path: root/doc/rfc/rfc2895.txt

Network Working Group                                       A. Bierman
Request for Comments: 2895                                    C. Bucci
Obsoletes: 2074                                    Cisco Systems, Inc.
Category: Standards Track                                     R. Iddon
                                                            3Com, Inc.
                                                           August 2000


      Remote Network Monitoring MIB Protocol Identifier Reference

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.

Abstract

   This memo defines a notation describing protocol layers in a protocol
   encapsulation, specifically for use in encoding INDEX values for the
   protocolDirTable, found in the RMON-2 MIB (Remote Network Monitoring
   Management Information Base) [RFC2021].  The definitions for the
   standard protocol directory base layer identifiers are also included.

   The first version of the RMON Protocol Identifiers Document [RFC2074]
   has been split into a standards-track Reference portion (this
   document), and an Informational document.  The RMON Protocol
   Identifier Macros document [RFC2896] now contains the non-normative
   portion of that specification.

   This document obsoletes RFC 2074.














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Table of Contents

   1 The SNMP Network Management Framework ..........................  3
   2 Overview .......................................................  3
   2.1 Terms ........................................................  4
   2.2 Relationship to the Remote Network Monitoring MIB ............  6
   2.3 Relationship to the RMON Protocol Identifier Macros Document .  6
   2.4 Relationship to the ATM-RMON MIB .............................  7
   2.4.1 Port Aggregation ...........................................  7
   2.4.2 Encapsulation Mappings .....................................  7
   2.4.3 Counting ATM Traffic in RMON-2 Collections .................  8
   2.5 Relationship to Other MIBs ...................................  9
   3 Protocol Identifier Encoding ...................................  9
   3.1 ProtocolDirTable INDEX Format Examples ....................... 11
   3.2 Protocol Identifier Macro Format ............................. 12
   3.2.1 Lexical Conventions ........................................ 12
   3.2.2 Notation for Syntax Descriptions ........................... 13
   3.2.3 Grammar for the PI Language ................................ 13
   3.2.4 Mapping of the Protocol Name ............................... 15
   3.2.5 Mapping of the VARIANT-OF Clause ........................... 16
   3.2.6 Mapping of the PARAMETERS Clause ........................... 17
   3.2.6.1 Mapping of the 'countsFragments(0)' BIT .................. 18
   3.2.6.2 Mapping of the 'tracksSessions(1)' BIT ................... 18
   3.2.7 Mapping of the ATTRIBUTES Clause ........................... 18
   3.2.8 Mapping of the DESCRIPTION Clause .......................... 19
   3.2.9 Mapping of the CHILDREN Clause ............................. 19
   3.2.10 Mapping of the ADDRESS-FORMAT Clause ...................... 20
   3.2.11 Mapping of the DECODING Clause ............................ 20
   3.2.12 Mapping of the REFERENCE Clause ........................... 20
   3.3 Evaluating an Index of the ProtocolDirTable .................. 21
   4 Base Layer Protocol Identifier Macros .......................... 22
   4.1 Base Identifier Encoding ..................................... 22
   4.1.1 Protocol Identifier Functions .............................. 22
   4.1.1.1 Function 0: None ......................................... 23
   4.1.1.2 Function 1: Protocol Wildcard Function ................... 23
   4.2 Base Layer Protocol Identifiers .............................. 24
   4.3 Encapsulation Layers ......................................... 31
   4.3.1 IEEE 802.1Q ................................................ 31
   5 Intellectual Property .......................................... 34
   6 Acknowledgements ............................................... 35
   7 References ..................................................... 35
   8 IANA Considerations ............................................ 39
   9 Security Considerations ........................................ 39
   10 Authors' Addresses ............................................ 40
   Appendix A ....................................................... 41
   11 Full Copyright Statement ...................................... 42





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1.  The SNMP Network Management Framework

   The SNMP Management Framework presently consists of five major
   components:

   o  An overall architecture, described in RFC 2571 [RFC2571].

   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 [RFC1155], STD 16, RFC 1212 [RFC1212] and RFC 1215
      [RFC1215].  The second version, called SMIv2, is described in STD
      58, RFC 2578 [RFC2578], STD 58, RFC 2579 [RFC2579] and STD 58, RFC
      2580 [RFC2580].

   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 [RFC1157]. A second version of the
      SNMP message protocol, which is not an Internet standards track
      protocol, is called SNMPv2c and described in RFC 1901 [RFC1901]
      and RFC 1906 [RFC1906].  The third version of the message protocol
      is called SNMPv3 and described in RFC 1906 [RFC1906], RFC 2572
      [RFC2572] and RFC 2574 [RFC2574].

   o  Protocol operations for accessing management information. The
      first set of protocol operations and associated PDU formats is
      described in STD 15, RFC 1157 [RFC1157]. A second set of protocol
      operations and associated PDU formats is described in RFC 1905
      [RFC1905].

   o  A set of fundamental applications described in RFC 2573 [RFC2573]
      and the view-based access control mechanism described in RFC 2575
      [RFC2575].

   A more detailed introduction to the current SNMP Management Framework
   can be found in RFC 2570 [RFC2570].

   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 does not specify a MIB module.

2.  Overview

   The RMON-2 MIB [RFC2021] uses hierarchically formatted OCTET STRINGs
   to globally identify individual protocol encapsulations in the
   protocolDirTable.



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   This guide contains algorithms and the authoritative set of base
   layer protocol identifier macros, for use within INDEX values in the
   protocolDirTable.

   This is the second revision of this document, and is intended to
   replace the first half of the first RMON-2 Protocol Identifiers
   document. [RFC2074].

2.1.  Terms

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

   Several terms are used throughout this document, as well as in the
   RMON-2 MIB [RFC2021], that should be introduced:

   parent protocol:
        Also called 'parent'; The encapsulating protocol identifier for
        a specific protocol layer, e.g., IP is the parent protocol of
        UDP.  Note that base layers cannot have parent protocols.  This
        term may be used to refer to a specific encapsulating protocol,
        or it may be used generically to refer to any encapsulating
        protocol.

   child protocol:
        Also called 'child'; An encapsulated protocol identifier for a
        specific protocol layer. e.g., UDP is a child protocol of IP.
        This term may be used to refer to a specific encapsulated
        protocol, or it may be used generically to refer to any
        encapsulated protocol.

   layer-identifier:
        An octet string fragment representing a particular protocol
        encapsulation layer or sub-layer.  A fragment consists of
        exactly four octets, encoded in network byte order.  If present,
        child layer-identifiers for a protocol MUST have unique values
        among each other. (See section 3.3 for more details.)

   protocol:
        A particular protocol layer, as specified by encoding rules in
        this document. Usually refers to a single layer in a given
        encapsulation. Note that this term is sometimes used in the
        RMON-2 MIB [RFC2021] to name a fully-specified protocol-
        identifier string.  In such a case, the protocol-identifier
        string is named for its upper-most layer. A named protocol may
        also refer to any encapsulation of that protocol.




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   protocol-identifier string:
        An octet string representing a particular protocol
        encapsulation, as specified by the encoding rules in this
        document. This string is identified in the RMON-2 MIB [RFC2021]
        as the protocolDirID object.  A protocol-identifier string is
        composed of one or more layer-identifiers read from left to
        right.  The left-most layer-identifier specifies a base layer
        encapsulation. Each layer-identifier to the right specifies a
        child layer protocol encapsulation.

   protocol-identifier macro:  Also called a PI macro; A macro-like
        textual construct used to describe a particular networking
        protocol. Only protocol attributes which are important for RMON
        use are documented. Note that the term 'macro' is historical,
        and PI macros are not real macros, nor are they ASN.1 macros.
        The current set of published RMON PI macros can be found in the
        RMON Protocol Identifier Macros document [RFC2896].

        The PI macro serves several purposes:

        - Names the protocol for use within the RMON-2 MIB [RFC2021].
        - Describes how the protocol is encoded into an octet string.
        - Describes how child protocols are identified (if applicable),
          and encoded into an octet string.
        - Describes which protocolDirParameters are allowed for the
          protocol.
        - Describes how the associated protocolDirType object is encoded
          for the protocol.
        - Provides reference(s) to authoritative documentation for the
          protocol.

   protocol-variant-identifier macro:
        Also called a PI-variant macro; A special kind of PI macro, used
        to describe a particular protocol layer, which cannot be
        identified with a deterministic, and (usually) hierarchical
        structure, like most networking protocols.

        Note that the PI-variant macro and the PI-macro are defined with
        a single set of syntax rules (see section 3.2), except that
        different sub-clauses are required for each type.

