ifCounterDiscontinuityTime is different for the
 two polls.  (Note that this test must be performed in addition to the
 normal checking of sysUpTime to detect an agent re-initialization.)
 Since such discards are a waste of network management processing and
 bandwidth, an agent should not update the value of
 ifCounterDiscontinuityTime unless absolutely necessary.
 While defining this new object is a change in the semantics of the
 ifTable counter objects, it is impractical to deprecate and redefine

McCloghrie & Kastenholz Standards Track [Page 12] RFC 2863 The Interfaces Group MIB June 2000

 all these counters because of their wide deployment and importance.
 Also, a survey of implementations indicates that many agents and
 management applications do not correctly implement this aspect of the
 current semantics (because of the burdensome issues mentioned above),
 such that the practical implications of such a change is small.
 Thus, this breach of the SMI's rules is considered to be acceptable.
 Note, however, that the addition of ifCounterDiscontinuityTime does
 not change the fact that:
    it is necessary at certain times for the assignment of
    ifIndex values to change on a re-initialization of the agent
    (such as a reboot).
 The possibility of ifIndex value re-assignment must be accommodated
 by a management application whenever the value of sysUpTime is reset
 to zero.
 Note also that some agents support multiple "naming scopes", e.g.,
 for an SNMPv1 agent, multiple values of the SNMPv1 community string.
 For such an agent (e.g., a CNM agent which supports a different
 subset of interfaces for different customers), there is no required
 relationship between the ifIndex values which identify interfaces in
 one naming scope and those which identify interfaces in another
 naming scope.  It is the agent's choice as to whether the same or
 different ifIndex values identify the same or different interfaces in
 different naming scopes.
 Because of the restriction of the value of ifIndex to be less than
 ifNumber, interfaces have been numbered with small integer values.
 This has led to the ability by humans to use the ifIndex values as
 (somewhat) user-friendly names for network interfaces (e.g.,
 "interface number 3").  With the relaxation of the restriction on the
 value of ifIndex, there is now the possibility that ifIndex values
 could be assigned as very large numbers (e.g., memory addresses).
 Such numbers would be much less user-friendly.  Therefore, this memo
 recommends that ifIndex values still be assigned as (relatively)
 small integer values starting at 1, even though the values in use at
 any one time are not necessarily contiguous.  (Note that this makes
 remembering which values have been assigned easy for agents which
 dynamically add new interfaces)
 A new problem is introduced by representing each sub-layer as an
 ifTable entry.  Previously, there usually was a simple, direct,
 mapping of interfaces to the physical ports on systems.  This mapping
 would be based on the ifIndex value.  However, by having an ifTable
 entry for each interface sub-layer, mapping from interfaces to
 physical ports becomes increasingly problematic.

McCloghrie & Kastenholz Standards Track [Page 13] RFC 2863 The Interfaces Group MIB June 2000

 To address this issue, a new object, ifName, is added to the MIB.
 This object contains the device's local name (e.g., the name used at
 the device's local console) for the interface of which the relevant
 entry in the ifTable is a component.  For example, consider a router
 having an interface composed of PPP running over an RS-232 port.  If
 the router uses the name "wan1" for the (combined) interface, then
 the ifName objects for the corresponding PPP and RS-232 entries in
 the ifTable would both have the value "wan1".  On the other hand, if
 the router uses the name "wan1.1" for the PPP interface and "wan1.2"
 for the RS-232 port, then the ifName objects for the corresponding
 PPP and RS-232 entries in the ifTable would have the values "wan1.1"
 and "wan1.2", respectively.  As an another example, consider an agent
 which responds to SNMP queries concerning an interface on some other
 (proxied) device:  if such a proxied device associates a particular
 identifier with an interface, then it is appropriate to use this
 identifier as the value of the interface's ifName, since the local
 console in this case is that of the proxied device.
 In contrast, the existing ifDescr object is intended to contain a
 description of an interface, whereas another new object, ifAlias,
 provides a location in which a network management application can
 store a non-volatile interface-naming value of its own choice.  The
 ifAlias object allows a network manager to give one or more
 interfaces their own unique names, irrespective of any interface-
 stack relationship.  Further, the ifAlias name is non-volatile, and
 thus an interface must retain its assigned ifAlias value across
 reboots, even if an agent chooses a new ifIndex value for the
 interface.

3.1.6. Counter Size

 As the speed of network media increase, the minimum time in which a
 32 bit counter will wrap decreases.  For example, a 10Mbs stream of
 back-to-back, full-size packets causes ifInOctets to wrap in just
 over 57 minutes; at 100Mbs, the minimum wrap time is 5.7 minutes, and
 at 1Gbs, the minimum is 34 seconds.  Requiring that interfaces be
 polled frequently enough not to miss a counter wrap is increasingly
 problematic.
 A rejected solution to this problem was to scale the counters; for
 example, ifInOctets could be changed to count received octets in,
 say, 1024 byte blocks.  While it would provide acceptable
 functionality at high rates of the counted-events, at low rates it
 suffers.  If there is little traffic on an interface, there might be
 a significant interval before enough of the counted-events occur to
 cause the scaled counter to be incremented.  Traffic would then
 appear to be very bursty, leading to incorrect conclusions of the
 network's performance.

McCloghrie & Kastenholz Standards Track [Page 14] RFC 2863 The Interfaces Group MIB June 2000

 Instead, this memo adopts expanded, 64 bit, counters.  These counters
 are provided in new "high capacity" groups.  The old, 32-bit,
 counters have not been deprecated.  The 64-bit counters are to be
 used only when the 32-bit counters do not provide enough capacity;
 that is, when the 32 bit counters could wrap too fast.
 For interfaces that operate at 20,000,000 (20 million) bits per
 second or less, 32-bit byte and packet counters MUST be supported.
 For interfaces that operate faster than 20,000,000 bits/second, and
 slower than 650,000,000 bits/second, 32-bit packet counters MUST be
 supported and 64-bit octet counters MUST be supported.  For
 interfaces that operate at 650,000,000 bits/second or faster, 64-bit
 packet counters AND 64-bit octet counters MUST be supported.
 These speed thresholds were chosen as reasonable compromises based on
 the following:
 (1)   The cost of maintaining 64-bit counters is relatively high, so
       minimizing the number of agents which must support them is
       desirable.  Common interfaces (such as 10Mbs Ethernet) should
       not require them.
 (2)   64-bit counters are a new feature, introduced in the SMIv2.  It
       is reasonable to expect that support for them will be spotty
       for the immediate future.  Thus, we wish to limit them to as
       few systems as possible.  This, in effect, means that 64-bit
       counters should be limited to higher speed interfaces.
       Ethernet (10,000,000 bps) and Token Ring (16,000,000 bps) are
       fairly wide-spread so it seems reasonable to not require 64-bit
       counters for these interfaces.
 (3)   The 32-bit octet counters will wrap in the following times, for
       the following interfaces (when transmitting maximum-sized
       packets back-to-back):
  1. 10Mbs Ethernet: 57 minutes,
  1. 16Mbs Token Ring: 36 minutes,
  1. a US T3 line (45 megabits): 12 minutes,
  1. FDDI: 5.7 minutes
 (4)   The 32-bit packet counters wrap in about 57 minutes when 64-
       byte packets are transmitted back-to-back on a 650,000,000
       bit/second link.

McCloghrie & Kastenholz Standards Track [Page 15] RFC 2863 The Interfaces Group MIB June 2000

 As an aside, a 1-terabit/second (1,000 Gbs) link will cause a 64 bit
 octet counter to wrap in just under 5 years.  Conversely, an
 81,000,000 terabit/second link is required to cause a 64-bit counter
 to wrap in 30 minutes.  We believe that, while technology rapidly
 marches forward, this link speed will not be achieved for at least
 several years, leaving sufficient time to evaluate the introduction
 of 96 bit counters.
 When 64-bit counters are in use, the 32-bit counters MUST still be
 available.  They will report the low 32-bits of the associated 64-bit
 count (e.g., ifInOctets will report the least significant 32 bits of
 ifHCInOctets).  This enhances inter-operability with existing
 implementations at a very minimal cost to agents.
 The new "high capacity" groups are:
 (1)   the ifHCFixedLengthGroup for character-oriented/fixed-length
       interfaces, and the ifHCPacketGroup for packet-based
       interfaces; both of these groups include 64 bit counters for
       octets, and
 (2)   the ifVHCPacketGroup for packet-based interfaces; this group
       includes 64 bit counters for octets and packets.

3.1.7. Interface Speed

 Network speeds are increasing.  The range of ifSpeed is limited to
 reporting a maximum speed of (2**31)-1 bits/second, or approximately
 2.2Gbs.  SONET defines an OC-48 interface, which is defined at
 operating at 48 times 51 Mbs, which is a speed in excess of 2.4Gbs.
 Thus, ifSpeed is insufficient for the future, and this memo defines
 an additional object: ifHighSpeed.
 The ifHighSpeed object reports the speed of the interface in
 1,000,000 (1 million) bits/second units.  Thus, the true speed of the
 interface will be the value reported by this object, plus or minus
 500,000 bits/second.
 Other alternatives considered (but rejected) were:
 (1)   Making the interface speed a 64-bit gauge.  This was rejected
       since the current SMI does not allow such a syntax.
    Furthermore, even if 64-bit gauges were available, their use would
    require additional complexity in agents due to an increased
    requirement for 64-bit operations.

McCloghrie & Kastenholz Standards Track [Page 16] RFC 2863 The Interfaces Group MIB June 2000

 (2)   We also considered making "high-32 bit" and "low-32-bit"
       objects which, when combined, would be a 64-bit value.  This
       simply seemed overly complex for what we are trying to do.
    Furthermore, a full 64-bits of precision does not seem necessary.
    The value of ifHighSpeed will be the only report of interface
    speed for interfaces that are faster than 4,294,967,295 bits per
    second.  At this speed, the granularity of ifHighSpeed will be
    1,000,000 bits per second, thus the error will be 1/4294, or about
    0.02%.  This seems reasonable.
 (3)   Adding a "scale" object, which would define the units which
       ifSpeed's value is.
    This would require two additional objects; one for the scaling
    object, and one to replace the current ifSpeed.  This later object
    is required since the semantics of ifSpeed would be significantly
    altered, and manager stations which do not understand the new
    semantics would be confused.

3.1.8. Multicast/Broadcast Counters

 In MIB-II, the ifTable counters for multicast and broadcast packets
 are combined as counters of non-unicast packets.  In contrast, the
 ifExtensions MIB [19] defined one set of counters for multicast, and
 a separate set for broadcast packets.  With the separate counters,
 the original combined counters become redundant.  To avoid this
 redundancy, the non-unicast counters are deprecated.
 For the output broadcast and multicast counters defined in RFC 1229,
 their definitions varied slightly from the packet counters in the
 ifTable, in that they did not count errors/discarded packets.  Thus,
 this memo defines new objects with better aligned definitions.
 Counters with 64 bits of range are also needed, as explained above.

3.1.9. Trap Enable

 In the multi-layer interface model, each sub-layer for which there is
 an entry in the ifTable can generate linkUp/linkDown Traps.  Since
 interface state changes would tend to propagate through the interface
 (from top to bottom, or bottom to top), it is likely that several
 traps would be generated for each linkUp/linkDown occurrence.
 It is desirable to provide a mechanism for manager stations to
 control the generation of these traps.  To this end, the
 ifLinkUpDownTrapEnable object has been added.  This object allows
 managers to limit generation of traps to just the sub-layers of
 interest.

McCloghrie & Kastenholz Standards Track [Page 17] RFC 2863 The Interfaces Group MIB June 2000

 The default setting should limit the number of traps generated to one
 per interface per linkUp/linkDown event.  Furthermore, it seems that
 the state changes of most interest to network managers occur at the
 lowest level of an interface stack.  Therefore we specify that by
 default, only the lowest sub-layer of the interface generate traps.

3.1.10. Addition of New ifType values

 Over time, there is the need to add new ifType enumerated values for
 new interface types.  If the syntax of ifType were defined in the MIB
 in section 6, then a new version of this MIB would have to be re-
 issued in order to define new values.  In the past, re-issuing of a
 MIB has occurred only after several years.
 Therefore, the syntax of ifType is changed to be a textual
 convention, such that the enumerated integer values are now defined
 in the textual convention, IANAifType, defined in a different
 document.  This allows additional values to be documented without
 having to re-issue a new version of this document.  The Internet
 Assigned Number Authority (IANA) is responsible for the assignment of
 all Internet numbers, including various SNMP-related numbers, and
 specifically, new ifType values.

3.1.11. InterfaceIndex Textual Convention

 A new textual convention, InterfaceIndex, has been defined.  This
 textual convention "contains" all of the semantics of the ifIndex
 object.  This allows other MIB modules to easily import the semantics
 of ifIndex.

