rfc1749.txt

著名的RFC文档,其中有一些文档是已经翻译成中文的的.

Network Working Group                                      K. McCloghrie
Request for Comments: 1749                                      F. Baker
Updates: 1748                                                  E. Decker
Category: Standards Track                            cisco Systems, Inc.
                                                           December 1994


           IEEE 802.5 Station Source Routing MIB 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 .............................................    1
   2. The SNMPv2 Network Management Framework ..................    2
   2.1 Object Definitions ......................................    2
   3. Overview .................................................    2
   3.1 Source Routing ..........................................    2
   3.2 Relationship to RFC 1748 ................................    3
   3.3 Relationship to RFC 1525 ................................    3
   3.4 Static Source Routes ....................................    4
   3.5 Destinations on the Local Ring ..........................    4
   4. Definitions ..............................................    4
   5. Acknowledgements .........................................    8
   6. References ...............................................    8
   7. Security Considerations ..................................    9
   8. Authors' Addresses .......................................   10

1.  Introduction

   This memo defines a portion of the Management Information Base (MIB)
   for use with network management protocols in the Internet community.
   In particular, it describes managed objects used by IEEE 802.5 end-
   stations for managing source routes on a Token Ring network where
   IEEE source-routing is in use.  IEEE source-routing is described in
   802.5 Token Ring Access Method and Physical Layer Specifications [8]
   and related ISO publications [9, 10, 11].

   This memo is an incremental update to RFC 1748 [6].  It is documented
   separately from the RFC 1748 solely due to the latter's maturity
   within the Internet standardization process.




McCloghrie, Baker & Decker                                      [Page 1]

RFC 1749      802.5 Station Source Routing MIB using SMIv2 December 1994


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.

      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 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

   This memo defines a single table: the 802.5 Station Source Routing
   Table, which contains the source routes known by a end-station on an
   IEEE 802.5 Token Ring network in which IEEE source-routing is in use.

3.1.  Source Routing

   Source routing extends the 802.5 protocol [8] by assigning a unique
   ring number to each ring within the extended LAN, and a bridge number
   to each source routing bridge's connection to a ring.  A Routing
   Information Field (RIF) must be included in frames which need to
   traverse multiple rings.  The format of the RIF is:






McCloghrie, Baker & Decker                                      [Page 2]

RFC 1749      802.5 Station Source Routing MIB using SMIv2 December 1994


              octets octets octets         octets
               1&2    3&4    5&6            17&18
             +------+------+------+-------+------+
             |  RC  |  RD  |  RD  | ...   |  RD  |
             +------+------+------+-------+------+
                     <---- 0 to 8 RD fields ---->

   The format of the Routing Control (RC) field is:

                            octet 1         octet 2
                       +---------------+---------------+
                       |b b b l l l l l|d f f f 0 0 0 0|
                       +---------------+---------------+
                          ^       ^     ^   ^
                          |       |     |   |
     Explorer indicator --+       |     |   +-- Max frame length*
            Length of RIF field --+     +-- Direction to use RDs

     * Note that the length of the Maximum frame length subfield
       has recently been extended to 6 bits.

   The format of each Routing Descriptor (RD) field is:

                     octet 1         octet 2
                 +---------------+---------------+
                 |r r r r r r r r r r r r i i i i|
                 +---------------+---------------+
                  <---- ring number ----> <----->
                                             ^
                                             |
                             bridge number --+

3.2.  Relationship to RFC 1748

   RFC 1748 [6], the IEEE 802.5 MIB, defines managed objects used for
   interfaces to IEEE 802.5 Token Ring subnetworks.  This memo is an
   incremental update to RFC 1748, and is documented independently
   solely due to the maturity of the definitions contained within RFC
   1748.

3.3.  Relationship to RFC 1525

   RFC 1525 [7] defines the MIB objects specific to source-routing for
   source-routing and SRT bridges.  This memo defines the MIB objects
   specific to source-routing for source-routing end-stations.