        A protocol identified with a PI-variant macro is actually a
        variant of a well known encapsulation that may be present in the
        protocolDirTable. This is used to document the IANA assigned
        protocols, which are needed to identify protocols which cannot
        be practically identified by examination of 'appropriate network
        traffic' (e.g. the packets which carry them).  All other
        protocols (which can be identified by examination of appropriate



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        network traffic) SHOULD be documented using the protocol-
        identifier macro.  (See section 3.2 for details.)

   protocol-parameter:
        A single octet, corresponding to a specific layer-identifier in
        the protocol-identifier. This octet is a bit-mask indicating
        special functions or capabilities that this agent is providing
        for the corresponding protocol.  (See section 3.2.6 for
        details.)

   protocol-parameters string:
        An octet string, which contains one protocol-parameter for each
        layer-identifier in the protocol-identifier.  This string is
        identified in the RMON-2 MIB [RFC2021] as the
        protocolDirParameters object. (See the section 3.2.6 for
        details.)

   protocolDirTable INDEX:
        A protocol-identifier and protocol-parameters octet string pair
        that have been converted to an INDEX value, according to the
        encoding rules in section 7.7 of RFC 1902 [RFC1902].

   pseudo-protocol:
        A convention or algorithm used only within this document for the
        purpose of encoding protocol-identifier strings.

   protocol encapsulation tree:
        Protocol encapsulations can be organized into an inverted tree.
        The nodes of the root are the base encapsulations. The children
        nodes, if any, of a node in the tree are the encapsulations of
        child protocols.

2.2.  Relationship to the Remote Network Monitoring MIB

   This document is intended to identify the encoding rules for the
   OCTET STRING objects protocolDirID and protocolDirParameters.  RMON-2
   tables, such as those in the new Protocol Distribution, Host, and
   Matrix groups, use a local INTEGER INDEX (protocolDirLocalIndex)
   rather than complete protocolDirTable INDEX strings, to identify
   protocols for counting purposes.  Only the protocolDirTable uses the
   protocolDirID and protocolDirParameters strings described in this
   document.

   This document is intentionally separated from the RMON-2 MIB objects
   [RFC2021] to allow updates to this document without any republication
   of MIB objects.





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   This document does not discuss auto-discovery and auto-population of
   the protocolDirTable. This functionality is not explicitly defined by
   the RMON standard. An agent SHOULD populate the directory with the
   'interesting' protocols on which the intended applications depend.

2.3.  Relationship to the RMON Protocol Identifier Macros Document

   The original RMON Protocol Identifiers document [RFC2074] contains
   the protocol directory reference material, as well as many examples
   of protocol identifier macros.

   These macros have been moved to a separate document called the RMON
   Protocol Identifier Macros document [RFC2896].  This will allow the
   normative text (this document) to advance on the standards track with
   the RMON-2 MIB [RFC2021], while the collection of PI macros is
   maintained in an Informational RFC.

   The PI Macros document is intentionally separated from this document
   to allow updates to the list of published PI macros without any
   republication of MIB objects or encoding rules.  Protocol Identifier
   macros submitted from the RMON working group and community at large
   (to the RMONMIB WG mailing list at 'rmonmib@ietf.org') will be
   collected, screened by the RMONMIB working group, and (if approved)
   added to a subsequent version of the PI Macros document.

   Macros submissions will be collected in the IANA's MIB files under
   the directory "ftp://ftp.isi.edu/mib/rmonmib/rmon2_pi_macros/" and in
   the RMONMIB working group mailing list message archive file
   www.ietf.org/mail-archive/working-
   groups/rmonmib/current/maillist.htm.

2.4.  Relationship to the ATM-RMON MIB

   The ATM Forum has standardized "Remote Monitoring MIB Extensions for
   ATM Networks" (ATM-RMON MIB) [AF-NM-TEST-0080.000], which provides
   RMON-like stats, host, matrix, and matrixTopN capability for NSAP
   address-based (ATM Adaption Layer 5, AAL-5) cell traffic.

2.4.1.  Port Aggregation

   It it possible to correlate ATM-RMON MIB data with packet-based
   RMON-2 [RFC2021] collections, but only if the ATM-RMON
   'portSelGrpTable' and 'portSelTable' are configured to provide the
   same level of port aggregation as used in the packet-based
   collection.  This will require an ATM-RMON 'portSelectGroup' to
   contain a single port, in the case of traditional RMON dataSources.





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2.4.2.  Encapsulation Mappings

   The RMON PI document does not contain explicit PI macro support for
   "Multiprotocol Encapsulation over ATM Adaptation Layer 5" [RFC1483],
   or ATM Forum "LAN Emulation over ATM" (LANE) [AF-LANE-0021.000].
   Instead, a probe must 'fit' the ATM encapsulation to one of the base
   layers defined in this document (i.e., llc, snap, or vsnap),
   regardless of how the raw data is obtained by the agent (e.g., VC-
   muxing vs. LLC-muxing, or routed vs. bridged formats).  See section
   3.2 for details on identifying and decoding a particular base layer.

   An NMS can determine some of the omitted encapsulation details by
   examining the interface type (ifType) of the dataSource for a
   particular RMON collection:

      RFC 1483 dataSource ifTypes:
           - aal5(49)

      LANE dataSource ifTypes:
           - aflane8023(59)
           - aflane8025(60)

   These dataSources require implementation of the ifStackTable from the
   Interfaces MIB [RFC2233].  It is possible that some implementations
   will use dataSource values which indicate an ifType of 'atm(37)'
   (because the ifStackTable is not supported), however this is strongly
   discouraged by the RMONMIB WG.

2.4.3.  Counting ATM Traffic in RMON-2 Collections

   The RMON-2 Application Layer (AL) and Network Layer (NL)
   (host/matrix/topN) tables require that octet counters be incremented
   by the size of the particular frame, not by the size of the frame
   attributed to a given protocol.

   Probe implementations must use the AAL-5 frame size (not the AAL-5
   payload size or encapsulated MAC frame size) as the 'frame size' for
   the purpose of incrementing RMON-2 octet counters (e.g.,
   'nlHostInOctets', 'alHostOutOctets').

   The RMONMIB WG has not addressed issues relating to packet capture of
   AAL-5 based traffic. Therefore, it is an implementation-specific
   matter whether padding octets (i.e., RFC 1483 VC-muxed, bridged 802.3
   or 802.5 traffic, or LANE traffic) are represented in the RMON-1
   'captureBufferPacketData' MIB object.   Normally, the first octet of
   the captured frame is the first octet of the destination MAC address
   (DA).




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2.5.  Relationship to Other MIBs

   The RMON Protocol Identifiers Reference document is intended for use
   with the protocolDirTable within the RMON MIB. It is not relevant to
   any other MIB, or intended for use with any other MIB.

3.  Protocol Identifier Encoding

   The protocolDirTable is indexed by two OCTET STRINGs, protocolDirID
   and protocolDirParameters. To encode the table index, each variable-
   length string is converted to an OBJECT IDENTIFIER fragment,
   according to the encoding rules in section 7.7 of RFC 1902 [RFC1902].
   Then the index fragments are simply concatenated.  (Refer to figures
   1a - 1d below for more detail.)

   The first OCTET STRING (protocolDirID) is composed of one or more 4-
   octet "layer-identifiers". The entire string uniquely identifies a
   particular node in the protocol encapsulation tree. The second OCTET
   STRING, (protocolDirParameters) which contains a corresponding number
   of 1-octet protocol-specific parameters, one for each 4-octet layer-
   identifier in the first string.

   A protocol layer is normally identified by a single 32-bit value.
   Each layer-identifier is encoded in the ProtocolDirID OCTET STRING
   INDEX as four sub-components [ a.b.c.d ], where 'a' - 'd' represent
   each byte of the 32-bit value in network byte order.  If a particular
   protocol layer cannot be encoded into 32 bits, then it must be
   defined as an 'ianaAssigned' protocol (see below for details on IANA
   assigned protocols).

   The following figures show the differences between the OBJECT
   IDENTIFIER and OCTET STRING encoding of the protocol identifier
   string.

                 Fig. 1a
       protocolDirTable INDEX Format
       -----------------------------

   +---+--------------------------+---+---------------+
   | c !                          | c !  protocolDir  |
   | n !  protocolDirID           | n !  Parameters   |
   | t !                          | t !               |
   +---+--------------------------+---+---------------+








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                 Fig. 1b
       protocolDirTable OCTET STRING Format
       ------------------------------------

    protocolDirID
   +----------------------------------------+
   |                                        |
   |              4 * N octets              |
   |                                        |
   +----------------------------------------+

   protocolDirParameters
   +----------+
   |          |
   | N octets |
   |          |
   +----------+

   N is the number of protocol-layer-identifiers required
   for the entire encapsulation of the named protocol.  Note
   that the layer following the base layer usually identifies
   a network layer protocol, but this is not always the case,
   (most notably for children of the 'vsnap' base-layer).