3.1.12. New states for IfOperStatus

 Three new states have been added to ifOperStatus: 'dormant',
 'notPresent', and 'lowerLayerDown'.
 The dormant state indicates that the relevant interface is not
 actually in a condition to pass packets (i.e., it is not 'up') but is
 in a "pending" state, waiting for some external event.  For "on-
 demand" interfaces, this new state identifies the situation where the
 interface is waiting for events to place it in the up state.
 Examples of such events might be:
 (1)   having packets to transmit before establishing a connection to
       a remote system;
 (2)   having a remote system establish a connection to the interface
       (e.g. dialing up to a slip-server).

McCloghrie & Kastenholz Standards Track [Page 18] RFC 2863 The Interfaces Group MIB June 2000

 The notPresent state is a refinement on the down state which
 indicates that the relevant interface is down specifically because
 some component (typically, a hardware component) is not present in
 the managed system.  Examples of use of the notPresent state are:
 (1)   to allow an interface's conceptual row including its counter
       values to be retained across a "hot swap" of a card/module,
       and/or
 (2)   to allow an interface's conceptual row to be created, and
       thereby enable interfaces to be pre-configured prior to
       installation of the hardware needed to make the interface
       operational.
 Agents are not required to support interfaces in the notPresent
 state.  However, from a conceptual viewpoint, when a row in the
 ifTable is created, it first enters the notPresent state and then
 subsequently transitions into the down state; similarly, when a row
 in the ifTable is deleted, it first enters the notPresent state and
 then subsequently the object instances are deleted.  For an agent
 with no support for notPresent, both of these transitions (from the
 notPresent state to the down state, and from the notPresent state to
 the instances being removed) are immediate, i.e., the transition does
 not last long enough to be recorded by ifOperStatus.  Even for those
 agents which do support interfaces in the notPresent state, the
 length of time and conditions under which an interface stays in the
 notPresent state is implementation-specific.
 The lowerLayerDown state is also a refinement on the down state.
 This new state indicates that this interface runs "on top of" one or
 more other interfaces (see ifStackTable) and that this interface is
 down specifically because one or more of these lower-layer interfaces
 are down.

3.1.13. IfAdminStatus and IfOperStatus

 The down state of ifOperStatus now has two meanings, depending on the
 value of ifAdminStatus.
 (1)   if ifAdminStatus is not down and ifOperStatus is down then a
       fault condition is presumed to exist on the interface.
 (2)   if ifAdminStatus is down, then ifOperStatus will normally also
       be down (or notPresent) i.e., there is not (necessarily) a
       fault condition on the interface.
 Note that when ifAdminStatus transitions to down, ifOperStatus will
 normally also transition to down.  In this situation, it is possible

McCloghrie & Kastenholz Standards Track [Page 19] RFC 2863 The Interfaces Group MIB June 2000

 that ifOperStatus's transition will not occur immediately, but rather
 after a small time lag to complete certain operations before going
 "down"; for example, it might need to finish transmitting a packet.
 If a manager station finds that ifAdminStatus is down and
 ifOperStatus is not down for a particular interface, the manager
 station should wait a short while and check again.  If the condition
 still exists, only then should it raise an error indication.
 Naturally, it should also ensure that ifLastChange has not changed
 during this interval.
 Whenever an interface table entry is created (usually as a result of
 system initialization), the relevant instance of ifAdminStatus is set
 to down, and ifOperStatus will be down or notPresent.
 An interface may be enabled in two ways: either as a result of
 explicit management action (e.g. setting ifAdminStatus to up) or as a
 result of the managed system's initialization process.  When
 ifAdminStatus changes to the up state, the related ifOperStatus
 should do one of the following:
 (1)   Change to the up state if and only if the interface is able to
       send and receive packets.
 (2)   Change to the lowerLayerDown state if and only if the interface
       is prevented from entering the up state because of the state of
       one or more of the interfaces beneath it in the interface
       stack.
 (3)   Change to the dormant state if and only if the interface is
       found to be operable, but the interface is waiting for other,
       external, events to occur before it can transmit or receive
       packets.  Presumably when the expected events occur, the
       interface will then change to the up state.
 (4)   Remain in the down state if an error or other fault condition
       is detected on the interface.
 (5)   Change to the unknown state if, for some reason, the state of
       the interface can not be ascertained.
 (6)   Change to the testing state if some test(s) must be performed
       on the interface. Presumably after completion of the test, the
       interface's state will change to up, dormant, or down, as
       appropriate.
 (7)   Remain in the notPresent state if interface components are
       missing.

McCloghrie & Kastenholz Standards Track [Page 20] RFC 2863 The Interfaces Group MIB June 2000

3.1.14. IfOperStatus in an Interface Stack

 When an interface is a part of an interface-stack, but is not the
 lowest interface in the stack, then:
 (1)   ifOperStatus has the value 'up' if it is able to pass packets
       due to one or more interfaces below it in the stack being 'up',
       irrespective of whether other interfaces below it are 'down', '
       dormant', 'notPresent', 'lowerLayerDown', 'unknown' or '
       testing'.
 (2)   ifOperStatus may have the value 'up' or 'dormant' if one or
       more interfaces below it in the stack are 'dormant', and all
       others below it are either 'down', 'dormant', 'notPresent', '
       lowerLayerDown', 'unknown' or 'testing'.
 (3)   ifOperStatus has the value 'lowerLayerDown' while all
       interfaces below it in the stack are either 'down', '
       notPresent', 'lowerLayerDown', or 'testing'.

3.1.15. Traps

 The exact definition of when linkUp and linkDown traps are generated
 has been changed to reflect the changes to ifAdminStatus and
 ifOperStatus.  Operational experience indicates that management
 stations are most concerned with an interface being in the down state
 and the fact that this state may indicate a failure.  Thus, it is
 most useful to instrument transitions into/out of either the up state
 or the down state.
 Instrumenting transitions into or out of the up state was rejected
 since it would have the drawback that a demand interface might have
 many transitions between up and dormant, leading to many linkUp traps
 and no linkDown traps.  Furthermore, if a node's only interface is
 the demand interface, then a transition to dormant would entail
 generation of a linkDown trap, necessitating bringing the link to the
 up state (and a linkUp trap)!!
 On the other hand, instrumenting transitions into or out of the down
 state (to/from all other states except notPresent) has the
 advantages:
 (1)   A transition into the down state (from a state other than
       notPresent) will occur when an error is detected on an
       interface.  Error conditions are presumably of great interest
       to network managers.

McCloghrie & Kastenholz Standards Track [Page 21] RFC 2863 The Interfaces Group MIB June 2000

 (2)   Departing the down state (to a state other than the notPresent
       state) generally indicates that the interface is going to
       either up or dormant, both of which are considered "healthy"
       states.
 Furthermore, it is believed that generating traps on transitions into
 or out of the down state (except to/from the notPresent state) is
 generally consistent with current usage and interpretation of these
 traps by manager stations.
 Transitions to/from the notPresent state are concerned with the
 insertion and removal of hardware, and are outside the scope of these
 traps.
 Therefore, this memo defines that LinkUp and linkDown traps are
 generated just after ifOperStatus leaves, or just before it enters,
 the down state, respectively; except that LinkUp and linkDown traps
 are never generated on transitions to/from the notPresent state.  For
 the purpose of deciding when these traps occur, the lowerLayerDown
 state and the down state are considered to be equivalent, i.e., there
 is no trap on transition from lowerLayerDown into down, and there is
 a trap on transition from any other state except down (and
 notPresent) into lowerLayerDown.
 Note that this definition allows a node with only one interface to
 transmit a linkDown trap before that interface goes down.  (Of
 course, when the interface is going down because of a failure
 condition, the linkDown trap probably cannot be successfully
 transmitted anyway.)
 Some interfaces perform a link "training" function when trying to
 bring the interface up.  In the event that such an interface were
 defective, then the training function would fail and the interface
 would remain down, and the training function might be repeated at
 appropriate intervals.  If the interface, while performing this
 training function, were considered to the in the testing state, then
 linkUp and linkDown traps would be generated for each start and end
 of the training function.  This is not the intent of the linkUp and
 linkDown traps, and therefore, while performing such a training
 function, the interface's state should be represented as down.
 An exception to the above generation of linkUp/linkDown traps on
 changes in ifOperStatus, occurs when an interface is "flapping",
 i.e., when it is rapidly oscillating between the up and down states.
 If traps were generated for each such oscillation, the network and
 the network management system would be flooded with unnecessary
 traps.  In such a situation, the agent should limit the rate at which
 it generates traps.

McCloghrie & Kastenholz Standards Track [Page 22] RFC 2863 The Interfaces Group MIB June 2000

3.1.16. ifSpecific

 The original definition of the OBJECT IDENTIFIER value of ifSpecific
 was not sufficiently clear.  As a result, different implementors used
 it differently, and confusion resulted.  Some implementations set the
 value of ifSpecific to the OBJECT IDENTIFIER that defines the media-
 specific MIB, i.e., the "foo" of:
              foo OBJECT IDENTIFIER ::= { transmission xxx }
 while others set it to be OBJECT IDENTIFIER of the specific table or
 entry in the appropriate media-specific MIB (i.e., fooTable or
 fooEntry), while still others set it be the OBJECT IDENTIFIER of the
 index object of the table's row, including instance identifier,
 (i.e., fooIfIndex.ifIndex).  A definition based on the latter would
 not be sufficient unless it also allowed for media-specific MIBs
 which include several tables, where each table has its own
 (different) indexing.
 The only definition that can both be made explicit and can cover all
 the useful situations is to have ifSpecific be the most general value
 for the media-specific MIB module (the first example given above).
 This effectively makes it redundant because it contains no more
 information than is provided by ifType.  Thus, ifSpecific has been
 deprecated.

3.1.17. Creation/Deletion of Interfaces

 While some interfaces, for example, most physical interfaces, cannot
 be created via network management, other interfaces such as logical
 interfaces sometimes can be.  The ifTable contains only generic
 information about an interface.  Almost all 'create-able' interfaces
 have other, media-specific, information through which configuration
 parameters may be supplied prior to creating such an interface.
 Thus, the ifTable does not itself support the creation or deletion of
 an interface (specifically, it has no RowStatus [6] column).  Rather,
 if a particular interface type supports the dynamic creation and/or
 deletion of an interface of that type, then that media-specific MIB
 should include an appropriate RowStatus object (see the ATM LAN-
 Emulation Client MIB [20] for an example of a MIB which does this).
 Typically, when such a RowStatus object is created/deleted, then the
 conceptual row in the ifTable appears/disappears as a by-product, and
 an ifIndex value (chosen by the agent) is stored in an appropriate
 object in the media-specific MIB.

McCloghrie & Kastenholz Standards Track [Page 23] RFC 2863 The Interfaces Group MIB June 2000

3.1.18. All Values Must be Known

 There are a number of situations where an agent does not know the
 value of one or more objects for a particular interface.  In all such
 circumstances, an agent MUST NOT instantiate an object with an
 incorrect value; rather, it MUST respond with the appropriate
 error/exception condition (e.g., noSuchInstance or noSuchName).
 One example is where an agent is unable to count the occurrences
 defined by one (or more) of the ifTable counters.  In this
 circumstance, the agent MUST NOT instantiate the particular counter
 with a value of, say, zero.  To do so would be to provide mis-
 information to a network management application reading the zero
 value, and thereby assuming that there have been no occurrences of
 the event (e.g., no input errors because ifInErrors is always zero).
 Sometimes the lack of knowledge of an object's value is temporary.
 For example, when the MTU of an interface is a configured value and a
 device dynamically learns the configured value through (after)
 exchanging messages over the interface (e.g., ATM LAN-Emulation
 [20]).  In such a case, the value is not known until after the
 ifTable entry has already been created.  In such a case, the ifTable
 entry should be created without an instance of the object whose value
 is unknown; later, when the value becomes known, the missing object
 can then be instantiated (e.g., the instance of ifMtu is only
 instantiated once the interface's MTU becomes known).
 As a result of this "known values" rule, management applications MUST
 be able to cope with the responses to retrieving the object instances
 within a conceptual row of the ifTable revealing that some of the
 row's columnar objects are missing/not available.

4. Media-Specific MIB Applicability

 The exact use and semantics of many objects in this MIB are open to
 some interpretation.  This is a result of the generic nature of this
 MIB.  It is not always possible to come up with specific,
 unambiguous, text that covers all cases and yet preserves the generic
 nature of the MIB.
 Therefore, it is incumbent upon a media-specific MIB designer to,
 wherever necessary, clarify the use of the objects in this MIB with
 respect to the media-specific MIB.

