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RFC 1658

Obsoletes RFC 1316

Network Working Group                                         B. Stewart
Request for Comments: 1658                                  Xyplex, Inc.
Obsoletes: 1316                                                July 1994
Category: Standards Track

      Definitions of Managed Objects for Character Stream Devices
                              using SMIv2

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.

Table of Contents

   1. Introduction ................................................    2
   2. The SNMPv2 Network Management Framework .....................    2
   2.1 Object Definitions .........................................    3
   3. Overview ....................................................    3
   3.1 Relationship to Interface MIB ..............................    4
   4. Definitions .................................................    4
   5. Acknowledgements ............................................   17
   6. References ..................................................   17
   7. Security Considerations .....................................   18
   8. Author's Address ............................................   18

1.  Introduction

   This memo defines an extension to the Management Information Base
   (MIB) for use with network management protocols in the Internet
   community.  In particular, it defines objects for the management of
   character stream devices.

2.  The SNMPv2 Network Management Framework

   The SNMPv2 Network Management Framework consists of four major
   components.  They are:

      o    RFC 1442 [1] which defines the SMI, the mechanisms used for
           describing and naming objects for the purpose of management.

      o    STD 17, RFC 1213 [2] defines MIB-II, the core set of managed
           objects for the Internet suite of protocols.

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RFC 1658                     Character MIB                     July 1994

      o    RFC 1445 [3] which defines the administrative and other
           architectural aspects of the framework.

      o    RFC 1448 [4] which defines the protocol used for network
           access to managed objects.

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

2.1.  Object Definitions

   Managed objects are accessed via a virtual information store, termed
   the Management Information Base or MIB.  Objects in the MIB are
   defined using the subset of Abstract Syntax Notation One (ASN.1)
   defined in the SMI.  In particular, each object object type is named
   by an OBJECT IDENTIFIER, an administratively assigned name.  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 descriptor, to
   refer to the object type.

3.  Overview

   The Character MIB applies to ports that carry a character stream,
   whether physical or virtual, serial or parallel, synchronous or
   asynchronous.  The most common example of a character stream device
   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 mandatory for all systems that offer character
   stream 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
   partner.  Sessions typically operate over a stack of network
   protocols.  A typical session, for example, uses Telnet over TCP.

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   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.

3.1.  Relationship to Interface MIB

   The Character MIB does not relate directly to the Interface MIB [1],
   since it is not intrinsically a network interface.  On the other
   hand, in most implementations where it is present, it will be above a
   physical sublayer interface, such as the RS-232-like [2] or
   Parallel-printer-like [3] MIBs.  Such physical interfaces typically
   are represented by a row in the interface table (ifTable), identified
   by a value of ifIndex.

4.  Definitions

   CHARACTER-MIB DEFINITIONS ::= BEGIN

   IMPORTS
       MODULE-IDENTITY, OBJECT-TYPE, NOTIFICATION-TYPE,
       Counter32, Integer32, Gauge32, TimeTicks
           FROM SNMPv2-SMI
       AutonomousType, InstancePointer
           FROM SNMPv2-TC
       InterfaceIndex
           FROM IF-MIB
       transmission, mib-2
           FROM RFC1213-MIB
       MODULE-COMPLIANCE, OBJECT-GROUP
           FROM SNMPv2-CONF;

   char MODULE-IDENTITY
       LAST-UPDATED "9405261700Z"
       ORGANIZATION "IETF Character MIB Working Group"
       CONTACT-INFO
               "        Bob Stewart
                Postal: Xyplex, Inc.
                        295 Foster Street
                        Littleton, MA 01460

                   Tel: 508-952-4816
                   Fax: 508-952-4887

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                E-mail: rlstewart@eng.xyplex.com"
       DESCRIPTION
               "The MIB module for character stream devices."
       ::= { mib-2 19 }

   PortIndex ::= TEXTUAL-CONVENTION
       DISPLAY-HINT "d"
       STATUS current
       DESCRIPTION
               "A unique value, greater than zero, for each
               character port in the managed system.  It is
               recommended that values are assigned contiguously
               starting from 1.  The value for each interface sub-
               layer must remain constant at least from one re-
               initialization of the entity's network management
               system to the next re-initialization.

