





Network Working Group                                          E. Decker
Request for Comments: 1493                           cisco Systems, Inc.
Obsoletes: 1286                                              P. Langille
                                           Digital Equipment Corporation
                                                          A. Rijsinghani
                                           Digital Equipment Corporation
                                                           K. McCloghrie
                                                Hughes LAN Systems, Inc.
                                                               July 1993


                     Definitions of Managed Objects
                              for Bridges

Status of this Memo


   This RFC specifies an IAB standards track protocol for the Internet
   community, and requests discussion and suggestions for improvements.
   Please refer to the current edition of the "IAB Official Protocol
   Standards" for the standardization state and status of this protocol.
   Distribution of this memo is unlimited.

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 objects for managing MAC bridges based on
   the IEEE 802.1D-1990 standard between Local Area Network (LAN)
   segments.  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.

Table of Contents

   1. The Network Management Framework ......................    2
   2. Objects ...............................................    2
   2.1 Format of Definitions ................................    3
   3. Overview ..............................................    3
   3.1 Structure of MIB .....................................    3
   3.1.1 The dot1dBase Group ................................    6
   3.1.2 The dot1dStp Group .................................    6
   3.1.3 The dot1dSr Group ..................................    6
   3.1.4 The dot1dTp Group ..................................    6
   3.1.5 The dot1dStatic Group ..............................    6
   3.2 Relationship to Other MIBs ...........................    6
   3.2.1 Relationship to the 'system' group .................    6
   3.2.2 Relationship to the 'interfaces' group .............    7



Decker, Langille, Rijsinghani & McCloghrie                      [Page 1]

RFC 1493                       Bridge MIB                      July 1993


   3.3 Textual Conventions ..................................    8
   4. Changes from RFC 1286 .................................    8
   5. Definitions ...........................................    9
   5.1 Groups in the Bridge MIB .............................   11
   5.2 The dot1dBase Group Definitions ......................   11
   5.3 The dot1dStp Group Definitions .......................   14
   5.4 The dot1dTp Group Definitions ........................   22
   5.5 The dot1dStatic Group Definitions ....................   28
   5.6 Traps for use by Bridges .............................   31
   6. Acknowledgments .......................................   31
   7. References ............................................   33
   8. Security Considerations ...............................   33
   9. Authors' Addresses ....................................   34

1.  The Network Management Framework

   The Internet-standard Network Management Framework consists of three
   components.  They are:

      STD16/RFC 1155 which defines the SMI, the mechanisms used for
      describing and naming objects for the purpose of management.
      STD16/RFC 1212 defines a more concise description mechanism, which
      is wholly consistent with the SMI.

      RFC 1156 which defines MIB-I, the core set of managed objects for
      the Internet suite of protocols.  STD17/RFC 1213, defines MIB-II,
      an evolution of MIB-I based on implementation experience and new
      operational requirements.

      STD15/RFC 1157 which defines the SNMP, 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.  Objects

   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) [7]
   defined in the SMI.  In particular, each object is named by an OBJECT
   IDENTIFIER, an administratively assigned name, which specifies an
   object type.  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 also refer to the object type.





Decker, Langille, Rijsinghani & McCloghrie                      [Page 2]

RFC 1493                       Bridge MIB                      July 1993


2.1.  Format of Definitions

   Section 5 contains the specification of all object types contained in
   this MIB module.  The object types are defined using the conventions
   defined in the SMI, as amended by the extensions specified in [9,10].

3.  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.

   There are two major modes defined for this bridging; transparent and
   source route.  The transparent method of bridging is defined in the
   draft IEEE 802.1d specification [11].  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.

   To be consistent with IAB directives and good engineering practice,
   an explicit attempt was made to keep this MIB as simple as possible.
   This was accomplished by applying the following criteria to objects
   proposed for inclusion:

          (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.

3.1.  Structure of MIB

   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.  Where
   appropriate the corresponding IEEE 802.1d [11] management object name
   is also included.



Decker, Langille, Rijsinghani & McCloghrie                      [Page 3]

RFC 1493                       Bridge MIB                      July 1993


          Bridge MIB Name                  IEEE 802.1d Name

          dot1dBridge
            dot1dBase
              BridgeAddress                Bridge.BridgeAddress
              NumPorts                     Bridge.NumberOfPorts
              Type
              PortTable
                Port                       BridgePort.PortNumber
                IfIndex
                Circuit
                DelayExceededDiscards        .DiscardTransitDelay
                MtuExceededDiscards          .DiscardOnError
            dot1dStp
              ProtocolSpecification
              Priority                     SpanningTreeProtocol
                                             .BridgePriority
              TimeSinceTopologyChange        .TimeSinceTopologyChange
              TopChanges                     .TopologyChangeCount
              DesignatedRoot                 .DesignatedRoot
              RootCost                       .RootCost
              RootPort                       .RootPort
              MaxAge                         .MaxAge
              HelloTime                      .HelloTime
              HoldTime                       .HoldTime
              ForwardDelay                   .ForwardDelay
              BridgeMaxAge                   .BridgeMaxAge
              BridgeHelloTime                .BridgeHelloTime
              BridgeForwardDelay             .BridgeForwardDelay
              PortTable
                Port                        SpanningTreeProtocolPort
                                              .PortNumber
                Priority                      .PortPriority
                State                         .SpanningTreeState
                Enable
                PathCost                      .PortPathCost
                DesignatedRoot                .DesignatedRoot
                DesignatedCost                .DesignatedCost
                DesignatedBridge              .DesignatedBridge
                DesignatedPort                .DesignatedPort
                ForwardTransitions
            dot1dTp
              LearnedEntryDiscards          BridgeFilter.DatabaseSize
                                              .NumDynamic,NumStatic
              AgingTime                     BridgeFilter.AgingTime
              FdbTable
                Address
                Port



Decker, Langille, Rijsinghani & McCloghrie                      [Page 4]

RFC 1493                       Bridge MIB                      July 1993


                Status
              PortTable
                Port
                MaxInfo
                InFrames                    BridgePort.FramesReceived
                OutFrames                     .ForwardOutbound
                InDiscards                    .DiscardInbound
            dot1dStatic
              StaticTable
                Address
                ReceivePort
                AllowedToGoTo
                Status

   The following IEEE 802.1d management objects have not been included
   in the Bridge MIB for the indicated reasons.

          IEEE 802.1d Object              Disposition

          Bridge.BridgeName               Same as sysDescr (MIB II)
          Bridge.BridgeUpTime             Same as sysUpTime (MIB II)
          Bridge.PortAddresses            Same as ifPhysAddress (MIB II)
          BridgePort.PortName             Same as ifDescr (MIB II)
          BridgePort.PortType             Same as ifType (MIB II)
          BridgePort.RoutingType          Derivable from the implemented
                                          groups

          SpanningTreeProtocol
              .BridgeIdentifier           Combination of dot1dStpPriority
                                          and dot1dBaseBridgeAddress
              .TopologyChange             Since this is transitory, it
                                          is not considered useful.
          SpanningTreeProtocolPort
              .Uptime                     Same as ifLastChange (MIB II)
              .PortIdentifier             Combination of dot1dStpPort
                                          and dot1dStpPortPriority
              .TopologyChangeAcknowledged Since this is transitory, it
                                          is not considered useful.
              .DiscardLackOfBuffers       Redundant

          Transmission Priority           These objects are not required
                                          as per the Pics Proforma and
                                          not considered useful.
              .TransmissionPriorityName
              .OutboundUserPriority
              .OutboundAccessPriority





Decker, Langille, Rijsinghani & McCloghrie                      [Page 5]

RFC 1493                       Bridge MIB                      July 1993


3.1.1.  The dot1dBase Group

   This mandatory group contains the objects which are applicable to all
   types of bridges.