McCloghrie & Kastenholz Standards Track [Page 24] RFC 2863 The Interfaces Group MIB June 2000

 Specific areas of clarification include
 Layering Model
    The media-specific MIB designer MUST completely and unambiguously
    specify the layering model used.  Each individual sub-layer must
    be identified, as must the ifStackTable's portrayal of the
    relationship(s) between the sub-layers.
 Virtual Circuits
    The media-specific MIB designer MUST specify whether virtual
    circuits are assigned entries in the ifTable or not.  If they are,
    compelling rationale must be presented.
 ifRcvAddressTable
    The media-specific MIB designer MUST specify the applicability of
    the ifRcvAddressTable.
 ifType
    For each of the ifType values to which the media-specific MIB
    applies, it must specify the mapping of ifType values to media-
    specific MIB module(s) and instances of MIB objects within those
    modules.
 ifXxxOctets
    The definitions of ifInOctets and ifOutOctets (and similarly,
    ifHCInOctets and ifHCOutOctets) specify that their values include
    framing characters.  The media-specific MIB designer MUST specify
    any special conditions of the media concerning the inclusion of
    framing characters, especially with respect to frames with errors.
 However, wherever this interface MIB is specific in the semantics,
 DESCRIPTION, or applicability of objects, the media-specific MIB
 designer MUST NOT change said semantics, DESCRIPTION, or
 applicability.

5. Overview

 This MIB consists of 4 tables:
 ifTable
    This table is the ifTable from MIB-II.
 ifXTable
    This table contains objects that have been added to the Interface
    MIB as a result of the Interface Evolution effort, or replacements
    for objects of the original (MIB-II) ifTable that were deprecated

McCloghrie & Kastenholz Standards Track [Page 25] RFC 2863 The Interfaces Group MIB June 2000

    because the semantics of said objects have significantly changed.
    This table also contains objects that were previously in the
    ifExtnsTable.
 ifStackTable
    This table contains objects that define the relationships among
    the sub-layers of an interface.
 ifRcvAddressTable
    This table contains objects that are used to define the media-
    level addresses which this interface will receive.  This table is
    a generic table.  The designers of media-specific MIBs must define
    exactly how this table applies to their specific MIB.

6. Interfaces Group Definitions

IF-MIB DEFINITIONS ::= BEGIN

IMPORTS

  MODULE-IDENTITY, OBJECT-TYPE, Counter32, Gauge32, Counter64,
  Integer32, TimeTicks, mib-2,
  NOTIFICATION-TYPE                        FROM SNMPv2-SMI
  TEXTUAL-CONVENTION, DisplayString,
  PhysAddress, TruthValue, RowStatus,
  TimeStamp, AutonomousType, TestAndIncr   FROM SNMPv2-TC
  MODULE-COMPLIANCE, OBJECT-GROUP,
  NOTIFICATION-GROUP                       FROM SNMPv2-CONF
  snmpTraps                                FROM SNMPv2-MIB
  IANAifType                               FROM IANAifType-MIB;

ifMIB MODULE-IDENTITY

  LAST-UPDATED "200006140000Z"
  ORGANIZATION "IETF Interfaces MIB Working Group"
  CONTACT-INFO
          "   Keith McCloghrie
              Cisco Systems, Inc.
              170 West Tasman Drive
              San Jose, CA  95134-1706
              US
              408-526-5260
              kzm@cisco.com"
  DESCRIPTION
          "The MIB module to describe generic objects for network
          interface sub-layers.  This MIB is an updated version of
          MIB-II's ifTable, and incorporates the extensions defined in
          RFC 1229."

McCloghrie & Kastenholz Standards Track [Page 26] RFC 2863 The Interfaces Group MIB June 2000

  REVISION      "200006140000Z"
  DESCRIPTION
          "Clarifications agreed upon by the Interfaces MIB WG, and
          published as RFC 2863."
  REVISION      "199602282155Z"
  DESCRIPTION
          "Revisions made by the Interfaces MIB WG, and published in
          RFC 2233."
  REVISION      "199311082155Z"
  DESCRIPTION
          "Initial revision, published as part of RFC 1573."
  ::= { mib-2 31 }

ifMIBObjects OBJECT IDENTIFIER ::= { ifMIB 1 }

interfaces OBJECT IDENTIFIER ::= { mib-2 2 }

– – Textual Conventions –

– OwnerString has the same semantics as used in RFC 1271

OwnerString ::= TEXTUAL-CONVENTION

  DISPLAY-HINT "255a"
  STATUS       deprecated
  DESCRIPTION
          "This data type is used to model an administratively
          assigned name of the owner of a resource.  This information
          is taken from the NVT ASCII character set.  It is suggested
          that this name contain one or more of the following: ASCII
          form of the manager station's transport address, management
          station name (e.g., domain name), network management
          personnel's name, location, or phone number.  In some cases
          the agent itself will be the owner of an entry.  In these
          cases, this string shall be set to a string starting with
          'agent'."
  SYNTAX       OCTET STRING (SIZE(0..255))

– InterfaceIndex contains the semantics of ifIndex and should be used – for any objects defined in other MIB modules that need these semantics.

InterfaceIndex ::= TEXTUAL-CONVENTION

  DISPLAY-HINT "d"
  STATUS       current
  DESCRIPTION

McCloghrie & Kastenholz Standards Track [Page 27] RFC 2863 The Interfaces Group MIB June 2000

          "A unique value, greater than zero, for each interface or
          interface sub-layer in the managed system.  It is
          recommended that values are assigned contiguously starting
          from 1.  The value for each interface sub-layer must remain
          constant at least from one re-initialization of the entity's
          network management system to the next re-initialization."
  SYNTAX       Integer32 (1..2147483647)

InterfaceIndexOrZero ::= TEXTUAL-CONVENTION

  DISPLAY-HINT "d"
  STATUS       current
  DESCRIPTION
          "This textual convention is an extension of the
          InterfaceIndex convention.  The latter defines a greater
          than zero value used to identify an interface or interface
          sub-layer in the managed system.  This extension permits the
          additional value of zero.  the value zero is object-specific
          and must therefore be defined as part of the description of
          any object which uses this syntax.  Examples of the usage of
          zero might include situations where interface was unknown,
          or when none or all interfaces need to be referenced."
  SYNTAX       Integer32 (0..2147483647)

ifNumber OBJECT-TYPE

  SYNTAX      Integer32
  MAX-ACCESS  read-only
  STATUS      current
  DESCRIPTION
          "The number of network interfaces (regardless of their
          current state) present on this system."
  ::= { interfaces 1 }

ifTableLastChange OBJECT-TYPE

  SYNTAX      TimeTicks
  MAX-ACCESS  read-only
  STATUS      current
  DESCRIPTION
          "The value of sysUpTime at the time of the last creation or
          deletion of an entry in the ifTable.  If the number of
          entries has been unchanged since the last re-initialization
          of the local network management subsystem, then this object
          contains a zero value."
  ::= { ifMIBObjects 5 }

– the Interfaces table

– The Interfaces table contains information on the entity's

McCloghrie & Kastenholz Standards Track [Page 28] RFC 2863 The Interfaces Group MIB June 2000

– interfaces. Each sub-layer below the internetwork-layer – of a network interface is considered to be an interface.

ifTable OBJECT-TYPE

  SYNTAX      SEQUENCE OF IfEntry
  MAX-ACCESS  not-accessible
  STATUS      current
  DESCRIPTION
          "A list of interface entries.  The number of entries is
          given by the value of ifNumber."
  ::= { interfaces 2 }

ifEntry OBJECT-TYPE

  SYNTAX      IfEntry
  MAX-ACCESS  not-accessible
  STATUS      current
  DESCRIPTION
          "An entry containing management information applicable to a
          particular interface."
  INDEX   { ifIndex }
  ::= { ifTable 1 }

IfEntry ::=

  SEQUENCE {
      ifIndex                 InterfaceIndex,
      ifDescr                 DisplayString,
      ifType                  IANAifType,
      ifMtu                   Integer32,
      ifSpeed                 Gauge32,
      ifPhysAddress           PhysAddress,
      ifAdminStatus           INTEGER,
      ifOperStatus            INTEGER,
      ifLastChange            TimeTicks,
      ifInOctets              Counter32,
      ifInUcastPkts           Counter32,
      ifInNUcastPkts          Counter32,  -- deprecated
      ifInDiscards            Counter32,
      ifInErrors              Counter32,
      ifInUnknownProtos       Counter32,
      ifOutOctets             Counter32,
      ifOutUcastPkts          Counter32,
      ifOutNUcastPkts         Counter32,  -- deprecated
      ifOutDiscards           Counter32,
      ifOutErrors             Counter32,
      ifOutQLen               Gauge32,    -- deprecated
      ifSpecific              OBJECT IDENTIFIER -- deprecated
  }

McCloghrie & Kastenholz Standards Track [Page 29] RFC 2863 The Interfaces Group MIB June 2000

ifIndex OBJECT-TYPE

  SYNTAX      InterfaceIndex
  MAX-ACCESS  read-only
  STATUS      current
  DESCRIPTION
          "A unique value, greater than zero, for each interface.  It
          is recommended that values are assigned contiguously
          starting from 1.  The value for each interface sub-layer
          must remain constant at least from one re-initialization of
          the entity's network management system to the next re-
          initialization."
  ::= { ifEntry 1 }

ifDescr OBJECT-TYPE

  SYNTAX      DisplayString (SIZE (0..255))
  MAX-ACCESS  read-only
  STATUS      current
  DESCRIPTION
          "A textual string containing information about the
          interface.  This string should include the name of the
          manufacturer, the product name and the version of the
          interface hardware/software."
  ::= { ifEntry 2 }

ifType OBJECT-TYPE

  SYNTAX      IANAifType
  MAX-ACCESS  read-only
  STATUS      current
  DESCRIPTION
          "The type of interface.  Additional values for ifType are
          assigned by the Internet Assigned Numbers Authority (IANA),
          through updating the syntax of the IANAifType textual
          convention."
  ::= { ifEntry 3 }

ifMtu OBJECT-TYPE

  SYNTAX      Integer32
  MAX-ACCESS  read-only
  STATUS      current
  DESCRIPTION
          "The size of the largest packet which can be sent/received
          on the interface, specified in octets.  For interfaces that
          are used for transmitting network datagrams, this is the
          size of the largest network datagram that can be sent on the
          interface."
  ::= { ifEntry 4 }

ifSpeed OBJECT-TYPE

McCloghrie & Kastenholz Standards Track [Page 30] RFC 2863 The Interfaces Group MIB June 2000

  SYNTAX      Gauge32
  MAX-ACCESS  read-only
  STATUS      current
  DESCRIPTION
          "An estimate of the interface's current bandwidth in bits
          per second.  For interfaces which do not vary in bandwidth
          or for those where no accurate estimation can be made, this
          object should contain the nominal bandwidth.  If the
          bandwidth of the interface is greater than the maximum value
          reportable by this object then this object should report its
          maximum value (4,294,967,295) and ifHighSpeed must be used
          to report the interace's speed.  For a sub-layer which has
          no concept of bandwidth, this object should be zero."
  ::= { ifEntry 5 }

ifPhysAddress OBJECT-TYPE

  SYNTAX      PhysAddress
  MAX-ACCESS  read-only
  STATUS      current
  DESCRIPTION
          "The interface's address at its protocol sub-layer.  For
          example, for an 802.x interface, this object normally
          contains a MAC address.  The interface's media-specific MIB
          must define the bit and byte ordering and the format of the
          value of this object.  For interfaces which do not have such
          an address (e.g., a serial line), this object should contain
          an octet string of zero length."
  ::= { ifEntry 6 }

ifAdminStatus OBJECT-TYPE

  SYNTAX  INTEGER {
              up(1),       -- ready to pass packets
              down(2),
              testing(3)   -- in some test mode
          }
  MAX-ACCESS  read-write
  STATUS      current
  DESCRIPTION
          "The desired state of the interface.  The testing(3) state
          indicates that no operational packets can be passed.  When a
          managed system initializes, all interfaces start with
          ifAdminStatus in the down(2) state.  As a result of either
          explicit management action or per configuration information
          retained by the managed system, ifAdminStatus is then
          changed to either the up(1) or testing(3) states (or remains
          in the down(2) state)."
  ::= { ifEntry 7 }

McCloghrie & Kastenholz Standards Track [Page 31] RFC 2863 The Interfaces Group MIB June 2000

ifOperStatus OBJECT-TYPE

  SYNTAX  INTEGER {
              up(1),        -- ready to pass packets
              down(2),
              testing(3),   -- in some test mode
              unknown(4),   -- status can not be determined
                            -- for some reason.
              dormant(5),
              notPresent(6),    -- some component is missing
              lowerLayerDown(7) -- down due to state of
                                -- lower-layer interface(s)
          }
  MAX-ACCESS  read-only
  STATUS      current
  DESCRIPTION
          "The current operational state of the interface.  The
          testing(3) state indicates that no operational packets can
          be passed.  If ifAdminStatus is down(2) then ifOperStatus
          should be down(2).  If ifAdminStatus is changed to up(1)
          then ifOperStatus should change to up(1) if the interface is
          ready to transmit and receive network traffic; it should
          change to dormant(5) if the interface is waiting for
          external actions (such as a serial line waiting for an
          incoming connection); it should remain in the down(2) state
          if and only if there is a fault that prevents it from going
          to the up(1) state; it should remain in the notPresent(6)
          state if the interface has missing (typically, hardware)
          components."
  ::= { ifEntry 8 }

ifLastChange OBJECT-TYPE

  SYNTAX      TimeTicks
  MAX-ACCESS  read-only
  STATUS      current
  DESCRIPTION
          "The value of sysUpTime at the time the interface entered
          its current operational state.  If the current state was
          entered prior to the last re-initialization of the local
          network management subsystem, then this object contains a
          zero value."
  ::= { ifEntry 9 }

ifInOctets OBJECT-TYPE

  SYNTAX      Counter32
  MAX-ACCESS  read-only
  STATUS      current
  DESCRIPTION
          "The total number of octets received on the interface,

