Network Working Group K. Norseth, Ed.

Network Working Group K. Norseth, Ed.
Request for Comments: 4188 L-3 Communications
Obsoletes: 1493 E. Bell, Ed.
Category: Standards Track 3Com Europe Limited
September 2005

Definitions of Managed Objects for Bridges

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 (2005).

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-1998 standard between Local Area Network (LAN)
segments. Provisions are made for the support of transparent
bridging. Provisions are also made so that these objects apply to
bridges connected by subnetworks other than LAN segments.

The MIB module presented in this memo is a translation of the
BRIDGE-MIB defined in RFC 1493 to the SMIv2 syntax.

This memo obsoletes RFC 1493.

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Table of Contents

1. The Internet-Standard Management Framework ......................2
2. Conventions .....................................................2
3. Overview ........................................................3
3.1. Structure of the MIB Module ................................3
3.1.1. The dot1dBase Subtree ...............................6
3.1.2. The dot1dStp Subtree ................................6
3.1.3. The dot1dSr Subtree .................................6
3.1.4. The dot1dTp Subtree .................................6
3.1.5. The dot1dStatic Subtree .............................6
3.2. Relationship to Other MIB Modules ..........................6
3.2.1. Relationship to the SNMPv2-MIB ......................7
3.2.2. Relationship to the IF-MIB ..........................7
4. Definitions .....................................................8
5. IANA Considerations ............................................39
6. Security Considerations ........................................39
7. Acknowledgements ...............................................40
8. Contact Information ............................................41
9. Changes from RFC 1493 ..........................................42
10. References ....................................................42
10.1. Normative References .....................................42
10.2. Informative References ...................................43

1. The Internet-Standard Management Framework

For a detailed overview of the documents that describe the current
Internet-Standard Management Framework, please refer to section 7 of
RFC 3410 [RFC3410].

Managed objects are accessed via a virtual information store, termed
the Management Information Base or MIB. MIB objects are generally
accessed through the Simple Network Management Protocol (SNMP).
Objects in the MIB are defined using the mechanisms defined in the
Structure of Management Information (SMI). This memo specifies a MIB
module that is compliant to the SMIv2, which is described in STD 58,
RFC 2578 [RFC2578], STD 58, RFC 2579 [RFC2579] and STD 58, RFC 2580
[RFC2580].

2. Conventions

The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
"OPTIONAL", when they appear in this document, are to be interpreted
as described in BCP 14, RFC 2119 [RFC2119].

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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
IEEE 802.1D specification [IEEE8021D]. This memo defines those
objects needed for the management of a bridging entity that operates
in the transparent mode, as well as some objects that apply to all
types of bridges.

To be consistent with IAB directives and good engineering practices,
an explicit attempt was made to keep this MIB module 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 that objects be essential for either fault or
configuration management.

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

4. Limit the total number of objects.

5. Exclude objects that are simply derivable from others in this or
other MIB modules.

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 the MIB Module

Objects in this MIB module are arranged into subtrees. Each subtree
is organized as a set of related objects. The overall structure and
assignment of objects to their subtrees is shown below. Where
appropriate, the corresponding IEEE 802.1D [IEEE8021D] management
object name is also included.

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RFC 4188 Bridge MIB September 2005

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

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dot1dTp
LearnedEntryDiscards BridgeFilter.DatabaseSize
.NumDynamic,NumStatic
AgingTime BridgeFilter.AgingTime
FdbTable
Address
Port
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 module for the indicated reasons.

IEEE 802.1D Object Disposition

Bridge.BridgeName Same as sysDescr (SNMPv2-MIB)
Bridge.BridgeUpTime Same as sysUpTime (SNMPv2-MIB)
Bridge.PortAddresses Same as ifPhysAddress (IF-MIB)
BridgePort.PortName Same as ifDescr (IF-MIB)
BridgePort.PortType Same as ifType (IF-MIB)
BridgePort.RoutingType Derivable from the implemented
subtrees

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

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

3.1.1 The dot1dBase Subtree

This subtree contains the objects that are applicable to all types of
bridges.

3.1.2 The dot1dStp Subtree

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

3.1.3 The dot1dSr Subtree

This subtree contains the objects that describe the entity's state
with respect to source route bridging. This subtree described in RFC
1525 [RFC1525] is applicable only to source route bridging.

3.1.4 The dot1dTp Subtree

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

3.1.5 The dot1dStatic Subtree

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

3.2 Relationship to Other MIB Modules

As described above, some IEEE 802.1D management objects have not been
included in this MIB module because they overlap with objects in
other MIB modules that are applicable to a bridge implementing this
MIB module.

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3.2.1 Relationship to the SNMPv2-MIB

The SNMPv2-MIB [RFC3418] defines objects that are generally
applicable to managed devices. These objects apply to the device as
a whole, irrespective of whether the device's sole functionality is
bridging, or whether bridging is only a subset of the device's
functionality.

As explained in Section 3.1, full support for the 802.1D management
objects requires that the SNMPv2-MIB objects sysDescr and sysUpTime
be implemented. Note that compliance with the current SNMPv2-MIB
module requires additional objects and notifications to be
implemented, as specified in RFC 3418 [RFC3418].

3.2.2 Relationship to the IF-MIB

The IF-MIB [RFC2863] defines managed objects for managing network
interfaces. A network 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.

As explained in Section 3.1, full support for the 802.1D management
objects requires that the IF-MIB objects ifIndex, ifType, ifDescr,
ifPhysAddress, and ifLastChange are implemented. Note that
compliance to the current IF-MIB module requires additional objects
and notifications to be implemented as specified in RFC 2863
[RFC2863].

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'
subtree, 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 that are 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).

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Some entities perform other functionalities 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 that
exclusively performs bridging, all protocols would be considered as
bridged, whereas in an entity that performs IP routing on IP
datagrams and only bridges other protocols, only the non-IP data
would be considered as having been bridged.