3.1.2.  The dot1dStp Group

   This group contains the objects that denote the bridge's state with
   respect to the Spanning Tree Protocol.  If a node does not
   implemented the Spanning Tree Protocol, this group will not be
   implemented.

3.1.3.  The dot1dSr Group

   This group contains the objects that describe the entity's state with
   respect to source route bridging.  If source routing is not supported
   this group will not be implemented.  This group is applicable to
   source route only, and SRT bridges.  This group will be described in
   a separate document applicable only to source route bridging.

3.1.4.  The dot1dTp Group

   This group contains objects that describe the entity's state with
   respect to transparent bridging.  If transparent bridging is not
   supported this group will not be implemented.  This group is
   applicable to transparent only and SRT bridges.

3.1.5.  The dot1dStatic Group

   This group contains objects that describe the entity's state with
   respect to destination-address filtering.  If destination-address
   filtering is not supported this group will not be implemented.  This
   group is applicable to any type of bridge which performs
   destination-address filtering.

3.2.  Relationship to Other MIBs

   As described above, some IEEE 802.1d management objects have not been
   included in this MIB because they overlap with objects in other MIBs
   applicable to a bridge implementing this MIB.  In particular, it is
   assumed that a bridge implementing this MIB will also implement (at
   least) the 'system' group and the 'interfaces' group defined in MIB-
   II [6].

3.2.1.  Relationship to the 'system' group

   In MIB-II, the 'system' group is defined as being mandatory for all
   systems such that each managed entity contains one instance of each



Decker, Langille, Rijsinghani & McCloghrie                      [Page 6]

RFC 1493                       Bridge MIB                      July 1993


   object in the 'system' group.  Thus, those objects apply to the
   entity as a whole irrespective of whether the entity's sole
   functionality is bridging, or whether bridging is only a subset of
   the entity's functionality.

3.2.2.  Relationship to the 'interfaces' group

   In MIB-II, the 'interfaces' group is defined as being mandatory for
   all systems and contains information on an entity's interfaces, where
   each interface is thought of as being attached to a `subnetwork'.
   (Note that this term is not to be confused with `subnet' which refers
   to an addressing partitioning scheme used in the Internet suite of
   protocols.) The term 'segment' is used in this memo to refer to such
   a subnetwork, whether it be an Ethernet segment, a 'ring', a WAN
   link, or even an X.25 virtual circuit.

   Implicit in this Bridge MIB is the notion of ports on a bridge.  Each
   of these ports is associated with one interface of the 'interfaces'
   group, and in most situations, each port is associated with a
   different interface. However, there are situations in which multiple
   ports are associated with the same interface.  An example of such a
   situation would be several ports each corresponding one-to-one with
   several X.25 virtual circuits but all on the same interface.

   Each port is uniquely identified by a port number.  A port number has
   no mandatory relationship to an interface number, but in the simple
   case a port number will have the same value as the corresponding
   interface's interface number.  Port numbers are in the range
   (1..dot1dBaseNumPorts).

   Some entities perform other functionality as well as bridging through
   the sending and receiving of data on their interfaces.  In such
   situations, only a subset of the data sent/received on an interface
   is within the domain of the entity's bridging functionality.  This
   subset is considered to be delineated according to a set of
   protocols, with some protocols being bridged, and other protocols not
   being bridged. For example, in an entity which exclusively performed
   bridging, all protocols would be considered as being bridged, whereas
   in an entity which performed IP routing on IP datagrams and only
   bridged other protocols, only the non-IP data would be considered as
   being bridged.

   Thus, this Bridge MIB (and in particular, its counters) are
   applicable only to that subset of the data on an entity's interfaces
   which is sent/received for a protocol being bridged.  All such data
   is sent/received via the ports of the bridge.





Decker, Langille, Rijsinghani & McCloghrie                      [Page 7]

RFC 1493                       Bridge MIB                      July 1993


3.3.  Textual Conventions

   The datatypes, MacAddress, BridgeId and Timeout, are used as textual
   conventions in this document.  These textual conventions have NO
   effect on either the syntax nor the semantics of any managed object.
   Objects defined using these conventions are always encoded by means
   of the rules that define their primitive type.  Hence, no changes to
   the SMI or the SNMP are necessary to accommodate these textual
   conventions which are adopted merely for the convenience of readers.

4.  Changes from RFC 1286

          (1)  Updated all text to remove references to source route
               bridging where not applicable.  SR MIB will be a separate
               document.

          (2)  Removed dot1dSrPortTable.  Retained OID definition of
               dot1dSr.

          (3)  Updated all references of "draft P802.1d/D9" to "IEEE
               802.1D-1990".

          (4)  Updated bibliography.

          (5)  Added clarification to description of dot1dPortPathCost.

          (6)  Put recommended default in description of
               dot1dStaticAllowedToGoTo.

          (7)  Put recommended default in description of
               dot1dStaticStatus.

          (8)  Put recommended default in description of
               dot1dTpAgingTime.  Specified range of (10..1000000).

          (9)  Updated all port number syntaxes, when used as index, to
               use the range (1..65535).

          (10) Updated definition of dot1dTpPortInFrames and
               dot1dTpPortOutFrames.

          (11) Added text to the traps indicating that they are
               optional.

          (12) Clarified definition of dot1dStpForwardDelay.






Decker, Langille, Rijsinghani & McCloghrie                      [Page 8]

RFC 1493                       Bridge MIB                      July 1993


5.  Definitions

          BRIDGE-MIB DEFINITIONS ::= BEGIN

          IMPORTS
                     Counter, TimeTicks
                             FROM RFC1155-SMI
                     mib-2
                             FROM RFC1213-MIB
                     OBJECT-TYPE
                             FROM RFC-1212
                     TRAP-TYPE
                             FROM RFC-1215;

          -- All representations of MAC addresses in this MIB Module
          -- use, as a textual convention (i.e. this convention does
          -- not affect their encoding), the data type:

          MacAddress ::= OCTET STRING (SIZE (6))    -- a 6 octet address
                                                    -- in the
                                                    -- "canonical"
                                                    -- order
          -- defined by IEEE 802.1a, i.e., as if it were transmitted
          -- least significant bit first, even though 802.5 (in
          -- contrast to other n802.x protocols) requires MAC
          -- addresses to be transmitted most significant bit first.
          --
          -- 16-bit addresses, if needed, are represented by setting
          -- their upper 4 octets to all 0's, i.e., AAFF would be
          -- represented as 00000000AAFF.


          -- Similarly, all representations of Bridge-Id in this MIB
          -- Module use, as a textual convention (i.e. this
          -- convention does not affect their encoding), the data
          -- type:

          BridgeId ::= OCTET STRING (SIZE (8))   -- the
                                                 -- Bridge-Identifier
                                                 -- as used in the
                                                 -- Spanning Tree
          -- Protocol to uniquely identify a bridge.  Its first two
          -- octets (in network byte order) contain a priority
          -- value and its last 6 octets contain the MAC address
          -- used to refer to a bridge in a unique fashion
          -- (typically, the numerically smallest MAC address
          -- of all ports on the bridge).