McCloghrie & Kastenholz Standards Track [Page 32] RFC 2863 The Interfaces Group MIB June 2000

          including framing characters.
          Discontinuities in the value of this counter can occur at
          re-initialization of the management system, and at other
          times as indicated by the value of
          ifCounterDiscontinuityTime."
  ::= { ifEntry 10 }

ifInUcastPkts OBJECT-TYPE

  SYNTAX      Counter32
  MAX-ACCESS  read-only
  STATUS      current
  DESCRIPTION
          "The number of packets, delivered by this sub-layer to a
          higher (sub-)layer, which were not addressed to a multicast
          or broadcast address at this sub-layer.
          Discontinuities in the value of this counter can occur at
          re-initialization of the management system, and at other
          times as indicated by the value of
          ifCounterDiscontinuityTime."
  ::= { ifEntry 11 }

ifInNUcastPkts OBJECT-TYPE

  SYNTAX  Counter32
  MAX-ACCESS  read-only
  STATUS      deprecated
  DESCRIPTION
          "The number of packets, delivered by this sub-layer to a
          higher (sub-)layer, which were addressed to a multicast or
          broadcast address at this sub-layer.
          Discontinuities in the value of this counter can occur at
          re-initialization of the management system, and at other
          times as indicated by the value of
          ifCounterDiscontinuityTime.
          This object is deprecated in favour of ifInMulticastPkts and
          ifInBroadcastPkts."
  ::= { ifEntry 12 }

ifInDiscards OBJECT-TYPE

  SYNTAX      Counter32
  MAX-ACCESS  read-only
  STATUS      current
  DESCRIPTION
          "The number of inbound packets which were chosen to be
          discarded even though no errors had been detected to prevent

McCloghrie & Kastenholz Standards Track [Page 33] RFC 2863 The Interfaces Group MIB June 2000

          their being deliverable to a higher-layer protocol.  One
          possible reason for discarding such a packet could be to
          free up buffer space.
          Discontinuities in the value of this counter can occur at
          re-initialization of the management system, and at other
          times as indicated by the value of
          ifCounterDiscontinuityTime."
  ::= { ifEntry 13 }

ifInErrors OBJECT-TYPE

  SYNTAX      Counter32
  MAX-ACCESS  read-only
  STATUS      current
  DESCRIPTION
          "For packet-oriented interfaces, the number of inbound
          packets that contained errors preventing them from being
          deliverable to a higher-layer protocol.  For character-
          oriented or fixed-length interfaces, the number of inbound
          transmission units that contained errors preventing them
          from being deliverable to a higher-layer protocol.
          Discontinuities in the value of this counter can occur at
          re-initialization of the management system, and at other
          times as indicated by the value of
          ifCounterDiscontinuityTime."
  ::= { ifEntry 14 }

ifInUnknownProtos OBJECT-TYPE

  SYNTAX      Counter32
  MAX-ACCESS  read-only
  STATUS      current
  DESCRIPTION
          "For packet-oriented interfaces, the number of packets
          received via the interface which were discarded because of
          an unknown or unsupported protocol.  For character-oriented
          or fixed-length interfaces that support protocol
          multiplexing the number of transmission units received via
          the interface which were discarded because of an unknown or
          unsupported protocol.  For any interface that does not
          support protocol multiplexing, this counter will always be
          0.
          Discontinuities in the value of this counter can occur at
          re-initialization of the management system, and at other
          times as indicated by the value of
          ifCounterDiscontinuityTime."
  ::= { ifEntry 15 }

McCloghrie & Kastenholz Standards Track [Page 34] RFC 2863 The Interfaces Group MIB June 2000

ifOutOctets OBJECT-TYPE

  SYNTAX      Counter32
  MAX-ACCESS  read-only
  STATUS      current
  DESCRIPTION
          "The total number of octets transmitted out of the
          interface, including framing characters.
          Discontinuities in the value of this counter can occur at
          re-initialization of the management system, and at other
          times as indicated by the value of
          ifCounterDiscontinuityTime."
  ::= { ifEntry 16 }

ifOutUcastPkts OBJECT-TYPE

  SYNTAX      Counter32
  MAX-ACCESS  read-only
  STATUS      current
  DESCRIPTION
          "The total number of packets that higher-level protocols
          requested be transmitted, and which were not addressed to a
          multicast or broadcast address at this sub-layer, including
          those that were discarded or not sent.
          Discontinuities in the value of this counter can occur at
          re-initialization of the management system, and at other
          times as indicated by the value of
          ifCounterDiscontinuityTime."
  ::= { ifEntry 17 }

ifOutNUcastPkts OBJECT-TYPE

  SYNTAX      Counter32
  MAX-ACCESS  read-only
  STATUS      deprecated
  DESCRIPTION
          "The total number of packets that higher-level protocols
          requested be transmitted, and which were addressed to a
          multicast or broadcast address at this sub-layer, including
          those that were discarded or not sent.
          Discontinuities in the value of this counter can occur at
          re-initialization of the management system, and at other
          times as indicated by the value of
          ifCounterDiscontinuityTime.
          This object is deprecated in favour of ifOutMulticastPkts
          and ifOutBroadcastPkts."
  ::= { ifEntry 18 }

McCloghrie & Kastenholz Standards Track [Page 35] RFC 2863 The Interfaces Group MIB June 2000

ifOutDiscards OBJECT-TYPE

  SYNTAX      Counter32
  MAX-ACCESS  read-only
  STATUS      current
  DESCRIPTION
          "The number of outbound packets which were chosen to be
          discarded even though no errors had been detected to prevent
          their being transmitted.  One possible reason for discarding
          such a packet could be to free up buffer space.
          Discontinuities in the value of this counter can occur at
          re-initialization of the management system, and at other
          times as indicated by the value of
          ifCounterDiscontinuityTime."
  ::= { ifEntry 19 }

ifOutErrors OBJECT-TYPE

  SYNTAX      Counter32
  MAX-ACCESS  read-only
  STATUS      current
  DESCRIPTION
          "For packet-oriented interfaces, the number of outbound
          packets that could not be transmitted because of errors.
          For character-oriented or fixed-length interfaces, the
          number of outbound transmission units that could not be
          transmitted because of errors.
          Discontinuities in the value of this counter can occur at
          re-initialization of the management system, and at other
          times as indicated by the value of
          ifCounterDiscontinuityTime."
  ::= { ifEntry 20 }

ifOutQLen OBJECT-TYPE

  SYNTAX      Gauge32
  MAX-ACCESS  read-only
  STATUS      deprecated
  DESCRIPTION
          "The length of the output packet queue (in packets)."
  ::= { ifEntry 21 }

ifSpecific OBJECT-TYPE

  SYNTAX      OBJECT IDENTIFIER
  MAX-ACCESS  read-only
  STATUS      deprecated
  DESCRIPTION
          "A reference to MIB definitions specific to the particular
          media being used to realize the interface.  It is

McCloghrie & Kastenholz Standards Track [Page 36] RFC 2863 The Interfaces Group MIB June 2000

          recommended that this value point to an instance of a MIB
          object in the media-specific MIB, i.e., that this object
          have the semantics associated with the InstancePointer
          textual convention defined in RFC 2579.  In fact, it is
          recommended that the media-specific MIB specify what value
          ifSpecific should/can take for values of ifType.  If no MIB
          definitions specific to the particular media are available,
          the value should be set to the OBJECT IDENTIFIER { 0 0 }."
  ::= { ifEntry 22 }

– – Extension to the interface table – – This table replaces the ifExtnsTable table. –

ifXTable OBJECT-TYPE

  SYNTAX      SEQUENCE OF IfXEntry
  MAX-ACCESS  not-accessible
  STATUS      current
  DESCRIPTION
          "A list of interface entries.  The number of entries is
          given by the value of ifNumber.  This table contains
          additional objects for the interface table."
  ::= { ifMIBObjects 1 }

ifXEntry OBJECT-TYPE

  SYNTAX      IfXEntry
  MAX-ACCESS  not-accessible
  STATUS      current
  DESCRIPTION
          "An entry containing additional management information
          applicable to a particular interface."
  AUGMENTS    { ifEntry }
  ::= { ifXTable 1 }

IfXEntry ::=

  SEQUENCE {
      ifName                  DisplayString,
      ifInMulticastPkts       Counter32,
      ifInBroadcastPkts       Counter32,
      ifOutMulticastPkts      Counter32,
      ifOutBroadcastPkts      Counter32,
      ifHCInOctets            Counter64,
      ifHCInUcastPkts         Counter64,
      ifHCInMulticastPkts     Counter64,

McCloghrie & Kastenholz Standards Track [Page 37] RFC 2863 The Interfaces Group MIB June 2000

      ifHCInBroadcastPkts     Counter64,
      ifHCOutOctets           Counter64,
      ifHCOutUcastPkts        Counter64,
      ifHCOutMulticastPkts    Counter64,
      ifHCOutBroadcastPkts    Counter64,
      ifLinkUpDownTrapEnable  INTEGER,
      ifHighSpeed             Gauge32,
      ifPromiscuousMode       TruthValue,
      ifConnectorPresent      TruthValue,
      ifAlias                 DisplayString,
      ifCounterDiscontinuityTime TimeStamp
  }

ifName OBJECT-TYPE

  SYNTAX      DisplayString
  MAX-ACCESS  read-only
  STATUS      current
  DESCRIPTION
          "The textual name of the interface.  The value of this
          object should be the name of the interface as assigned by
          the local device and should be suitable for use in commands
          entered at the device's `console'.  This might be a text
          name, such as `le0' or a simple port number, such as `1',
          depending on the interface naming syntax of the device.  If
          several entries in the ifTable together represent a single
          interface as named by the device, then each will have the
          same value of ifName.  Note that for an agent which responds
          to SNMP queries concerning an interface on some other
          (proxied) device, then the value of ifName for such an
          interface is the proxied device's local name for it.
          If there is no local name, or this object is otherwise not
          applicable, then this object contains a zero-length string."
  ::= { ifXEntry 1 }

ifInMulticastPkts OBJECT-TYPE

  SYNTAX      Counter32
  MAX-ACCESS  read-only
  STATUS      current
  DESCRIPTION
          "The number of packets, delivered by this sub-layer to a
          higher (sub-)layer, which were addressed to a multicast
          address at this sub-layer.  For a MAC layer protocol, this
          includes both Group and Functional addresses.
          Discontinuities in the value of this counter can occur at
          re-initialization of the management system, and at other

McCloghrie & Kastenholz Standards Track [Page 38] RFC 2863 The Interfaces Group MIB June 2000

          times as indicated by the value of
          ifCounterDiscontinuityTime."
  ::= { ifXEntry 2 }

ifInBroadcastPkts OBJECT-TYPE

  SYNTAX      Counter32
  MAX-ACCESS  read-only
  STATUS      current
  DESCRIPTION
          "The number of packets, delivered by this sub-layer to a
          higher (sub-)layer, which were addressed to a broadcast
          address at this sub-layer.
          Discontinuities in the value of this counter can occur at
          re-initialization of the management system, and at other
          times as indicated by the value of
          ifCounterDiscontinuityTime."
  ::= { ifXEntry 3 }

ifOutMulticastPkts OBJECT-TYPE

  SYNTAX      Counter32
  MAX-ACCESS  read-only
  STATUS      current
  DESCRIPTION
          "The total number of packets that higher-level protocols
          requested be transmitted, and which were addressed to a
          multicast address at this sub-layer, including those that
          were discarded or not sent.  For a MAC layer protocol, this
          includes both Group and Functional addresses.
          Discontinuities in the value of this counter can occur at
          re-initialization of the management system, and at other
          times as indicated by the value of
          ifCounterDiscontinuityTime."
  ::= { ifXEntry 4 }

ifOutBroadcastPkts OBJECT-TYPE

  SYNTAX      Counter32
  MAX-ACCESS  read-only
  STATUS      current
  DESCRIPTION
          "The total number of packets that higher-level protocols
          requested be transmitted, and which were addressed to a
          broadcast address at this sub-layer, including those that
          were discarded or not sent.
          Discontinuities in the value of this counter can occur at
          re-initialization of the management system, and at other

McCloghrie & Kastenholz Standards Track [Page 39] RFC 2863 The Interfaces Group MIB June 2000

          times as indicated by the value of
          ifCounterDiscontinuityTime."
  ::= { ifXEntry 5 }