                  Fig. 1c
      protocolDirTable INDEX Format Example
      -------------------------------------

   protocolDirID                   protocolDirParameters
   +---+--------+--------+--------+--------+---+---+---+---+---+
   | c |  proto |  proto |  proto |  proto | c |par|par|par|par|
   | n |  base  | L(B+1) | L(B+2) | L(B+3) | n |ba-| L3| L4| L5|
   | t |(+flags)|   L3   |   L4   |   L5   | t |se |   |   |   |
   +---+--------+--------+--------+--------+---+---+---+---+---+ subOID
   | 1 |   4    |    4   |    4   |    4   | 1 | 1 | 1 | 1 | 1 | count

   When encoded in a protocolDirTable INDEX, each of the two
   strings must be preceded by a length sub-component. In this
   example, N equals '4', the first 'cnt' field would contain
   the value '16', and the second 'cnt' field would contain
   the value '4'.










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                  Fig. 1d
     protocolDirTable OCTET STRING Format Example
     --------------------------------------------

   protocolDirID
   +--------+--------+--------+--------+
   |  proto |  proto |  proto |  proto |
   |   base |    L3  |   L4   |   L5   |
   |        |        |        |        |
   +--------+--------+--------+--------+ octet
   |    4   |    4   |    4   |    4   | count


   protocolDirParameters
   +---+---+---+---+
   |par|par|par|par|
   |ba-| L3| L4| L5|
   |se |   |   |   |
   +---+---+---+---+ octet
   | 1 | 1 | 1 | 1 | count


   Although this example indicates four encapsulated protocols, in
   practice, any non-zero number of layer-identifiers may be present,
   theoretically limited only by OBJECT IDENTIFIER length restrictions,
   as specified in section 3.5 of RFC 1902 [RFC1902].

3.1.  ProtocolDirTable INDEX Format Examples

   The following PI identifier fragments are examples of some fully
   encoded protocolDirTable INDEX values for various encapsulations.

    -- HTTP; fragments counted from IP and above
    ether2.ip.tcp.www-http =
       16.0.0.0.1.0.0.8.0.0.0.0.6.0.0.0.80.4.0.1.0.0

    -- SNMP over UDP/IP over SNAP
    snap.ip.udp.snmp =
       16.0.0.0.3.0.0.8.0.0.0.0.17.0.0.0.161.4.0.0.0.0

    -- SNMP over IPX over SNAP
    snap.ipx.snmp =
       12.0.0.0.3.0.0.129.55.0.0.144.15.3.0.0.0

    -- SNMP over IPX over raw8023
    ianaAssigned.ipxOverRaw8023.snmp =
       12.0.0.0.5.0.0.0.1.0.0.144.15.3.0.0.0




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    -- IPX over LLC
    llc.ipx =
       8.0.0.0.2.0.0.0.224.2.0.0

    -- SNMP over UDP/IP over any link layer
    ether2.ip.udp.snmp
       16.1.0.0.1.0.0.8.0.0.0.0.17.0.0.0.161.4.0.0.0.0

    -- IP over any link layer; base encoding is IP over ether2
    ether2.ip
       8.1.0.0.1.0.0.8.0.2.0.0

    -- AppleTalk Phase 2 over ether2
    ether2.atalk
      8.0.0.0.1.0.0.128.155.2.0.0

    -- AppleTalk Phase 2 over vsnap
    vsnap.apple-oui.atalk
      12.0.0.0.4.0.8.0.7.0.0.128.155.3.0.0.0

3.2.  Protocol Identifier Macro Format

   The following example is meant to introduce the protocol-identifier
   macro. This macro-like construct is used to represent both protocols
   and protocol-variants.

   If the 'VariantOfPart' component of the macro is present, then the
   macro represents a protocol-variant instead of a protocol.  This
   clause is currently used only for IANA assigned protocols, enumerated
   under the 'ianaAssigned' base-layer.  The VariantOfPart component
   MUST be present for IANA assigned protocols.

3.2.1.  Lexical Conventions

   The PI language defines the following keywords:

         ADDRESS-FORMAT
         ATTRIBUTES
         CHILDREN
         DECODING
         DESCRIPTION
         PARAMETERS
         PROTOCOL-IDENTIFIER
         REFERENCE
         VARIANT-OF






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   The PI language defines the following punctuation elements:

        {     left curly brace
        }     right curly brace
        (     left parenthesis
        )     right parenthesis
        ,     comma
        ::=   two colons and an equal sign
        --    two dashes

3.2.2.  Notation for Syntax Descriptions

   An extended form of the BNF notation is used to specify the syntax of
   the PI language. The rules for this notation are shown below:

     *  Literal values are specified in quotes, for example "REFERENCE"

     *  Non-terminal items are surrounded by less than (<) and greater
        than (>) characters, for example <parmList>

     *  Terminal items are specified without surrounding quotes or less
        than and greater than characters, for example 'lcname'

     *  A vertical bar (|) is used to indicate a choice between items,
        for example 'number | hstr'

     *  Ellipsis are used to indicate that the previous item may be
        repeated one or more times, for example <parm>...

     *  Square brackets are used to enclose optional items, for example
        [ "," <parm> ]

     *  An equals character (=) is used to mean "defined as," for
        example '<protoName> = pname'

3.2.3.  Grammar for the PI Language

   The following are "terminals" of the grammar and are identical to the
   same lexical elements from the MIB module language, except for hstr
   and pname:

       <lc>     = "a" | "b" | "c" | ... | "z"
       <uc>     = "A" | "B" | "C" | ... | "Z"
       <letter> = <lc> | <uc>
       <digit>  = "0" | "1" | ... | "9"
       <hdigit> = <digit> | "a" | "A" | "b" | "B" | ... | "f" | "F"





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       <lcname> = <lc> [ <lcrest> ]
       <lcrest> = ( <letter> | <digit> | "-" ) [ <lcrest> ]

       <pname>  = ( <letter> | <digit> ) [ <pnrest> ]
       <pnrest> = ( <letter> | <digit> | "-" | "_" | "*" ) [ <pnrest> ]

       <number> = <digit> [ <number> ]  -- to a max dec. value of 4g-1

       <hstr>   = "0x" <hrest>          -- to a max dec. value of 4g-1
       <hrest>  = <hdigit> [ <hrest> ]

       <lf>     = linefeed char
       <cr>     = carriage return char
       <eoln>   = <cr><lf> | <lf>

       <sp>     = " "
       <tab>    = "    "
       <wspace> = { <sp> | <tab> | <eoln> } [<wspace>]

       <string> = """ [ <strest> ] """
       <strest> = ( <letter> | <digit> | <wspace> ) [ <strest> ]

   The following is the extended BNF notation for the grammar with
   starting symbol <piFile>:

       -- a file containing one or more Protocol Identifier (PI)
       -- definitions
       <piFile> = <piDefinition>...

       -- a PI definition
       <piDefinition> =
         <protoName> "PROTOCOL-IDENTIFIER"
             [ "VARIANT-OF" <protoName> ]
               "PARAMETERS" "{" [ <parmList> ] "}"
               "ATTRIBUTES" "{" [ <attrList> ] "}"
               "DESCRIPTION" string
             [ "CHILDREN" string ]
             [ "ADDRESS-FORMAT" string ]
             [ "DECODING" string ]
             [ "REFERENCE" string ]
               "::=" "{" <encapList> "}"

       -- a protocol name
       <protoName> = pname

       -- a list of parameters
       <parmList> = <parm> [ "," <parm> ]...




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       -- a parameter
       <parm> = lcname [<wspace>] "(" [<wspace>]
                 <nonNegNum> [<wspace>] ")" [<wspace>]

       -- list of attributes
       <attrList> = <attr> [ [<wspace>] "," [<wspace>] <attr> ]...

       -- an attribute
       <attr> = lcname [<wspace>] "(" [<wspace>]
                 <nonNegNum> [<wspace>] ")"

       -- a non-negative number
       <nonNegNum> = number | hstr

       -- list of encapsulation values
       <encapList> = <encapValue> [ [<wspace>] ","
                       [<wspace>] <encapValue> ]...