Decker, Langille, Rijsinghani & McCloghrie                      [Page 9]

RFC 1493                       Bridge MIB                      July 1993


          -- Several objects in this MIB module represent values of
          -- timers used by the Spanning Tree Protocol.  In this
          -- MIB, these timers have values in units of hundreths of
          -- a second (i.e. 1/100 secs).
          -- These timers, when stored in a Spanning Tree Protocol's
          -- BPDU, are in units of 1/256 seconds.  Note, however,
          -- that 802.1D-1990 specifies a settable granularity of
          -- no more than 1 second for these timers.  To avoid
          -- ambiguity, a data type is defined here as a textual
          -- convention and all representation of these timers
          -- in this MIB module are defined using this data type.  An
          -- algorithm is also defined for converting between the
          -- different units, to ensure a timer's value is not
          -- distorted by multiple conversions.
          -- The data type is:

          Timeout ::= INTEGER -- a STP timer in units of 1/100 seconds

          -- To convert a Timeout value into a value in units of
          -- 1/256 seconds, the following algorithm should be used:
          --
          --      b  = floor( (n * 256) / 100)
          --
          -- where:
          --      floor   =  quotient [ignore remainder]
          --      n is the value in 1/100 second units
          --      b is the value in 1/256 second units
          --
          -- To convert the value from 1/256 second units back to
          -- 1/100 seconds, the following algorithm should be used:
          --
          --      n = ceiling( (b * 100) / 256)
          --
          -- where:
          --      ceiling =  quotient [if remainder is 0], or
          --                 quotient + 1 [if remainder is non-zero]
          --      n is the value in 1/100 second units
          --      b is the value in 1/256 second units
          --
          -- Note: it is important that the arithmetic operations are
          -- done in the order specified (i.e., multiply first, divide
          -- second).


             dot1dBridge   OBJECT IDENTIFIER ::= { mib-2 17 }






Decker, Langille, Rijsinghani & McCloghrie                     [Page 10]

RFC 1493                       Bridge MIB                      July 1993


          -- groups in the Bridge MIB

          dot1dBase     OBJECT IDENTIFIER ::= { dot1dBridge 1 }

          dot1dStp      OBJECT IDENTIFIER ::= { dot1dBridge 2 }

          dot1dSr       OBJECT IDENTIFIER ::= { dot1dBridge 3 }
          -- separately documented

          dot1dTp       OBJECT IDENTIFIER ::= { dot1dBridge 4 }

          dot1dStatic   OBJECT IDENTIFIER ::= { dot1dBridge 5 }


          -- the dot1dBase group

          -- Implementation of the dot1dBase group is mandatory for all
          -- bridges.

          dot1dBaseBridgeAddress OBJECT-TYPE
              SYNTAX  MacAddress
              ACCESS  read-only
              STATUS  mandatory
              DESCRIPTION
                      "The MAC address used by this bridge when it must
                      be referred to in a unique fashion.   It is
                      recommended that this be the numerically smallest
                      MAC address of all ports that belong to this
                      bridge.  However it is only required to be unique.
                      When concatenated with dot1dStpPriority a unique
                      BridgeIdentifier is formed which is used in the
                      Spanning Tree Protocol."
              REFERENCE
                      "IEEE 802.1D-1990: Sections 6.4.1.1.3 and 3.12.5"
              ::= { dot1dBase 1 }

          dot1dBaseNumPorts OBJECT-TYPE
              SYNTAX  INTEGER
              ACCESS  read-only
              STATUS  mandatory
              DESCRIPTION
                      "The number of ports controlled by this bridging
                      entity."
              REFERENCE
                      "IEEE 802.1D-1990: Section 6.4.1.1.3"
              ::= { dot1dBase 2 }

          dot1dBaseType OBJECT-TYPE



Decker, Langille, Rijsinghani & McCloghrie                     [Page 11]

RFC 1493                       Bridge MIB                      July 1993


              SYNTAX  INTEGER {
                          unknown(1),
                          transparent-only(2),
                          sourceroute-only(3),
                          srt(4)
                      }
              ACCESS  read-only
              STATUS  mandatory
              DESCRIPTION
                      "Indicates what type of bridging this bridge can
                      perform.  If a bridge is actually performing a
                      certain type of bridging this will be indicated by
                      entries in the port table for the given type."
              ::= { dot1dBase 3 }

          -- The Generic Bridge Port Table

          dot1dBasePortTable OBJECT-TYPE
              SYNTAX  SEQUENCE OF Dot1dBasePortEntry
              ACCESS  not-accessible
              STATUS  mandatory
              DESCRIPTION
                      "A table that contains generic information about
                      every port that is associated with this bridge.
                      Transparent, source-route, and srt ports are
                      included."
              ::= { dot1dBase 4 }

          dot1dBasePortEntry OBJECT-TYPE
              SYNTAX  Dot1dBasePortEntry
              ACCESS  not-accessible
              STATUS  mandatory
              DESCRIPTION
                      "A list of information for each port of the
                      bridge."
              REFERENCE
                      "IEEE 802.1D-1990: Section 6.4.2, 6.6.1"
              INDEX  { dot1dBasePort }
              ::= { dot1dBasePortTable 1 }


          Dot1dBasePortEntry ::=
              SEQUENCE {
                  dot1dBasePort
                      INTEGER,
                  dot1dBasePortIfIndex
                      INTEGER,
                  dot1dBasePortCircuit



Decker, Langille, Rijsinghani & McCloghrie                     [Page 12]

RFC 1493                       Bridge MIB                      July 1993


                      OBJECT IDENTIFIER,
                  dot1dBasePortDelayExceededDiscards
                      Counter,
                  dot1dBasePortMtuExceededDiscards
                      Counter
              }

          dot1dBasePort OBJECT-TYPE
              SYNTAX  INTEGER (1..65535)
              ACCESS  read-only
              STATUS  mandatory
              DESCRIPTION
                      "The port number of the port for which this entry
                      contains bridge management information."
              ::= { dot1dBasePortEntry 1 }

          dot1dBasePortIfIndex OBJECT-TYPE
              SYNTAX  INTEGER
              ACCESS  read-only
              STATUS  mandatory
              DESCRIPTION
                      "The value of the instance of the ifIndex object,
                      defined in MIB-II, for the interface corresponding
                      to this port."
              ::= { dot1dBasePortEntry 2 }

          dot1dBasePortCircuit OBJECT-TYPE
              SYNTAX  OBJECT IDENTIFIER
              ACCESS  read-only
              STATUS  mandatory
              DESCRIPTION
                      "For a port which (potentially) has the same value
                      of dot1dBasePortIfIndex as another port on the
                      same bridge, this object contains the name of an
                      object instance unique to this port.  For example,
                      in the case where multiple ports correspond one-
                      to-one with multiple X.25 virtual circuits, this
                      value might identify an (e.g., the first) object
                      instance associated with the X.25 virtual circuit
                      corresponding to this port.