               In a system where the character ports are attached
               to hardware represented by an ifIndex, it is
               conventional, but not required, to make the
               character port index equal to the corresponding
               ifIndex."
       SYNTAX Integer32

   -- Generic Character information

   charNumber OBJECT-TYPE
       SYNTAX Integer32
       MAX-ACCESS read-only
       STATUS current
       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
       MAX-ACCESS not-accessible
       STATUS current
       DESCRIPTION
           "A list of port entries.  The number of entries is
           given by the value of charNumber."
       ::= { char 2 }

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

   CharPortEntry ::=
       SEQUENCE {
           charPortIndex
               PortIndex,
           charPortName
               DisplayString,
           charPortType
               INTEGER,
           charPortHardware
               AutonomousType,
           charPortReset
               INTEGER,
           charPortAdminStatus
               INTEGER,
           charPortOperStatus
               INTEGER,
           charPortLastChange
               TimeTicks,
           charPortInFlowType
               INTEGER,
           charPortOutFlowType
               INTEGER,
           charPortInFlowState
               INTEGER,
           charPortOutFlowState
               INTEGER,
           charPortInCharacters
               Counter32,
           charPortOutCharacters
               Counter32,
           charPortAdminOrigin
               INTEGER,
           charPortSessionMaximum
               INTEGER,
           charPortSessionNumber
               Gauge32,
           charPortSessionIndex
               INTEGER,
           charPortInFlowTypes

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               OCTET STRING,
           charPortOutFlowTypes
               OCTET STRING,
           charPortLowerIfIndex
               InterfaceIndex
       }

   charPortIndex OBJECT-TYPE
       SYNTAX PortIndex
       MAX-ACCESS read-only
       STATUS current
       DESCRIPTION
           "A unique value for each character port, perhaps
           corresponding to the same value of ifIndex when the
           character port is associated with a hardware port
           represented by an ifIndex."
       ::= { charPortEntry 1 }

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

   charPortType OBJECT-TYPE
       SYNTAX INTEGER { physical(1), virtual(2) }
       MAX-ACCESS read-only
       STATUS current
       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
       MAX-ACCESS read-only
       STATUS current
       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

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           identifier:

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

   charPortReset OBJECT-TYPE
       SYNTAX INTEGER { ready(1), execute(2) }
       MAX-ACCESS read-write
       STATUS current
       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) }
       MAX-ACCESS read-write
       STATUS current
       DESCRIPTION
           "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.

           'enabled' corresponds to ifAdminStatus 'up'.
           'disabled' and 'off' correspond to ifAdminStatus
           'down'.  'maintenance' corresponds to ifAdminStatus
           'test'."
       ::= { charPortEntry 6 }

   charPortOperStatus OBJECT-TYPE
       SYNTAX INTEGER { up(1), down(2),
                        maintenance(3), absent(4), active(5) }
       MAX-ACCESS read-only
       STATUS current
       DESCRIPTION
           "The port's actual, operational state, independent

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           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).

           'up' and 'active' correspond to ifOperStatus 'up'.
           'down' and 'absent' correspond to ifOperStatus
           'down'.  'maintenance' corresponds to ifOperStatus
           'test'."
       ::= { charPortEntry 7 }

   charPortLastChange OBJECT-TYPE
       SYNTAX TimeTicks
       MAX-ACCESS read-only
       STATUS current
       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 is deprecated in favor of
   -- charPortInFlowTypes

   charPortInFlowType OBJECT-TYPE
       SYNTAX INTEGER { none(1), xonXoff(2), hardware(3),
                        ctsRts(4), dsrDtr(5) }
       MAX-ACCESS read-write
       STATUS deprecated
       DESCRIPTION
           "The port's type of input 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 simplicity's sake."
       ::= { charPortEntry 9 }

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   -- charPortOutFlowType is deprecated in favor of
   -- charPortOutFlowTypes

   charPortOutFlowType OBJECT-TYPE
       SYNTAX INTEGER { none(1), xonXoff(2), hardware(3),
                        ctsRts(4), dsrDtr(5) }
       MAX-ACCESS read-write
       STATUS deprecated
       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) }
       MAX-ACCESS read-only
       STATUS current
       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) }
       MAX-ACCESS read-only
       STATUS current
       DESCRIPTION
           "The current operational state of output 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 12 }

   charPortInCharacters OBJECT-TYPE
       SYNTAX Counter32
       MAX-ACCESS read-only