       -- an encapsulation value
       <encapValue> = <baseEncapValue> | <normalEncapValue>

       -- base encapsulation value
       <baseEncapValue> = <nonNegNum>

       -- normal encapsulation value
        <normalEncapValue> = <protoName> <wspace> <nonNegNum>

       -- comment
       <two dashes> <text> <end-of-line>

3.2.4.  Mapping of the Protocol Name

   The "protoName" value, called the "protocol name" shall be an ASCII
   string consisting of one up to 64 characters from the following:

        "A" through "Z"
        "a" through "z"
        "0" through "9"
        dash (-)
        underbar (_)
        asterisk (*)
        plus(+)

   The first character of the protocol name is limited to one of the
   following:

        "A" through "Z"
        "a" through "z"



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        "0" through "9"

   This value SHOULD be the name or acronym identifying the protocol.
   Note that case is significant.  The value selected for the protocol
   name SHOULD match the "most well-known" name or acronym for the
   indicated protocol.  For example, the document indicated by the URL:

       ftp://ftp.isi.edu/in-notes/iana/assignments/protocol-numbers

   defines IP Protocol field values, so protocol-identifier macros for
   children of IP SHOULD be given names consistent with the protocol
   names found in this authoritative document.  Likewise, children of
   UDP and TCP SHOULD be given names consistent with the port number
   name assignments found in:

       ftp://ftp.isi.edu/in-notes/iana/assignments/port-numbers

   When the "well-known name" contains characters not allowed in
   protocol names, they MUST be changed to a dash character ("-") . In
   the event that the first character must be changed, the protocol name
   is prepended with the letter "p", so the former first letter may be
   changed to a dash.

   For example, z39.50 becomes z39-50 and 914c/g becomes 914c-g.  The
   following protocol names are legal:

       ftp, ftp-data, whois++, sql*net, 3com-tsmux, ocs_cmu

   Note that it is possible in actual implementation that different
   encapsulations of the same protocol (which are represented by
   different entries in the protocolDirTable) will be assigned the same
   protocol name.  The protocolDirID INDEX value defines a particular
   protocol, not the protocol name string.

3.2.5.  Mapping of the VARIANT-OF Clause

   This clause is present for IANA assigned protocols only.  It
   identifies the protocol-identifier macro that most closely represents
   this particular protocol, and is known as the "reference protocol".
   A protocol-identifier macro MUST exist for the reference protocol.
   When this clause is present in a protocol-identifier macro, the macro
   is called a 'protocol-variant-identifier'.

   Any clause (e.g. CHILDREN, ADDRESS-FORMAT) in the reference
   protocol-identifier macro SHOULD NOT be duplicated in the protocol-
   variant-identifier macro, if the 'variant' protocols' semantics are
   identical for a given clause.




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   Since the PARAMETERS and ATTRIBUTES clauses MUST be present in a
   protocol-identifier, an empty 'ParamList' and 'AttrList' (i.e.
   "PARAMETERS {}") MUST be present in a protocol-variant-identifier
   macro, and the 'ParamList' and 'AttrList' found in the reference
   protocol-identifier macro examined instead.

   Note that if an 'ianaAssigned' protocol is defined that is not a
   variant of any other documented protocol, then the protocol-
   identifier macro SHOULD be used instead of the protocol-variant-
   identifier version of the macro.

3.2.6.  Mapping of the PARAMETERS Clause

   The protocolDirParameters object provides an NMS the ability to turn
   on and off expensive probe resources. An agent may support a given
   parameter all the time, not at all, or subject to current resource
   load.

   The PARAMETERS clause is a list of bit definitions which can be
   directly encoded into the associated ProtocolDirParameters octet in
   network byte order. Zero or more bit definitions may be present. Only
   bits 0-7 are valid encoding values. This clause defines the entire
   BIT set allowed for a given protocol. A conforming agent may choose
   to implement a subset of zero or more of these PARAMETERS.

   By convention, the following common bit definitions are used by
   different protocols.  These bit positions MUST NOT be used for other
   parameters. They MUST be reserved if not used by a given protocol.

   Bits are encoded in a single octet. Bit 0 is the high order (left-
   most) bit in the octet, and bit 7 is the low order (right-most) bit
   in the first octet. Reserved bits and unspecified bits in the octet
   are set to zero.

     Table 3.1  Reserved PARAMETERS Bits
     ------------------------------------

 Bit Name              Description
 ---------------------------------------------------------------------
 0   countsFragments   higher-layer protocols encapsulated within
                       this protocol will be counted correctly even
                       if this protocol fragments the upper layers
                       into multiple packets.
 1   tracksSessions    correctly attributes all packets of a protocol
                       which starts sessions on well known ports or
                       sockets and then transfers them to dynamically
                       assigned ports or sockets thereafter (e.g. TFTP).




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   The PARAMETERS clause MUST be present in all protocol-identifier
   macro declarations, but may be equal to zero (empty).

3.2.6.1.  Mapping of the 'countsFragments(0)' BIT

   This bit indicates whether the probe is correctly attributing all
   fragmented packets of the specified protocol, even if individual
   frames carrying this protocol cannot be identified as such.  Note
   that the probe is not required to actually present any re-assembled
   datagrams (for address-analysis, filtering, or any other purpose) to
   the NMS.

   This bit MUST only be set in a protocolDirParameters octet which
   corresponds to a protocol that supports fragmentation and reassembly
   in some form. Note that TCP packets are not considered 'fragmented-
   streams' and so TCP is not eligible.

   This bit MAY be set in more than one protocolDirParameters octet
   within a protocolDirTable INDEX, in the event an agent can count
   fragments at more than one protocol layer.

3.2.6.2.  Mapping of the 'tracksSessions(1)' BIT

   The 'tracksSessions(1)' bit indicates whether frames which are part
   of remapped sessions (e.g. TFTP download sessions) are correctly
   counted by the probe. For such a protocol, the probe must usually
   analyze all packets received on the indicated interface, and maintain
   some state information, (e.g. the remapped UDP port number for TFTP).

   The semantics of the 'tracksSessions' parameter are independent of
   the other protocolDirParameters definitions, so this parameter MAY be
   combined with any other legal parameter configurations.

3.2.7.  Mapping of the ATTRIBUTES Clause

   The protocolDirType object provides an NMS with an indication of a
   probe's capabilities for decoding a given protocol, or the general
   attributes of the particular protocol.

   The ATTRIBUTES clause is a list of bit definitions which are encoded
   into the associated instance of ProtocolDirType. The BIT definitions
   are specified in the SYNTAX clause of the protocolDirType MIB object.









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        Table 3.2  Reserved ATTRIBUTES Bits
        ------------------------------------

    Bit Name              Description
    ---------------------------------------------------------------------
    0  hasChildren        indicates that there may be children of
                          this protocol defined in the protocolDirTable
                          (by either the agent or the manager).
    1  addressRecognitionCapable
                          indicates that this protocol can be used
                          to generate host and matrix table entries.

   The ATTRIBUTES clause MUST be present in all protocol-identifier
   macro declarations, but MAY be empty.

3.2.8.  Mapping of the DESCRIPTION Clause

   The DESCRIPTION clause provides a textual description of the protocol
   identified by this macro.  Notice that it SHOULD NOT contain details
   about items covered by the CHILDREN, ADDRESS-FORMAT, DECODING and
   REFERENCE clauses.

   The DESCRIPTION clause MUST be present in all protocol-identifier
   macro declarations.

3.2.9.  Mapping of the CHILDREN Clause

   The CHILDREN clause provides a description of child protocols for
   protocols which support them. It has three sub-sections:

  -  Details on the field(s)/value(s) used to select the child protocol,
     and how that selection process is performed

  -  Details on how the value(s) are encoded in the protocol identifier
     octet string

  -  Details on how child protocols are named with respect to their
     parent protocol label(s)

   The CHILDREN clause MUST be present in all protocol-identifier macro
   declarations in which the 'hasChildren(0)' BIT is set in the
   ATTRIBUTES clause.









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3.2.10.  Mapping of the ADDRESS-FORMAT Clause

   The ADDRESS-FORMAT clause provides a description of the OCTET-STRING
   format(s) used when encoding addresses.

   This clause MUST be present in all protocol-identifier macro
   declarations in which the 'addressRecognitionCapable(1)' BIT is set
   in the ATTRIBUTES clause.

3.2.11.  Mapping of the DECODING Clause

   The DECODING clause provides a description of the decoding procedure
   for the specified protocol. It contains useful decoding hints for the
   implementor, but SHOULD NOT over-replicate information in documents
   cited in the REFERENCE clause.  It might contain a complete
   description of any decoding information required.

   For 'extensible' protocols ('hasChildren(0)' BIT set) this includes
   offset and type information for the field(s) used for child selection
   as well as information on determining the start of the child
   protocol.

   For 'addressRecognitionCapable' protocols this includes offset and
   type information for the field(s) used to generate addresses.

   The DECODING clause is optional, and MAY be omitted if the REFERENCE
   clause contains pointers to decoding information for the specified
   protocol.

3.2.12.  Mapping of the REFERENCE Clause

   If a publicly available reference document exists for this protocol
   it SHOULD be listed here.  Typically this will be a URL if possible;
   if not then it will be the name and address of the controlling body.

   The CHILDREN, ADDRESS-FORMAT, and DECODING clauses SHOULD limit the
   amount of information which may currently be obtained from an
   authoritative document, such as the Assigned Numbers document
   [RFC1700].  Any duplication or paraphrasing of information should be
   brief and consistent with the authoritative document.