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

4. Definitions

BRIDGE-MIB DEFINITIONS ::= BEGIN

-- ---------------------------------------------------------- --
-- MIB for IEEE 802.1D devices
-- ---------------------------------------------------------- --
IMPORTS
MODULE-IDENTITY, OBJECT-TYPE, NOTIFICATION-TYPE,
Counter32, Integer32, TimeTicks, mib-2
FROM SNMPv2-SMI
TEXTUAL-CONVENTION, MacAddress
FROM SNMPv2-TC
MODULE-COMPLIANCE, OBJECT-GROUP, NOTIFICATION-GROUP
FROM SNMPv2-CONF
InterfaceIndex FROM IF-MIB
;

dot1dBridge MODULE-IDENTITY
LAST-UPDATED "200509190000Z"
ORGANIZATION "IETF Bridge MIB Working Group"
CONTACT-INFO
"Email: [email protected]

K.C. Norseth (Editor)
L-3 Communications
Tel: +1 801-594-2809
Email: [email protected]
Postal: 640 N. 2200 West.
Salt Lake City, Utah 84116-0850

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RFC 4188 Bridge MIB September 2005

Les Bell (Editor)
3Com Europe Limited
Phone: +44 1442 438025
Email: [email protected]
Postal: 3Com Centre, Boundary Way
Hemel Hempstead
Herts. HP2 7YU
UK

Send comments to <[email protected]>"
DESCRIPTION
"The Bridge MIB module for managing devices that support
IEEE 802.1D.

Copyright (C) The Internet Society (2005). This version of
this MIB module is part of RFC 4188; see the RFC itself for
full legal notices."
REVISION "200509190000Z"
DESCRIPTION
"Third revision, published as part of RFC 4188.

The MIB module has been converted to SMIv2 format.
Conformance statements have been added and some
description and reference clauses have been updated.

The object dot1dStpPortPathCost32 was added to
support IEEE 802.1t and the permissible values of
dot1dStpPriority and dot1dStpPortPriority have been
clarified for bridges supporting IEEE 802.1t or
IEEE 802.1w.

The interpretation of dot1dStpTimeSinceTopologyChange
has been clarified for bridges supporting the Rapid
Spanning Tree Protocol (RSTP)."
REVISION "199307310000Z"
DESCRIPTION
"Second revision, published as part of RFC 1493."
REVISION "199112310000Z"
DESCRIPTION
"Initial revision, published as part of RFC 1286."
::= { mib-2 17 }

-- ---------------------------------------------------------- --
-- Textual Conventions
-- ---------------------------------------------------------- --

BridgeId ::= TEXTUAL-CONVENTION

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STATUS current
DESCRIPTION
"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)."
SYNTAX OCTET STRING (SIZE (8))

Timeout ::= TEXTUAL-CONVENTION
DISPLAY-HINT "d"
STATUS current
DESCRIPTION
"A Spanning Tree Protocol (STP) timer in units of 1/100
seconds. 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
hundredths 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-1998 specifies a settable granularity of no more
than one second for these timers. To avoid ambiguity,
a conversion algorithm is defined below for converting
between the different units, which ensures a timer's
value is not distorted by multiple conversions.

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 nonzero]
n is the value in 1/100 second units

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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)."
SYNTAX Integer32

-- ---------------------------------------------------------- --
-- subtrees in the Bridge MIB
-- ---------------------------------------------------------- --

dot1dNotifications OBJECT IDENTIFIER ::= { dot1dBridge 0 }

dot1dBase OBJECT IDENTIFIER ::= { dot1dBridge 1 }
dot1dStp OBJECT IDENTIFIER ::= { dot1dBridge 2 }

dot1dSr OBJECT IDENTIFIER ::= { dot1dBridge 3 }
-- documented in RFC 1525

dot1dTp OBJECT IDENTIFIER ::= { dot1dBridge 4 }
dot1dStatic OBJECT IDENTIFIER ::= { dot1dBridge 5 }

-- Subtrees used by Bridge MIB Extensions:
-- pBridgeMIB MODULE-IDENTITY ::= { dot1dBridge 6 }
-- qBridgeMIB MODULE-IDENTITY ::= { dot1dBridge 7 }
-- Note that the practice of registering related MIB modules
-- below dot1dBridge has been discouraged since there is no
-- robust mechanism to track such registrations.

dot1dConformance OBJECT IDENTIFIER ::= { dot1dBridge 8 }

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

dot1dBaseBridgeAddress OBJECT-TYPE

SYNTAX MacAddress
MAX-ACCESS read-only
STATUS current
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

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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-1998: clauses 14.4.1.1.3 and 7.12.5"
::= { dot1dBase 1 }

dot1dBaseNumPorts OBJECT-TYPE
SYNTAX Integer32
UNITS "ports"
MAX-ACCESS read-only
STATUS current
DESCRIPTION
"The number of ports controlled by this bridging
entity."
REFERENCE
"IEEE 802.1D-1998: clause 14.4.1.1.3"
::= { dot1dBase 2 }

dot1dBaseType OBJECT-TYPE
SYNTAX INTEGER {
unknown(1),
transparent-only(2),
sourceroute-only(3),
srt(4)
}
MAX-ACCESS read-only
STATUS current
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
MAX-ACCESS not-accessible
STATUS current
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 }

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dot1dBasePortEntry OBJECT-TYPE
SYNTAX Dot1dBasePortEntry
MAX-ACCESS not-accessible
STATUS current

DESCRIPTION
"A list of information for each port of the bridge."
REFERENCE
"IEEE 802.1D-1998: clause 14.4.2, 14.6.1"
INDEX { dot1dBasePort }
::= { dot1dBasePortTable 1 }

Dot1dBasePortEntry ::=
SEQUENCE {
dot1dBasePort
Integer32,
dot1dBasePortIfIndex
InterfaceIndex,
dot1dBasePortCircuit
OBJECT IDENTIFIER,
dot1dBasePortDelayExceededDiscards
Counter32,
dot1dBasePortMtuExceededDiscards
Counter32
}

dot1dBasePort OBJECT-TYPE
SYNTAX Integer32 (1..65535)
MAX-ACCESS read-only
STATUS current
DESCRIPTION
"The port number of the port for which this entry
contains bridge management information."
::= { dot1dBasePortEntry 1 }

