rfc2674.txt

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Network Working Group                                             E. Bell
Request for Comments: 2674                                     3Com Corp.
Category: Standards Track                                        A. Smith
                                                         Extreme Networks
                                                              P. Langille
                                                       Newbridge Networks
                                                          A. Rijhsinghani
                                                        Cabletron Systems
                                                            K. McCloghrie
                                                            cisco Systems
                                                              August 1999


        Definitions of Managed Objects for Bridges with Traffic
        Classes, Multicast Filtering and Virtual LAN Extensions

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.

Copyright Notice

   Copyright (C) The Internet Society (1999).  All Rights Reserved.

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 two MIB modules for managing the new
   capabilities of MAC bridges defined by the IEEE 802.1D-1998 MAC
   Bridges and the IEEE 802.1Q-1998 Virtual LAN (VLAN) standards for
   bridging between Local Area Network (LAN) segments.  One MIB module
   defines objects for managing the 'Traffic Classes' and 'Enhanced
   Multicast Filtering' components of IEEE 802.1D-1998.  The other MIB
   module defines objects for managing IEEE 802.1Q VLANs.

   Provisions are made for support of transparent bridging.  Provisions
   are also made so that these objects apply to bridges connected by
   subnetworks other than LAN segments.  This memo also includes several
   MIB modules in a manner that is compliant to the SMIv2 [V2SMI].

   This memo supplements RFC 1493 [BRIDGEMIB] and (to a lesser extent)
   RFC 1525 [SBRIDGEMIB].




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Table of Contents

   1 The SNMP Management Framework ................................... 3
   2 Overview ........................................................ 4
   2.1 Scope ......................................................... 4
   3 Structure of MIBs ............................................... 5
   3.1 Structure of Extended Bridge MIB module ....................... 5
   3.1.1 Relationship to IEEE 802.1D-1998 Manageable Objects ......... 6
   3.1.2 Relationship to IEEE 802.1Q Manageable Objects .............. 8
   3.1.3 The dot1dExtBase Group ...................................... 8
   3.1.4 The dot1dPriority Group ..................................... 9
   3.1.5 The dot1dGarp Group ......................................... 9
   3.1.6 The dot1dGmrp Group ......................................... 9
   3.1.7 The dot1dTpHCPortTable ...................................... 9
   3.1.8 The dot1dTpPortOverflowTable ................................ 9
   3.2 Structure of Virtual Bridge MIB module ........................ 9
   3.2.1 Relationship to IEEE 802.1Q Manageable Objects .............. 9
   3.2.2 The dot1qBase Group .........................................13
   3.2.3 The dot1qTp Group ...........................................13
   3.2.4 The dot1qStatic Group .......................................13
   3.2.5 The dot1qVlan Group .........................................13
   3.3 Textual Conventions ...........................................13
   3.4 Relationship to Other MIBs ....................................14
   3.4.1 Relationship to the 'system' group ..........................14
   3.4.2 Relation to Interfaces MIB ..................................14
   3.4.2.1 Layering Model ............................................15
   3.4.2.2 ifStackTable ..............................................16
   3.4.2.3 ifRcvAddressTable .........................................16
   3.4.3 Relation to Original Bridge MIB .............................16
   3.4.3.1 The dot1dBase Group .......................................16
   3.4.3.2 The dot1dStp Group ........................................17
   3.4.3.3 The dot1dTp Group .........................................17
   3.4.3.4 The dot1dStatic Group .....................................17
   3.4.3.5 Additions to the Original Bridge MIB ......................18
   4 Definitions for Extended Bridge MIB .............................18
   5 Definitions for Virtual Bridge MIB ..............................39
   6 Acknowledgments .................................................80
   7 Security Considerations .........................................80
   8 References ......................................................81
   9 Authors' Addresses ..............................................84
   10 Intellectual Property ..........................................85
   11 Full Copyright Statement .......................................86









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1.  The SNMP Management Framework

   The SNMP Management Framework presently consists of five major
   components:

    o  An overall architecture, described in an Architecture for
       Describing SNMP Management Frameworks [ARCH].

    o  Mechanisms for describing and naming objects and events for the
       purpose of management.  The first version of this Structure of
       Management Information (SMI) is called SMIv1 and described in STD
       16, RFC 1155 [V1SMI], STD 16, RFC 1212 [V1CONCISE] and RFC 1215
       [V1TRAPS]. The second version, called SMIv2, is described in STD
       58, RFC 2578 [V2SMI], STD 58, RFC 2579 [V2TC] and STD 58, RFC
       2580 [V2CONFORM].

    o  Message protocols for transferring management information.  The
       first version of the SNMP message protocol is called SNMPv1 and
       described in STD 15, RFC 1157 [V1PROTO].  A second version of the
       SNMP message protocol, which is not an Internet standards track
       protocol, is called SNMPv2c and described in RFC 1901
       [V2COMMUNITY] and RFC 1906 [V2TRANS].  The third version of the
       message protocol is called SNMPv3 and described in RFC 1906
       [V2TRANS], Message Processing and Dispatching [V3MPC] and User-
       based Security Model [V3USM].

    o  Protocol operations for accessing management information.  The
       first set of protocol operations and associated PDU formats is
       described in STD 15, RFC 1157 [V1PROTO].  A second set of
       protocol operations and associated PDU formats is described in
       RFC 1905 [V2PROTO].

    o  A set of fundamental applications described in SNMPv3
       Applications [V3APPS] and the view-based access control mechanism
       described in View-based Access Control Model [V3VACM].

