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RFC 1316

Definitions of Managed Objects for Character Stream Devices

Pages: 17
Obsoleted by:  1658

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Network Working Group                                 B. Stewart, Editor
Request for Comments: 1316                                  Xyplex, Inc.
                                                              April 1992


                     Definitions of Managed Objects
                      for Character Stream Devices

Status of this Memo

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

1.  Abstract

   This memo defines a portion of the Management Information Base (MIB)
   for use with network management protocols in TCP/IP based internets.
   In particular it defines objects for the management of character
   stream devices.

2.  The Network Management Framework

   The Internet-standard Network Management Framework consists of three
   components.  They are:

   RFC 1155 which defines the SMI, the mechanisms used for describing
   and naming objects for the purpose of management. RFC 1212 defines a
   more concise description mechanism, which is wholly consistent with
   the SMI.

   RFC 1156 which defines MIB-I, the core set of managed objects for the
   Internet suite of protocols.  RFC 1213, defines MIB-II, an evolution
   of MIB-I based on implementation experience and new operational
   requirements.

   RFC 1157 which defines the SNMP, the protocol used for network access
   to managed objects.

   The Framework permits new objects to be defined for the purpose of
   experimentation and evaluation.

3.  Objects

   Managed objects are accessed via a virtual information store, termed
   the Management Information Base or MIB. Objects in the MIB are
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   defined using the subset of Abstract Syntax Notation One (ASN.1) [7]
   defined in the SMI.  In particular, each object has a name, a syntax,
   and an encoding.  The name is an object identifier, an
   administratively assigned name, which specifies an object type.

   The object type together with an object instance serves to uniquely
   identify a specific instantiation of the object. For human
   convenience, we often use a textual string, termed the OBJECT
   DESCRIPTOR, to also refer to the object type.

   The syntax of an object type defines the abstract data structure
   corresponding to that object type.  The ASN.1 language is used for
   this purpose.  However, the SMI [3] purposely restricts the ASN.1
   constructs which may be used. These restrictions are explicitly made
   for simplicity.

   The encoding of an object type is simply how that object type is
   represented using the object type's syntax. Implicitly tied to the
   notion of an object type's syntax and encoding is how the object type
   is represented when being transmitted on the network.

   The SMI specifies the use of the basic encoding rules of ASN.1 [8],
   subject to the additional requirements imposed by the SNMP.

3.1.  Format of Definitions

   Section 5 contains the specification of all object types contained in
   this MIB module.  The object types are defined using the conventions
   defined in the SMI, as amended by the extensions specified in [9,10].

4.  Overview

   The Character MIB applies to interface ports that carry a character
   stream, whether physical or virtual, serial or parallel, synchronous
   or asynchronous.  The most common example of a character port is a
   hardware terminal port with an RS-232 interface.  Another common
   hardware example is a parallel printer port, say with a Centronics
   interface.  The concept also includes virtual terminal ports, such as
   a software connection point for a remote console.

   The Character MIB is one of a set of MIBs designed for complementary
   use.  At this writing, the set comprises:

        Character MIB
        PPP MIB
        RS-232-like MIB
        Parallel-printer-like MIB
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   The RS-232-like MIB and the Parallel-printer-like MIB represent the
   physical layer, providing service to higher layers such as the
   Character MIB or PPP MIB.  Further MIBs may appear above these.

   The following diagram shows two possible "MIB stacks", each using the
   RS-232-like MIB.

                                               .-----------------.
                    .-----------------.        |  Standard MIB   |
                    |   Telnet MIB    |        | Interface Group |
                    |-----------------|        |-----------------|
                    |  Character MIB  |        |     PPP MIB     |
                    |-----------------|        |-----------------|
                    | RS-232-like MIB |        | RS-232-like MIB |
                    `-----------------'        `-----------------'

   The intent of the model is for the physical-level MIBs to represent
   the lowest level, regardless of the higher level that may be using
   it.  In turn, separate higher level MIBs represent specific
   applications, such as a terminal (the Character MIB) or a network
   connection (the PPP MIB).

   For the most part, character ports are distinct from network
   interfaces (which are already covered by the Interface group).  In
   general, they are attachment points for non-network devices.  The
   exception is a character port that can support a network protocol,
   such as SLIP or PPP.  This implies the existence of a corresponding
   entry in the Interfaces table, with ifOperStatus of 'off' while the
   port is not running a network protocol and 'on' if it is.  The intent
   is that such usage is exclusive of non-network character stream
   usage.  That is, while switched to network use, charPortOperStatus
   would be 'down' and Character MIB operational values such as
   charPortInFlowState and charPortInCharacters would be inactive.