                      For a port which has a unique value of
                      dot1dBasePortIfIndex, this object can have the
                      value { 0 0 }."
              ::= { dot1dBasePortEntry 3 }

          dot1dBasePortDelayExceededDiscards OBJECT-TYPE
              SYNTAX  Counter



Decker, Langille, Rijsinghani & McCloghrie                     [Page 13]

RFC 1493                       Bridge MIB                      July 1993


              ACCESS  read-only
              STATUS  mandatory
              DESCRIPTION
                      "The number of frames discarded by this port due
                      to excessive transit delay through the bridge.  It
                      is incremented by both transparent and source
                      route bridges."
              REFERENCE
                       "IEEE 802.1D-1990: Section 6.6.1.1.3"
              ::= { dot1dBasePortEntry 4 }

          dot1dBasePortMtuExceededDiscards OBJECT-TYPE
              SYNTAX  Counter
              ACCESS  read-only
              STATUS  mandatory
              DESCRIPTION
                      "The number of frames discarded by this port due
                      to an excessive size.  It is incremented by both
                      transparent and source route bridges."
              REFERENCE
                      "IEEE 802.1D-1990: Section 6.6.1.1.3"
              ::= { dot1dBasePortEntry 5 }


          -- the dot1dStp group

          -- Implementation of the dot1dStp group is optional.  It is
          -- implemented by those bridges that support the Spanning Tree
          -- Protocol.


          dot1dStpProtocolSpecification OBJECT-TYPE
              SYNTAX  INTEGER {
                          unknown(1),
                          decLb100(2),
                          ieee8021d(3)
                      }
              ACCESS  read-only
              STATUS  mandatory
              DESCRIPTION
                      "An indication of what version of the Spanning
                      Tree Protocol is being run.  The value
                      'decLb100(2)' indicates the DEC LANbridge 100
                      Spanning Tree protocol.  IEEE 802.1d
                      implementations will return 'ieee8021d(3)'.  If
                      future versions of the IEEE Spanning Tree Protocol
                      are released that are incompatible with the
                      current version a new value will be defined."



Decker, Langille, Rijsinghani & McCloghrie                     [Page 14]

RFC 1493                       Bridge MIB                      July 1993


              ::= { dot1dStp 1 }

          dot1dStpPriority OBJECT-TYPE
              SYNTAX  INTEGER (0..65535)
              ACCESS  read-write
              STATUS  mandatory
              DESCRIPTION
                      "The value of the write-able portion of the Bridge
                      ID, i.e., the first two octets of the (8 octet
                      long) Bridge ID.  The other (last) 6 octets of the
                      Bridge ID are given by the value of
                      dot1dBaseBridgeAddress."
              REFERENCE
                      "IEEE 802.1D-1990: Section 4.5.3.7"
              ::= { dot1dStp 2 }

          dot1dStpTimeSinceTopologyChange OBJECT-TYPE
              SYNTAX  TimeTicks
              ACCESS  read-only
              STATUS  mandatory
              DESCRIPTION
                      "The time (in hundredths of a second) since the
                      last time a topology change was detected by the
                      bridge entity."
              REFERENCE
                      "IEEE 802.1D-1990: Section 6.8.1.1.3"
              ::= { dot1dStp 3 }

          dot1dStpTopChanges OBJECT-TYPE
              SYNTAX  Counter
              ACCESS  read-only
              STATUS  mandatory
              DESCRIPTION
                      "The total number of topology changes detected by
                      this bridge since the management entity was last
                      reset or initialized."
              REFERENCE
                      "IEEE 802.1D-1990: Section 6.8.1.1.3"
              ::= { dot1dStp 4 }

          dot1dStpDesignatedRoot OBJECT-TYPE
              SYNTAX  BridgeId
              ACCESS  read-only
              STATUS  mandatory
              DESCRIPTION
                      "The bridge identifier of the root of the spanning
                      tree as determined by the Spanning Tree Protocol
                      as executed by this node.  This value is used as



Decker, Langille, Rijsinghani & McCloghrie                     [Page 15]

RFC 1493                       Bridge MIB                      July 1993


                      the Root Identifier parameter in all Configuration
                      Bridge PDUs originated by this node."
              REFERENCE
                      "IEEE 802.1D-1990: Section 4.5.3.1"
              ::= { dot1dStp 5 }

          dot1dStpRootCost OBJECT-TYPE
              SYNTAX  INTEGER
              ACCESS  read-only
              STATUS  mandatory
              DESCRIPTION
                      "The cost of the path to the root as seen from
                      this bridge."
              REFERENCE
                      "IEEE 802.1D-1990: Section 4.5.3.2"
              ::= { dot1dStp 6 }

          dot1dStpRootPort OBJECT-TYPE
              SYNTAX  INTEGER
              ACCESS  read-only
              STATUS  mandatory
              DESCRIPTION
                      "The port number of the port which offers the
                      lowest cost path from this bridge to the root
                      bridge."
              REFERENCE
                      "IEEE 802.1D-1990: Section 4.5.3.3"
              ::= { dot1dStp 7 }

          dot1dStpMaxAge OBJECT-TYPE
              SYNTAX  Timeout
              ACCESS  read-only
              STATUS  mandatory
              DESCRIPTION
                      "The maximum age of Spanning Tree Protocol
                      information learned from the network on any port
                      before it is discarded, in units of hundredths of
                      a second.  This is the actual value that this
                      bridge is currently using."
              REFERENCE
                      "IEEE 802.1D-1990: Section 4.5.3.4"
              ::= { dot1dStp 8 }

          dot1dStpHelloTime OBJECT-TYPE
              SYNTAX  Timeout
              ACCESS  read-only
              STATUS  mandatory
              DESCRIPTION



Decker, Langille, Rijsinghani & McCloghrie                     [Page 16]

RFC 1493                       Bridge MIB                      July 1993


                      "The amount of time between the transmission of
                      Configuration bridge PDUs by this node on any port
                      when it is the root of the spanning tree or trying
                      to become so, in units of hundredths of a second.
                      This is the actual value that this bridge is
                      currently using."
              REFERENCE
                      "IEEE 802.1D-1990: Section 4.5.3.5"
              ::= { dot1dStp 9 }

          dot1dStpHoldTime OBJECT-TYPE
              SYNTAX  INTEGER
              ACCESS  read-only
              STATUS  mandatory
              DESCRIPTION
                      "This time value determines the interval length
                      during which no more than two Configuration bridge
                      PDUs shall be transmitted by this node, in units
                      of hundredths of a second."
              REFERENCE
                      "IEEE 802.1D-1990: Section 4.5.3.14"
              ::= { dot1dStp 10 }

          dot1dStpForwardDelay OBJECT-TYPE
              SYNTAX  Timeout
              ACCESS  read-only
              STATUS  mandatory
              DESCRIPTION
                      "This time value, measured in units of hundredths
                      of a second, controls how fast a port changes its
                      spanning state when moving towards the Forwarding
                      state.  The value determines how long the port
                      stays in each of the Listening and Learning
                      states, which precede the Forwarding state.  This
                      value is also used, when a topology change has
                      been detected and is underway, to age all dynamic
                      entries in the Forwarding Database.  [Note that
                      this value is the one that this bridge is
                      currently using, in contrast to
                      dot1dStpBridgeForwardDelay which is the value that
                      this bridge and all others would start using
                      if/when this bridge were to become the root.]"
              REFERENCE
                      "IEEE 802.1D-1990: Section 4.5.3.6"
              ::= { dot1dStp 11 }

          dot1dStpBridgeMaxAge OBJECT-TYPE
              SYNTAX  Timeout (600..4000)



Decker, Langille, Rijsinghani & McCloghrie                     [Page 17]