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

dot1dBasePortCircuit OBJECT-TYPE
SYNTAX OBJECT IDENTIFIER
MAX-ACCESS read-only

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STATUS current
DESCRIPTION
"For a port that (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 Counter32
MAX-ACCESS read-only
STATUS current
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-1998: clause 14.6.1.1.3"
::= { dot1dBasePortEntry 4 }

dot1dBasePortMtuExceededDiscards OBJECT-TYPE
SYNTAX Counter32
MAX-ACCESS read-only
STATUS current
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-1998: clause 14.6.1.1.3"
::= { dot1dBasePortEntry 5 }

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

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dot1dStpProtocolSpecification OBJECT-TYPE
SYNTAX INTEGER {
unknown(1),
decLb100(2),
ieee8021d(3)
}
MAX-ACCESS read-only
STATUS current
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
that are incompatible with the current version
are released a new value will be defined."
::= { dot1dStp 1 }

dot1dStpPriority OBJECT-TYPE
SYNTAX Integer32 (0..65535)
MAX-ACCESS read-write
STATUS current
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.
On bridges supporting IEEE 802.1t or IEEE 802.1w,
permissible values are 0-61440, in steps of 4096."
REFERENCE
"IEEE 802.1D-1998 clause 8.10.2, Table 8-4,
IEEE 802.1t clause 8.10.2, Table 8-4, clause 14.3."
::= { dot1dStp 2 }

dot1dStpTimeSinceTopologyChange OBJECT-TYPE
SYNTAX TimeTicks
UNITS "centi-seconds"
MAX-ACCESS read-only
STATUS current
DESCRIPTION
"The time (in hundredths of a second) since the
last time a topology change was detected by the
bridge entity.
For RSTP, this reports the time since the tcWhile
timer for any port on this Bridge was nonzero."
REFERENCE
"IEEE 802.1D-1998 clause 14.8.1.1.,
IEEE 802.1w clause 14.8.1.1."

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::= { dot1dStp 3 }

dot1dStpTopChanges OBJECT-TYPE
SYNTAX Counter32
MAX-ACCESS read-only
STATUS current
DESCRIPTION
"The total number of topology changes detected by
this bridge since the management entity was last
reset or initialized."
REFERENCE
"IEEE 802.1D-1998 clause 14.8.1.1."
::= { dot1dStp 4 }

dot1dStpDesignatedRoot OBJECT-TYPE
SYNTAX BridgeId
MAX-ACCESS read-only
STATUS current
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
the Root Identifier parameter in all Configuration
Bridge PDUs originated by this node."
REFERENCE
"IEEE 802.1D-1998: clause 8.5.3.1"
::= { dot1dStp 5 }

dot1dStpRootCost OBJECT-TYPE
SYNTAX Integer32
MAX-ACCESS read-only
STATUS current
DESCRIPTION
"The cost of the path to the root as seen from
this bridge."
REFERENCE
"IEEE 802.1D-1998: clause 8.5.3.2"
::= { dot1dStp 6 }

dot1dStpRootPort OBJECT-TYPE
SYNTAX Integer32
MAX-ACCESS read-only
STATUS current
DESCRIPTION
"The port number of the port that offers the lowest
cost path from this bridge to the root bridge."
REFERENCE
"IEEE 802.1D-1998: clause 8.5.3.3"

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::= { dot1dStp 7 }

dot1dStpMaxAge OBJECT-TYPE
SYNTAX Timeout
UNITS "centi-seconds"
MAX-ACCESS read-only
STATUS current
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-1998: clause 8.5.3.4"
::= { dot1dStp 8 }

dot1dStpHelloTime OBJECT-TYPE
SYNTAX Timeout
UNITS "centi-seconds"
MAX-ACCESS read-only
STATUS current
DESCRIPTION
"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-1998: clause 8.5.3.5"
::= { dot1dStp 9 }

dot1dStpHoldTime OBJECT-TYPE
SYNTAX Integer32
UNITS "centi-seconds"
MAX-ACCESS read-only
STATUS current
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-1998: clause 8.5.3.14"
::= { dot1dStp 10 }

dot1dStpForwardDelay OBJECT-TYPE
SYNTAX Timeout
UNITS "centi-seconds"

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MAX-ACCESS read-only
STATUS current
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-1998: clause 8.5.3.6"
::= { dot1dStp 11 }

dot1dStpBridgeMaxAge OBJECT-TYPE
SYNTAX Timeout (600..4000)
UNITS "centi-seconds"
MAX-ACCESS read-write
STATUS current
DESCRIPTION
"The value that all bridges use for MaxAge when this
bridge is acting as the root. Note that 802.1D-1998
specifies that the range for this parameter is related
to the value of dot1dStpBridgeHelloTime. The
granularity of this timer is specified by 802.1D-1998 to
be 1 second. An agent may return a badValue error if a
set is attempted to a value that is not a whole number
of seconds."
REFERENCE
"IEEE 802.1D-1998: clause 8.5.3.8"
::= { dot1dStp 12 }

dot1dStpBridgeHelloTime OBJECT-TYPE
SYNTAX Timeout (100..1000)
UNITS "centi-seconds"
MAX-ACCESS read-write
STATUS current
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-1998 to be 1 second. An
agent may return a badValue error if a set is attempted

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to a value that is not a whole number of seconds."
REFERENCE
"IEEE 802.1D-1998: clause 8.5.3.9"
::= { dot1dStp 13 }

dot1dStpBridgeForwardDelay OBJECT-TYPE
SYNTAX Timeout (400..3000)
UNITS "centi-seconds"
MAX-ACCESS read-write
STATUS current
DESCRIPTION
"The value that all bridges use for ForwardDelay when
this bridge is acting as the root. Note that
802.1D-1998 specifies that the range for this parameter
is related to the value of dot1dStpBridgeMaxAge. The
granularity of this timer is specified by 802.1D-1998 to
be 1 second. An agent may return a badValue error if a
set is attempted to a value that is not a whole number
of seconds."
REFERENCE
"IEEE 802.1D-1998: clause 8.5.3.10"
::= { dot1dStp 14 }