   The Character MIB is mandatory for all systems that offer character
   ports.  This includes, for example, terminal servers, general-purpose
   time-sharing hosts, and even such systems as a bridge with a
   (virtual) console port.  It may or may not include character ports
   that do not support network sessions, depending on the system's
   needs.

   The Character MIB's central abstraction is a port.  Physical ports
   have a one-to-one correspondence with hardware ports. Virtual ports
   are software entities analogous to physical ports, but with no
   hardware connector.

   Each port supports one or more sessions.  A session represents a
   virtual connection that carries characters between the port and some
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   partner.  Sessions typically operate over a stack of network
   protocols.  A typical session, for example, uses Telnet over TCP.

   The MIB comprises one base object and two tables, detailed in the
   following sections.  The tables contain objects for ports and
   sessions.

   The MIB intentionally contains no distinction between what is often
   called permanent and operational or volatile data bases.  For the
   purposes of this MIB, handling of such distinctions is implementation
   specific.

5.  Definitions

                    RFC1316-MIB DEFINITIONS ::= BEGIN

                    IMPORTS
                            Counter, TimeTicks, Gauge
                                    FROM RFC1155-SMI
                            DisplayString
                                    FROM RFC1213-MIB
                            OBJECT-TYPE
                                    FROM RFC-1212;

            -- this is the MIB module for character stream devices

            char    OBJECT IDENTIFIER ::= { mib-2 19 }

            -- Textual Conventions

                AutonomousType    ::= OBJECT IDENTIFIER

            -- The object identifier is an independently extensible type
            -- identification value.  It may, for example indicate a
            -- particular sub-tree with further MIB definitions, or
            -- define something like a protocol type or type of
            -- hardware.

                InstancePointer   ::= OBJECT IDENTIFIER

            -- The object identifier is a pointer to a specific instance
            -- of a MIB object in this agent's implemented MIB.  By
            -- convention, it is the first object in the conceptual row
            -- for the instance.
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            -- the generic Character group

            -- Implementation of this group is mandatory for all
            -- systems that offer character ports

            charNumber OBJECT-TYPE
                SYNTAX INTEGER
                ACCESS read-only
                STATUS mandatory
                DESCRIPTION
                    "The number of entries in charPortTable, regardless
                    of their current state."
                ::= { char 1 }


            -- the Character Port table

            charPortTable OBJECT-TYPE
                SYNTAX SEQUENCE OF CharPortEntry
                ACCESS not-accessible
                STATUS mandatory
                DESCRIPTION
                    "A list of port entries.  The number of entries is
                    given by the value of charNumber."
                ::= { char 2 }

            charPortEntry OBJECT-TYPE
                SYNTAX CharPortEntry
                ACCESS not-accessible
                STATUS mandatory
                DESCRIPTION
                    "Status and parameter values for a character port."
                INDEX { charPortIndex }
                ::= { charPortTable 1 }

            CharPortEntry ::=
                SEQUENCE {
                    charPortIndex
                        INTEGER,
                    charPortName
                        DisplayString,
                    charPortType
                        INTEGER,
                    charPortHardware
                        AutonomousType,
                    charPortReset
                        INTEGER,
                    charPortAdminStatus
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                        INTEGER,
                    charPortOperStatus
                        INTEGER,
                    charPortLastChange
                        TimeTicks,
                    charPortInFlowType
                        INTEGER,
                    charPortOutFlowType
                        INTEGER,
                    charPortInFlowState
                        INTEGER,
                    charPortOutFlowState
                        INTEGER,
                    charPortInCharacters
                        Counter,
                    charPortOutCharacters
                        Counter,
                    charPortAdminOrigin
                        INTEGER,
                    charPortSessionMaximum
                        INTEGER,
                    charPortSessionNumber
                        Gauge,
                    charPortSessionIndex
                        INTEGER
                }

            charPortIndex OBJECT-TYPE
                SYNTAX INTEGER
                ACCESS read-only
                STATUS mandatory
                DESCRIPTION
                    "A unique value for each character port.  Its value
                    ranges between 1 and the value of charNumber.  By
                    convention and if possible, hardware port numbers
                    come first, with a simple, direct mapping.  The
                    value for each port must remain constant at least
                    from one re-initialization of the network management
                    agent to the next."
                ::= { charPortEntry 1 }