RFC 1493                       Bridge MIB                      July 1993


              ACCESS  read-write
              STATUS  mandatory
              DESCRIPTION
                      "The value that all bridges use for MaxAge when
                      this bridge is acting as the root.  Note that
                      802.1D-1990 specifies that the range for this
                      parameter is related to the value of
                      dot1dStpBridgeHelloTime. The granularity of this
                      timer is specified by 802.1D-1990 to be 1 second.
                      An agent may return a badValue error if a set is
                      attempted to a value which is not a whole number
                      of seconds."
              REFERENCE
                      "IEEE 802.1D-1990: Section 4.5.3.8"
              ::= { dot1dStp 12 }

          dot1dStpBridgeHelloTime OBJECT-TYPE
              SYNTAX  Timeout (100..1000)
              ACCESS  read-write
              STATUS  mandatory
              DESCRIPTION
                      "The value that all bridges use for HelloTime when
                      this bridge is acting as the root.  The
                      granularity of this timer is specified by 802.1D-
                      1990 to be 1 second.  An agent may return a
                      badValue error if a set is attempted to a value
                      which is not a whole number of seconds."
              REFERENCE
                      "IEEE 802.1D-1990: Section 4.5.3.9"
              ::= { dot1dStp 13 }

          dot1dStpBridgeForwardDelay OBJECT-TYPE
              SYNTAX  Timeout (400..3000)
              ACCESS  read-write
              STATUS  mandatory
              DESCRIPTION
                      "The value that all bridges use for ForwardDelay
                      when this bridge is acting as the root.  Note that
                      802.1D-1990 specifies that the range for this
                      parameter is related to the value of
                      dot1dStpBridgeMaxAge.  The granularity of this
                      timer is specified by 802.1D-1990 to be 1 second.
                      An agent may return a badValue error if a set is
                      attempted to a value which is not a whole number
                      of seconds."
              REFERENCE
                      "IEEE 802.1D-1990: Section 4.5.3.10"
              ::= { dot1dStp 14 }



Decker, Langille, Rijsinghani & McCloghrie                     [Page 18]

RFC 1493                       Bridge MIB                      July 1993


          -- The Spanning Tree Port Table

          dot1dStpPortTable OBJECT-TYPE
              SYNTAX  SEQUENCE OF Dot1dStpPortEntry
              ACCESS  not-accessible
              STATUS  mandatory
              DESCRIPTION
                      "A table that contains port-specific information
                      for the Spanning Tree Protocol."
              ::= { dot1dStp 15 }

          dot1dStpPortEntry OBJECT-TYPE
              SYNTAX  Dot1dStpPortEntry
              ACCESS  not-accessible
              STATUS  mandatory
              DESCRIPTION
                      "A list of information maintained by every port
                      about the Spanning Tree Protocol state for that
                      port."
              INDEX   { dot1dStpPort }
              ::= { dot1dStpPortTable 1 }

          Dot1dStpPortEntry ::=
              SEQUENCE {
                  dot1dStpPort
                      INTEGER,
                  dot1dStpPortPriority
                      INTEGER,
                  dot1dStpPortState
                      INTEGER,
                  dot1dStpPortEnable
                      INTEGER,
                  dot1dStpPortPathCost
                      INTEGER,
                  dot1dStpPortDesignatedRoot
                      BridgeId,
                  dot1dStpPortDesignatedCost
                      INTEGER,
                  dot1dStpPortDesignatedBridge
                      BridgeId,
                  dot1dStpPortDesignatedPort
                      OCTET STRING,
                  dot1dStpPortForwardTransitions
                      Counter
              }

          dot1dStpPort OBJECT-TYPE
              SYNTAX  INTEGER (1..65535)



Decker, Langille, Rijsinghani & McCloghrie                     [Page 19]

RFC 1493                       Bridge MIB                      July 1993


              ACCESS  read-only
              STATUS  mandatory
              DESCRIPTION
                      "The port number of the port for which this entry
                      contains Spanning Tree Protocol management
                      information."
              REFERENCE
                      "IEEE 802.1D-1990: Section 6.8.2.1.2"
              ::= { dot1dStpPortEntry 1 }

          dot1dStpPortPriority OBJECT-TYPE
              SYNTAX  INTEGER (0..255)
              ACCESS  read-write
              STATUS  mandatory
              DESCRIPTION
                      "The value of the priority field which is
                      contained in the first (in network byte order)
                      octet of the (2 octet long) Port ID.  The other
                      octet of the Port ID is given by the value of
                      dot1dStpPort."
              REFERENCE
                      "IEEE 802.1D-1990: Section 4.5.5.1"
              ::= { dot1dStpPortEntry 2 }

          dot1dStpPortState OBJECT-TYPE
              SYNTAX  INTEGER {
                          disabled(1),
                          blocking(2),
                          listening(3),
                          learning(4),
                          forwarding(5),
                          broken(6)
                      }
              ACCESS  read-only
              STATUS  mandatory
              DESCRIPTION
                      "The port's current state as defined by
                      application of the Spanning Tree Protocol.  This
                      state controls what action a port takes on
                      reception of a frame.  If the bridge has detected
                      a port that is malfunctioning it will place that
                      port into the broken(6) state.  For ports which
                      are disabled (see dot1dStpPortEnable), this object
                      will have a value of disabled(1)."
              REFERENCE
                      "IEEE 802.1D-1990: Section 4.5.5.2"
              ::= { dot1dStpPortEntry 3 }




Decker, Langille, Rijsinghani & McCloghrie                     [Page 20]

RFC 1493                       Bridge MIB                      July 1993


          dot1dStpPortEnable OBJECT-TYPE
              SYNTAX  INTEGER {
                          enabled(1),
                          disabled(2)
                      }
              ACCESS  read-write
              STATUS  mandatory
              DESCRIPTION
                      "The enabled/disabled status of the port."
              REFERENCE
                      "IEEE 802.1D-1990: Section 4.5.5.2"
              ::= { dot1dStpPortEntry 4 }

          dot1dStpPortPathCost OBJECT-TYPE
              SYNTAX  INTEGER (1..65535)
              ACCESS  read-write
              STATUS  mandatory
              DESCRIPTION
                      "The contribution of this port to the path cost of
                      paths towards the spanning tree root which include
                      this port.  802.1D-1990 recommends that the
                      default value of this parameter be in inverse
                      proportion to the speed of the attached LAN."
              REFERENCE
                      "IEEE 802.1D-1990: Section 4.5.5.3"
              ::= { dot1dStpPortEntry 5 }

          dot1dStpPortDesignatedRoot OBJECT-TYPE
              SYNTAX  BridgeId
              ACCESS  read-only
              STATUS  mandatory
              DESCRIPTION
                      "The unique Bridge Identifier of the Bridge
                      recorded as the Root in the Configuration BPDUs
                      transmitted by the Designated Bridge for the
                      segment to which the port is attached."
              REFERENCE
                      "IEEE 802.1D-1990: Section 4.5.5.4"
              ::= { dot1dStpPortEntry 6 }

          dot1dStpPortDesignatedCost OBJECT-TYPE
              SYNTAX  INTEGER
              ACCESS  read-only
              STATUS  mandatory
              DESCRIPTION
                      "The path cost of the Designated Port of the
                      segment connected to this port.  This value is
                      compared to the Root Path Cost field in received



Decker, Langille, Rijsinghani & McCloghrie                     [Page 21]