– – High Capacity Counter objects. These objects are all – 64 bit versions of the "basic" ifTable counters. These – objects all have the same basic semantics as their 32-bit – counterparts, however, their syntax has been extended – to 64 bits. –

ifHCInOctets OBJECT-TYPE

  SYNTAX      Counter64
  MAX-ACCESS  read-only
  STATUS      current
  DESCRIPTION
          "The total number of octets received on the interface,
          including framing characters.  This object is a 64-bit
          version of ifInOctets.
          Discontinuities in the value of this counter can occur at
          re-initialization of the management system, and at other
          times as indicated by the value of
          ifCounterDiscontinuityTime."
  ::= { ifXEntry 6 }

ifHCInUcastPkts OBJECT-TYPE

  SYNTAX      Counter64
  MAX-ACCESS  read-only
  STATUS      current
  DESCRIPTION
          "The number of packets, delivered by this sub-layer to a
          higher (sub-)layer, which were not addressed to a multicast
          or broadcast address at this sub-layer.  This object is a
          64-bit version of ifInUcastPkts.
          Discontinuities in the value of this counter can occur at
          re-initialization of the management system, and at other
          times as indicated by the value of
          ifCounterDiscontinuityTime."
  ::= { ifXEntry 7 }

ifHCInMulticastPkts OBJECT-TYPE

  SYNTAX      Counter64
  MAX-ACCESS  read-only
  STATUS      current
  DESCRIPTION

McCloghrie & Kastenholz Standards Track [Page 40] RFC 2863 The Interfaces Group MIB June 2000

          "The number of packets, delivered by this sub-layer to a
          higher (sub-)layer, which were addressed to a multicast
          address at this sub-layer.  For a MAC layer protocol, this
          includes both Group and Functional addresses.  This object
          is a 64-bit version of ifInMulticastPkts.
          Discontinuities in the value of this counter can occur at
          re-initialization of the management system, and at other
          times as indicated by the value of
          ifCounterDiscontinuityTime."
  ::= { ifXEntry 8 }

ifHCInBroadcastPkts OBJECT-TYPE

  SYNTAX      Counter64
  MAX-ACCESS  read-only
  STATUS      current
  DESCRIPTION
          "The number of packets, delivered by this sub-layer to a
          higher (sub-)layer, which were addressed to a broadcast
          address at this sub-layer.  This object is a 64-bit version
          of ifInBroadcastPkts.
          Discontinuities in the value of this counter can occur at
          re-initialization of the management system, and at other
          times as indicated by the value of
          ifCounterDiscontinuityTime."
  ::= { ifXEntry 9 }

ifHCOutOctets OBJECT-TYPE

  SYNTAX      Counter64
  MAX-ACCESS  read-only
  STATUS      current
  DESCRIPTION
          "The total number of octets transmitted out of the
          interface, including framing characters.  This object is a
          64-bit version of ifOutOctets.
          Discontinuities in the value of this counter can occur at
          re-initialization of the management system, and at other
          times as indicated by the value of
          ifCounterDiscontinuityTime."
  ::= { ifXEntry 10 }

ifHCOutUcastPkts OBJECT-TYPE

  SYNTAX      Counter64
  MAX-ACCESS  read-only
  STATUS      current
  DESCRIPTION

McCloghrie & Kastenholz Standards Track [Page 41] RFC 2863 The Interfaces Group MIB June 2000

          "The total number of packets that higher-level protocols
          requested be transmitted, and which were not addressed to a
          multicast or broadcast address at this sub-layer, including
          those that were discarded or not sent.  This object is a
          64-bit version of ifOutUcastPkts.
          Discontinuities in the value of this counter can occur at
          re-initialization of the management system, and at other
          times as indicated by the value of
          ifCounterDiscontinuityTime."
  ::= { ifXEntry 11 }

ifHCOutMulticastPkts OBJECT-TYPE

  SYNTAX      Counter64
  MAX-ACCESS  read-only
  STATUS      current
  DESCRIPTION
          "The total number of packets that higher-level protocols
          requested be transmitted, and which were addressed to a
          multicast address at this sub-layer, including those that
          were discarded or not sent.  For a MAC layer protocol, this
          includes both Group and Functional addresses.  This object
          is a 64-bit version of ifOutMulticastPkts.
          Discontinuities in the value of this counter can occur at
          re-initialization of the management system, and at other
          times as indicated by the value of
          ifCounterDiscontinuityTime."
  ::= { ifXEntry 12 }

ifHCOutBroadcastPkts OBJECT-TYPE

  SYNTAX      Counter64
  MAX-ACCESS  read-only
  STATUS      current
  DESCRIPTION
          "The total number of packets that higher-level protocols
          requested be transmitted, and which were addressed to a
          broadcast address at this sub-layer, including those that
          were discarded or not sent.  This object is a 64-bit version
          of ifOutBroadcastPkts.
          Discontinuities in the value of this counter can occur at
          re-initialization of the management system, and at other
          times as indicated by the value of
          ifCounterDiscontinuityTime."
  ::= { ifXEntry 13 }

ifLinkUpDownTrapEnable OBJECT-TYPE

McCloghrie & Kastenholz Standards Track [Page 42] RFC 2863 The Interfaces Group MIB June 2000

  SYNTAX      INTEGER { enabled(1), disabled(2) }
  MAX-ACCESS  read-write
  STATUS      current
  DESCRIPTION
          "Indicates whether linkUp/linkDown traps should be generated
          for this interface.
          By default, this object should have the value enabled(1) for
          interfaces which do not operate on 'top' of any other
          interface (as defined in the ifStackTable), and disabled(2)
          otherwise."
  ::= { ifXEntry 14 }

ifHighSpeed OBJECT-TYPE

  SYNTAX      Gauge32
  MAX-ACCESS  read-only
  STATUS      current
  DESCRIPTION
          "An estimate of the interface's current bandwidth in units
          of 1,000,000 bits per second.  If this object reports a
          value of `n' then the speed of the interface is somewhere in
          the range of `n-500,000' to `n+499,999'.  For interfaces
          which do not vary in bandwidth or for those where no
          accurate estimation can be made, this object should contain
          the nominal bandwidth.  For a sub-layer which has no concept
          of bandwidth, this object should be zero."
  ::= { ifXEntry 15 }

ifPromiscuousMode OBJECT-TYPE

  SYNTAX      TruthValue
  MAX-ACCESS  read-write
  STATUS      current
  DESCRIPTION
          "This object has a value of false(2) if this interface only
          accepts packets/frames that are addressed to this station.
          This object has a value of true(1) when the station accepts
          all packets/frames transmitted on the media.  The value
          true(1) is only legal on certain types of media.  If legal,
          setting this object to a value of true(1) may require the
          interface to be reset before becoming effective.
          The value of ifPromiscuousMode does not affect the reception
          of broadcast and multicast packets/frames by the interface."
  ::= { ifXEntry 16 }

ifConnectorPresent OBJECT-TYPE

  SYNTAX      TruthValue
  MAX-ACCESS  read-only

McCloghrie & Kastenholz Standards Track [Page 43] RFC 2863 The Interfaces Group MIB June 2000

  STATUS      current
  DESCRIPTION
          "This object has the value 'true(1)' if the interface
          sublayer has a physical connector and the value 'false(2)'
          otherwise."
  ::= { ifXEntry 17 }

ifAlias OBJECT-TYPE

  SYNTAX      DisplayString (SIZE(0..64))
  MAX-ACCESS  read-write
  STATUS      current
  DESCRIPTION
          "This object is an 'alias' name for the interface as
          specified by a network manager, and provides a non-volatile
          'handle' for the interface.
          On the first instantiation of an interface, the value of
          ifAlias associated with that interface is the zero-length
          string.  As and when a value is written into an instance of
          ifAlias through a network management set operation, then the
          agent must retain the supplied value in the ifAlias instance
          associated with the same interface for as long as that
          interface remains instantiated, including across all re-
          initializations/reboots of the network management system,
          including those which result in a change of the interface's
          ifIndex value.
          An example of the value which a network manager might store
          in this object for a WAN interface is the (Telco's) circuit
          number/identifier of the interface.
          Some agents may support write-access only for interfaces
          having particular values of ifType.  An agent which supports
          write access to this object is required to keep the value in
          non-volatile storage, but it may limit the length of new
          values depending on how much storage is already occupied by
          the current values for other interfaces."
  ::= { ifXEntry 18 }

ifCounterDiscontinuityTime OBJECT-TYPE

  SYNTAX      TimeStamp
  MAX-ACCESS  read-only
  STATUS      current
  DESCRIPTION
          "The value of sysUpTime on the most recent occasion at which
          any one or more of this interface's counters suffered a
          discontinuity.  The relevant counters are the specific
          instances associated with this interface of any Counter32 or

McCloghrie & Kastenholz Standards Track [Page 44] RFC 2863 The Interfaces Group MIB June 2000

          Counter64 object contained in the ifTable or ifXTable.  If
          no such discontinuities have occurred since the last re-
          initialization of the local management subsystem, then this
          object contains a zero value."
  ::= { ifXEntry 19 }

– The Interface Stack Group – – Implementation of this group is optional, but strongly recommended – for all systems –

ifStackTable OBJECT-TYPE

   SYNTAX        SEQUENCE OF IfStackEntry
   MAX-ACCESS    not-accessible
   STATUS        current
   DESCRIPTION
          "The table containing information on the relationships
          between the multiple sub-layers of network interfaces.  In
          particular, it contains information on which sub-layers run
          'on top of' which other sub-layers, where each sub-layer
          corresponds to a conceptual row in the ifTable.  For
          example, when the sub-layer with ifIndex value x runs over
          the sub-layer with ifIndex value y, then this table
          contains:
            ifStackStatus.x.y=active
          For each ifIndex value, I, which identifies an active
          interface, there are always at least two instantiated rows
          in this table associated with I.  For one of these rows, I
          is the value of ifStackHigherLayer; for the other, I is the
          value of ifStackLowerLayer.  (If I is not involved in
          multiplexing, then these are the only two rows associated
          with I.)
          For example, two rows exist even for an interface which has
          no others stacked on top or below it:
            ifStackStatus.0.x=active
            ifStackStatus.x.0=active "
   ::= { ifMIBObjects 2 }

ifStackEntry OBJECT-TYPE

   SYNTAX        IfStackEntry
   MAX-ACCESS    not-accessible
   STATUS        current

McCloghrie & Kastenholz Standards Track [Page 45] RFC 2863 The Interfaces Group MIB June 2000

   DESCRIPTION
          "Information on a particular relationship between two sub-
          layers, specifying that one sub-layer runs on 'top' of the
          other sub-layer.  Each sub-layer corresponds to a conceptual
          row in the ifTable."
   INDEX { ifStackHigherLayer, ifStackLowerLayer }
   ::= { ifStackTable 1 }

IfStackEntry ::=

  SEQUENCE {
      ifStackHigherLayer  InterfaceIndexOrZero,
      ifStackLowerLayer   InterfaceIndexOrZero,
      ifStackStatus       RowStatus
   }

ifStackHigherLayer OBJECT-TYPE

   SYNTAX        InterfaceIndexOrZero
   MAX-ACCESS    not-accessible
   STATUS        current
   DESCRIPTION
          "The value of ifIndex corresponding to the higher sub-layer
          of the relationship, i.e., the sub-layer which runs on 'top'
          of the sub-layer identified by the corresponding instance of
          ifStackLowerLayer.  If there is no higher sub-layer (below
          the internetwork layer), then this object has the value 0."
   ::= { ifStackEntry 1 }

ifStackLowerLayer OBJECT-TYPE

   SYNTAX        InterfaceIndexOrZero
   MAX-ACCESS    not-accessible
   STATUS        current
   DESCRIPTION
          "The value of ifIndex corresponding to the lower sub-layer
          of the relationship, i.e., the sub-layer which runs 'below'
          the sub-layer identified by the corresponding instance of
          ifStackHigherLayer.  If there is no lower sub-layer, then
          this object has the value 0."
   ::= { ifStackEntry 2 }

ifStackStatus OBJECT-TYPE

  SYNTAX         RowStatus
  MAX-ACCESS     read-create
  STATUS         current
  DESCRIPTION

McCloghrie & Kastenholz Standards Track [Page 46] RFC 2863 The Interfaces Group MIB June 2000

          "The status of the relationship between two sub-layers.
          Changing the value of this object from 'active' to
          'notInService' or 'destroy' will likely have consequences up
          and down the interface stack.  Thus, write access to this
          object is likely to be inappropriate for some types of
          interfaces, and many implementations will choose not to
          support write-access for any type of interface."
  ::= { ifStackEntry 3 }

ifStackLastChange OBJECT-TYPE

  SYNTAX         TimeTicks
  MAX-ACCESS     read-only
  STATUS         current
  DESCRIPTION
          "The value of sysUpTime at the time of the last change of
          the (whole) interface stack.  A change of the interface
          stack is defined to be any creation, deletion, or change in
          value of any instance of ifStackStatus.  If the interface
          stack has been unchanged since the last re-initialization of
          the local network management subsystem, then this object
          contains a zero value."
  ::= { ifMIBObjects 6 }

– Generic Receive Address Table – – This group of objects is mandatory for all types of – interfaces which can receive packets/frames addressed to – more than one address. – – This table replaces the ifExtnsRcvAddr table. The main – difference is that this table makes use of the RowStatus – textual convention, while ifExtnsRcvAddr did not.

ifRcvAddressTable OBJECT-TYPE

  SYNTAX      SEQUENCE OF IfRcvAddressEntry
  MAX-ACCESS  not-accessible
  STATUS      current
  DESCRIPTION
          "This table contains an entry for each address (broadcast,
          multicast, or uni-cast) for which the system will receive
          packets/frames on a particular interface, except as follows:
  1. for an interface operating in promiscuous mode, entries

are only required for those addresses for which the system

          would receive frames were it not operating in promiscuous
          mode.