-- ---------------------------------------------------------- --
-- The Spanning Tree Port Table
-- ---------------------------------------------------------- --

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

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

Dot1dStpPortEntry ::=
SEQUENCE {

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dot1dStpPort
Integer32,
dot1dStpPortPriority
Integer32,
dot1dStpPortState
INTEGER,
dot1dStpPortEnable
INTEGER,
dot1dStpPortPathCost
Integer32,
dot1dStpPortDesignatedRoot
BridgeId,
dot1dStpPortDesignatedCost
Integer32,
dot1dStpPortDesignatedBridge
BridgeId,
dot1dStpPortDesignatedPort
OCTET STRING,
dot1dStpPortForwardTransitions
Counter32,
dot1dStpPortPathCost32
Integer32
}

dot1dStpPort OBJECT-TYPE
SYNTAX Integer32 (1..65535)
MAX-ACCESS read-only
STATUS current
DESCRIPTION
"The port number of the port for which this entry
contains Spanning Tree Protocol management information."
REFERENCE
"IEEE 802.1D-1998: clause 14.8.2.1.2"
::= { dot1dStpPortEntry 1 }

dot1dStpPortPriority OBJECT-TYPE
SYNTAX Integer32 (0..255)
MAX-ACCESS read-write
STATUS current
DESCRIPTION
"The value of the priority field that 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.
On bridges supporting IEEE 802.1t or IEEE 802.1w,
permissible values are 0-240, in steps of 16."
REFERENCE
"IEEE 802.1D-1998 clause 8.10.2, Table 8-4,

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IEEE 802.1t clause 8.10.2, Table 8-4, clause 14.3."
::= { dot1dStpPortEntry 2 }

dot1dStpPortState OBJECT-TYPE
SYNTAX INTEGER {
disabled(1),
blocking(2),
listening(3),
learning(4),
forwarding(5),
broken(6)
}
MAX-ACCESS read-only
STATUS current
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 that are disabled (see dot1dStpPortEnable), this
object will have a value of disabled(1)."
REFERENCE
"IEEE 802.1D-1998: clause 8.5.5.2"
::= { dot1dStpPortEntry 3 }

dot1dStpPortEnable OBJECT-TYPE
SYNTAX INTEGER {
enabled(1),
disabled(2)
}
MAX-ACCESS read-write
STATUS current
DESCRIPTION
"The enabled/disabled status of the port."
REFERENCE
"IEEE 802.1D-1998: clause 8.5.5.2"
::= { dot1dStpPortEntry 4 }

dot1dStpPortPathCost OBJECT-TYPE
SYNTAX Integer32 (1..65535)
MAX-ACCESS read-write
STATUS current
DESCRIPTION
"The contribution of this port to the path cost of
paths towards the spanning tree root which include
this port. 802.1D-1998 recommends that the default
value of this parameter be in inverse proportion to

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the speed of the attached LAN.

New implementations should support dot1dStpPortPathCost32.
If the port path costs exceeds the maximum value of this
object then this object should report the maximum value,
namely 65535. Applications should try to read the
dot1dStpPortPathCost32 object if this object reports
the maximum value."
REFERENCE "IEEE 802.1D-1998: clause 8.5.5.3"
::= { dot1dStpPortEntry 5 }

dot1dStpPortDesignatedRoot OBJECT-TYPE
SYNTAX BridgeId
MAX-ACCESS read-only
STATUS current
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-1998: clause 8.5.5.4"
::= { dot1dStpPortEntry 6 }

dot1dStpPortDesignatedCost OBJECT-TYPE
SYNTAX Integer32
MAX-ACCESS read-only
STATUS current
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 bridge PDUs."
REFERENCE
"IEEE 802.1D-1998: clause 8.5.5.5"
::= { dot1dStpPortEntry 7 }

dot1dStpPortDesignatedBridge OBJECT-TYPE
SYNTAX BridgeId
MAX-ACCESS read-only
STATUS current
DESCRIPTION
"The Bridge Identifier of the bridge that this
port considers to be the Designated Bridge for
this port's segment."
REFERENCE
"IEEE 802.1D-1998: clause 8.5.5.6"
::= { dot1dStpPortEntry 8 }

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dot1dStpPortDesignatedPort OBJECT-TYPE
SYNTAX OCTET STRING (SIZE (2))
MAX-ACCESS read-only
STATUS current
DESCRIPTION
"The Port Identifier of the port on the Designated
Bridge for this port's segment."
REFERENCE
"IEEE 802.1D-1998: clause 8.5.5.7"
::= { dot1dStpPortEntry 9 }

dot1dStpPortForwardTransitions OBJECT-TYPE
SYNTAX Counter32
MAX-ACCESS read-only
STATUS current
DESCRIPTION
"The number of times this port has transitioned
from the Learning state to the Forwarding state."
::= { dot1dStpPortEntry 10 }

dot1dStpPortPathCost32 OBJECT-TYPE
SYNTAX Integer32 (1..200000000)
MAX-ACCESS read-write
STATUS current
DESCRIPTION
"The contribution of this port to the path cost of
paths towards the spanning tree root which include
this port. 802.1D-1998 recommends that the default
value of this parameter be in inverse proportion to
the speed of the attached LAN.