   The REFERENCE clause is optional, but SHOULD be implemented if an
   authoritative reference exists for the protocol (especially for
   standard protocols).







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3.3.  Evaluating an Index of the ProtocolDirTable

   The following evaluation is done after a protocolDirTable INDEX value
   has been converted into two OCTET STRINGs according to the INDEX
   encoding rules specified in the SMI [RFC1902].

   Protocol-identifiers are evaluated left to right, starting with the
   protocolDirID, which length MUST be evenly divisible by four. The
   protocolDirParameters length MUST be exactly one quarter of the
   protocolDirID string length.

   Protocol-identifier parsing starts with the base layer identifier,
   which MUST be present, and continues for one or more upper layer
   identifiers, until all OCTETs of the protocolDirID have been used.
   Layers MUST NOT be skipped, so identifiers such as 'SNMP over IP' or
   'TCP over ether2' can not exist.

   The base-layer-identifier also contains a 'special function
   identifier' which may apply to the rest of the protocol identifier.

   Wild-carding at the base layer within a protocol encapsulation is the
   only supported special function at this time. (See section 4.1.1.2
   for details.)

   After the protocol-identifier string (which is the value of
   protocolDirID) has been parsed, each octet of the protocol-parameters
   string is evaluated, and applied to the corresponding protocol layer.

   A protocol-identifier label MAY map to more than one value.  For
   instance, 'ip' maps to 5 distinct values, one for each supported
   encapsulation.  (see the 'IP' section under 'L3 Protocol Identifiers'
   in the RMON Protocol Identifier Macros document [RFC2896]).

   It is important to note that these macros are conceptually expanded
   at implementation time, not at run time.

   If all the macros are expanded completely by substituting all
   possible values of each label for each child protocol, a list of all
   possible protocol-identifiers is produced.  So 'ip' would result in 5
   distinct protocol-identifiers.  Likewise each child of 'ip' would map
   to at least 5 protocol-identifiers, one for each encapsulation (e.g.
   ip over ether2, ip over LLC, etc.).









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4.  Base Layer Protocol Identifier Macros

   The following PROTOCOL IDENTIFIER macros can be used to construct
   protocolDirID and protocolDirParameters strings.

   An identifier is encoded by constructing the base-identifier, then
   adding one layer-identifier for each encapsulated protocol.

   Refer to the RMON Protocol Identifier Macros document [RFC2896] for a
   listing of the non-base layer PI macros published by the working
   group. Note that other PI macro documents may exist, and it should be
   possible for an implementor to populate the protocolDirTable without
   the use of the PI Macro document [RFC2896].

4.1.  Base Identifier Encoding

   The first layer encapsulation is called the base identifier and it
   contains optional protocol-function information and the base layer
   (e.g.  MAC layer) enumeration value used in this protocol identifier.

   The base identifier is encoded as four octets as shown in figure 2.

             Fig. 2
        base-identifier format
        +---+---+---+---+
        |   |   |   |   |
        | f |op1|op2| m |
        |   |   |   |   |
        +---+---+---+---+ octet
        | 1 | 1 | 1 | 1 | count

   The first octet ('f') is the special function code, found in table
   4.1.  The next two octets ('op1' and 'op2') are operands for the
   indicated function. If not used, an operand must be set to zero.  The
   last octet, 'm', is the enumerated value for a particular base layer
   encapsulation, found in table 4.2.  All four octets are encoded in
   network-byte-order.

4.1.1.  Protocol Identifier Functions

   The base layer identifier contains information about any special
   functions to perform during collections of this protocol, as well as
   the base layer encapsulation identifier.

   The first three octets of the identifier contain the function code
   and two optional operands. The fourth octet contains the particular
   base layer encapsulation used in this protocol (fig. 2).




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      Table 4.1  Assigned Protocol Identifier Functions
      -------------------------------------------------

            Function     ID    Param1               Param2
            ----------------------------------------------------
            none          0    not used (0)         not used (0)
            wildcard      1    not used (0)         not used (0)

4.1.1.1.  Function 0: None

   If the function ID field (1st octet) is equal to zero, the 'op1' and
   'op2' fields (2nd and 3rd octets) must also be equal to zero. This
   special value indicates that no functions are applied to the protocol
   identifier encoded in the remaining octets. The identifier represents
   a normal protocol encapsulation.

4.1.1.2.  Function 1: Protocol Wildcard Function

   The wildcard function (function-ID = 1), is used to aggregate
   counters, by using a single protocol value to indicate potentially
   many base layer encapsulations of a particular network layer
   protocol. A protocolDirEntry of this type will match any base-layer
   encapsulation of the same network layer protocol.

   The 'op1' field (2nd octet) is not used and MUST be set to zero.

   The 'op2' field (3rd octet) is not used and MUST be set to zero.

   Each wildcard protocol identifier MUST be defined in terms of a 'base
   encapsulation'. This SHOULD be as 'standard' as possible for
   interoperability purposes.  The lowest possible base layer value
   SHOULD be chosen.  So, if an encapsulation over 'ether2' is
   permitted, than this should be used as the base encapsulation. If not
   then an encapsulation over LLC should be used, if permitted.  And so
   on for each of the defined base layers.

   It should be noted that an agent does not have to support the non-
   wildcard protocol identifier over the same base layer.  For instance
   a token ring only device would not normally support IP over the
   ether2 base layer.  Nevertheless it should use the ether2 base layer
   for defining the wildcard IP encapsulation.  The agent MAY also
   support counting some or all of the individual encapsulations for the
   same protocols, in addition to wildcard counting.  Note that the
   RMON-2 MIB [RFC2021] does not require that agents maintain counters
   for multiple encapsulations of the same protocol.  It is an
   implementation-specific matter as to how an agent determines which
   protocol combinations to allow in the protocolDirTable at any given
   time.



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4.2.  Base Layer Protocol Identifiers

   The base layer is mandatory, and defines the base encapsulation of
   the packet and any special functions for this identifier.

   There are no suggested protocolDirParameters bits for the base layer.

   The suggested value for the ProtocolDirDescr field for the base layer
   is given by the corresponding "Name" field in the table 4.2 below.
   However, implementations are only required to use the appropriate
   integer identifier values.

   For most base layer protocols, the protocolDirType field should
   contain bits set for  the 'hasChildren(0)' and '
   addressRecognitionCapable(1)' attributes.  However, the special
   'ianaAssigned' base layer should have no parameter or attribute bits
   set.

   By design, only 255 different base layer encapsulations are
   supported.  There are five base encapsulation values defined at this
   time. Very few new base encapsulations (e.g. for new media types) are
   expected to be added over time.

     Table 4.2  Base Layer Encoding Values
     --------------------------------------

           Name          ID
           ------------------
           ether2        1
           llc           2
           snap          3
           vsnap         4
           ianaAssigned  5

 -- Ether2 Encapsulation

ether2 PROTOCOL-IDENTIFIER
    PARAMETERS { }
    ATTRIBUTES {
     hasChildren(0),
        addressRecognitionCapable(1)
    }
    DESCRIPTION
       "DIX Ethernet, also called Ethernet-II."
    CHILDREN
       "The Ethernet-II type field is used to select child protocols.
       This is a 16-bit field.  Child protocols are deemed to start at
       the first octet after this type field.



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       Children of this protocol are encoded as [ 0.0.0.1 ], the
       protocol identifier for 'ether2' followed by [ 0.0.a.b ] where
       'a' and 'b' are the network byte order encodings of the high
       order byte and low order byte of the Ethernet-II type value.

       For example, a protocolDirID-fragment value of:
          0.0.0.1.0.0.8.0 defines IP encapsulated in ether2.

       Children of ether2 are named as 'ether2' followed by the type
       field value in hexadecimal.  The above example would be declared
       as:
          ether2 0x0800"
    ADDRESS-FORMAT
       "Ethernet addresses are 6 octets in network order."
    DECODING
       "Only type values greater than 1500 decimal indicate Ethernet-II
       frames; lower values indicate 802.3 encapsulation (see below)."
    REFERENCE
       "The authoritative list of Ether Type values is identified by the
       URL:

          ftp://ftp.isi.edu/in-notes/iana/assignments/ethernet-numbers"
    ::= { 1 }

 -- LLC Encapsulation

llc PROTOCOL-IDENTIFIER
    PARAMETERS { }
    ATTRIBUTES {
     hasChildren(0),
     addressRecognitionCapable(1)
    }
    DESCRIPTION
       "The Logical Link Control (LLC) 802.2 protocol."
    CHILDREN
       "The LLC Source Service Access Point (SSAP) and Destination
       Service Access Point (DSAP) are used to select child protocols.
       Each of these is one octet long, although the least significant
       bit is a control bit and should be masked out in most situations.
       Typically SSAP and DSAP (once masked) are the same for a given
       protocol - each end implicitly knows whether it is the server or
       client in a client/server protocol.  This is only a convention,
       however, and it is possible for them to be different.  The SSAP
       is matched against child protocols first.  If none is found then
       the DSAP is matched instead.  The child protocol is deemed to
       start at the first octet after the LLC control field(s).





