RFC 2674
Definitions of Managed Objects for Bridges with Traffic Classes, Multicast Filtering and Virtual LAN Extensions
Network Working Group E. Bell Request for Comments: 2674 3Com Corp. Category: Standards Track A. Smith Extreme Networks P. Langille Newbridge Networks A. Rijhsinghani Cabletron Systems K. McCloghrie cisco Systems August 1999 Definitions of Managed Objects for Bridges with Traffic Classes, Multicast Filtering and Virtual LAN Extensions Status of this Memo This document specifies an Internet standards track protocol for the Internet community, and requests discussion and suggestions for improvements. Please refer to the current edition of the "Internet Official Protocol Standards" (STD 1) for the standardization state and status of this protocol. Distribution of this memo is unlimited. Copyright Notice Copyright (C) The Internet Society (1999). All Rights Reserved.Abstract
This memo defines a portion of the Management Information Base (MIB) for use with network management protocols in TCP/IP based internets. In particular, it defines two MIB modules for managing the new capabilities of MAC bridges defined by the IEEE 802.1D-1998 MAC Bridges and the IEEE 802.1Q-1998 Virtual LAN (VLAN) standards for bridging between Local Area Network (LAN) segments. One MIB module defines objects for managing the 'Traffic Classes' and 'Enhanced Multicast Filtering' components of IEEE 802.1D-1998. The other MIB module defines objects for managing IEEE 802.1Q VLANs. Provisions are made for support of transparent bridging. Provisions are also made so that these objects apply to bridges connected by subnetworks other than LAN segments. This memo also includes several MIB modules in a manner that is compliant to the SMIv2 [V2SMI]. This memo supplements RFC 1493 [BRIDGEMIB] and (to a lesser extent) RFC 1525 [SBRIDGEMIB].
Table of Contents
1 The SNMP Management Framework ................................... 3 2 Overview ........................................................ 4 2.1 Scope ......................................................... 4 3 Structure of MIBs ............................................... 5 3.1 Structure of Extended Bridge MIB module ....................... 5 3.1.1 Relationship to IEEE 802.1D-1998 Manageable Objects ......... 6 3.1.2 Relationship to IEEE 802.1Q Manageable Objects .............. 8 3.1.3 The dot1dExtBase Group ...................................... 8 3.1.4 The dot1dPriority Group ..................................... 9 3.1.5 The dot1dGarp Group ......................................... 9 3.1.6 The dot1dGmrp Group ......................................... 9 3.1.7 The dot1dTpHCPortTable ...................................... 9 3.1.8 The dot1dTpPortOverflowTable ................................ 9 3.2 Structure of Virtual Bridge MIB module ........................ 9 3.2.1 Relationship to IEEE 802.1Q Manageable Objects .............. 9 3.2.2 The dot1qBase Group .........................................13 3.2.3 The dot1qTp Group ...........................................13 3.2.4 The dot1qStatic Group .......................................13 3.2.5 The dot1qVlan Group .........................................13 3.3 Textual Conventions ...........................................13 3.4 Relationship to Other MIBs ....................................14 3.4.1 Relationship to the 'system' group ..........................14 3.4.2 Relation to Interfaces MIB ..................................14 3.4.2.1 Layering Model ............................................15 3.4.2.2 ifStackTable ..............................................16 3.4.2.3 ifRcvAddressTable .........................................16 3.4.3 Relation to Original Bridge MIB .............................16 3.4.3.1 The dot1dBase Group .......................................16 3.4.3.2 The dot1dStp Group ........................................17 3.4.3.3 The dot1dTp Group .........................................17 3.4.3.4 The dot1dStatic Group .....................................17 3.4.3.5 Additions to the Original Bridge MIB ......................18 4 Definitions for Extended Bridge MIB .............................18 5 Definitions for Virtual Bridge MIB ..............................39 6 Acknowledgments .................................................80 7 Security Considerations .........................................80 8 References ......................................................81 9 Authors' Addresses ..............................................84 10 Intellectual Property ..........................................85 11 Full Copyright Statement .......................................86