This object replaces dot1dStpPortPathCost to support
IEEE 802.1t."
REFERENCE
"IEEE 802.1t clause 8.10.2, Table 8-5."
::= { dot1dStpPortEntry 11 }

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

dot1dTpLearnedEntryDiscards OBJECT-TYPE
SYNTAX Counter32

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MAX-ACCESS read-only
STATUS current
DESCRIPTION
"The total number of Forwarding Database entries that
have been or would have been learned, but have been
discarded due to a lack of storage space in the
Forwarding Database. If this counter is increasing, it
indicates that the Forwarding Database is regularly
becoming full (a condition that 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-1998: clause 14.7.1.1.3"
::= { dot1dTp 1 }

dot1dTpAgingTime OBJECT-TYPE
SYNTAX Integer32 (10..1000000)
UNITS "seconds"
MAX-ACCESS read-write
STATUS current
DESCRIPTION
"The timeout period in seconds for aging out
dynamically-learned forwarding information.
802.1D-1998 recommends a default of 300 seconds."
REFERENCE
"IEEE 802.1D-1998: clause 14.7.1.1.3"
::= { dot1dTp 2 }

-- ---------------------------------------------------------- --
-- The Forwarding Database for Transparent Bridges
-- ---------------------------------------------------------- --

dot1dTpFdbTable OBJECT-TYPE
SYNTAX SEQUENCE OF Dot1dTpFdbEntry
MAX-ACCESS not-accessible
STATUS current
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

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SYNTAX Dot1dTpFdbEntry
MAX-ACCESS not-accessible
STATUS current
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
Integer32,
dot1dTpFdbStatus
INTEGER
}

dot1dTpFdbAddress OBJECT-TYPE
SYNTAX MacAddress
MAX-ACCESS read-only
STATUS current
DESCRIPTION
"A unicast MAC address for which the bridge has
forwarding and/or filtering information."
REFERENCE
"IEEE 802.1D-1998: clause 7.9.1, 7.9.2"
::= { dot1dTpFdbEntry 1 }

dot1dTpFdbPort OBJECT-TYPE
SYNTAX Integer32
MAX-ACCESS read-only
STATUS current
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 }

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dot1dTpFdbStatus OBJECT-TYPE
SYNTAX INTEGER {
other(1),
invalid(2),
learned(3),
self(4),
mgmt(5)
}
MAX-ACCESS read-only
STATUS current
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 no 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 }

-- ---------------------------------------------------------- --
-- Port Table for Transparent Bridges
-- ---------------------------------------------------------- --

dot1dTpPortTable OBJECT-TYPE
SYNTAX SEQUENCE OF Dot1dTpPortEntry
MAX-ACCESS not-accessible
STATUS current
DESCRIPTION
"A table that contains information about every port that
is associated with this transparent bridge."

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RFC 4188 Bridge MIB September 2005

::= { dot1dTp 4 }

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

Dot1dTpPortEntry ::=
SEQUENCE {
dot1dTpPort
Integer32,
dot1dTpPortMaxInfo
Integer32,
dot1dTpPortInFrames
Counter32,
dot1dTpPortOutFrames
Counter32,
dot1dTpPortInDiscards
Counter32
}

dot1dTpPort OBJECT-TYPE
SYNTAX Integer32 (1..65535)
MAX-ACCESS read-only
STATUS current
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
-- 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 Integer32
UNITS "bytes"
MAX-ACCESS read-only
STATUS current
DESCRIPTION
"The maximum size of the INFO (non-MAC) field that

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this port will receive or transmit."
::= { dot1dTpPortEntry 2 }

dot1dTpPortInFrames OBJECT-TYPE
SYNTAX Counter32
UNITS "frames"
MAX-ACCESS read-only
STATUS current
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-1998: clause 14.6.1.1.3"
::= { dot1dTpPortEntry 3 }

dot1dTpPortOutFrames OBJECT-TYPE
SYNTAX Counter32
UNITS "frames"
MAX-ACCESS read-only
STATUS current
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-1998: clause 14.6.1.1.3"
::= { dot1dTpPortEntry 4 }

dot1dTpPortInDiscards OBJECT-TYPE
SYNTAX Counter32
UNITS "frames"
MAX-ACCESS read-only
STATUS current
DESCRIPTION
"Count of received valid frames that were discarded
(i.e., filtered) by the Forwarding Process."
REFERENCE
"IEEE 802.1D-1998: clause 14.6.1.1.3"
::= { dot1dTpPortEntry 5 }

-- ---------------------------------------------------------- --

Norseth & Bell, Eds. Standards Track [Page 28]

RFC 4188 Bridge MIB September 2005

-- The Static (Destination-Address Filtering) Database
-- ---------------------------------------------------------- --
-- Implementation of this subtree is optional.
-- ---------------------------------------------------------- --

dot1dStaticTable OBJECT-TYPE
SYNTAX SEQUENCE OF Dot1dStaticEntry
MAX-ACCESS not-accessible
STATUS current
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-1998: clause 14.7.2"
::= { dot1dStatic 1 }

dot1dStaticEntry OBJECT-TYPE
SYNTAX Dot1dStaticEntry
MAX-ACCESS not-accessible
STATUS current
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-1998: clause 14.7.2"
INDEX { dot1dStaticAddress, dot1dStaticReceivePort }
::= { dot1dStaticTable 1 }

Dot1dStaticEntry ::=
SEQUENCE {
dot1dStaticAddress MacAddress,
dot1dStaticReceivePort Integer32,
dot1dStaticAllowedToGoTo OCTET STRING,
dot1dStaticStatus INTEGER
}

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RFC 4188 Bridge MIB September 2005

dot1dStaticAddress OBJECT-TYPE
SYNTAX MacAddress
MAX-ACCESS read-create
STATUS current
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-1998: clause 7.9.1, 7.9.2"
::= { dot1dStaticEntry 1 }

dot1dStaticReceivePort OBJECT-TYPE
SYNTAX Integer32 (0..65535)
MAX-ACCESS read-create
STATUS current
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 (SIZE (0..512))
MAX-ACCESS read-create
STATUS current
DESCRIPTION
"The set of ports to which frames received from a
specific port and destined for a specific MAC 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.