McCloghrie, Baker & Decker                                      [Page 3]

RFC 1749      802.5 Station Source Routing MIB using SMIv2 December 1994


3.4.  Static Source Routes

   It is unclear how many, if any, existing systems allow the creation
   or deletion of "static" 802.5 source routes by network management.
   However, SNMPv2 SMI defines that the MAX-ACCESS clause as specifying
   the maximal level of access which makes "protocol sense".  Thus, this
   memo provides support for static source routes through the
   dot5SrRouteStatus object, but the conformance statements allow for
   stations which do not support static source routes, by requiring that
   compliant agents only need provide read-access to dot5SrRouteStatus.

3.5.  Destinations on the Local Ring

   Entries should be included in the dot5SrRouteTable for destination
   MAC addresses which are on the same ring as the instrumented 802.5
   interface.  For such entries, dot5SrRouteDescr has the value of the
   zero-length string, and dot5SrRouteControl has the corresponding
   value.

4.  Definitions

TOKENRING-STATION-SR-MIB DEFINITIONS ::= BEGIN

IMPORTS
    MODULE-IDENTITY, OBJECT-TYPE
                                         FROM SNMPv2-SMI
    TEXTUAL-CONVENTION, RowStatus, MacAddress
                                         FROM SNMPv2-TC
    MODULE-COMPLIANCE, OBJECT-GROUP      FROM SNMPv2-CONF
    mib-2, ifIndex                       FROM RFC1213-MIB;

dot5SrMIB MODULE-IDENTITY
    LAST-UPDATED "9412161000Z"
    ORGANIZATION "IETF Interfaces MIB Working Group"
    CONTACT-INFO
            "       Keith McCloghrie
            Postal: Cisco Systems, Inc.
                    170 West Tasman Drive
                    San Jose, CA  95134-1706
                    US

             Phone: [phone]
             Email: [e-mail]"
    DESCRIPTION
            "The MIB module for managing source routes in
            end-stations on IEEE 802.5 Token Ring networks."
    ::= { mib-2 42 }




McCloghrie, Baker & Decker                                      [Page 4]

RFC 1749      802.5 Station Source Routing MIB using SMIv2 December 1994


dot5SrMIBObjects OBJECT IDENTIFIER ::= { dot5SrMIB 1 }

SourceRoute ::= TEXTUAL-CONVENTION
    DISPLAY-HINT "1x:"
    STATUS       current
    DESCRIPTION
                 "Represents a Source Route, containing an
                 embedded sequence of bridge and ring ID's,
                 as used by 802.5 Source Routing."
    REFERENCE    "Annex C of ISO/IEC 10038: 1993,
                 [ANSI/IEEE Std 802.1D, 1993]"
    SYNTAX       OCTET STRING (SIZE(0..30))


--           The 802.5 Station Source Route Table
--

dot5SrRouteTable   OBJECT-TYPE
    SYNTAX      SEQUENCE OF Dot5SrRouteEntry
    MAX-ACCESS  not-accessible
    STATUS      current
    DESCRIPTION
               "The table of source-routing routes.
               This represents the 802.5 RIF database."
    ::= { dot5SrMIBObjects 1 }

dot5SrRouteEntry  OBJECT-TYPE
    SYNTAX      Dot5SrRouteEntry
    MAX-ACCESS  not-accessible
    STATUS      current
    DESCRIPTION
                "Information on a specific route.

                An entry is created whenever a 'Single Path
                Explorer' or an 'All Paths Explorer' discovers
                a route to a neighbor not currently in the table,
                or whenever an 'All Paths Explorer' discovers a
                better (e.g., shorter) route than the route currently
                stored in the table.  This is done on behalf of
                any network layer client.

                The ifIndex value in the INDEX clause refers to
                the value of MIB-II's ifIndex object for the
                interface on which the route is in effect."
    INDEX  { ifIndex, dot5SrRouteDestination }
    ::= { dot5SrRouteTable 1 }

Dot5SrRouteEntry ::= SEQUENCE {



McCloghrie, Baker & Decker                                      [Page 5]