1. The SNMP Management Framework
The SNMP Management Framework presently consists of five major components: o An overall architecture, described in an Architecture for Describing SNMP Management Frameworks [ARCH]. o Mechanisms for describing and naming objects and events for the purpose of management. The first version of this Structure of Management Information (SMI) is called SMIv1 and described in STD 16, RFC 1155 [V1SMI], STD 16, RFC 1212 [V1CONCISE] and RFC 1215 [V1TRAPS]. The second version, called SMIv2, is described in STD 58, RFC 2578 [V2SMI], STD 58, RFC 2579 [V2TC] and STD 58, RFC 2580 [V2CONFORM]. o Message protocols for transferring management information. The first version of the SNMP message protocol is called SNMPv1 and described in STD 15, RFC 1157 [V1PROTO]. A second version of the SNMP message protocol, which is not an Internet standards track protocol, is called SNMPv2c and described in RFC 1901 [V2COMMUNITY] and RFC 1906 [V2TRANS]. The third version of the message protocol is called SNMPv3 and described in RFC 1906 [V2TRANS], Message Processing and Dispatching [V3MPC] and User- based Security Model [V3USM]. o Protocol operations for accessing management information. The first set of protocol operations and associated PDU formats is described in STD 15, RFC 1157 [V1PROTO]. A second set of protocol operations and associated PDU formats is described in RFC 1905 [V2PROTO]. o A set of fundamental applications described in SNMPv3 Applications [V3APPS] and the view-based access control mechanism described in View-based Access Control Model [V3VACM]. Managed objects are accessed via a virtual information store, termed the Management Information Base or MIB. Objects in the MIB are defined using the mechanisms defined in the SMI. This memo specifies a MIB module that is compliant to the SMIv2. A MIB conforming to the SMIv1 can be produced through the appropriate translations. The resulting translated MIB must be semantically equivalent, except where objects or events are omitted because no translation is possible (use of Counter64). Some machine readable information in SMIv2 will be converted into textual descriptions in
SMIv1 during the translation process. However, this loss of machine readable information is not considered to change the semantics of the MIB.2. Overview
A common device present in many networks is the Bridge. This device is used to connect Local Area Network segments below the network layer. These devices are often known as 'layer 2 switches'. There are two major modes defined for this bridging: Source-Route and transparent. Source-Route bridging is described by IEEE 802.5 [802.5]. and is not discussed further in this document. The transparent method of bridging is defined by IEEE 802.1D-1998 [802.1D] which is an update to the original IEEE 802.1D specification [802.1D-ORIG]. Managed objects for that original specification of transparent bridging were defined in RFC 1493 [BRIDGEMIB]. The original IEEE 802.1D is augmented by IEEE 802.1Q-1998 [802.1Q] to provide support for 'virtual bridged LANs' where a single bridged physical LAN network may be used to support multiple logical bridged LANs, each of which offers a service approximately the same as that defined by IEEE 802.1D. Such virtual LANs (VLANs) are an integral feature of switched LAN networks. A VLAN can be viewed as a group of end-stations on multiple LAN segments and can communicate as if they were on a single LAN. IEEE 802.1Q defines port-based Virtual LANs where membership is determined by the bridge port on which data frames are received. This memo defines the objects needed for the management of port-based VLANs in bridge entities. This memo defines those objects needed for the management of a bridging entity operating in the transparent mode, as well as some objects applicable to all types of bridges. Managed objects for Source-Route bridging are defined in RFC 1525 [SRBRIDGEMIB].2.1. Scope
This MIB includes a comprehensive set of managed objects which attempts to match the set defined in IEEE 802.1D and IEEE 802.1Q. However, to be consistent with the spirit of the SNMP Framework, a subjective judgement was made to omit the objects from those standards most 'costly' to implement in an agent and least 'essential' for fault and configuration management. The omissions are described in section 3 below.