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RFC 4188 Bridge MIB September 2005

The value of this object may exceed the required minimum
maximum message size of some SNMP transport (484 bytes,
in the case of SNMP over UDP, see RFC 3417, section 3.2).
SNMP engines on bridges supporting a large number of
ports must support appropriate maximum message sizes."
::= { dot1dStaticEntry 3 }

dot1dStaticStatus OBJECT-TYPE
SYNTAX INTEGER {
other(1),
invalid(2),
permanent(3),
deleteOnReset(4),
deleteOnTimeout(5)
}
MAX-ACCESS read-create
STATUS current
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."
::= { dot1dStaticEntry 4 }

-- ---------------------------------------------------------- --
-- Notifications for use by Bridges
-- ---------------------------------------------------------- --
-- Notifications for the Spanning Tree Protocol
-- ---------------------------------------------------------- --

newRoot NOTIFICATION-TYPE
-- OBJECTS { }
STATUS current
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

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root, e.g., upon expiration of the Topology Change Timer,
immediately subsequent to its election. Implementation
of this trap is optional."
::= { dot1dNotifications 1 }

topologyChange NOTIFICATION-TYPE
-- OBJECTS { }
STATUS current
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."
::= { dot1dNotifications 2 }

-- ---------------------------------------------------------- --
-- IEEE 802.1D MIB - Conformance Information
-- ---------------------------------------------------------- --

dot1dGroups OBJECT IDENTIFIER ::= { dot1dConformance 1 }
dot1dCompliances OBJECT IDENTIFIER ::= { dot1dConformance 2 }

-- ---------------------------------------------------------- --
-- units of conformance
-- ---------------------------------------------------------- --

-- ---------------------------------------------------------- --
-- the dot1dBase group
-- ---------------------------------------------------------- --

dot1dBaseBridgeGroup OBJECT-GROUP
OBJECTS {
dot1dBaseBridgeAddress,
dot1dBaseNumPorts,
dot1dBaseType
}
STATUS current
DESCRIPTION
"Bridge level information for this device."
::= { dot1dGroups 1 }

dot1dBasePortGroup OBJECT-GROUP
OBJECTS {
dot1dBasePort,
dot1dBasePortIfIndex,
dot1dBasePortCircuit,

Norseth & Bell, Eds. Standards Track [Page 32]

RFC 4188 Bridge MIB September 2005

dot1dBasePortDelayExceededDiscards,
dot1dBasePortMtuExceededDiscards
}
STATUS current
DESCRIPTION
"Information for each port on this device."
::= { dot1dGroups 2 }

-- ---------------------------------------------------------- --
-- the dot1dStp group
-- ---------------------------------------------------------- --

dot1dStpBridgeGroup OBJECT-GROUP
OBJECTS {
dot1dStpProtocolSpecification,
dot1dStpPriority,
dot1dStpTimeSinceTopologyChange,
dot1dStpTopChanges,
dot1dStpDesignatedRoot,
dot1dStpRootCost,
dot1dStpRootPort,
dot1dStpMaxAge,
dot1dStpHelloTime,
dot1dStpHoldTime,
dot1dStpForwardDelay,
dot1dStpBridgeMaxAge,
dot1dStpBridgeHelloTime,
dot1dStpBridgeForwardDelay
}
STATUS current
DESCRIPTION
"Bridge level Spanning Tree data for this device."
::= { dot1dGroups 3 }

dot1dStpPortGroup OBJECT-GROUP
OBJECTS {
dot1dStpPort,
dot1dStpPortPriority,
dot1dStpPortState,
dot1dStpPortEnable,
dot1dStpPortPathCost,
dot1dStpPortDesignatedRoot,
dot1dStpPortDesignatedCost,
dot1dStpPortDesignatedBridge,
dot1dStpPortDesignatedPort,
dot1dStpPortForwardTransitions
}
STATUS current

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DESCRIPTION
"Spanning Tree data for each port on this device."
::= { dot1dGroups 4 }

dot1dStpPortGroup2 OBJECT-GROUP
OBJECTS {
dot1dStpPort,
dot1dStpPortPriority,
dot1dStpPortState,
dot1dStpPortEnable,
dot1dStpPortDesignatedRoot,
dot1dStpPortDesignatedCost,
dot1dStpPortDesignatedBridge,
dot1dStpPortDesignatedPort,
dot1dStpPortForwardTransitions,
dot1dStpPortPathCost32
}
STATUS current
DESCRIPTION
"Spanning Tree data for each port on this device."
::= { dot1dGroups 5 }

dot1dStpPortGroup3 OBJECT-GROUP
OBJECTS {
dot1dStpPortPathCost32
}
STATUS current
DESCRIPTION
"Spanning Tree data for devices supporting 32-bit
path costs."
::= { dot1dGroups 6 }

-- ---------------------------------------------------------- --
-- the dot1dTp group
-- ---------------------------------------------------------- --

dot1dTpBridgeGroup OBJECT-GROUP
OBJECTS {
dot1dTpLearnedEntryDiscards,
dot1dTpAgingTime
}
STATUS current
DESCRIPTION
"Bridge level Transparent Bridging data."
::= { dot1dGroups 7 }

dot1dTpFdbGroup OBJECT-GROUP
OBJECTS {

Norseth & Bell, Eds. Standards Track [Page 34]

RFC 4188 Bridge MIB September 2005

dot1dTpFdbAddress,
dot1dTpFdbPort,
dot1dTpFdbStatus
}

STATUS current
DESCRIPTION
"Filtering Database information for the Bridge."
::= { dot1dGroups 8 }

dot1dTpGroup OBJECT-GROUP
OBJECTS {
dot1dTpPort,
dot1dTpPortMaxInfo,
dot1dTpPortInFrames,
dot1dTpPortOutFrames,
dot1dTpPortInDiscards
}
STATUS current
DESCRIPTION
"Dynamic Filtering Database information for each port of
the Bridge."
::= { dot1dGroups 9 }

-- ---------------------------------------------------------- --
-- The Static (Destination-Address Filtering) Database
-- ---------------------------------------------------------- --

dot1dStaticGroup OBJECT-GROUP
OBJECTS {
dot1dStaticAddress,
dot1dStaticReceivePort,
dot1dStaticAllowedToGoTo,
dot1dStaticStatus
}
STATUS current
DESCRIPTION
"Static Filtering Database information for each port of
the Bridge."
::= { dot1dGroups 10 }

-- ---------------------------------------------------------- --
-- The Trap Notification Group
-- ---------------------------------------------------------- --

dot1dNotificationGroup NOTIFICATION-GROUP
NOTIFICATIONS {
newRoot,

Norseth & Bell, Eds. Standards Track [Page 35]

RFC 4188 Bridge MIB September 2005

topologyChange
}
STATUS current
DESCRIPTION
"Group of objects describing notifications (traps)."
::= { dot1dGroups 11 }

-- ---------------------------------------------------------- --
-- compliance statements
-- ---------------------------------------------------------- --

bridgeCompliance1493 MODULE-COMPLIANCE
STATUS current
DESCRIPTION
"The compliance statement for device support of bridging
services, as per RFC1493."