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       STATUS current
       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 Counter32
       MAX-ACCESS read-only
       STATUS current
       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) }
       MAX-ACCESS read-write
       STATUS current
       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 (-1..2147483647)
       MAX-ACCESS read-write
       STATUS current
       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 }

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   charPortSessionNumber OBJECT-TYPE
       SYNTAX Gauge32
       MAX-ACCESS read-only
       STATUS current
       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 (0..2147483647)
       MAX-ACCESS read-only
       STATUS current
       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 }

   charPortInFlowTypes OBJECT-TYPE
       SYNTAX OCTET STRING (SIZE (1))
       MAX-ACCESS read-write
       STATUS current
       DESCRIPTION
           "The port's types of input flow control at the
           software level.  Hardware-level flow control is
           independently controlled by the appropriate
           hardware-level MIB.

           A value of zero indicates no flow control.
           Depending on the specific implementation, any or
           all combinations of flow control may be chosen by
           adding the values:

           128  xonXoff, recognizing XON and XOFF characters
           64   enqHost, ENQ/ACK to allow input to host
           32   enqTerm, ACK to allow output to port
           "
       ::= { charPortEntry 19 }

   charPortOutFlowTypes OBJECT-TYPE
       SYNTAX OCTET STRING (SIZE (1))
       MAX-ACCESS read-write
       STATUS current
       DESCRIPTION
           "The port's types of output flow control at the
           software level.  Hardware-level flow control is
           independently controlled by the appropriate

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           hardware-level MIB.

           A value of zero indicates no flow control.
           Depending on the specific implementation, any or
           all combinations of flow control may be chosen by
           adding the values:

           128  xonXoff, recognizing XON and XOFF characters
           64   enqHost, ENQ/ACK to allow input to host
           32   enqTerm, ACK to allow output to port
           "
       ::= { charPortEntry 20 }

   charPortLowerIfIndex OBJECT-TYPE
       SYNTAX InterfaceIndex
       MAX-ACCESS read-only
       STATUS current
       DESCRIPTION
           "The ifIndex value of the lower level hardware supporting
           this character port, zero if none."
       ::= { charPortEntry 21 }

   -- the Character Session table

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

   charSessEntry OBJECT-TYPE
       SYNTAX CharSessEntry
       MAX-ACCESS not-accessible
       STATUS current
       DESCRIPTION
           "Status and parameter values for a character port
           session."
       INDEX { charSessPortIndex, charSessIndex }
       ::= { charSessTable 1 }

   CharSessEntry ::=
       SEQUENCE {
           charSessPortIndex
               PortIndex,
           charSessIndex

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               INTEGER,
           charSessKill
               INTEGER,
           charSessState
               INTEGER,
           charSessProtocol
               AutonomousType,
           charSessOperOrigin
               INTEGER,
           charSessInCharacters
               Counter32,
           charSessOutCharacters
               Counter32,
           charSessConnectionId
               InstancePointer,
           charSessStartTime
               TimeTicks
       }

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

   charSessIndex OBJECT-TYPE
       SYNTAX INTEGER (1..2147483647)
       MAX-ACCESS read-only
       STATUS current
       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 }

   charSessKill OBJECT-TYPE
       SYNTAX INTEGER { ready(1), execute(2) }
       MAX-ACCESS read-write
       STATUS current
       DESCRIPTION

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           "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) }
       MAX-ACCESS read-only
       STATUS current
       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
       MAX-ACCESS read-only
       STATUS current
       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 }

   charSessOperOrigin OBJECT-TYPE
       SYNTAX INTEGER { unknown(1), network(2), local(3) }
       MAX-ACCESS read-only
       STATUS current
       DESCRIPTION