Historical note: The original bridge MIB [BRIDGEMIB] used the following principles for determining inclusion of an object in the BRIDGE-MIB module: (1) Start with a small set of essential objects and add only as further objects are needed. (2) Require objects be essential for either fault or configuration management. (3) Consider evidence of current use and/or utility. (4) Limit the total of objects. (5) Exclude objects which are simply derivable from others in this or other MIBs. (6) Avoid causing critical sections to be heavily instrumented. The guideline that was followed is one counter per critical section per layer.3. Structure of MIBs
This document defines additional objects, on top of those existing in the original BRIDGE-MIB module defined in [BRIDGEMIB]: that MIB module is to be maintained unchanged for backwards compatibility. Section 3.4.3 of the present document contains some recommendations regarding usage of objects in the original bridge MIB by devices implementing the enhancements defined here. Two MIB modules are defined here: (1) Managed objects for an extended bridge MIB module P-BRIDGE-MIB for the traffic class and multicast filtering enhancements defined by IEEE 802.1D-1998 [802.1D]. (2) Managed objects for a virtual bridge MIB module Q-BRIDGE-MIB for the Virtual LAN bridging enhancements defined by IEEE 802.1Q-1998 [802.1Q].3.1. Structure of Extended Bridge MIB module
Objects in this MIB are arranged into groups. Each group is organized as a set of related objects. The overall structure and assignment of objects to their groups is shown below.
3.1.1. Relationship to IEEE 802.1D-1998 Manageable Objects
This section contains a cross-reference to the objects defined in IEEE 802.1D-1998 [802.1D]. It also details those objects that are not considered necessary in this MIB module. Some objects defined by IEEE 802.1D-1998 have been included in the virtual bridge MIB module rather than this one: entries in dot1qTpGroupTable, dot1qForwardAllTable and dot1qForwardUnregisteredTable are required for virtual bridged LANs with additional indexing (e.g. per-VLAN, per-FDB) and so are not defined here. Instead, devices which do not implement virtual bridged LANs but do implement the Extended Forwarding Services defined by IEEE 802.1D (i.e. dynamic learning of multicast group addresses and group service requirements in the filtering database) should implement these tables with a fixed value for dot1qFdbId (the value 1 is recommended) or dot1qVlanIndex (the value 1 is recommended). Devices which support Extended Filtering Services should support dot1qTpGroupTable, dot1qForwardAllTable and dot1qForwardUnregisteredTable.
Extended Bridge MIB Name IEEE 802.1D-1998 Name
dot1dExtBase Bridge
dot1dDeviceCapabilities
dot1dExtendedFilteringServices
dot1dTrafficClasses
dot1dTrafficClassesEnabled
dot1dGmrpStatus .ApplicantAdministrativeControl
dot1dPriority
dot1dPortPriorityTable
dot1dPortDefaultUserPriority .UserPriority
dot1dPortNumTrafficClasses
dot1dUserPriorityRegenTable .UserPriorityRegenerationTable
dot1dUserPriority
dot1dRegenUserPriority
dot1dTrafficClassTable .TrafficClassTable
dot1dTrafficClassPriority
dot1dTrafficClass
dot1dPortOutboundAccessPriorityTable
.OutboundAccessPriorityTable
dot1dPortOutboundAccessPriority
dot1dGarp
dot1dPortGarpTable
dot1dPortGarpJoinTime .JoinTime
dot1dPortGarpLeaveTime .LeaveTime
dot1dPortGarpLeaveAllTime .LeaveAllTime
dot1dGmrp
dot1dPortGmrpTable
dot1dPortGmrpStatus .ApplicantAdministrativeControl
dot1dPortGmrpFailedRegistrations .FailedRegistrations
dot1dPortGmrpLastPduOrigin .OriginatorOfLastPDU
dot1dTp
dot1dTpHCPortTable
dot1dTpHCPortInFrames .BridgePort.FramesReceived
dot1dTpHCPortOutFrames .ForwardOutBound
dot1dTpHCPortInDiscards .DiscardInbound
dot1dTpPortOverflowTable
dot1dTpPortInOverflowFrames .BridgePort.FramesReceived
dot1dTpPortOutOverflowFrames .ForwardOutBound
dot1dTpPortInOverflowDiscards .DiscardInbound
The following IEEE 802.1D-1998 management objects have not been
included in the Bridge MIB for the indicated reasons.
IEEE 802.1D-1998 Object Disposition
Bridge.StateValue not considered useful
Bridge.ApplicantAdministrativeControl
not provided per-attribute
(e.g. per-VLAN, per-Group).
Only per-{device,port,application}
control is provided in this MIB.
3.1.2. Relationship to IEEE 802.1Q Manageable Objects
This section contains section number cross-references to manageable
objects defined in IEEE 802.1Q-1998 [802.1Q]. These objects have
been included in this MIB as they provide a natural fit with the IEEE
802.1D objects with which they are co-located.