MODULE
MANDATORY-GROUPS {
dot1dBaseBridgeGroup,
dot1dBasePortGroup
}

GROUP dot1dStpBridgeGroup
DESCRIPTION
"Implementation of this group is mandatory for bridges
that support the Spanning Tree Protocol."

GROUP dot1dStpPortGroup
DESCRIPTION
"Implementation of this group is mandatory for bridges
that support the Spanning Tree Protocol."

GROUP dot1dTpBridgeGroup
DESCRIPTION
"Implementation of this group is mandatory for bridges
that support the transparent bridging mode. A
transparent or SRT bridge will implement this group."

GROUP dot1dTpFdbGroup
DESCRIPTION
"Implementation of this group is mandatory for bridges
that support the transparent bridging mode. A
transparent or SRT bridge will implement this group."

GROUP dot1dTpGroup
DESCRIPTION
"Implementation of this group is mandatory for bridges

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RFC 4188 Bridge MIB September 2005

that support the transparent bridging mode. A
transparent or SRT bridge will implement this group."

GROUP dot1dStaticGroup
DESCRIPTION
"Implementation of this group is optional."

GROUP dot1dNotificationGroup
DESCRIPTION
"Implementation of this group is optional."
::= { dot1dCompliances 1 }

bridgeCompliance4188 MODULE-COMPLIANCE
STATUS current
DESCRIPTION
"The compliance statement for device support of bridging
services. This supports 32-bit Path Cost values and the
more restricted bridge and port priorities, as per IEEE
802.1t.

Full support for the 802.1D management objects requires that
the SNMPv2-MIB [RFC3418] objects sysDescr, and sysUpTime, as
well as the IF-MIB [RFC2863] objects ifIndex, ifType,
ifDescr, ifPhysAddress, and ifLastChange are implemented."

MODULE
MANDATORY-GROUPS {
dot1dBaseBridgeGroup,
dot1dBasePortGroup
}

GROUP dot1dStpBridgeGroup
DESCRIPTION
"Implementation of this group is mandatory for
bridges that support the Spanning Tree Protocol."

OBJECT dot1dStpPriority
SYNTAX Integer32 (0|4096|8192|12288|16384|20480|24576
|28672|32768|36864|40960|45056|49152
|53248|57344|61440)
DESCRIPTION
"The possible values defined by IEEE 802.1t."

GROUP dot1dStpPortGroup2
DESCRIPTION
"Implementation of this group is mandatory for
bridges that support the Spanning Tree Protocol."

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RFC 4188 Bridge MIB September 2005

GROUP dot1dStpPortGroup3
DESCRIPTION
"Implementation of this group is mandatory for bridges
that support the Spanning Tree Protocol and 32-bit path
costs. In particular, this includes devices supporting
IEEE 802.1t and IEEE 802.1w."

OBJECT dot1dStpPortPriority
SYNTAX Integer32 (0|16|32|48|64|80|96|112|128
|144|160|176|192|208|224|240)
DESCRIPTION
"The possible values defined by IEEE 802.1t."

GROUP dot1dTpBridgeGroup
DESCRIPTION
"Implementation of this group is mandatory for
bridges that support the transparent bridging
mode. A transparent or SRT bridge will implement
this group."

GROUP dot1dTpFdbGroup
DESCRIPTION
"Implementation of this group is mandatory for
bridges that support the transparent bridging
mode. A transparent or SRT bridge will implement
this group."

GROUP dot1dTpGroup
DESCRIPTION
"Implementation of this group is mandatory for
bridges that support the transparent bridging
mode. A transparent or SRT bridge will implement
this group."

GROUP dot1dStaticGroup
DESCRIPTION
"Implementation of this group is optional."

GROUP dot1dNotificationGroup
DESCRIPTION
"Implementation of this group is optional."

::= { dot1dCompliances 2 }

END

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RFC 4188 Bridge MIB September 2005

5. IANA Considerations

The MIB module in this document uses the following IANA-assigned
OBJECT IDENTIFIER values that are recorded in the SMI Numbers
registry:

Descriptor OBJECT IDENTIFIER value
---------- -----------------------
dot1dBridge { mib-2 17 }

6. Security Considerations

There are a number of management objects defined in this MIB module
that have a MAX-ACCESS clause of read-write and/or read-create. Such
objects may be considered sensitive or vulnerable in some network
environments. The support for SET operations in a non-secure
environment without proper protection can have a negative effect on
network operations.

Some of the readable objects in this MIB module (i.e., objects with a
MAX-ACCESS other than not-accessible) may be considered sensitive or
vulnerable in some network environments. It is thus important to
control even GET and/or NOTIFY access to these objects and possibly
to even encrypt the values of these objects when sending them over
the network via SNMP.

These are the tables and objects and their sensitivity/vulnerability:

o The writable objects dot1dStpPriority, dot1dStpBridgeMaxAge,
dot1dStpBridgeHelloTime, dot1dStpBridgeForwardDelay,
dot1dStpPortPriority, dot1dStpPortEnable, dot1dStpPortPathCost,
and dot1dStpPortPathCost32 influence the spanning tree protocol.
Unauthorized write access to these objects can cause the spanning
tree protocol to compute other default topologies or it can change
the speed in which the spanning tree protocol reacts to failures.

o The writable object dot1dTpAgingTime controls how fast
dynamically-learned forwarding information is aged out. Setting
this object to a large value may simplify forwarding table
overflow attacks.

o The writable dot1dStaticTable provides a filtering mechanism
controlling to which ports frames originating from a specific
source may be forwarded. Write access to this table can be used
to turn provisioned filtering off or to add filters to prevent
rightful use of the network.