RFC 1493                       Bridge MIB                      July 1993


                      bridge PDUs."
              REFERENCE
                      "IEEE 802.1D-1990: Section 4.5.5.5"
              ::= { dot1dStpPortEntry 7 }

          dot1dStpPortDesignatedBridge OBJECT-TYPE
              SYNTAX  BridgeId
              ACCESS  read-only
              STATUS  mandatory
              DESCRIPTION
                      "The Bridge Identifier of the bridge which this
                      port considers to be the Designated Bridge for
                      this port's segment."
              REFERENCE
                      "IEEE 802.1D-1990: Section 4.5.5.6"
              ::= { dot1dStpPortEntry 8 }

          dot1dStpPortDesignatedPort OBJECT-TYPE
              SYNTAX  OCTET STRING (SIZE (2))
              ACCESS  read-only
              STATUS  mandatory
              DESCRIPTION
                      "The Port Identifier of the port on the Designated
                      Bridge for this port's segment."
              REFERENCE
                      "IEEE 802.1D-1990: Section 4.5.5.7"
              ::= { dot1dStpPortEntry 9 }

          dot1dStpPortForwardTransitions OBJECT-TYPE
              SYNTAX  Counter
              ACCESS  read-only
              STATUS  mandatory
              DESCRIPTION
                      "The number of times this port has transitioned
                      from the Learning state to the Forwarding state."
              ::= { dot1dStpPortEntry 10 }


          -- the dot1dTp group

          -- Implementation of the dot1dTp group is optional.  It is
          -- implemented by those bridges that support the transparent
          -- bridging mode.  A transparent or SRT bridge will implement
          -- this group.


          dot1dTpLearnedEntryDiscards OBJECT-TYPE
              SYNTAX  Counter



Decker, Langille, Rijsinghani & McCloghrie                     [Page 22]

RFC 1493                       Bridge MIB                      July 1993


              ACCESS  read-only
              STATUS  mandatory
              DESCRIPTION
                      "The total number of Forwarding Database entries,
                      which have been or would have been learnt, but
                      have been discarded due to a lack of space to
                      store them in the Forwarding Database.  If this
                      counter is increasing, it indicates that the
                      Forwarding Database is regularly becoming full (a
                      condition which has unpleasant performance effects
                      on the subnetwork).  If this counter has a
                      significant value but is not presently increasing,
                      it indicates that the problem has been occurring
                      but is not persistent."
              REFERENCE
                      "IEEE 802.1D-1990: Section 6.7.1.1.3"
              ::= { dot1dTp 1 }

          dot1dTpAgingTime OBJECT-TYPE
              SYNTAX   INTEGER (10..1000000)
              ACCESS   read-write
              STATUS   mandatory
              DESCRIPTION
                      "The timeout period in seconds for aging out
                      dynamically learned forwarding information.
                      802.1D-1990 recommends a default of 300 seconds."
              REFERENCE
                      "IEEE 802.1D-1990: Section 6.7.1.1.3"
              ::= { dot1dTp 2 }


          --  The Forwarding Database for Transparent Bridges

          dot1dTpFdbTable OBJECT-TYPE
              SYNTAX  SEQUENCE OF Dot1dTpFdbEntry
              ACCESS  not-accessible
              STATUS  mandatory
              DESCRIPTION
                      "A table that contains information about unicast
                      entries for which the bridge has forwarding and/or
                      filtering information.  This information is used
                      by the transparent bridging function in
                      determining how to propagate a received frame."
              ::= { dot1dTp 3 }

          dot1dTpFdbEntry OBJECT-TYPE
              SYNTAX  Dot1dTpFdbEntry
              ACCESS  not-accessible



Decker, Langille, Rijsinghani & McCloghrie                     [Page 23]

RFC 1493                       Bridge MIB                      July 1993


              STATUS  mandatory
              DESCRIPTION
                      "Information about a specific unicast MAC address
                      for which the bridge has some forwarding and/or
                      filtering information."
              INDEX   { dot1dTpFdbAddress }
              ::= { dot1dTpFdbTable 1 }

          Dot1dTpFdbEntry ::=
              SEQUENCE {
                  dot1dTpFdbAddress
                      MacAddress,
                  dot1dTpFdbPort
                      INTEGER,
                  dot1dTpFdbStatus
                      INTEGER
              }

          dot1dTpFdbAddress OBJECT-TYPE
              SYNTAX  MacAddress
              ACCESS  read-only
              STATUS  mandatory
              DESCRIPTION
                      "A unicast MAC address for which the bridge has
                      forwarding and/or filtering information."
              REFERENCE
                      "IEEE 802.1D-1990: Section 3.9.1, 3.9.2"
              ::= { dot1dTpFdbEntry 1 }

          dot1dTpFdbPort OBJECT-TYPE
              SYNTAX  INTEGER
              ACCESS  read-only
              STATUS  mandatory
              DESCRIPTION
                      "Either the value '0', or the port number of the
                      port on which a frame having a source address
                      equal to the value of the corresponding instance
                      of dot1dTpFdbAddress has been seen.  A value of
                      '0' indicates that the port number has not been
                      learned but that the bridge does have some
                      forwarding/filtering information about this
                      address (e.g. in the dot1dStaticTable).
                      Implementors are encouraged to assign the port
                      value to this object whenever it is learned even
                      for addresses for which the corresponding value of
                      dot1dTpFdbStatus is not learned(3)."
              ::= { dot1dTpFdbEntry 2 }




Decker, Langille, Rijsinghani & McCloghrie                     [Page 24]

RFC 1493                       Bridge MIB                      July 1993


          dot1dTpFdbStatus OBJECT-TYPE
              SYNTAX  INTEGER {
                          other(1),
                          invalid(2),
                          learned(3),
                          self(4),
                          mgmt(5)
                      }
              ACCESS  read-only
              STATUS  mandatory
              DESCRIPTION
                      "The status of this entry.  The meanings of the
                      values are:

                        other(1)   : none of the following.  This would
                                     include the case where some other
                                     MIB object (not the corresponding
                                     instance of dot1dTpFdbPort, nor an
                                     entry in the dot1dStaticTable) is
                                     being used to determine if and how
                                     frames addressed to the value of
                                     the corresponding instance of
                                     dot1dTpFdbAddress are being
                                     forwarded.

                        invalid(2) : this entry is not longer valid
                                     (e.g., it was learned but has since
                                     aged-out), but has not yet been
                                     flushed from the table.

                        learned(3) : the value of the corresponding
                                     instance of dot1dTpFdbPort was
                                     learned, and is being used.

                        self(4)    : the value of the corresponding
                                     instance of dot1dTpFdbAddress
                                     represents one of the bridge's
                                     addresses.  The corresponding
                                     instance of dot1dTpFdbPort
                                     indicates which of the bridge's
                                     ports has this address.