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       Children of 'llc' are encoded as [ 0.0.0.2 ], the protocol
       identifier component for LLC followed by [ 0.0.0.a ] where 'a' is
       the SAP value which maps to the child protocol.  For example, a
       protocolDirID-fragment value of:
          0.0.0.2.0.0.0.240

       defines NetBios over LLC.

       Children are named as 'llc' followed by the SAP value in
       hexadecimal.  So the above example would have been named:
          llc 0xf0"
    ADDRESS-FORMAT
       "The address consists of 6 octets of MAC address in network
       order.  Source routing bits should be stripped out of the address
       if present."
    DECODING
       "Notice that LLC has a variable length protocol header; there are
       always three octets (DSAP, SSAP, control).  Depending on the
       value of the control bits in the DSAP, SSAP and control fields
       there may be an additional octet of control information.

       LLC can be present on several different media.  For 802.3 and
       802.5 its presence is mandated (but see ether2 and raw 802.3
       encapsulations).  For 802.5 there is no other link layer
       protocol.

       Notice also that the raw802.3 link layer protocol may take
       precedence over this one in a protocol specific manner such that
       it may not be possible to utilize all LSAP values if raw802.3 is
       also present."
    REFERENCE
       "The authoritative list of LLC LSAP values is controlled by the
       IEEE Registration Authority:
       IEEE Registration Authority
          c/o Iris Ringel
          IEEE Standards Dept
          445 Hoes Lane, P.O. Box 1331
          Piscataway, NJ 08855-1331
          Phone +1 908 562 3813
          Fax: +1 908 562 1571"
    ::= { 2 }

 -- SNAP over LLC (Organizationally Unique Identifier, OUI=000)
 -- Encapsulation

snap PROTOCOL-IDENTIFIER
    PARAMETERS { }
    ATTRIBUTES {



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     hasChildren(0),
     addressRecognitionCapable(1)
    }
    DESCRIPTION
       "The Sub-Network Access Protocol (SNAP) is layered on top of LLC
       protocol, allowing Ethernet-II protocols to be run over a media
       restricted to LLC."
    CHILDREN
       "Children of 'snap' are identified by Ethernet-II type values;
       the SNAP Protocol Identifier field (PID) is used to select the
       appropriate child.  The entire SNAP protocol header is consumed;
       the child protocol is assumed to start at the next octet after
       the PID.

       Children of 'snap' are encoded as [ 0.0.0.3 ], the protocol
       identifier for 'snap', followed by [ 0.0.a.b ] where 'a' and 'b'
       are the high order byte and low order byte of the Ethernet-II
       type value.

       For example, a protocolDirID-fragment value of:
          0.0.0.3.0.0.8.0

       defines the IP/SNAP protocol.

       Children of this protocol are named 'snap' followed by the
       Ethernet-II type value in hexadecimal.  The above example would
       be named:

          snap 0x0800"
    ADDRESS-FORMAT
         "The address format for SNAP is the same as that for LLC"
    DECODING
       "SNAP is only present over LLC.  Both SSAP and DSAP will be 0xAA
       and a single control octet will be present.  There are then three
       octets of Organizationally Unique Identifier (OUI) and two octets
       of PID.  For this encapsulation the OUI must be 0x000000 (see
       'vsnap' below for non-zero OUIs)."
    REFERENCE
       "SNAP Identifier values are assigned by the IEEE Standards
       Office.  The address is:
            IEEE Registration Authority
            c/o Iris Ringel
            IEEE Standards Dept
            445 Hoes Lane, P.O. Box 1331
            Piscataway, NJ 08855-1331
            Phone +1 908 562 3813
            Fax: +1 908 562 1571"
    ::= { 3 }



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 -- Vendor SNAP over LLC (OUI != 000) Encapsulation

vsnap PROTOCOL-IDENTIFIER
    PARAMETERS { }
    ATTRIBUTES {
     hasChildren(0),
     addressRecognitionCapable(1)
    }
    DESCRIPTION
       "This pseudo-protocol handles all SNAP packets which do not have
       a zero OUI.  See 'snap' above for details of those that have a
       zero OUI value."
    CHILDREN
       "Children of 'vsnap' are selected by the 3 octet OUI; the PID is
       not parsed; child protocols are deemed to start with the first
       octet of the SNAP PID field, and continue to the end of the
       packet.  Children of 'vsnap' are encoded as [ 0.0.0.4 ], the
       protocol identifier for 'vsnap', followed by [ 0.a.b.c ] where
       'a', 'b' and 'c' are the 3 octets of the OUI field in network
       byte order.

       For example, a protocolDirID-fragment value of:
         0.0.0.4.0.8.0.7 defines the Apple-specific set of protocols
       over vsnap.

       Children are named as 'vsnap <OUI>', where the '<OUI>' field is
       represented as 3 octets in hexadecimal notation.

       So the above example would be named:
         'vsnap 0x080007'"
    ADDRESS-FORMAT
       "The LLC address format is inherited by 'vsnap'.  See the 'llc'
       protocol identifier for more details."
    DECODING
       "Same as for 'snap' except the OUI is non-zero and the SNAP
       Protocol Identifier is not parsed."
    REFERENCE
       "SNAP Identifier values are assigned by the IEEE Standards
       Office.  The address is:
            IEEE Registration Authority
            c/o Iris Ringel
            IEEE Standards Dept
            445 Hoes Lane, P.O. Box 1331
            Piscataway, NJ 08855-1331
            Phone +1 908 562 3813
            Fax: +1 908 562 1571"
    ::= { 4 }




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 -- IANA Assigned Protocols

ianaAssigned PROTOCOL-IDENTIFIER
    PARAMETERS { }
    ATTRIBUTES { }
    DESCRIPTION
       "This branch contains protocols which do not conform easily to
       the hierarchical format utilized in the other link layer
       branches.  Usually, such a protocol 'almost' conforms to a
       particular 'well-known' identifier format, but additional
       criteria are used (e.g. configuration-based), making protocol
       identification difficult or impossible by examination of
       appropriate network traffic (preventing the any 'well-known'
       protocol-identifier macro from being used).

       Sometimes well-known protocols are simply remapped to a different
       port number by one or more venders (e.g. SNMP). These protocols
       can be identified with the 'limited extensibility' feature of the
       protocolDirTable, and do not need special IANA assignments.

       A centrally located list of these enumerated protocols must be
       maintained by IANA to insure interoperability. (See section 2.3
       for details on the document update procedure.)  Support for new
       link-layers will be added explicitly, and only protocols which
       cannot possibly be represented in a better way will be considered
       as 'ianaAssigned' protocols.

       IANA protocols are identified by the base-layer-selector value [
       0.0.0.5 ], followed by the four octets [ 0.0.a.b ] of the integer
       value corresponding to the particular IANA protocol.

       Do not create children of this protocol unless you are sure that
       they cannot be handled by the more conventional link layers
       above."
    CHILDREN
       "Children of this protocol are identified by implementation-
       specific means, described (as best as possible) in the 'DECODING'
       clause within the protocol-variant-identifier macro for each
       enumerated protocol.

       Children of this protocol are encoded as [ 0.0.0.5 ], the
       protocol identifier for 'ianaAssigned', followed by [ 0.0.a.b ]
       where 'a', 'b' are the network byte order encodings of the high
       order byte and low order byte of the enumeration value for the
       particular IANA assigned protocol.






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       For example, a protocolDirID-fragment value of:
          0.0.0.5.0.0.0.1

       defines the IPX protocol encapsulated directly in 802.3

       Children are named 'ianaAssigned' followed by the numeric value
       of the particular IANA assigned protocol.  The above example
       would be named:

          'ianaAssigned 1' "
    DECODING
       "The 'ianaAssigned' base layer is a pseudo-protocol and is not
       decoded."
    REFERENCE
       "Refer to individual PROTOCOL-IDENTIFIER macros for information
       on each child of the IANA assigned protocol."
    ::= { 5 }

 -- The following protocol-variant-identifier macro declarations are
 -- used to identify the RMONMIB IANA assigned protocols in a
 -- proprietary way, by simple enumeration.

ipxOverRaw8023 PROTOCOL-IDENTIFIER
    VARIANT-OF  ipx
    PARAMETERS      { }
    ATTRIBUTES  { }
    DESCRIPTION
       "This pseudo-protocol describes an encapsulation of IPX over
       802.3, without a type field.