   Managed objects are accessed via a virtual information store, termed
   the Management Information Base or MIB.  Objects in the MIB are
   defined using the mechanisms defined in the SMI.

   This memo specifies a MIB module that is compliant to the SMIv2.  A
   MIB conforming to the SMIv1 can be produced through the appropriate
   translations.  The resulting translated MIB must be semantically
   equivalent, except where objects or events are omitted because no
   translation is possible (use of Counter64).  Some machine readable
   information in SMIv2 will be converted into textual descriptions in





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   SMIv1 during the translation process.  However, this loss of machine
   readable information is not considered to change the semantics of the
   MIB.

2.  Overview

   A common device present in many networks is the Bridge.  This device
   is used to connect Local Area Network segments below the network
   layer.  These devices are often known as 'layer 2 switches'.

   There are two major modes defined for this bridging: Source-Route and
   transparent.  Source-Route bridging is described by IEEE 802.5
   [802.5].  and is not discussed further in this document.

   The transparent method of bridging is defined by IEEE 802.1D-1998
   [802.1D] which is an update to the original IEEE 802.1D specification
   [802.1D-ORIG].  Managed objects for that original specification of
   transparent bridging were defined in RFC 1493 [BRIDGEMIB].

   The original IEEE 802.1D is augmented by IEEE 802.1Q-1998 [802.1Q] to
   provide support for 'virtual bridged LANs' where a single bridged
   physical LAN network may be used to support multiple logical bridged
   LANs, each of which offers a service approximately the same as that
   defined by IEEE 802.1D.  Such virtual LANs (VLANs) are an integral
   feature of switched LAN networks.  A VLAN can be viewed as a group of
   end-stations on multiple LAN segments and can communicate as if they
   were on a single LAN.  IEEE 802.1Q defines port-based Virtual LANs
   where membership is determined by the bridge port on which data
   frames are received.  This memo defines the objects needed for the
   management of port-based VLANs in bridge entities.

   This memo defines those objects needed for the management of a
   bridging entity operating in the transparent mode, as well as some
   objects applicable to all types of bridges.  Managed objects for
   Source-Route bridging are defined in RFC 1525 [SRBRIDGEMIB].

2.1.  Scope

   This MIB includes a comprehensive set of managed objects which
   attempts to match the set defined in IEEE 802.1D and IEEE 802.1Q.
   However, to be consistent with the spirit of the SNMP Framework, a
   subjective judgement was made to omit the objects from those
   standards most 'costly' to implement in an agent and least
   'essential' for fault and configuration management.  The omissions
   are described in section 3 below.






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   Historical note:

   The original bridge MIB [BRIDGEMIB] used the following principles for
   determining inclusion of an object in the BRIDGE-MIB module:

   (1)   Start with a small set of essential objects and add only as
         further objects are needed.

   (2)   Require objects be essential for either fault or configuration
         management.

   (3)   Consider evidence of current use and/or utility.

   (4)   Limit the total of objects.

   (5)   Exclude objects which are simply derivable from others in
         this or other MIBs.

   (6)   Avoid causing critical sections to be heavily instrumented.
         The  guideline that was followed is one counter per critical
         section per layer.

3.  Structure of MIBs

   This document defines additional objects, on top of those existing in
   the original BRIDGE-MIB module defined in [BRIDGEMIB]: that MIB
   module is to be maintained unchanged for backwards compatibility.
   Section 3.4.3 of the present document contains some recommendations
   regarding usage of objects in the original bridge MIB by devices
   implementing the enhancements defined here.

   Two MIB modules are defined here:

   (1)   Managed objects for an extended bridge MIB module P-BRIDGE-MIB
         for the traffic class and multicast filtering enhancements
         defined by IEEE 802.1D-1998 [802.1D].

   (2)   Managed objects for a virtual bridge MIB module Q-BRIDGE-MIB
         for the Virtual LAN bridging enhancements defined by IEEE
         802.1Q-1998 [802.1Q].

3.1.  Structure of Extended Bridge MIB module

   Objects in this MIB are arranged into groups.  Each group is
   organized as a set of related objects.  The overall structure and
   assignment of objects to their groups is shown below.





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3.1.1.  Relationship to IEEE 802.1D-1998 Manageable Objects

   This section contains a cross-reference to the objects defined in
   IEEE 802.1D-1998 [802.1D].  It also details those objects that are
   not considered necessary in this MIB module.

   Some objects defined by IEEE 802.1D-1998 have been included in the
   virtual bridge MIB module rather than this one: entries in
   dot1qTpGroupTable, dot1qForwardAllTable and
   dot1qForwardUnregisteredTable are required for virtual bridged LANs
   with additional indexing (e.g. per-VLAN, per-FDB) and so are not
   defined here.  Instead, devices which do not implement virtual
   bridged LANs but do implement the Extended Forwarding Services
   defined by IEEE 802.1D (i.e. dynamic learning of multicast group
   addresses and group service requirements in the filtering database)
   should implement these tables with a fixed value for dot1qFdbId (the
   value 1 is recommended) or dot1qVlanIndex (the value 1 is
   recommended).  Devices which support Extended Filtering Services
   should support dot1qTpGroupTable, dot1qForwardAllTable and
   dot1qForwardUnregisteredTable.































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RFC 2674                 Bridge MIB Extensions               August 1999


   Extended Bridge MIB Name            IEEE 802.1D-1998 Name

   dot1dExtBase                        Bridge
     dot1dDeviceCapabilities
       dot1dExtendedFilteringServices
       dot1dTrafficClasses
     dot1dTrafficClassesEnabled
     dot1dGmrpStatus                    .ApplicantAdministrativeControl