Extended Bridge MIB Name IEEE 802.1Q-1998 Section and Name
dot1dExtBase Bridge
dot1dDeviceCapabilities
dot1qStaticEntryIndividualPort 5.2 implementation options
dot1qIVLCapable
dot1qSVLCapable
dot1qHybridCapable
dot1qConfigurablePvidTagging 12.10.1.1 read bridge vlan
config
dot1dLocalVlanCapable
dot1dPortCapabilitiesTable
dot1dPortCapabilities
dot1qDot1qTagging 5.2 implementation options
dot1qConfigurableAcceptableFrameTypes
5.2 implementation options
dot1qIngressFiltering 5.2 implementation options
3.1.3. The dot1dExtBase Group
This group contains the objects which are applicable to all bridges
implementing the traffic class and multicast filtering features of
IEEE 802.1D-1998 [802.1D]. It includes per-device configuration of
GARP and GMRP protocols. This group will be implemented by all
devices which implement the extensions defined in 802.1D-1998.
3.1.4. The dot1dPriority Group
This group contains the objects for configuring and reporting status of priority-based queuing mechanisms in a bridge. This includes per- port user_priority treatment, mapping of user_priority in frames into internal traffic classes and outbound user_priority and access_priority.3.1.5. The dot1dGarp Group
This group contains the objects for configuring and reporting on operation of the Generic Attribute Registration Protocol (GARP).3.1.6. The dot1dGmrp Group
This group contains the objects for configuring and reporting on operation of the GARP Multicast Registration Protocol (GMRP).3.1.7. The dot1dTpHCPortTable
This table extends the dot1dTp group from the original bridge MIB [BRIDGEMIB] and contains the objects for reporting port bridging statistics for high capacity network interfaces.3.1.8. The dot1dTpPortOverflowTable
This table extends the dot1dTp group from the original bridge MIB [BRIDGEMIB] and contains the objects for reporting the upper bits of port bridging statistics for high capacity network interfaces for when 32-bit counters are inadequate.3.2. Structure of Virtual Bridge MIB module
Objects in this MIB are arranged into groups. Each group is organized as a set of related objects. The overall structure and assignment of objects to their groups is shown below. Some manageable objects defined in the original bridge MIB [BRIDGEMIB] need to be indexed differently when they are used in a VLAN bridging environment: these objects are, therefore, effectively duplicated by new objects with different indexing which are defined in the Virtual Bridge MIB.3.2.1. Relationship to IEEE 802.1Q Manageable Objects
This section contains section-number cross-references to manageable objects defined in clause 12 of IEEE 802.1Q-1998 [802.1Q]. It also details those objects that are not considered necessary in this MIB module.
Note: unlike IEEE 802.1D-1998, IEEE 802.1Q-1998 [802.1Q] did not define exact syntax for a set of managed objects: the following cross-references indicate the section numbering of the descriptions of management operations from clause 12 in the latter document. Virtual Bridge MIB object IEEE 802.1Q-1998 Reference dot1qBase dot1qVlanVersionNumber 12.10.1.1 read bridge vlan config dot1qMaxVlanId 12.10.1.1 read bridge vlan config dot1qMaxSupportedVlans 12.10.1.1 read bridge vlan config dot1qNumVlans dot1qGvrpStatus 12.9.2.1/2 read/set garp applicant controls dot1qTp dot1qFdbTable dot1qFdbId dot1qFdbDynamicCount 12.7.1.1.3 read filtering d/base dot1qTpFdbTable dot1qTpFdbAddress dot1qTpFdbPort dot1qTpFdbStatus dot1qTpGroupTable 12.7.7.1 read filtering entry dot1qTpGroupAddress dot1qTpGroupEgressPorts dot1qTpGroupLearnt dot1qForwardAllTable 12.7.7.1 read filtering entry dot1qForwardAllPorts