            charPortName OBJECT-TYPE
                SYNTAX DisplayString (SIZE (0..32))
                ACCESS read-write
                STATUS mandatory
                DESCRIPTION
                    "An administratively assigned name for the port,
                    typically with some local significance."
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                ::= { charPortEntry 2 }

            charPortType OBJECT-TYPE
                SYNTAX INTEGER { physical(1), virtual(2) }
                ACCESS read-only
                STATUS mandatory
                DESCRIPTION
                    "The port's type, 'physical' if the port represents
                    an external hardware connector, 'virtual' if it does
                    not."
                ::= { charPortEntry 3 }

            charPortHardware OBJECT-TYPE
                SYNTAX AutonomousType
                ACCESS read-only
                STATUS mandatory
                DESCRIPTION
                    "A reference to hardware MIB definitions specific to
                    a physical port's external connector.  For example,
                    if the connector is RS-232, then the value of this
                    object refers to a MIB sub-tree defining objects
                    specific to RS-232.  If an agent is not configured
                    to have such values, the agent returns the object
                    identifier:

                        nullHardware OBJECT IDENTIFIER ::= { 0 0 }
                    "
                ::= { charPortEntry 4 }

            charPortReset OBJECT-TYPE
                SYNTAX INTEGER { ready(1), execute(2) }
                ACCESS read-write
                STATUS mandatory
                DESCRIPTION
                    "A control to force the port into a clean, initial
                    state, both hardware and software, disconnecting all
                    the port's existing sessions.  In response to a
                    get-request or get-next-request, the agent always
                    returns 'ready' as the value.  Setting the value to
                    'execute' causes a reset."
                ::= { charPortEntry 5 }

            charPortAdminStatus OBJECT-TYPE
                SYNTAX INTEGER { enabled(1), disabled(2), off(3),
                                 maintenance(4) }
                ACCESS read-write
                STATUS mandatory
                DESCRIPTION
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                    "The port's desired state, independent of flow
                    control.  'enabled' indicates that the port is
                    allowed to pass characters and form new sessions.
                    'disabled' indicates that the port is allowed to
                    pass characters but not form new sessions.  'off'
                    indicates that the port is not allowed to pass
                    characters or have any sessions. 'maintenance'
                    indicates a maintenance mode, exclusive of normal
                    operation, such as running a test."
                ::= { charPortEntry 6 }

            charPortOperStatus OBJECT-TYPE
                SYNTAX INTEGER { up(1), down(2),
                                 maintenance(3), absent(4), active(5) }
                ACCESS read-only
                STATUS mandatory
                DESCRIPTION
                    "The port's actual, operational state, independent
                    of flow control.  'up' indicates able to function
                    normally.  'down' indicates inability to function
                    for administrative or operational reasons.
                    'maintenance' indicates a maintenance mode,
                    exclusive of normal operation, such as running a
                    test.  'absent' indicates that port hardware is not
                    present.  'active' indicates up with a user present
                    (e.g. logged in)."
                ::= { charPortEntry 7 }

            charPortLastChange OBJECT-TYPE
                SYNTAX TimeTicks
                ACCESS read-only
                STATUS mandatory
                DESCRIPTION
                    "The value of sysUpTime at the time the port entered
                    its current operational state.  If the current state
                    was entered prior to the last reinitialization of
                    the local network management subsystem, then this
                    object contains a zero value."
                ::= { charPortEntry 8 }

            charPortInFlowType OBJECT-TYPE
                SYNTAX INTEGER { none(1), xonXoff(2), hardware(3),
                                 ctsRts(4), dsrDtr(5) }
                ACCESS read-write
                STATUS mandatory
                DESCRIPTION
                    "The port's type of input flow control.  'none'
                    indicates no flow control at this level or below.
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                    'xonXoff' indicates software flow control by
                    recognizing XON and XOFF characters.  'hardware'
                    indicates flow control delegated to the lower level,
                    for example a parallel port.