       Refer to the macro for IPX for additional information about this
       protocol."
    DECODING
       "Whenever the 802.3 header indicates LLC a set of protocol
       specific tests needs to be applied to determine whether this is a
       'raw8023' packet or a true 802.2 packet.  The nature of these
       tests depends on the active child protocols for 'raw8023' and is
       beyond the scope of this document."
    ::= {
     ianaAssigned 1,             -- [0.0.0.1]
     802-1Q       0x05000001     -- 1Q_IANA [5.0.0.1]
    }









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4.3.  Encapsulation Layers

   Encapsulation layers are positioned between the base layer and the
   network layer.  It is an implementation-specific matter whether a
   probe exposes all such encapsulations in its RMON-2 Protocol
   Directory.

4.3.1.  IEEE 802.1Q

   RMON probes may encounter 'VLAN tagged' frames on monitored links.
   The IEEE Virtual LAN (VLAN) encapsulation standards [IEEE802.1Q] and
   [IEEE802.1D-1998], define an encapsulation layer inserted after the
   MAC layer and before the network layer.  This section defines a PI
   macro which supports most (but not all) features of that
   encapsulation layer.

   Most notably, the RMON PI macro '802-1Q' does not expose the Token
   Ring Encapsulation (TR-encaps) bit in the TCI portion of the VLAN
   header.  It is an implementation specific matter whether an RMON
   probe converts LLC-Token Ring (LLC-TR) formatted frames to LLC-Native
   (LLC-N) format, for the purpose of RMON collection.

   In order to support the Ethernet and LLC-N formats in the most
   efficient manner, and still maintain alignment with the RMON-2 '
   collapsed' base layer approach (i.e., support for snap and vsnap),
   the children of 802dot1Q are encoded a little differently than the
   children of other base layer identifiers.

802-1Q   PROTOCOL-IDENTIFIER
    PARAMETERS { }
    ATTRIBUTES {
     hasChildren(0)
    }
    DESCRIPTION
       "IEEE 802.1Q VLAN Encapsulation header.

       Note that the specific encoding of the TPID field is not
       explicitly identified by this PI macro.  Ethernet-encoded vs.
       SNAP-encoded TPID fields can be identified by the ifType of the
       data source for a particular RMON collection, since the SNAP-
       encoded format is used exclusively on Token Ring and FDDI media.
       Also, no information held in the TCI field (including the TR-
       encap bit) is identified in protocolDirID strings utilizing this
       PI macro."







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    CHILDREN
       "The first byte of the 4-byte child identifier is used to
       distinguish the particular base encoding that follows the 802.1Q
       header.  The remaining three bytes are used exactly as defined by
       the indicated base layer encoding.

       In order to simplify the child encoding for the most common
       cases, the 'ether2' and 'snap' base layers are combined into a
       single identifier, with a value of zero.  The other base layers
       are encoded with values taken from Table 4.2.

                     802-1Q Base ID Values
                     ---------------------

                 Base             Table 4.2   Base-ID
                 Layer            Encoding    Encoding
                 -------------------------------------
                  ether2           1           0
                  llc              2           2
                  snap             3           0
                  vsnap            4           4
                  ianaAssigned     5           5

       The generic child layer-identifier format is shown below:

            802-1Q  Child Layer-Identifier Format
            +--------+--------+--------+--------+
            |  Base  |                          |
            |   ID   |   base-specific format   |
            |        |                          |
            +--------+--------+--------+--------+
            |    1   |             3            | octet count

       Base ID == 0
       ------------
       For payloads encoded with either the Ethernet or LLC/SNAP headers
       following the VLAN header, children of this protocol are
       identified exactly as described for the 'ether2' or 'snap' base
       layers.

       Children are encoded as [ 0.0.129.0 ], the protocol identifier
       for '802-1Q' followed by [ 0.0.a.b ] where 'a' and 'b' are the
       network byte order encodings of the high order byte and low order
       byte of the Ethernet-II type value.

       For example, a protocolDirID-fragment value of:
          0.0.0.1.0.0.129.0.0.0.8.0
       defines IP, VLAN-encapsulated in ether2.



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       Children of this format are named as '802-1Q' followed by the
       type field value in hexadecimal.

       So the above example would be declared as:
          '802-1Q 0x0800'.

       Base ID == 2
       ------------
       For payloads encoded with a (non-SNAP) LLC header following the
       VLAN header, children of this protocol are identified exactly as
       described for the 'llc' base layer.

       Children are encoded as [ 0.0.129.0 ], the protocol identifier
       component for 802.1Q, followed by [ 2.0.0.a ] where 'a' is the
       SAP value which maps to the child protocol.  For example, a
       protocolDirID-fragment value of:
          0.0.0.1.0.0.129.0.2.0.0.240

       defines NetBios, VLAN-encapsulated over LLC.

       Children are named as '802-1Q' followed by the SAP value in
       hexadecimal, with the leading octet set to the value 2.

       So the above example would have been named:
          '802-1Q 0x020000f0'

       Base ID == 4
       ------------
       For payloads encoded with  LLC/SNAP (non-zero OUI) headers
       following the VLAN header, children of this protocol are
       identified exactly as described for the 'vsnap' base layer.

       Children are encoded as [ 0.0.129.0 ], the protocol identifier
       for '802-1Q', followed by [ 4.a.b.c ] where 'a', 'b' and 'c' are
       the 3 octets of the OUI field in network byte order.

       For example, a protocolDirID-fragment value of:
         0.0.0.1.0.0.129.0.4.8.0.7 defines the Apple-specific set of
       protocols, VLAN-encapsulated over vsnap.

       Children are named as '802-1Q' followed by the <OUI> value, which
       is represented as 3 octets in hexadecimal notation, with a
       leading octet set to the value 4.

       So the above example would be named:
         '802-1Q 0x04080007'.





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       Base ID == 5
       ------------
       For payloads which can only be identified as 'ianaAssigned'
       protocols, children of this protocol are identified exactly as
       described for the 'ianaAssigned' base layer.

       Children are encoded as [ 0.0.129.0 ], the protocol identifier
       for '802-1Q', followed by [ 5.0.a.b ] where 'a' and 'b' are the
       network byte order encodings of the high order byte and low order
       byte of the enumeration value for the particular IANA assigned
       protocol.

       For example, a protocolDirID-fragment value of:
          0.0.0.1.0.0.129.0.5.0.0.0.1

       defines the IPX protocol, VLAN-encapsulated directly in 802.3

       Children are named '802-1Q' followed by the numeric value of the
       particular IANA assigned protocol, with a leading octet set to
       the value of 5.

       Children are named '802-1Q' followed by the hexadecimal encoding
       of the child identifier.  The above example would be named:

          '802-1Q 0x05000001'.  "
    DECODING
       "VLAN headers and tagged frame structure are defined in
       [IEEE802.1Q]."
    REFERENCE
       "The 802.1Q Protocol is defined in the Draft Standard for Virtual
       Bridged Local Area Networks [IEEE802.1Q]."
    ::= {
        ether2 0x8100       -- Ethernet or SNAP encoding of TPID
        -- snap 0x8100      ** excluded to reduce PD size & complexity
    }

5.  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



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   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.

6.  Acknowledgements

   This document was produced by the IETF RMONMIB Working Group.

   The authors wish to thank the following people for their
   contributions to this document:

        Anil Singhal
        Frontier Software Development, Inc.

        Jeanne Haney
        Bay Networks

        Dan Hansen
        Network General Corp.

   Special thanks are in order to the following people for writing RMON
   PI macro compilers, and improving the specification of the PI macro
   language:

        David Perkins
        DeskTalk Systems, Inc.

        Skip Koppenhaver
        Technically Elite, Inc.

7.  References

   [AF-LANE-0021.000]    LAN Emulation Sub-working Group, B. Ellington,
                         "LAN Emulation over ATM - Version 1.0", AF-
                         LANE-0021.000, ATM Forum, IBM, January 1995.

   [AF-NM-TEST-0080.000] Network Management Sub-working Group, Test
                         Sub-working Group, A. Bierman, "Remote
                         Monitoring MIB Extensions for ATM Networks",
                         AF- NM-TEST-0080.000, ATM Forum, Cisco Systems,
                         February 1997.




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   [IEEE802.1D-1998]     LAN MAN Standards Committee of the IEEE
                         Computer Society, "Information technology --
                         Telecommunications and information exchange
                         between systems -- Local and metropolitan area
                         networks -- Common specification -- Part 3:
                         Media Access Control (MAC) Bridges", ISO/IEC
                         Final DIS 15802-3 (IEEE P802.1D/D17) Institute
                         of Electrical and Electronics Engineers, Inc.,
                         May 1998.