dot1qForwardAllStaticPorts dot1qForwardAllForbiddenPorts dot1qForwardUnregisteredTable 12.7.7.1 read filtering entry dot1qForwardUnregisteredPorts dot1qForwardUnregisteredStaticPorts dot1qForwardUnregisteredForbiddenPorts dot1qStatic dot1qStaticUnicastTable 12.7.7.1 create/delete/read filtering entry 12.7.6.1 read permanent database dot1qStaticUnicastAddress dot1qStaticUnicastReceivePort dot1qStaticUnicastAllowedToGoTo dot1qStaticUnicastStatus dot1qStaticMulticastTable 12.7.7.1 create/delete/read filtering entry 12.7.6.1 read permanent database dot1qStaticMulticastAddress dot1qStaticMulticastReceivePort dot1qStaticMulticastStaticEgressPorts
dot1qStaticMulticastForbiddenEgressPorts
dot1qStaticMulticastStatus
dot1qVlan
dot1qVlanNumDeletes
dot1qVlanCurrentTable 12.10.2.1 read vlan configuration
12.10.3.5 read VID to FID
allocations
12.10.3.6 read FID allocated to
VID
12.10.3.7 read VIDs allocated to
FID
dot1qVlanTimeMark
dot1qVlanIndex
dot1qVlanFdbId
dot1qVlanCurrentEgressPorts
dot1qVlanCurrentUntaggedPorts
dot1qVlanStatus
dot1qVlanCreationTime
dot1qVlanStaticTable 12.7.7.1/2/3 create/delete/read
filtering entry
12.7.6.1 read permanent database
12.10.2.2 create vlan config
12.10.2.3 delete vlan config
dot1qVlanStaticName 12.4.1.3 set bridge name
dot1qVlanStaticEgressPorts
dot1qVlanForbiddenEgressPorts
dot1qVlanStaticUntaggedPorts
dot1qVlanStaticRowStatus
dot1qNextFreeLocalVlanIndex
dot1qPortVlanTable 12.10.1.1 read bridge vlan
configuration
dot1qPvid 12.10.1.2 configure PVID values
dot1qPortAcceptableFrameTypes 12.10.1.3 configure acceptable
frame types parameter
dot1qPortIngressFiltering 12.10.1.4 configure ingress
filtering parameters
dot1qPortGvrpStatus 12.9.2.2 read/set garp applicant
controls
dot1qPortGvrpFailedRegistrations
dot1qPortGvrpLastPduOrigin
dot1qPortVlanStatisticsTable 12.6.1.1 read forwarding port
counters
dot1qTpVlanPortInFrames
dot1qTpVlanPortOutFrames
dot1qTpVlanPortInDiscards
dot1qTpVlanPortInOverflowFrames
dot1qTpVlanPortOutOverflowFrames
dot1qTpVlanPortInOverflowDiscards
dot1qPortVlanHCStatisticsTable 12.6.1.1 read forwarding port
counters
dot1qTpVlanPortHCInFrames
dot1qTpVlanPortHCOutFrames
dot1qTpVlanPortHCInDiscards
dot1qLearningConstraintsTable 12.10.3.1/3/4 read/set/delete
vlan learning constraints
12.10.3.2 read vlan learning
constraints for VID
dot1qConstraintVlan
dot1qConstraintSet
dot1qConstraintType
dot1qConstraintStatus
dot1qConstraintSetDefault
dot1qConstraintTypeDefault
The following IEEE 802.1Q management objects have not been included
in the Bridge MIB for the indicated reasons.
IEEE 802.1Q-1998 Operation Disposition
reset bridge (12.4.1.4) not considered useful
reset vlan bridge (12.10.1.5) not considered useful
read forwarding port counters (12.6.1.1)
discard on error details not considered useful
read permanent database (12.7.6.1)
permanent database size not considered useful
number of static filtering count rows in
entries dot1qStaticUnicastTable +
dot1qStaticMulticastTable
number of static VLAN count rows in
registration entries dot1qVlanStaticTable
read filtering entry range use GetNext operation.
(12.7.7.4)
read filtering database (12.7.1.1)
filtering database size not considered useful
number of dynamic group address count rows applicable to each
entries (12.7.1.3) FDB in dot1dTpGroupTable
read garp state (12.9.3.1) not considered useful
notify vlan registration failure not considered useful
(12.10.1.6)
notify learning constraint violation
(12.10.3.10) not considered useful
3.2.2. The dot1qBase Group
This mandatory group contains the objects which are applicable to all
bridges implementing IEEE 802.1Q virtual LANs.