                    'ctsRts' and 'dsrDtr' are specific to RS-232-like
                    ports.  Although not architecturally pure, they are
                    included here for simplicity's sake."
                ::= { charPortEntry 9 }

            charPortOutFlowType OBJECT-TYPE
                SYNTAX INTEGER { none(1), xonXoff(2), hardware(3),
                                 ctsRts(4), dsrDtr(5) }
                ACCESS read-write
                STATUS mandatory
                DESCRIPTION
                    "The port's type of output flow control.  'none'
                    indicates no flow control at this level or below.
                    'xonXoff' indicates software flow control by
                    recognizing XON and XOFF characters.  'hardware'
                    indicates flow control delegated to the lower level,
                    for example a parallel port.

                    'ctsRts' and 'dsrDtr' are specific to RS-232-like
                    ports.  Although not architecturally pure, they are
                    included here for simplicy's sake."
                ::= { charPortEntry 10 }

            charPortInFlowState OBJECT-TYPE
                SYNTAX INTEGER { none(1), unknown(2), stop(3), go(4) }
                ACCESS read-only
                STATUS mandatory
                DESCRIPTION
                    "The current operational state of input flow control
                    on the port.  'none' indicates not applicable.
                    'unknown' indicates this level does not know.
                    'stop' indicates flow not allowed.  'go' indicates
                    flow allowed."
                ::= { charPortEntry 11 }

            charPortOutFlowState OBJECT-TYPE
                SYNTAX INTEGER { none(1), unknown(2), stop(3), go(4) }
                ACCESS read-only
                STATUS mandatory
                DESCRIPTION
                    "The current operational state of output flow
                    control on the port.  'none' indicates not
                    applicable.  'unknown' indicates this level does not
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                    know.  'stop' indicates flow not allowed.  'go'
                    indicates flow allowed."
                ::= { charPortEntry 12 }

            charPortInCharacters OBJECT-TYPE
                SYNTAX Counter
                ACCESS read-only
                STATUS mandatory
                DESCRIPTION
                    "Total number of characters detected as input from
                    the port since system re-initialization and while
                    the port operational state was 'up', 'active', or
                    'maintenance', including, for example, framing, flow
                    control (i.e. XON and XOFF), each occurrence of a
                    BREAK condition, locally-processed input, and input
                    sent to all sessions."
                ::= { charPortEntry 13 }

            charPortOutCharacters OBJECT-TYPE
                SYNTAX Counter
                ACCESS read-only
                STATUS mandatory
                DESCRIPTION
                    "Total number of characters detected as output to
                    the port since system re-initialization and while
                    the port operational state was 'up', 'active', or
                    'maintenance', including, for example, framing, flow
                    control (i.e. XON and XOFF), each occurrence of a
                    BREAK condition, locally-created output, and output
                    received from all sessions."
                ::= { charPortEntry 14 }

            charPortAdminOrigin OBJECT-TYPE
                SYNTAX INTEGER { dynamic(1), network(2), local(3),
                                 none(4) }
                ACCESS read-write
                STATUS mandatory
                DESCRIPTION
                    "The administratively allowed origin for
                    establishing session on the port.  'dynamic' allows
                    'network' or 'local' session establishment. 'none'
                    disallows session establishment."
                ::= { charPortEntry 15 }

            charPortSessionMaximum OBJECT-TYPE
                SYNTAX INTEGER
                ACCESS read-write
                STATUS mandatory
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                DESCRIPTION
                    "The maximum number of concurrent sessions allowed
                    on the port.  A value of -1 indicates no maximum.
                    Setting the maximum to less than the current number
                    of sessions has unspecified results."
                ::= { charPortEntry 16 }

            charPortSessionNumber OBJECT-TYPE
                SYNTAX Gauge
                ACCESS read-only
                STATUS mandatory
                DESCRIPTION
                    "The number of open sessions on the port that are in
                    the connecting, connected, or disconnecting state."
                ::= { charPortEntry 17 }

            charPortSessionIndex OBJECT-TYPE
                SYNTAX INTEGER
                ACCESS read-only
                STATUS mandatory
                DESCRIPTION
                    "The value of charSessIndex for the port's first or
                    only active session.  If the port has no active
                    session, the agent returns the value zero."
                ::= { charPortEntry 18 }