McCloghrie & Kastenholz Standards Track [Page 47] RFC 2863 The Interfaces Group MIB June 2000

  1. for 802.5 functional addresses, only one entry is

required, for the address which has the functional address

          bit ANDed with the bit mask of all functional addresses for
          which the interface will accept frames.
          A system is normally able to use any unicast address which
          corresponds to an entry in this table as a source address."
  ::= { ifMIBObjects 4 }

ifRcvAddressEntry OBJECT-TYPE

  SYNTAX      IfRcvAddressEntry
  MAX-ACCESS  not-accessible
  STATUS      current
  DESCRIPTION
          "A list of objects identifying an address for which the
          system will accept packets/frames on the particular
          interface identified by the index value ifIndex."
  INDEX  { ifIndex, ifRcvAddressAddress }
  ::= { ifRcvAddressTable 1 }

IfRcvAddressEntry ::=

  SEQUENCE {
      ifRcvAddressAddress   PhysAddress,
      ifRcvAddressStatus    RowStatus,
      ifRcvAddressType      INTEGER
  }

ifRcvAddressAddress OBJECT-TYPE

  SYNTAX      PhysAddress
  MAX-ACCESS  not-accessible
  STATUS      current
  DESCRIPTION
          "An address for which the system will accept packets/frames
          on this entry's interface."
  ::= { ifRcvAddressEntry 1 }

ifRcvAddressStatus OBJECT-TYPE

  SYNTAX      RowStatus
  MAX-ACCESS  read-create
  STATUS      current
  DESCRIPTION
          "This object is used to create and delete rows in the
          ifRcvAddressTable."
  ::= { ifRcvAddressEntry 2 }

ifRcvAddressType OBJECT-TYPE

  SYNTAX      INTEGER {

McCloghrie & Kastenholz Standards Track [Page 48] RFC 2863 The Interfaces Group MIB June 2000

                  other(1),
                  volatile(2),
                  nonVolatile(3)
              }
  MAX-ACCESS  read-create
  STATUS      current
  DESCRIPTION
          "This object has the value nonVolatile(3) for those entries
          in the table which are valid and will not be deleted by the
          next restart of the managed system.  Entries having the
          value volatile(2) are valid and exist, but have not been
          saved, so that will not exist after the next restart of the
          managed system.  Entries having the value other(1) are valid
          and exist but are not classified as to whether they will
          continue to exist after the next restart."
  DEFVAL  { volatile }
  ::= { ifRcvAddressEntry 3 }

– definition of interface-related traps.

linkDown NOTIFICATION-TYPE

  OBJECTS { ifIndex, ifAdminStatus, ifOperStatus }
  STATUS  current
  DESCRIPTION
          "A linkDown trap signifies that the SNMP entity, acting in
          an agent role, has detected that the ifOperStatus object for
          one of its communication links is about to enter the down
          state from some other state (but not from the notPresent
          state).  This other state is indicated by the included value
          of ifOperStatus."
  ::= { snmpTraps 3 }

linkUp NOTIFICATION-TYPE

  OBJECTS { ifIndex, ifAdminStatus, ifOperStatus }
  STATUS  current
  DESCRIPTION
          "A linkUp trap signifies that the SNMP entity, acting in an
          agent role, has detected that the ifOperStatus object for
          one of its communication links left the down state and
          transitioned into some other state (but not into the
          notPresent state).  This other state is indicated by the
          included value of ifOperStatus."
  ::= { snmpTraps 4 }

– conformance information

McCloghrie & Kastenholz Standards Track [Page 49] RFC 2863 The Interfaces Group MIB June 2000

ifConformance OBJECT IDENTIFIER ::= { ifMIB 2 }

ifGroups OBJECT IDENTIFIER ::= { ifConformance 1 } ifCompliances OBJECT IDENTIFIER ::= { ifConformance 2 }

– compliance statements

ifCompliance3 MODULE-COMPLIANCE

  STATUS  current
  DESCRIPTION
          "The compliance statement for SNMP entities which have
          network interfaces."
  MODULE  -- this module
      MANDATORY-GROUPS { ifGeneralInformationGroup,
                         linkUpDownNotificationsGroup }

– The groups: – ifFixedLengthGroup – ifHCFixedLengthGroup – ifPacketGroup – ifHCPacketGroup – ifVHCPacketGroup – are mutually exclusive; at most one of these groups is implemented – for a particular interface. When any of these groups is implemented – for a particular interface, then ifCounterDiscontinuityGroup must – also be implemented for that interface.

      GROUP       ifFixedLengthGroup
      DESCRIPTION
          "This group is mandatory for those network interfaces which
          are character-oriented or transmit data in fixed-length
          transmission units, and for which the value of the
          corresponding instance of ifSpeed is less than or equal to
          20,000,000 bits/second."
      GROUP       ifHCFixedLengthGroup
      DESCRIPTION
          "This group is mandatory for those network interfaces which
          are character-oriented or transmit data in fixed-length
          transmission units, and for which the value of the
          corresponding instance of ifSpeed is greater than 20,000,000
          bits/second."
      GROUP       ifPacketGroup
      DESCRIPTION

McCloghrie & Kastenholz Standards Track [Page 50] RFC 2863 The Interfaces Group MIB June 2000

          "This group is mandatory for those network interfaces which
          are packet-oriented, and for which the value of the
          corresponding instance of ifSpeed is less than or equal to
          20,000,000 bits/second."
      GROUP       ifHCPacketGroup
      DESCRIPTION
          "This group is mandatory only for those network interfaces
          which are packet-oriented and for which the value of the
          corresponding instance of ifSpeed is greater than 20,000,000
          bits/second but less than or equal to 650,000,000
          bits/second."
      GROUP       ifVHCPacketGroup
      DESCRIPTION
          "This group is mandatory only for those network interfaces
          which are packet-oriented and for which the value of the
          corresponding instance of ifSpeed is greater than
          650,000,000 bits/second."
      GROUP       ifCounterDiscontinuityGroup
      DESCRIPTION
          "This group is mandatory for those network interfaces that
          are required to maintain counters (i.e., those for which one
          of the ifFixedLengthGroup, ifHCFixedLengthGroup,
          ifPacketGroup, ifHCPacketGroup, or ifVHCPacketGroup is
          mandatory)."
      GROUP       ifRcvAddressGroup
      DESCRIPTION
          "The applicability of this group MUST be defined by the
          media-specific MIBs.  Media-specific MIBs must define the
          exact meaning, use, and semantics of the addresses in this
          group."
      OBJECT      ifLinkUpDownTrapEnable
      MIN-ACCESS  read-only
      DESCRIPTION
          "Write access is not required."
      OBJECT      ifPromiscuousMode
      MIN-ACCESS  read-only
      DESCRIPTION
          "Write access is not required."
      OBJECT       ifAdminStatus

McCloghrie & Kastenholz Standards Track [Page 51] RFC 2863 The Interfaces Group MIB June 2000

      SYNTAX       INTEGER { up(1), down(2) }
      MIN-ACCESS   read-only
      DESCRIPTION
          "Write access is not required, nor is support for the value
          testing(3)."
      OBJECT       ifAlias
      MIN-ACCESS   read-only
      DESCRIPTION
          "Write access is not required."
  ::= { ifCompliances 3 }

– units of conformance

ifGeneralInformationGroup OBJECT-GROUP

  OBJECTS { ifIndex, ifDescr, ifType, ifSpeed, ifPhysAddress,
            ifAdminStatus, ifOperStatus, ifLastChange,
            ifLinkUpDownTrapEnable, ifConnectorPresent,
            ifHighSpeed, ifName, ifNumber, ifAlias,
            ifTableLastChange }
  STATUS  current
  DESCRIPTION
          "A collection of objects providing information applicable to
          all network interfaces."
  ::= { ifGroups 10 }

– the following five groups are mutually exclusive; at most – one of these groups is implemented for any interface

ifFixedLengthGroup OBJECT-GROUP

  OBJECTS { ifInOctets, ifOutOctets, ifInUnknownProtos,
            ifInErrors, ifOutErrors }
  STATUS  current
  DESCRIPTION
          "A collection of objects providing information specific to
          non-high speed (non-high speed interfaces transmit and
          receive at speeds less than or equal to 20,000,000
          bits/second) character-oriented or fixed-length-transmission
          network interfaces."
  ::= { ifGroups 2 }

ifHCFixedLengthGroup OBJECT-GROUP

  OBJECTS { ifHCInOctets, ifHCOutOctets,
            ifInOctets, ifOutOctets, ifInUnknownProtos,
            ifInErrors, ifOutErrors }
  STATUS  current
  DESCRIPTION

McCloghrie & Kastenholz Standards Track [Page 52] RFC 2863 The Interfaces Group MIB June 2000

          "A collection of objects providing information specific to
          high speed (greater than 20,000,000 bits/second) character-
          oriented or fixed-length-transmission network interfaces."
  ::= { ifGroups 3 }

ifPacketGroup OBJECT-GROUP

  OBJECTS { ifInOctets, ifOutOctets, ifInUnknownProtos,
            ifInErrors, ifOutErrors,
            ifMtu, ifInUcastPkts, ifInMulticastPkts,
            ifInBroadcastPkts, ifInDiscards,
            ifOutUcastPkts, ifOutMulticastPkts,
            ifOutBroadcastPkts, ifOutDiscards,
            ifPromiscuousMode }
  STATUS  current
  DESCRIPTION
          "A collection of objects providing information specific to
          non-high speed (non-high speed interfaces transmit and
          receive at speeds less than or equal to 20,000,000
          bits/second) packet-oriented network interfaces."
  ::= { ifGroups 4 }

ifHCPacketGroup OBJECT-GROUP

  OBJECTS { ifHCInOctets, ifHCOutOctets,
            ifInOctets, ifOutOctets, ifInUnknownProtos,
            ifInErrors, ifOutErrors,
            ifMtu, ifInUcastPkts, ifInMulticastPkts,
            ifInBroadcastPkts, ifInDiscards,
            ifOutUcastPkts, ifOutMulticastPkts,
            ifOutBroadcastPkts, ifOutDiscards,
            ifPromiscuousMode }
  STATUS  current
  DESCRIPTION
          "A collection of objects providing information specific to
          high speed (greater than 20,000,000 bits/second but less
          than or equal to 650,000,000 bits/second) packet-oriented
          network interfaces."
  ::= { ifGroups 5 }

ifVHCPacketGroup OBJECT-GROUP

  OBJECTS { ifHCInUcastPkts, ifHCInMulticastPkts,
            ifHCInBroadcastPkts, ifHCOutUcastPkts,
            ifHCOutMulticastPkts, ifHCOutBroadcastPkts,
            ifHCInOctets, ifHCOutOctets,
            ifInOctets, ifOutOctets, ifInUnknownProtos,
            ifInErrors, ifOutErrors,
            ifMtu, ifInUcastPkts, ifInMulticastPkts,
            ifInBroadcastPkts, ifInDiscards,
            ifOutUcastPkts, ifOutMulticastPkts,

McCloghrie & Kastenholz Standards Track [Page 53] RFC 2863 The Interfaces Group MIB June 2000

            ifOutBroadcastPkts, ifOutDiscards,
            ifPromiscuousMode }
  STATUS  current
  DESCRIPTION
          "A collection of objects providing information specific to
          higher speed (greater than 650,000,000 bits/second) packet-
          oriented network interfaces."
  ::= { ifGroups 6 }

ifRcvAddressGroup OBJECT-GROUP

  OBJECTS { ifRcvAddressStatus, ifRcvAddressType }
  STATUS  current
  DESCRIPTION
          "A collection of objects providing information on the
          multiple addresses which an interface receives."
  ::= { ifGroups 7 }

ifStackGroup2 OBJECT-GROUP

  OBJECTS { ifStackStatus, ifStackLastChange }
  STATUS  current
  DESCRIPTION
          "A collection of objects providing information on the
          layering of MIB-II interfaces."
  ::= { ifGroups 11 }

ifCounterDiscontinuityGroup OBJECT-GROUP

  OBJECTS { ifCounterDiscontinuityTime }
  STATUS  current
  DESCRIPTION
          "A collection of objects providing information specific to
          interface counter discontinuities."
  ::= { ifGroups 13 }

linkUpDownNotificationsGroup NOTIFICATION-GROUP

  NOTIFICATIONS { linkUp, linkDown }
  STATUS  current
  DESCRIPTION
          "The notifications which indicate specific changes in the
          value of ifOperStatus."
  ::= { ifGroups 14 }