                        mgmt(5)    : the value of the corresponding
                                     instance of dot1dTpFdbAddress is
                                     also the value of an existing
                                     instance of dot1dStaticAddress."
              ::= { dot1dTpFdbEntry 3 }




Decker, Langille, Rijsinghani & McCloghrie                     [Page 25]

RFC 1493                       Bridge MIB                      July 1993


          --  Port Table for Transparent Bridges

          dot1dTpPortTable OBJECT-TYPE
              SYNTAX  SEQUENCE OF Dot1dTpPortEntry
              ACCESS  not-accessible
              STATUS  mandatory
              DESCRIPTION
                      "A table that contains information about every
                      port that is associated with this transparent
                      bridge."
              ::= { dot1dTp 4 }

          dot1dTpPortEntry OBJECT-TYPE
              SYNTAX  Dot1dTpPortEntry
              ACCESS  not-accessible
              STATUS  mandatory
              DESCRIPTION
                      "A list of information for each port of a
                      transparent bridge."
              INDEX   { dot1dTpPort }
              ::= { dot1dTpPortTable 1 }

          Dot1dTpPortEntry ::=
              SEQUENCE {
                  dot1dTpPort
                      INTEGER,
                  dot1dTpPortMaxInfo
                      INTEGER,
                  dot1dTpPortInFrames
                      Counter,
                  dot1dTpPortOutFrames
                      Counter,
                  dot1dTpPortInDiscards
                      Counter
              }

          dot1dTpPort OBJECT-TYPE
              SYNTAX  INTEGER (1..65535)
              ACCESS  read-only
              STATUS  mandatory
              DESCRIPTION
                      "The port number of the port for which this entry
                      contains Transparent bridging management
                      information."
              ::= { dot1dTpPortEntry 1 }

          -- It would be nice if we could use ifMtu as the size of the
          -- largest INFO field, but we can't because ifMtu is defined



Decker, Langille, Rijsinghani & McCloghrie                     [Page 26]

RFC 1493                       Bridge MIB                      July 1993


          -- to be the size that the (inter-)network layer can use which
          -- can differ from the MAC layer (especially if several layers
          -- of encapsulation are used).

          dot1dTpPortMaxInfo OBJECT-TYPE
              SYNTAX  INTEGER
              ACCESS  read-only
              STATUS  mandatory
              DESCRIPTION
                      "The maximum size of the INFO (non-MAC) field that
                      this port will receive or transmit."
              ::= { dot1dTpPortEntry 2 }

          dot1dTpPortInFrames OBJECT-TYPE
              SYNTAX  Counter
              ACCESS  read-only
              STATUS  mandatory
              DESCRIPTION
                      "The number of frames that have been received by
                      this port from its segment. Note that a frame
                      received on the interface corresponding to this
                      port is only counted by this object if and only if
                      it is for a protocol being processed by the local
                      bridging function, including bridge management
                      frames."
              REFERENCE
                      "IEEE 802.1D-1990: Section 6.6.1.1.3"
              ::= { dot1dTpPortEntry 3 }

          dot1dTpPortOutFrames OBJECT-TYPE
              SYNTAX  Counter
              ACCESS  read-only
              STATUS  mandatory
              DESCRIPTION
                      "The number of frames that have been transmitted
                      by this port to its segment.  Note that a frame
                      transmitted on the interface corresponding to this
                      port is only counted by this object if and only if
                      it is for a protocol being processed by the local
                      bridging function, including bridge management
                      frames."
              REFERENCE
                      "IEEE 802.1D-1990: Section 6.6.1.1.3"
              ::= { dot1dTpPortEntry 4 }

          dot1dTpPortInDiscards OBJECT-TYPE
              SYNTAX   Counter
              ACCESS   read-only



Decker, Langille, Rijsinghani & McCloghrie                     [Page 27]

RFC 1493                       Bridge MIB                      July 1993


              STATUS   mandatory
              DESCRIPTION
                      "Count of valid frames received which were
                      discarded (i.e., filtered) by the Forwarding
                      Process."
              REFERENCE
                      "IEEE 802.1D-1990: Section 6.6.1.1.3"
              ::= { dot1dTpPortEntry 5 }


          -- The Static (Destination-Address Filtering) Database

          -- Implementation of this group is optional.


          dot1dStaticTable OBJECT-TYPE
              SYNTAX  SEQUENCE OF Dot1dStaticEntry
              ACCESS  not-accessible
              STATUS  mandatory
              DESCRIPTION
                      "A table containing filtering information
                      configured into the bridge by (local or network)
                      management specifying the set of ports to which
                      frames received from specific ports and containing
                      specific destination addresses are allowed to be
                      forwarded.  The value of zero in this table as the
                      port number from which frames with a specific
                      destination address are received, is used to
                      specify all ports for which there is no specific
                      entry in this table for that particular
                      destination address.  Entries are valid for
                      unicast and for group/broadcast addresses."
              REFERENCE
                      "IEEE 802.1D-1990: Section 6.7.2"
              ::= { dot1dStatic 1 }

          dot1dStaticEntry OBJECT-TYPE
              SYNTAX  Dot1dStaticEntry
              ACCESS  not-accessible
              STATUS  mandatory
              DESCRIPTION
                      "Filtering information configured into the bridge
                      by (local or network) management specifying the
                      set of ports to which frames received from a
                      specific port and containing a specific
                      destination address are allowed to be forwarded."
              REFERENCE
                      "IEEE 802.1D-1990: Section 6.7.2"



Decker, Langille, Rijsinghani & McCloghrie                     [Page 28]

RFC 1493                       Bridge MIB                      July 1993


              INDEX   { dot1dStaticAddress, dot1dStaticReceivePort }
              ::= { dot1dStaticTable 1 }

          Dot1dStaticEntry ::=
              SEQUENCE {
                  dot1dStaticAddress
                      MacAddress,
                  dot1dStaticReceivePort
                      INTEGER,
                  dot1dStaticAllowedToGoTo
                      OCTET STRING,
                  dot1dStaticStatus
                      INTEGER
              }

          dot1dStaticAddress OBJECT-TYPE
              SYNTAX  MacAddress
              ACCESS  read-write
              STATUS  mandatory
              DESCRIPTION
                      "The destination MAC address in a frame to which
                      this entry's filtering information applies.  This
                      object can take the value of a unicast address, a
                      group address or the broadcast address."
              REFERENCE
                      "IEEE 802.1D-1990: Section 3.9.1, 3.9.2"
              ::= { dot1dStaticEntry 1 }

          dot1dStaticReceivePort OBJECT-TYPE
              SYNTAX  INTEGER
              ACCESS  read-write
              STATUS  mandatory
              DESCRIPTION
                      "Either the value '0', or the port number of the
                      port from which a frame must be received in order
                      for this entry's filtering information to apply.
                      A value of zero indicates that this entry applies
                      on all ports of the bridge for which there is no
                      other applicable entry."
              ::= { dot1dStaticEntry 2 }

          dot1dStaticAllowedToGoTo OBJECT-TYPE
              SYNTAX  OCTET STRING
              ACCESS  read-write
              STATUS  mandatory
              DESCRIPTION
                      "The set of ports to which frames received from a
                      specific port and destined for a specific MAC



Decker, Langille, Rijsinghani & McCloghrie                     [Page 29]

RFC 1493                       Bridge MIB                      July 1993


                      address, are allowed to be forwarded.  Each octet
                      within the value of this object specifies a set of
                      eight ports, with the first octet specifying ports
                      1 through 8, the second octet specifying ports 9
                      through 16, etc.  Within each octet, the most
                      significant bit represents the lowest numbered
                      port, and the least significant bit represents the
                      highest numbered port.  Thus, each port of the
                      bridge is represented by a single bit within the
                      value of this object.  If that bit has a value of
                      '1' then that port is included in the set of
                      ports; the port is not included if its bit has a
                      value of '0'.  (Note that the setting of the bit
                      corresponding to the port from which a frame is
                      received is irrelevant.)  The default value of
                      this object is a string of ones of appropriate
                      length."
              ::= { dot1dStaticEntry 3 }

          dot1dStaticStatus OBJECT-TYPE
              SYNTAX  INTEGER {
                          other(1),
                          invalid(2),
                          permanent(3),
                          deleteOnReset(4),
                          deleteOnTimeout(5)
                      }
              ACCESS  read-write
              STATUS  mandatory
              DESCRIPTION
                      "This object indicates the status of this entry.
                      The default value is permanent(3).