   [IEEE802.1Q]          LAN MAN Standards Committee of the IEEE
                         Computer Society, "IEEE Standards for Local and
                         Metropolitan Area Networks:  Virtual Bridged
                         Local Area Networks", Draft Standard
                         P802.1Q/D11, Institute of Electrical and
                         Electronics Engineers, Inc., July 1998.

   [RFC1155]             Rose, M. and K. McCloghrie, "Structure and
                         Identification of Management Information for
                         TCP/IP-based Internets", STD 16, RFC 1155, May
                         1990.

   [RFC1157]             Case, J., Fedor, M., Schoffstall, M. and J.
                         Davin, "Simple Network Management Protocol",
                         STD 15, RFC 1157, May 1990.

   [RFC1212]             Rose, M. and K. McCloghrie, "Concise MIB
                         Definitions", STD 16, RFC 1212, March 1991.

   [RFC1215]             Rose, M., "A Convention for Defining Traps for
                         use with the SNMP", RFC 1215, March 1991.

   [RFC1483]             Heinanen, J., "Multiprotocol Encapsulation over
                         ATM Adaptation Layer 5", RFC 1483, July 1993.

   [RFC1700]             Reynolds, J. and J. Postel, "Assigned Numbers",
                         STD 2, RFC 1700,  October 1994.

   [RFC1901]             Case, J., McCloghrie, K., Rose, M. and S.
                         Waldbusser, "Introduction to Community-based
                         SNMPv2", RFC 1901, January 1996.

   [RFC1902]             Case, J., McCloghrie, K., Rose, M. and S.
                         Waldbusser, "Structure of Management
                         Information for version 2 of the Simple Network
                         Management Protocol (SNMPv2)", RFC 1902,
                         January 1996.




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   [RFC1903]             Case, J., McCloghrie, K., Rose, M. and S.
                         Waldbusser, "Textual Conventions for version 2
                         of the Simple Network Management Protocol
                         (SNMPv2)", RFC 1903, January 1996.

   [RFC1904]             Case, J., McCloghrie, K., Rose, M. and S.
                         Waldbusser, "Conformance Statements for version
                         2 of the Simple Network Management Protocol
                         (SNMPv2)", RFC 1904, January 1996.

   [RFC1905]             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.

   [RFC1906]             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.

   [RFC2021]             Waldbusser, S., "Remote Network Monitoring MIB
                         (RMON-2)", RFC 2021, January 1997.

   [RFC2074]             Bierman, A. and R. Iddon, "Remote Network
                         Monitoring MIB Protocol Identifiers", RFC 2074,
                         January 1997.

   [RFC2119]             Bradner, S., "Key words for use in RFCs to
                         Indicate Requirement Levels", BCP 14, RFC 2119,
                         March 1997.

   [RFC2233]             McCloghrie, K. and F. Kastenholz, "The
                         Interfaces Group MIB Using SMIv2", RFC 2233,
                         November 1997.

   [RFC2271]             Harrington, D., Presuhn, R. and B. Wijnen, "An
                         Architecture for Describing SNMP Management
                         Frameworks", RFC 2271, January 1998.

   [RFC2272]             Case, J., Harrington D., Presuhn R. and B.
                         Wijnen, "Message Processing and Dispatching for
                         the Simple Network Management Protocol (SNMP)",
                         RFC 2272, January 1998.

   [RFC2273]             Levi, D., Meyer, P. and B. Stewart, "SNMPv3
                         Applications", RFC 2273, January 1998.





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   [RFC2274]             Blumenthal, U. and B. Wijnen, "User-based
                         Security Model (USM) for version 3 of the
                         Simple Network Management Protocol (SNMPv3)",
                         RFC 2274, January 1998.

   [RFC2275]             Wijnen, B., Presuhn, R. and K. McCloghrie,
                         "View-based Access Control Model (VACM) for the
                         Simple Network Management Protocol (SNMP)", RFC
                         2275, January 1998.

   [RFC2570]             Case, J., Mundy, R., Partain, D. and B.
                         Stewart, "Introduction to Version 3 of the
                         Internet-standard Network Management
                         Framework", RFC 2570, April 1999.

   [RFC2571]             Harrington, D., Presuhn, R. and B. Wijnen, "An
                         Architecture for Describing SNMP Management
                         Frameworks", RFC 2571, April 1999.

   [RFC2572]             Case, J., Harrington D., Presuhn R. and B.
                         Wijnen, "Message Processing and Dispatching for
                         the Simple Network Management Protocol (SNMP)",
                         RFC 2572, April 1999.

   [RFC2573]             Levi, D., Meyer, P. and B. Stewart, "SNMPv3
                         Applications", RFC 2573, April 1999.

   [RFC2574]             Blumenthal, U. and B. Wijnen, "User-based
                         Security Model (USM) for version 3 of the
                         Simple Network Management Protocol (SNMPv3)",
                         RFC 2574, April 1999.

   [RFC2575]             Wijnen, B., Presuhn, R. and K. McCloghrie,
                         "View-based Access Control Model (VACM) for the
                         Simple Network Management Protocol (SNMP)", RFC
                         2575, April 1999.

   [RFC2578]             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.

   [RFC2579]             McCloghrie, K., Perkins, D., Schoenwaelder, J.,
                         Case, J., Rose, M. and S. Waldbusser, "Textual
                         Conventions for SMIv2", STD 58, RFC 2579, April
                         1999.





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   [RFC2580]             McCloghrie, K., Perkins, D., Schoenwaelder, J.,
                         Case, J., Rose, M. and S. Waldbusser,
                         "Conformance Statements for SMIv2", STD 58, RFC
                         2580, April 1999.

   [RFC2896]             Bierman, A., Bucci, C. and R. Iddon, "Remote
                         Network Monitoring MIB Protocol Identifier
                         Macros", RFC 2896, August 2000.

8.  IANA Considerations

   The protocols identified in this specification are almost entirely
   defined in external documents.  In some rare cases, an arbitrary
   Protocol Identifier assignment must be made in order to support a
   particular protocol in the RMON-2 protocolDirTable. Protocol
   Identifier macros for such protocols will be defined under the '
   ianaAssigned' base layer (see sections 3. and 4.2).

   At this time, only one protocol is defined under the ianaAssigned
   base layer, called 'ipxOverRaw8023' (see section 4.2).

9.  Security Considerations

   This document discusses the syntax and semantics of textual
   descriptions of networking protocols, not the definition of any
   networking behavior.  As such, no security considerations are raised
   by this memo.
























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10.  Authors' Addresses

   Andy Bierman
   Cisco Systems, Inc.
   170 West Tasman Drive
   San Jose, CA USA 95134

   Phone: +1 408-527-3711
   EMail: abierman@cisco.com


   Chris Bucci
   Cisco Systems, Inc.
   170 West Tasman Drive
   San Jose, CA USA 95134

   Phone: +1 408-527-5337
   EMail: cbucci@cisco.com


   Robin Iddon
   c/o 3Com Inc.
   Blackfriars House
   40/50 Blackfrias Street
   Edinburgh, EH1 1NE, UK

   Phone: +44 131.558.3888
   EMail: None























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Appendix A: Changes since RFC 2074

   The differences between RFC 2074 and this document are:

   -  RFC 2074 has been split into a reference document
      (this document) on the standards track and an informational
      document [RFC2896], in order to remove most
      protocol identifier macros out of the standards track document.
   -  Administrative updates; added an author, added copyrights,
      updated SNMP framework boilerplate;
   -  Updated overview section.
   -  Section 2.1 MUST, SHOULD text added per template
   -  Section 2.1 added some new terms
      - parent protocol
      - child protocol
      - protocol encapsulation tree
   -  Added section 2.3 about splitting into 2 documents:

      "Relationship to the RMON Protocol Identifier Macros Document"
   -  Added section 2.4 "Relationship to the ATM-RMON MIB"
   -  rewrote section 3.2 "Protocol Identifier Macro Format"
      But no semantic changes were made; The PI macro syntax
      is now specified in greater detail using BNF notation.
   -  Section 3.2.3.1 "Mapping of the 'countsFragments(0)' BIT"
       - this section was clarified to allow multiple
         protocolDirParameters octets in a given PI string
         to set the 'countsFragments' bit. The RFC version
         says just one octet can set this BIT. It is a
         useful feature to identify fragmentation at
         multiple layers, and most RMON-2 agents were
         already doing this, so the WG agreed to this
         clarification.
   -  Added section 4.3 "Encapsualtion Layers"
   -  This document ends after the base layer encapsulation
      definitions (through RFC 2074, section 5.2)
   -  Added Intellectual Property section
   -  Moved RFC 2074 section 5.3
      "L3: Children of Base Protocol Identifiers"
      through the end of RFC 2074, to the PI Reference [RFC2896]
      document, in which many new protocol identifier macros were
      added for application protocols and non-IP protocol
      stacks.
   -  Acknowledgements section has been updated








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11.  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.



















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