– Deprecated Definitions - Objects

– – The Interface Test Table – – This group of objects is optional. However, a media-specific

McCloghrie & Kastenholz Standards Track [Page 54] RFC 2863 The Interfaces Group MIB June 2000

– MIB may make implementation of this group mandatory. – – This table replaces the ifExtnsTestTable –

ifTestTable OBJECT-TYPE

  SYNTAX      SEQUENCE OF IfTestEntry
  MAX-ACCESS  not-accessible
  STATUS      deprecated
  DESCRIPTION
          "This table contains one entry per interface.  It defines
          objects which allow a network manager to instruct an agent
          to test an interface for various faults.  Tests for an
          interface are defined in the media-specific MIB for that
          interface.  After invoking a test, the object ifTestResult
          can be read to determine the outcome.  If an agent can not
          perform the test, ifTestResult is set to so indicate.  The
          object ifTestCode can be used to provide further test-
          specific or interface-specific (or even enterprise-specific)
          information concerning the outcome of the test.  Only one
          test can be in progress on each interface at any one time.
          If one test is in progress when another test is invoked, the
          second test is rejected.  Some agents may reject a test when
          a prior test is active on another interface.
          Before starting a test, a manager-station must first obtain
          'ownership' of the entry in the ifTestTable for the
          interface to be tested.  This is accomplished with the
          ifTestId and ifTestStatus objects as follows:
        try_again:
            get (ifTestId, ifTestStatus)
            while (ifTestStatus != notInUse)
                /*
                 * Loop while a test is running or some other
                 * manager is configuring a test.
                 */
                short delay
                get (ifTestId, ifTestStatus)
            }
            /*
             * Is not being used right now -- let's compete
             * to see who gets it.
             */
            lock_value = ifTestId
            if ( set(ifTestId = lock_value, ifTestStatus = inUse,

McCloghrie & Kastenholz Standards Track [Page 55] RFC 2863 The Interfaces Group MIB June 2000

                     ifTestOwner = 'my-IP-address') == FAILURE)
                /*
                 * Another manager got the ifTestEntry -- go
                 * try again
                 */
                goto try_again;
            /*
             * I have the lock
             */
            set up any test parameters.
            /*
             * This starts the test
             */
            set(ifTestType = test_to_run);
            wait for test completion by polling ifTestResult
            when test completes, agent sets ifTestResult
                 agent also sets ifTestStatus = 'notInUse'
            retrieve any additional test results, and ifTestId
            if (ifTestId == lock_value+1) results are valid
          A manager station first retrieves the value of the
          appropriate ifTestId and ifTestStatus objects, periodically
          repeating the retrieval if necessary, until the value of
          ifTestStatus is 'notInUse'.  The manager station then tries
          to set the same ifTestId object to the value it just
          retrieved, the same ifTestStatus object to 'inUse', and the
          corresponding ifTestOwner object to a value indicating
          itself.  If the set operation succeeds then the manager has
          obtained ownership of the ifTestEntry, and the value of the
          ifTestId object is incremented by the agent (per the
          semantics of TestAndIncr).  Failure of the set operation
          indicates that some other manager has obtained ownership of
          the ifTestEntry.
          Once ownership is obtained, any test parameters can be
          setup, and then the test is initiated by setting ifTestType.
          On completion of the test, the agent sets ifTestStatus to
          'notInUse'.  Once this occurs, the manager can retrieve the
          results.  In the (rare) event that the invocation of tests
          by two network managers were to overlap, then there would be
          a possibility that the first test's results might be
          overwritten by the second test's results prior to the first

McCloghrie & Kastenholz Standards Track [Page 56] RFC 2863 The Interfaces Group MIB June 2000

          results being read.  This unlikely circumstance can be
          detected by a network manager retrieving ifTestId at the
          same time as retrieving the test results, and ensuring that
          the results are for the desired request.
          If ifTestType is not set within an abnormally long period of
          time after ownership is obtained, the agent should time-out
          the manager, and reset the value of the ifTestStatus object
          back to 'notInUse'.  It is suggested that this time-out
          period be 5 minutes.
          In general, a management station must not retransmit a
          request to invoke a test for which it does not receive a
          response; instead, it properly inspects an agent's MIB to
          determine if the invocation was successful.  Only if the
          invocation was unsuccessful, is the invocation request
          retransmitted.
          Some tests may require the interface to be taken off-line in
          order to execute them, or may even require the agent to
          reboot after completion of the test.  In these
          circumstances, communication with the management station
          invoking the test may be lost until after completion of the
          test.  An agent is not required to support such tests.
          However, if such tests are supported, then the agent should
          make every effort to transmit a response to the request
          which invoked the test prior to losing communication.  When
          the agent is restored to normal service, the results of the
          test are properly made available in the appropriate objects.
          Note that this requires that the ifIndex value assigned to
          an interface must be unchanged even if the test causes a
          reboot.  An agent must reject any test for which it cannot,
          perhaps due to resource constraints, make available at least
          the minimum amount of information after that test
          completes."
  ::= { ifMIBObjects 3 }

ifTestEntry OBJECT-TYPE

  SYNTAX       IfTestEntry
  MAX-ACCESS   not-accessible
  STATUS       deprecated
  DESCRIPTION
          "An entry containing objects for invoking tests on an
          interface."
  AUGMENTS  { ifEntry }
  ::= { ifTestTable 1 }

IfTestEntry ::=

McCloghrie & Kastenholz Standards Track [Page 57] RFC 2863 The Interfaces Group MIB June 2000

  SEQUENCE {
      ifTestId           TestAndIncr,
      ifTestStatus       INTEGER,
      ifTestType         AutonomousType,
      ifTestResult       INTEGER,
      ifTestCode         OBJECT IDENTIFIER,
      ifTestOwner        OwnerString
  }

ifTestId OBJECT-TYPE

  SYNTAX       TestAndIncr
  MAX-ACCESS   read-write
  STATUS       deprecated
  DESCRIPTION
          "This object identifies the current invocation of the
          interface's test."
  ::= { ifTestEntry 1 }

ifTestStatus OBJECT-TYPE

  SYNTAX       INTEGER { notInUse(1), inUse(2) }
  MAX-ACCESS   read-write
  STATUS       deprecated
  DESCRIPTION
          "This object indicates whether or not some manager currently
          has the necessary 'ownership' required to invoke a test on
          this interface.  A write to this object is only successful
          when it changes its value from 'notInUse(1)' to 'inUse(2)'.
          After completion of a test, the agent resets the value back
          to 'notInUse(1)'."
  ::= { ifTestEntry 2 }

ifTestType OBJECT-TYPE

  SYNTAX       AutonomousType
  MAX-ACCESS   read-write
  STATUS       deprecated
  DESCRIPTION
          "A control variable used to start and stop operator-
          initiated interface tests.  Most OBJECT IDENTIFIER values
          assigned to tests are defined elsewhere, in association with
          specific types of interface.  However, this document assigns
          a value for a full-duplex loopback test, and defines the
          special meanings of the subject identifier:
              noTest  OBJECT IDENTIFIER ::= { 0 0 }
          When the value noTest is written to this object, no action
          is taken unless a test is in progress, in which case the
          test is aborted.  Writing any other value to this object is

McCloghrie & Kastenholz Standards Track [Page 58] RFC 2863 The Interfaces Group MIB June 2000

          only valid when no test is currently in progress, in which
          case the indicated test is initiated.
          When read, this object always returns the most recent value
          that ifTestType was set to.  If it has not been set since
          the last initialization of the network management subsystem
          on the agent, a value of noTest is returned."
  ::= { ifTestEntry 3 }

ifTestResult OBJECT-TYPE

  SYNTAX       INTEGER {
                   none(1),          -- no test yet requested
                   success(2),
                   inProgress(3),
                   notSupported(4),
                   unAbleToRun(5),   -- due to state of system
                   aborted(6),
                   failed(7)
               }
  MAX-ACCESS   read-only
  STATUS       deprecated
  DESCRIPTION
          "This object contains the result of the most recently
          requested test, or the value none(1) if no tests have been
          requested since the last reset.  Note that this facility
          provides no provision for saving the results of one test
          when starting another, as could be required if used by
          multiple managers concurrently."
  ::= { ifTestEntry 4 }

ifTestCode OBJECT-TYPE

  SYNTAX       OBJECT IDENTIFIER
  MAX-ACCESS   read-only
  STATUS       deprecated
  DESCRIPTION
          "This object contains a code which contains more specific
          information on the test result, for example an error-code
          after a failed test.  Error codes and other values this
          object may take are specific to the type of interface and/or
          test.  The value may have the semantics of either the
          AutonomousType or InstancePointer textual conventions as
          defined in RFC 2579.  The identifier:
              testCodeUnknown  OBJECT IDENTIFIER ::= { 0 0 }
          is defined for use if no additional result code is
          available."
  ::= { ifTestEntry 5 }

McCloghrie & Kastenholz Standards Track [Page 59] RFC 2863 The Interfaces Group MIB June 2000

ifTestOwner OBJECT-TYPE

  SYNTAX       OwnerString
  MAX-ACCESS   read-write
  STATUS       deprecated
  DESCRIPTION
          "The entity which currently has the 'ownership' required to
          invoke a test on this interface."
  ::= { ifTestEntry 6 }

– Deprecated Definitions - Groups

ifGeneralGroup OBJECT-GROUP

  OBJECTS { ifDescr, ifType, ifSpeed, ifPhysAddress,
            ifAdminStatus, ifOperStatus, ifLastChange,
            ifLinkUpDownTrapEnable, ifConnectorPresent,
            ifHighSpeed, ifName }
  STATUS  deprecated
  DESCRIPTION
          "A collection of objects deprecated in favour of
          ifGeneralInformationGroup."
  ::= { ifGroups 1 }

ifTestGroup OBJECT-GROUP

  OBJECTS { ifTestId, ifTestStatus, ifTestType,
            ifTestResult, ifTestCode, ifTestOwner }
  STATUS  deprecated
  DESCRIPTION
          "A collection of objects providing the ability to invoke
          tests on an interface."
  ::= { ifGroups 8 }

ifStackGroup OBJECT-GROUP

  OBJECTS { ifStackStatus }
  STATUS  deprecated
  DESCRIPTION
          "The previous collection of objects providing information on
          the layering of MIB-II interfaces."
  ::= { ifGroups 9 }

ifOldObjectsGroup OBJECT-GROUP

  OBJECTS { ifInNUcastPkts, ifOutNUcastPkts,
            ifOutQLen, ifSpecific }
  STATUS  deprecated
  DESCRIPTION

McCloghrie & Kastenholz Standards Track [Page 60] RFC 2863 The Interfaces Group MIB June 2000

          "The collection of objects deprecated from the original MIB-
          II interfaces group."
  ::= { ifGroups 12 }

– Deprecated Definitions - Compliance

ifCompliance MODULE-COMPLIANCE

  STATUS  deprecated
  DESCRIPTION
          "A compliance statement defined in a previous version of
          this MIB module, for SNMP entities which have network
          interfaces."
  MODULE  -- this module
      MANDATORY-GROUPS { ifGeneralGroup, ifStackGroup }
      GROUP       ifFixedLengthGroup
      DESCRIPTION
          "This group is mandatory for all network interfaces which
          are character-oriented or transmit data in fixed-length
          transmission units."
      GROUP       ifHCFixedLengthGroup
      DESCRIPTION
          "This group is mandatory only for those network interfaces
          which are character-oriented or transmit data in fixed-
          length transmission units, and for which the value of the
          corresponding instance of ifSpeed is greater than 20,000,000
          bits/second."
      GROUP       ifPacketGroup
      DESCRIPTION
          "This group is mandatory for all network interfaces which
          are packet-oriented."
      GROUP       ifHCPacketGroup
      DESCRIPTION
          "This group is mandatory only for those network interfaces
          which are packet-oriented and for which the value of the
          corresponding instance of ifSpeed is greater than
          650,000,000 bits/second."
      GROUP       ifTestGroup
      DESCRIPTION
          "This group is optional.  Media-specific MIBs which require
          interface tests are strongly encouraged to use this group
          for invoking tests and reporting results.  A medium specific
          MIB which has mandatory tests may make implementation of