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RFC 4188 Bridge MIB September 2005

o The readable objects defined in the BRIDGE-MIB module provide
information about the topology of a bridged network and the
attached active stations. The addresses listed in the
dot1dTpFdbTable usually reveal information about the manufacturer
of the MAC hardware, which can be useful information for mounting
other specific attacks.

o The two notifications newRoot and topologyChange are emitted
during spanning tree computation and may trigger management
systems to inspect the status of bridges and to recompute internal
topology information. Hence, forged notifications may cause
management systems to perform unnecessary computations and to
generate additional SNMP traffic directed to the bridges in a
network. Therefore, forged notifications may be part of a denial
of service attack.

SNMP versions prior to SNMPv3 did not include adequate security.
Even if the network itself is secure (for example by using IPSec),
even then, there is no control as to who on the secure network is
allowed to access and GET/SET (read/change/create/delete) the objects
in this MIB module.

It is RECOMMENDED that implementers consider the security features as
provided by the SNMPv3 framework (see [RFC3410], section 8),
including full support for the SNMPv3 cryptographic mechanisms (for
authentication and privacy).

Further, deployment of SNMP versions prior to SNMPv3 is NOT
RECOMMENDED. Instead, it is RECOMMENDED to deploy SNMPv3 and to
enable cryptographic security. It is then a customer/operator
responsibility to ensure that the SNMP entity giving access to an
instance of this MIB module is properly configured to give access to
the objects only to those principals (users) that have legitimate
rights to indeed GET or SET (change/create/delete) them.

7. Acknowledgements

The MIB module presented in this memo is a translation of the
BRIDGE-MIB defined in [RFC1493] to the SMIv2 syntax. The original
authors of the SMIv1 module were E. Decker, P. Langille, A.
Rijsinghani, and K. McCloghrie. Further acknowledgement is given to
the members of the original Bridge Working Group in [RFC1493].

This document was produced on behalf of the Bridge MIB Working Group
in the Operations and Management area of the Internet Engineering
Task Force. The editors wish to thank the members of the Bridge MIB
Working Group, especially Mike MacFadden, John Flick, and Bert
Visscher for their many comments and suggestions that improved this

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RFC 4188 Bridge MIB September 2005

effort. Juergen Schoenwaelder helped in finalizing the document for
publication.

8. Contact Information

The original version of this document was the result of significant
work by four major contributors:

E. Decker

P. Langille

A. Rijsinghan
Accton Technology Corporation
5 Mount Royal Ave
Marlboro, MA 01752
USA

K. McCloghrie
Cisco Systems, Inc.
170 West Tasman Drive
San Jose, CA 95134
USA

The conversion to the SMIv2 format is based on work done by the
following two contributors:

Kenyon C. Norseth
L-3 Communications
640 N. 2200 West
Salt Lake City, Utah 84116-0850
USA

E. Bell
3Com Europe Limited
3Com Centre, Boundary Way
Hemel Hempstead Herts. HP2 7YU
UK

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RFC 4188 Bridge MIB September 2005

9. Changes from RFC 1493

The following changes have been made from RFC 1493.

1. Translated the MIB definitions to use SMIv2. This includes the
introduction of conformance statements. ASN.1 type definitions
have been converted into textual-conventions and several UNITS
clauses were added.

2. The object dot1dStpPortPathCost32 was added to support IEEE
802.1t.

3. Permissible values for dot1dStpPriority and dot1dStpPortPriority
have been clarified for bridges supporting IEEE 802.1t or IEEE
802.1w.

4. Interpretation of dot1dStpTimeSinceTopologyChange has been
clarified for bridges supporting the rapid spanning tree protocol
(RSTP).

5. Updated the introductory boilerplate text, the security
considerations section, and the references to comply with the
current IETF standards and guidelines.

6. Updated references to point to newer IEEE 802.1d documents.

7. Additions and clarifications in various description clauses.

10. References

10.1 Normative References

[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.

[RFC2578] McCloghrie, K., Perkins, D., and J. Schoenwaelder,
"Structure of Management Information Version 2 (SMIv2)",
STD 58, RFC 2578, April 1999.

[RFC2579] McCloghrie, K., Perkins, D., and J. Schoenwaelder,
"Textual Conventions for SMIv2", STD 58, RFC 2579, April
1999.

[RFC2580] McCloghrie, K., Perkins, D., and J. Schoenwaelder,
"Conformance Statements for SMIv2", STD 58, RFC 2580,
April 1999.

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RFC 4188 Bridge MIB September 2005

[RFC3418] Presuhn, R., "Management Information Base (MIB) for the
Simple Network Management Protocol (SNMP)", STD 62, RFC
3418, December 2002.

[RFC2863] McCloghrie, K. and F. Kastenholz, "The Interfaces Group
MIB", RFC 2863, June 2000.

[IEEE8021D] IEEE Project 802 Local and Metropolitan Area Networks,
"ANSI/IEEE Standard 802.1D-1998 MAC Bridges", March 1998.

10.2 Informative References

[RFC3410] Case, J., Mundy, R., Partain, D., and B. Stewart,
"Introduction and Applicability Statements for Internet-
Standard Management Framework", RFC 3410, December 2002.

[RFC1493] Decker, E., Langille, P., Rijsinghani, A., and K.
McCloghrie, "Definitions of Managed Objects for Bridges",
RFC 1493, July 1993.

[RFC1525] Decker, E., McCloghrie, K., Langille, P., and A.
Rijsinghani, "Definitions of Managed Objects for Source
Routing Bridges", RFC 1525, September 1993.

Authors' Addresses

Kenyon C. Norseth (editor)
L-3 Communications
640 N. 2200 West
Salt Lake City, Utah 84116-0850
USA

Phone: +1 801-594-2809
EMail: [email protected]

E. Bell (editor)
3Com Europe Limited
3Com Centre, Boundary Way
Hemel Hempstead Herts. HP2 7YU
UK

Phone: +44 1442 438025
EMail: [email protected]

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RFC 4188 Bridge MIB September 2005

Full Copyright Statement

Copyright (C) The Internet Society (2005).

This document is subject to the rights, licenses and restrictions
contained in BCP 78, and except as set forth therein, the authors
retain all their rights.

This document and the information contained herein are provided on an
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