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           "The session's source of establishment."
       ::= { charSessEntry 6 }

   charSessInCharacters OBJECT-TYPE
       SYNTAX Counter32
       MAX-ACCESS read-only
       STATUS current
       DESCRIPTION
           "This session's subset of charPortInCharacters."
       ::= { charSessEntry 7 }

   charSessOutCharacters OBJECT-TYPE
       SYNTAX Counter32
       MAX-ACCESS read-only
       STATUS current
       DESCRIPTION
           "This session's subset of charPortOutCharacters."
       ::= { charSessEntry 8 }

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

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   -- conformance information

   charConformance OBJECT IDENTIFIER ::= { char 5 }

   charGroups      OBJECT IDENTIFIER ::= { charConformance 1 }
   charCompliances OBJECT IDENTIFIER ::= { charConformance 2 }

   -- compliance statements

   charCompliance MODULE-COMPLIANCE
       STATUS  current
       DESCRIPTION
               "The compliance statement for SNMPv2 entities
               which have Character hardware interfaces."

       MODULE  -- this module
           MANDATORY-GROUPS { charGroup }
       ::= { charCompliances 1 }

   -- units of conformance

   charGroup    OBJECT-GROUP
       OBJECTS { charNumber, charPortIndex, charPortName,
                 charPortType, charPortHardware, charPortReset,
                 charPortAdminStatus, charPortOperStatus,
                 charPortLastChange,
                 charPortInFlowState, charPortOutFlowState,
                 charPortAdminOrigin, charPortSessionMaximum,
                 charPortInFlowTypes, charPortOutFlowTypes,
                 charPortInCharacters, charPortOutCharacters,
                 charPortSessionNumber, charPortSessionIndex,
                 charPortLowerIfIndex,
                 charSessPortIndex, charSessIndex,
                 charSessKill, charSessState,
                 charSessProtocol, charSessOperOrigin,
                 charSessInCharacters, charSessOutCharacters,
                 charSessConnectionId, charSessStartTime }
       STATUS  current
       DESCRIPTION
               "A collection of objects providing information
                applicable to all Character interfaces."
       ::= { charGroups 1 }

   END

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5.  Acknowledgements

   This memo was produced by the IETF Character MIB Working Group.

6.  References

   [1] Case, J., McCloghrie, K., Rose, M., and S. Waldbusser, "Structure
       of Management Information for version 2 of the Simple Network
       Management Protocol (SNMPv2)", RFC 1442, SNMP Research,Inc.,
       Hughes LAN Systems, Dover Beach Consulting, Inc., Carnegie Mellon
       University, April 1993.

   [2] McCloghrie, K., and M. Rose, Editors, "Management Information
       Base for Network Management of TCP/IP-based internets: MIB-II",
       STD 17, RFC 1213, Hughes LAN Systems, Performance Systems
       International, March 1991.

   [3] Galvin, J., and K. McCloghrie, "Administrative Model for version
       2 of the Simple Network Management Protocol (SNMPv2)", RFC 1445,
       Trusted Information Systems, Hughes LAN Systems, April 1993.

   [4] Case, J., McCloghrie, K., Rose, M., and S. Waldbusser, "Protocol
       Operations for version 2 of the Simple Network Management
       Protocol (SNMPv2)", RFC 1448, SNMP Research,Inc., Hughes LAN
       Systems, Dover Beach Consulting, Inc., Carnegie Mellon
       University, April 1993.

   [5] McCloghrie, K., and F. Kastenholz, "Evolution of the Interfaces
       Group of MIB-II", RFC 1573, Hughes LAN Systems, FTP Software,
       January 1994.

   [6] Stewart, B., "Definitions of Managed Objects for RS-232-like
       Hardware Devices using SMIv2", RFC 1659, Xyplex, Inc., July 1994.

   [7] Stewart, B., "Definitions of Managed Objects for Parallel-
       printer-like Hardware Devices using SMIv2", RFC 1660, Xyplex,
       Inc., July 1994.

Stewart                                                        [Page 17]



RFC 1658                     Character MIB                     July 1994

7.  Security Considerations

   Security issues are not discussed in this memo.

8.  Author's Address

   Bob Stewart
   Xyplex, Inc.
   295 Foster Street
   Littleton, MA 01460

   Phone: 508-952-4816
   Fax: 508-952-4887
   EMail: rlstewart@eng.xyplex.com

Stewart                                                        [Page 18]