McCloghrie & Kastenholz Standards Track [Page 61] RFC 2863 The Interfaces Group MIB June 2000

          this group mandatory."
      GROUP       ifRcvAddressGroup
      DESCRIPTION
          "The applicability of this group MUST be defined by the
          media-specific MIBs.  Media-specific MIBs must define the
          exact meaning, use, and semantics of the addresses in this
          group."
      OBJECT      ifLinkUpDownTrapEnable
      MIN-ACCESS  read-only
      DESCRIPTION
          "Write access is not required."
      OBJECT      ifPromiscuousMode
      MIN-ACCESS  read-only
      DESCRIPTION
          "Write access is not required."
      OBJECT      ifStackStatus
      SYNTAX      INTEGER { active(1) } -- subset of RowStatus
      MIN-ACCESS  read-only
      DESCRIPTION
          "Write access is not required, and only one of the six
          enumerated values for the RowStatus textual convention need
          be supported, specifically: active(1)."
      OBJECT       ifAdminStatus
      SYNTAX       INTEGER { up(1), down(2) }
      MIN-ACCESS   read-only
      DESCRIPTION
          "Write access is not required, nor is support for the value
          testing(3)."
  ::= { ifCompliances 1 }

ifCompliance2 MODULE-COMPLIANCE

  STATUS      deprecated
  DESCRIPTION
          "A compliance statement defined in a previous version of
          this MIB module, for SNMP entities which have network
          interfaces."
  MODULE  -- this module
      MANDATORY-GROUPS { ifGeneralInformationGroup, ifStackGroup2,
                         ifCounterDiscontinuityGroup }
      GROUP       ifFixedLengthGroup
      DESCRIPTION

McCloghrie & Kastenholz Standards Track [Page 62] RFC 2863 The Interfaces Group MIB June 2000

          "This group is mandatory for all network interfaces which
          are character-oriented or transmit data in fixed-length
          transmission units."
      GROUP       ifHCFixedLengthGroup
      DESCRIPTION
          "This group is mandatory only for those network interfaces
          which are character-oriented or transmit data in fixed-
          length transmission units, and for which the value of the
          corresponding instance of ifSpeed is greater than 20,000,000
          bits/second."
      GROUP       ifPacketGroup
      DESCRIPTION
          "This group is mandatory for all network interfaces which
          are packet-oriented."
      GROUP       ifHCPacketGroup
      DESCRIPTION
          "This group is mandatory only for those network interfaces
          which are packet-oriented and for which the value of the
          corresponding instance of ifSpeed is greater than
          650,000,000 bits/second."
      GROUP       ifRcvAddressGroup
      DESCRIPTION
          "The applicability of this group MUST be defined by the
          media-specific MIBs.  Media-specific MIBs must define the
          exact meaning, use, and semantics of the addresses in this
          group."
      OBJECT      ifLinkUpDownTrapEnable
      MIN-ACCESS  read-only
      DESCRIPTION
          "Write access is not required."
      OBJECT      ifPromiscuousMode
      MIN-ACCESS  read-only
      DESCRIPTION
          "Write access is not required."
      OBJECT      ifStackStatus
      SYNTAX      INTEGER { active(1) } -- subset of RowStatus
      MIN-ACCESS  read-only
      DESCRIPTION
          "Write access is not required, and only one of the six
          enumerated values for the RowStatus textual convention need
          be supported, specifically: active(1)."

McCloghrie & Kastenholz Standards Track [Page 63] RFC 2863 The Interfaces Group MIB June 2000

      OBJECT       ifAdminStatus
      SYNTAX       INTEGER { up(1), down(2) }
      MIN-ACCESS   read-only
      DESCRIPTION
          "Write access is not required, nor is support for the value
          testing(3)."
      OBJECT       ifAlias
      MIN-ACCESS   read-only
      DESCRIPTION
          "Write access is not required."
  ::= { ifCompliances 2 }

END

7. Acknowledgements

 This memo has been produced by the IETF's Interfaces MIB working-
 group.
 The original proposal evolved from conversations and discussions with
 many people, including at least the following: Fred Baker, Ted
 Brunner, Chuck Davin, Jeremy Greene, Marshall Rose, Kaj Tesink, and
 Dean Throop.

8. References

 [1]  Harrington, D., Presuhn, R. and B. Wijnen, "An Architecture for
      Describing SNMP Management Frameworks", RFC 2571, April 1999.
 [2]  Rose, M. and K. McCloghrie, "Structure and Identification of
      Management Information for TCP/IP-based Internets", STD 16, RFC
      1155, May 1990.
 [3]  Rose, M. and K. McCloghrie, "Concise MIB Definitions", STD 16,
      RFC 1212, March 1991.
 [4]  Rose, M., "A Convention for Defining Traps for use with the
      SNMP", RFC 1215, March 1991.
 [5]  McCloghrie, K., Perkins, D., Schoenwaelder, J., Case, J., Rose,
      M.  and S. Waldbusser, "Structure of Management Information
      Version 2 (SMIv2)", STD 58, RFC 2578, April 1999.
 [6]  McCloghrie, K., Perkins, D., Schoenwaelder, J., Case, J., Rose,
      M. and S. Waldbusser, "Textual Conventions for SMIv2", STD 58,
      RFC 2579, April 1999.

McCloghrie & Kastenholz Standards Track [Page 64] RFC 2863 The Interfaces Group MIB June 2000

 [7]  McCloghrie, K., Perkins, D., Schoenwaelder, J., Case, J., Rose,
      M.  and S. Waldbusser, "Conformance Statements for SMIv2", STD
      58, RFC 2580, April 1999.
 [8]  Case, J., Fedor, M., Schoffstall, M. and J. Davin, "Simple
      Network Management Protocol", STD 15, RFC 1157, May 1990.
 [9]  Case, J., McCloghrie, K., Rose, M. and S. Waldbusser,
      "Introduction to Community-based SNMPv2", RFC 1901, January
      1996.
 [10] Case, J., McCloghrie, K., Rose, M. and S. Waldbusser, "Transport
      Mappings for Version 2 of the Simple Network Management Protocol
      (SNMPv2)", RFC 1906, January 1996.
 [11] Case, J., Harrington D., Presuhn R. and B. Wijnen, "Message
      Processing and Dispatching for the Simple Network Management
      Protocol (SNMP)", RFC 2572, January 1998.
 [12] Blumenthal, U. and B. Wijnen, "User-based Security Model (USM)
      for version 3 of the Simple Network Management Protocol
      (SNMPv3)", RFC 2574, January 1998.
 [13] Case, J., McCloghrie, K., Rose, M. and S. Waldbusser, "Protocol
      Operations for Version 2 of the Simple Network Management
      Protocol (SNMPv2)", RFC 1905, January 1996.
 [14] Levi, D., Meyer, P. and B. Stewart, "SMPv3 Applications", RFC
      2573, January 1998.
 [15] Wijnen, B., Presuhn, R. and K. McCloghrie, "View-based Access
      Control Model (VACM) for the Simple Network Management Protocol
      (SNMP)", RFC 2575, January 1998.
 [16] Bradner, S., "Key words for use in RFCs to Indicate Requirements
      Levels", BCP 14, RFC 2119, March 1997.
 [17] McCloghrie, K. and M. Rose, "Management Information Base for
      Network Management of TCP/IP-based internets - MIB-II", STD 17.
      RFC 1213, March 1991.
 [18] Postel, J., "Internet Protocol", STD 5, RFC 791, September 1981.
 [19] McCloghrie, K., "Extensions to the Generic-Interface MIB", RFC
      1229, May 1991.

McCloghrie & Kastenholz Standards Track [Page 65] RFC 2863 The Interfaces Group MIB June 2000

 [20] ATM Forum Technical Committee, "LAN Emulation Client Management:
      Version 1.0 Specification", af-lane-0044.000, ATM Forum,
      September 1995.
 [21] Stewart, B., "Definitions of Managed Objects for Character
      Stream Devices using SMIv2", RFC 1658, July 1994.
 [22] Case, J., Mundy, R., Partain, D. and B. Stewart, "Introduction
      to Version 3 of the Internet-standard Network Management
      Framework", RFC 2570, April 1999.
 [23] McCloghrie, K. and F. Kastenholz, "Evolution of the Interfaces
      Group of MIB-II", RFC 1573, January 1994.
 [24] McCloghrie, K. and F. Kastenholz, "The Interfaces Group MIB
      using SMIv2", RFC 2233, November 1997.

9. Security Considerations

 There are a number of management objects defined in this MIB that
 have a MAX-ACCESS clause of read-write and/or read-create.  Such
 objects may be considered sensitive or vulnerable in some network
 environments.  The support for SET operations in a non-secure
 environment without proper protection can have a negative effect on
 network operations.
 In particular, write-able objects allow an administrator to control
 the interfaces and to perform tests on the interfaces, and
 unauthorized access to these could cause a denial of service, or in
 combination with other (e.g., physical) security breaches, could
 cause unauthorized connectivity to a device.
 SNMPv1 by itself is not a secure environment.  Even if the network
 itself is secure (for example by using IPSec), even then, 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.
 It is recommended that the implementers consider the security
 features as provided by the SNMPv3 framework.  Specifically, the use
 of the User-based Security Model RFC 2574 [12] and the View- based
 Access Control Model RFC 2575 [15] is recommended.
 It is then a customer/user responsibility to ensure that the SNMP
 entity giving access to an instance of this MIB, is properly
 configured to give access to the objects only to those principals
 (users) that have legitimate rights to indeed GET or SET
 (change/create/delete) them.

McCloghrie & Kastenholz Standards Track [Page 66] RFC 2863 The Interfaces Group MIB June 2000

10. Authors' Addresses

 Keith McCloghrie
 Cisco Systems, Inc.
 170 West Tasman Drive
 San Jose, CA  95134-1706
 Phone: 408-526-5260
 EMail: kzm@cisco.com"
 Frank Kastenholz
 Argon Networks
 25 Porter Rd
 Littleton Ma 01460
 Phone: (508)685-4000
 EMail: kasten@argon.com

11. Changes from RFC 2233

 Added linkUpDownNotificationsGroup.
 Changed the status of the definition of OwnerString in this MIB to be
 deprecated, because it is only used by ifTestOwner, which is now
 deprecated, and because other MIBs should import OwnerString from RFC
 1757 or its successors.
 Added ifCompliance3 as a replacement for ifCompliance2 to omit the
 ifStackGroup2 group, and add linkUpDownNotificationsGroup.  Also,
 corrected the omission of ifVHCPacketGroup, and typos in the
 DESCRIPTIONs of ifHCPacketGroup and ifFixedLengthGroup.  Obsoleted
 ifCompliance2.
 Modified syntax of ifStackHigherLayer and ifStackLowerLayer to be
 InterfaceIndexOrZero.
 Added requirement that media-specific MIB designers specify any
 special conditions concerning the counting of framing characters in
 ifInOctets and ifOutOctets.
 Corrected a typo in the DESCRIPTION of the linkUp notification.
 Modified the introductory SNMP Network Management Framework
 boilerplate text.

McCloghrie & Kastenholz Standards Track [Page 67] RFC 2863 The Interfaces Group MIB June 2000

12. Notice on Intellectual Property

 The IETF takes no position regarding the validity or scope of any
 intellectual property or other rights that might be claimed to
 pertain to the implementation or use of the technology described in
 this document or the extent to which any license under such rights
 might or might not be available; neither does it represent that it
 has made any effort to identify any such rights.  Information on the
 IETF's procedures with respect to rights in standards-track and
 standards-related documentation can be found in BCP-11.  Copies of
 claims of rights made available for publication and any assurances of
 licenses to be made available, or the result of an attempt made to
 obtain a general license or permission for the use of such
 proprietary rights by implementors or users of this specification can
 be obtained from the IETF Secretariat.
 The IETF invites any interested party to bring to its attention any
 copyrights, patents or patent applications, or other proprietary
 rights which may cover technology that may be required to practice
 this standard.  Please address the information to the IETF Executive
 Director.

McCloghrie & Kastenholz Standards Track [Page 68] RFC 2863 The Interfaces Group MIB June 2000

13. Full Copyright Statement

 Copyright (C) The Internet Society (2000).  All Rights Reserved.
 This document and translations of it may be copied and furnished to
 others, and derivative works that comment on or otherwise explain it
 or assist in its implementation may be prepared, copied, published
 and distributed, in whole or in part, without restriction of any
 kind, provided that the above copyright notice and this paragraph are
 included on all such copies and derivative works.  However, this
 document itself may not be modified in any way, such as by removing
 the copyright notice or references to the Internet Society or other
 Internet organizations, except as needed for the purpose of
 developing Internet standards in which case the procedures for
 copyrights defined in the Internet Standards process must be
 followed, or as required to translate it into languages other than
 English.
 The limited permissions granted above are perpetual and will not be
 revoked by the Internet Society or its successors or assigns.
 This document and the information contained herein is provided on an
 "AS IS" basis and THE INTERNET SOCIETY AND THE INTERNET ENGINEERING
 TASK FORCE DISCLAIMS ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING
 BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION
 HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF
 MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.

Acknowledgement

 Funding for the RFC Editor function is currently provided by the
 Internet Society.

McCloghrie & Kastenholz Standards Track [Page 69]

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