            -- the Character Session table

            charSessTable OBJECT-TYPE
                SYNTAX SEQUENCE OF CharSessEntry
                ACCESS not-accessible
                STATUS mandatory
                DESCRIPTION
                    "A list of port session entries."
                ::= { char 3 }

            charSessEntry OBJECT-TYPE
                SYNTAX CharSessEntry
                ACCESS not-accessible
                STATUS mandatory
                DESCRIPTION
                    "Status and parameter values for a character port
                    session."
                INDEX { charSessPortIndex, charSessIndex }
                ::= { charSessTable 1 }
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            CharSessEntry ::=
                SEQUENCE {
                    charSessPortIndex
                        INTEGER,
                    charSessIndex
                        INTEGER,
                    charSessKill
                        INTEGER,
                    charSessState
                        INTEGER,
                    charSessProtocol
                        AutonomousType,
                    charSessOperOrigin
                        INTEGER,
                    charSessInCharacters
                        Counter,
                    charSessOutCharacters
                        Counter,
                    charSessConnectionId
                        InstancePointer,
                    charSessStartTime
                        TimeTicks
                }

            charSessPortIndex OBJECT-TYPE
                SYNTAX INTEGER
                ACCESS read-only
                STATUS mandatory
                DESCRIPTION
                    "The value of charPortIndex for the port to which
                    this session belongs."
                ::= { charSessEntry 1 }

            charSessIndex OBJECT-TYPE
                SYNTAX INTEGER
                ACCESS read-only
                STATUS mandatory
                DESCRIPTION
                    "The session index in the context of the port, a
                    non-zero positive integer.  Session indexes within a
                    port need not be sequential.  Session indexes may be
                    reused for different ports.  For example, port 1 and
                    port 3 may both have a session 2 at the same time.
                    Session indexes may have any valid integer value,
                    with any meaning convenient to the agent
                    implementation."
                ::= { charSessEntry 2 }
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            charSessKill OBJECT-TYPE
                SYNTAX INTEGER { ready(1), execute(2) }
                ACCESS read-write
                STATUS mandatory
                DESCRIPTION
                    "A control to terminate the session.  In response to
                    a get-request or get-next-request, the agent always
                    returns 'ready' as the value.  Setting the value to
                    'execute' causes termination."
                ::= { charSessEntry 3 }

            charSessState OBJECT-TYPE
                SYNTAX INTEGER { connecting(1), connected(2),
                                 disconnecting(3) }
                ACCESS read-only
                STATUS mandatory
                DESCRIPTION
                    "The current operational state of the session,
                    disregarding flow control.  'connected' indicates
                    that character data could flow on the network side
                    of session.  'connecting' indicates moving from
                    nonexistent toward 'connected'.  'disconnecting'
                    indicates moving from 'connected' or 'connecting' to
                    nonexistent."
                ::= { charSessEntry 4 }

            charSessProtocol OBJECT-TYPE
                SYNTAX AutonomousType
                ACCESS read-only
                STATUS mandatory
                DESCRIPTION
                    "The network protocol over which the session is
                    running.  Other OBJECT IDENTIFIER values may be
                    defined elsewhere, in association with specific
                    protocols.  However, this document assigns those of
                    known interest as of this writing."
                ::= { charSessEntry 5 }

            wellKnownProtocols OBJECT IDENTIFIER ::= { char 4 }

            protocolOther  OBJECT IDENTIFIER ::= {wellKnownProtocols 1}
            protocolTelnet OBJECT IDENTIFIER ::= {wellKnownProtocols 2}
            protocolRlogin OBJECT IDENTIFIER ::= {wellKnownProtocols 3}
            protocolLat    OBJECT IDENTIFIER ::= {wellKnownProtocols 4}
            protocolX29    OBJECT IDENTIFIER ::= {wellKnownProtocols 5}
            protocolVtp    OBJECT IDENTIFIER ::= {wellKnownProtocols 6}
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            charSessOperOrigin OBJECT-TYPE
                SYNTAX INTEGER { unknown(1), network(2), local(3) }
                ACCESS read-only
                STATUS mandatory
                DESCRIPTION
                    "The session's source of establishment."
                ::= { charSessEntry 6 }

            charSessInCharacters OBJECT-TYPE
                SYNTAX Counter
                ACCESS read-only
                STATUS mandatory
                DESCRIPTION
                    "This session's subset of charPortInCharacters."
                ::= { charSessEntry 7 }

            charSessOutCharacters OBJECT-TYPE
                SYNTAX Counter
                ACCESS read-only
                STATUS mandatory
                DESCRIPTION
                    "This session's subset of charPortOutCharacters."
                ::= { charSessEntry 8 }

            charSessConnectionId OBJECT-TYPE
                SYNTAX InstancePointer
                ACCESS read-only
                STATUS mandatory
                DESCRIPTION
                    "A reference to additional local MIB information.
                    This should be the highest available related MIB,
                    corresponding to charSessProtocol, such as Telnet.
                    For example, the value for a TCP connection (in the
                    absence of a Telnet MIB) is the object identifier of
                    tcpConnState.  If an agent is not configured to have
                    such values, the agent returns the object
                    identifier:

                        nullConnectionId OBJECT IDENTIFIER ::= { 0 0 }
                    "
                ::= { charSessEntry 9 }

            charSessStartTime OBJECT-TYPE
                SYNTAX TimeTicks
                ACCESS read-only
                STATUS mandatory
                DESCRIPTION
                    "The value of sysUpTime in MIB-2 when the session
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                    entered connecting state."
                ::= { charSessEntry 10 }

            END

6.  Acknowledgements

   Based on several private MIBs, this document was produced by the
   Character MIB Working Group:

                Anne Ambler, Spider
                Charles Bazaar, Emulex
                Christopher Bucci, Datability
                Anthony Chung, Hughes LAN Systems
                George Conant, Xyplex
                John Cook, Chipcom
                James Davin, MIT-LCS
                Shawn Gallagher, DEC
                Tom Grant, Xylogics
                Frank Huang, Emulex
                David Jordan, Emulex
                Satish Joshi, SynOptics
                Frank Kastenholz, Clearpoint
                Ken Key, University of Tennessee
                Jim Kinder, Fibercom
                Rajeev Kochhar, 3Com
                John LoVerso, Xylogics
                Keith McCloghrie, Hughes LAN Systems
                Donald Merritt, BRL
                David Perkins, 3Com
                Jim Reinstedler, Ungerman-Bass
                Marshall Rose, PSI
                Ron Strich, SSDS
                Dean Throop, DG
                Bill Townsend, Xylogics
                Jesse Walker, DEC
                David Waitzman, BBN
                Bill Westfield, cisco

7.  References

   [1] Cerf, V., "IAB Recommendations for the Development of
       Internet  Network Management Standards", RFC 1052, NRI,
       April 1988.

   [2] Cerf, V., "Report of the Second Ad Hoc Network
       Management Review  Group", RFC 1109, NRI, August 1989.
ToP   noToC   RFC1316 - Page 16
   [3] Rose M., and K. McCloghrie, "Structure and
       Identification of  Management Information for TCP/IP-based
       internets", RFC 1155,  Performance Systems International,
       Hughes LAN Systems, May 1990.

   [4] McCloghrie K., and M. Rose, "Management Information Base
       for  Network Management of TCP/IP-based internets", RFC
       1156, Hughes  LAN Systems, Performance Systems
       International, May 1990.

   [5] Case, J., Fedor, M., Schoffstall, M., and J. Davin,
       "Simple  Network Management Protocol", RFC 1157, SNMP
       Research,  Performance Systems International, Performance
       Systems  International, MIT Laboratory for Computer Science,
       May 1990.

   [6] McCloghrie K., and M. Rose, Editors, "Management
       Information Base  for Network Management of TCP/IP-based
       internets", RFC 1213,  Performance Systems International,
       March 1991.

   [7] Information processing systems - Open Systems
       Interconnection -  Specification of Abstract Syntax Notation
       One (ASN.1),  International Organization for
       Standardization, International  Standard 8824, December
       1987.

   [8] Information processing systems - Open Systems
       Interconnection -  Specification of Basic Encoding Rules for
       Abstract Notation One  (ASN.1), International Organization
       for Standardization,  International Standard 8825, December
       1987.

   [9] Rose, M., and K. McCloghrie, Editors, "Concise MIB
       Definitions",  RFC 1212, Performance Systems International,
       Hughes LAN Systems,  March 1991.

  [10] Rose, M., Editor, "A Convention for Defining Traps for
       use with  the SNMP", RFC 1215, Performance Systems
       International, March 1991.

8.  Security Considerations

   Security issues are not discussed in this memo.
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9.  Author's Address

   Bob Stewart
   Xyplex, Inc.
   330 Codman Hill Road
   Boxborough, MA 01719

   Phone: (508) 264-9900
   EMail: rlstewart@eng.xyplex.com