                           other(1) - this entry is currently in use but
                                the conditions under which it will
                                remain so are different from each of the
                                following values.
                           invalid(2) - writing this value to the object
                                removes the corresponding entry.
                           permanent(3) - this entry is currently in use
                                and will remain so after the next reset
                                of the bridge.
                           deleteOnReset(4) - this entry is currently in
                                use and will remain so until the next
                                reset of the bridge.
                           deleteOnTimeout(5) - this entry is currently
                                in use and will remain so until it is
                                aged out."



Decker, Langille, Rijsinghani & McCloghrie                     [Page 30]

RFC 1493                       Bridge MIB                      July 1993


              ::= { dot1dStaticEntry 4 }


          -- Traps for use by Bridges

          -- Traps for the Spanning Tree Protocol

          newRoot TRAP-TYPE
              ENTERPRISE  dot1dBridge
              DESCRIPTION
                      "The newRoot trap indicates that the sending agent
                      has become the new root of the Spanning Tree; the
                      trap is sent by a bridge soon after its election
                      as the new root, e.g., upon expiration of the
                      Topology Change Timer immediately subsequent to
                      its election.  Implementation of this trap is
                      optional."
              ::= 1

          topologyChange TRAP-TYPE
              ENTERPRISE  dot1dBridge
              DESCRIPTION
                      "A topologyChange trap is sent by a bridge when
                      any of its configured ports transitions from the
                      Learning state to the Forwarding state, or from
                      the Forwarding state to the Blocking state.  The
                      trap is not sent if a newRoot trap is sent for the
                      same transition.  Implementation of this trap is
                      optional."
              ::= 2

          END

6.  Acknowledgments

   This document was produced on behalf of the Bridge Sub-Working Group
   of the SNMP Working Group of the Internet Engineering Task Force.
   Over the course of its deliberations, the working group received four
   separate documents for consideration as the basis for its work.  The
   first was submitted by Stan Froyd of Advanced Computer
   Communications; the second by Richard Fox of SynOptics; the third by
   Eric Decker of cisco Inc. and Keith McCloghrie of Hughes LAN Systems;
   and the fourth by Paul Langille and Anil Rijsinghani of Digital
   Equipment Corp. After considering the submissions, the working group
   chose to proceed with a document formed as a conjunction of the
   latter two submissions.  This document is the result.





Decker, Langille, Rijsinghani & McCloghrie                     [Page 31]

RFC 1493                       Bridge MIB                      July 1993


   The authors wish to thank the members of the Bridge Working Group for
   their many comments and suggestions which improved this effort. In
   particular, Fred Baker (chairman of the working group) of ACC, Steve
   Sherry of Xyplex, and Frank Kastenholz of Clearpoint Research Corp.
   Others members of the Bridge Working Group who contributed to this
   effort are:

               Bill Anderson, Mitre
               Karl Auerbach, Epilogue
               Fred Baker, ACC (chair)
               Terry Bradley, Wellfleet
               Ted Brunner, Bellcore
               Jeffrey Buffum, Apollo
               Chris ChioTasso, Fibronics
               Anthony Chung, HLS
               Chuck Davin, MIT-LCS
               Andy Davis, Spider
               Eric Decker, cisco
               Nadya El-Afandi, Network Systems
               Gary Ellis,HP/Apollo
               Richard Fox, SynOptics
               Stan Froyd, ACC
               Frank Kastenholz, Clearpoint Research
               Shirnshon Kaufman,
               Jim Kinder, Fibercom
               Cheryl Krupczak,NCR
               Paul Langille, Digital
               Peter Lin,Vitalink
               Keith McCloghrie, HLS
               Donna McMaster, SynOptics
               Dave Perkins, 3Com
               Jim Reinstedler, Ungermann Bass
               Anil Rijsinghani, Digital
               Mark Schaefer, David Systems
               Steve Sherry, Xyplex
               Bob Stewart, Xyplex
               Emil Sturniolo,
               Kevin Synott, Retix
               Ian Thomas, Chipcom
               Maurice Turcott, Racal
               Fei Xu,










Decker, Langille, Rijsinghani & McCloghrie                     [Page 32]

RFC 1493                       Bridge MIB                      July 1993


7.  References

   [1] Cerf, V., "IAB Recommendations for the Development of Internet
       Network Management Standards", RFC 1052, NRI, April 1988.

   [2] Cerf, V., "Report of the Second Ad Hoc Network Management Review
       Group", RFC 1109, NRI, August 1989.

   [3] Rose M., and K. McCloghrie, "Structure and Identification of
       Management Information for TCP/IP-based internets", STD 16, RFC
       1155, Performance Systems International, Hughes LAN Systems, May
       1990.

   [4] Case, J., Fedor, M., Schoffstall, M., and J. Davin, "Simple
       Network Management Protocol", STD 15, RFC 1157, SNMP Research,
       Performance Systems International, Performance Systems
       International, MIT Laboratory for Computer Science, May 1990.

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

   [6] Information processing systems - Open Systems Interconnection -
       Specification of Abstract Syntax Notation One (ASN.1),
       International Organization for Standardization, International
       Standard 8824, December 1987.

   [7] Information processing systems - Open Systems Interconnection -
       Specification of Basic Encoding Rules for Abstract Notation One
       (ASN.1), International Organization for Standardization,
       International Standard 8825, December 1987.

   [8] Rose, M., and K. McCloghrie, Editors, "Concise MIB Definitions",
       STD 16, RFC 1212, Performance Systems International, Hughes LAN
       Systems, March 1991.

   [9] Rose, M., Editor, "A Convention for Defining Traps for use with
       the SNMP", RFC 1215, Performance Systems International, March
       1991.

  [10] ANSI/IEEE Standard 802.1D-1990 MAC Bridges, IEEE Project 802
       Local and Metropolitan Area Networks, (March 8, 1991).

  [11] ISO DIS 10038 MAC Bridges.

8.  Security Considerations

   Security issues are not discussed in this memo.



Decker, Langille, Rijsinghani & McCloghrie                     [Page 33]

RFC 1493                       Bridge MIB                      July 1993


9.  Authors' Addresses

   Eric B. Decker
   cisco Systems, Inc.
   1525 O'Brien Dr.
   Menlo Park, CA  94025

   Phone: (415) 326-1941
   Email: cire@cisco.com


   Paul Langille
   Digital Equipment Corporation
   Digital Drive, MK02-2/K03
   Merrimack, NH 03054

   Phone: (603) 884-4045
   EMail: langille@edwin.enet.dec.com


   Anil Rijsinghani
   Digital Equipment Corporation
   550 King Street
   Littleton, MA 01460

   Phone: (508) 486-6786
   EMail: anil@levers.enet.dec.com


   Keith McCloghrie
   Hughes LAN Systems, Inc.
   1225 Charleston Road
   Mountain View, CA 94043

   Phone: (415) 966-7934
   EMail: kzm@hls.com















Decker, Langille, Rijsinghani & McCloghrie                     [Page 34]
