Network Working Group B. Stewart Request for Comments: 1658 Xyplex, Inc. Obsoletes: 1316 July 1994 Category: Standards Track
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.
1. Introduction
2. The SNMPv2 Network Management Framework
2.1 Object Definitions
3. Overview
3.1 Relationship to Interface MIB
4. Definitions
5. Acknowledgements
6. References
7. Security Considerations
8. Author's Address
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.
The SNMPv2 Network Management Framework consists of four major components. They are:
The Framework permits new objects to be defined for the purpose of experimentation and evaluation.
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.
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.
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.
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.
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
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 }
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
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
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
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 }
-- 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
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 }
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
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
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
"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
"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 }
-- 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
This memo was produced by the IETF Character MIB Working Group.
[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.
Security issues are not discussed in this memo.
Bob Stewart
Xyplex, Inc.
295 Foster Street
Littleton, MA 01460
Phone: 508-952-4816
Fax: 508-952-4887
EMail: rlstewart@eng.xyplex.com