📄 rfc1493.txt
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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
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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.
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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.
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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).
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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 }
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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
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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
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