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Network Working Group                                                B.Srewart
Request for Comments: 1658                                           Xyplex.Inc
Obsoletes:1316                                                           
July1994
Category: Standards Track                            


使用SMIv2的字符流設備管理對象定義
(RFC1658—— Definitions of Managed Objects for Character Stream Devices using SMIv2)

本備忘錄狀態
   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.

目錄
1.  介紹	2
2.  SNMPv2網絡管理框架	2
2.1.  對象定義	2
3.  概要	2
3.1.  與MIB接口的關系	3
4.  定義	3
5.  感謝	18
6.  References	18
7.  安全考慮	19
8.  作者聯系方式	19

1.  介紹
   本備忘錄詳細說明了一個和互聯網社區的網絡管理協議一起使用的管理信息基礎的擴
展。特別的，它定義了字符流設備的管理對象。
2.  SNMPv2網絡管理框架
   SNMPv2 網絡管理框架包含四個主要的部分。它們是：

      o    RFC 1442 [1] 它定義了SMI, 一個用來描述和命名管理目的對象的機制。

      o    STD 17, RFC 1213 [2] 定義了MIB-II,  互聯網協議套件管理對象的核心集。

      o    RFC 1445 [3] 定義了框架的管理和其他體系方面。

      o    RFC 1448 [4] 定義了用于從網絡訪問管理對象的協議。

   本框架允許定義用于實驗和評估所使用的新對象。
2.1.  對象定義
   在管理信息基礎（MIB）期間，通過實際信息存儲來訪問被管理對象。用在SMI中定義的
Abstract Syntax Notation One (ASN.1)來定義MIB中的對象。 特別的，由對象標志符
（OBJECT IDENTIFIER）命名每一個目標對象類型，這是一個管理可分配的名字。對象類型
和對象實例服務器唯一識別一個特定的對象實例。為方便的原因，在描述中引用到對象類型
時，我們通常用文本字符串來表示。
3.  概要
   不管物理上存在的還是虛擬的，串行或并行的、同步或異步的，字符MIB應用于攜帶一
個字符流的端口。最常見的字符流設備例子是帶有RS-232接口的硬件終端端口。另一個常
見的硬件例子是以Centronics命名的并行打印機端口。此也包括虛擬中斷端口，如到一個
遠程控制臺的軟件連接指針。
   對所有系統字符來說，MIB是強制用來提供字符流端口。 這里包含，舉例來說，終端服
務、
  通用目的的時間共享（time-sharing）主機，甚至作為一個（虛）控制臺端口的橋的系統。
依賴于系統的需要， 它可能包含不支持網絡會話的字符端口。

   字符MIB的最核心抽象是端口。物理端口與硬件端口是一一對應的。虛擬端口是軟件實
體模擬成硬件端口，但是沒有硬件與之相連。每一個端口支持一個或多個會話。一個會話表
示一個虛擬連接帶有該端口與其他端口之間通信的特征。 典型的，會話在網絡協議棧上進
行。典型的會話很多，如使用基于TCP的Telnet。

   MIB包含一個基本對象和兩個表，將在以下部分詳述。表中包含端口和對話的對象。MIB
特意不區分我們經常叫常量和變量或可變數據集。由于MIB的這個目的，對這種區分是特定
執行的。
3.1.  與MIB接口的關系
   字符MIB不直接與MIB [1]接口相關，因為它不是一個固有的網絡接口。另一個方面，
在它所出現的大多數場合中，它總是在物理子層接口之上，如類RS-232[2]或類并行打印機
[3]的MIB。典型的，這樣的物理接口由在接口表中的一行來表示，由ifIndex的值來識別。
4.  定義
   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."