3.2.3. The dot1qTp Group
This group contains objects that control the operation and report the
status of transparent bridging. This includes management of the
dynamic Filtering Databases for both unicast and multicast
forwarding. This group will be implemented by all bridges that
perform destination-address filtering.
3.2.4. The dot1qStatic Group
This group contains objects that control static configuration
information for transparent bridging. This includes management of
the static entries in the Filtering Databases for both unicast and
multicast forwarding.
3.2.5. The dot1qVlan Group
This group contains objects that control configuration and report
status of the Virtual LANs known to a bridge. This includes
management of the statically configured VLANs as well as reporting
VLANs discovered by other means e.g. GVRP. It also controls
configuration and reports status of per-port objects relating to
VLANs and reports traffic statistics. It also provides for
management of the VLAN Learning Constraints.
3.3. Textual Conventions
The datatypes MacAddress, BridgeId, Timeout, EnabledStatus, PortList,
VlanIndex and VlanId 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.
3.4. 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 defined in MIB-II [MIB2], the 'interfaces' group defined in [INTERFACEMIB] and the original bridge MIB [BRIDGEMIB].3.4.1. 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 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.3.4.2. Relation to Interfaces MIB
The Interfaces Group MIB [INTERFACEMIB], requires that any MIB which is an adjunct of the Interfaces Group MIB, clarify specific areas within the Interfaces Group MIB. These areas were intentionally left vague in the Interfaces Group MIB to avoid over-constraining the MIB, thereby precluding management of certain media-types. The Interfaces Group MIB enumerates several areas which a media- specific MIB must clarify. Each of these areas is addressed in a following subsection. The implementor is referred to the Interfaces Group MIB in order to understand the general intent of these areas. In the Interfaces Group MIB, 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 Extended Bridge MIB is the notion of ports on a bridge. Each of these ports is associated with one interface of the 'interfaces' group (one row in ifTable) 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 Extended Bridge MIB (and in particular, its counters) is 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.3.4.2.1. Layering Model
This memo assumes the interpretation of the Interfaces Group to be in accordance with the Interfaces Group MIB [INTERFACEMIB] which states that the interfaces table (ifTable) contains information on the managed resource's interfaces and that each sub-layer below the internetwork layer of a network interface is considered an interface. This document recommends that, within an entity, VLANs which are instantiated as an entry in dot1qVlanCurrentTable by either management configuration through dot1qVlanStaticTable or by dynamic means (e.g. through GVRP), are NOT also represented by an entry in ifTable. Where an entity contains higher-layer protocol entities e.g. IP-layer interfaces that transmit and receive traffic to/from a VLAN, these should be represented in the ifTable as interfaces of type propVirtual(53). Protocol-specific types such as l3ipxvlan(137) should not be used here since there is no implication that the bridge will perform any protocol filtering before delivering up to these virtual interfaces.
3.4.2.2. ifStackTable
In addition, the Interfaces Group MIB [INTERFACEMIB] defines a table 'ifStackTable' for describing the relationship between logical interfaces within an entity. It is anticipated that implementors will use this table to describe the binding of e.g. IP interfaces to physical ports, although the presence of VLANs makes the representation less than perfect for showing connectivity: the ifStackTable cannot represent the full capability of the IEEE 802.1Q VLAN bridging standard since that makes a distinction between VLAN bindings on 'ingress' to and 'egress' from a port: these relationships may or may not be symmetrical whereas Interface MIB Evolution assumes a symmetrical binding for transmit and receive. This makes it necessary to define other manageable objects for configuring which ports are members of which VLANs.3.4.2.3. ifRcvAddressTable
This table contains all MAC addresses, unicast, multicast, and broadcast, for which an interface will receive packets and forward them up to a higher layer entity for local consumption. Note that this does not include addresses for data-link layer control protocols such as Spanning-Tree, GMRP or GVRP. The format of the address, contained in ifRcvAddressAddress, is the same as for ifPhysAddress. This table does not include unicast or multicast addresses which are accepted for possible forwarding out some other port. This table is explicitly not intended to provide a bridge address filtering mechanism.3.4.3. Relation to Original Bridge MIB
This section defines how objects in the original bridge MIB module [BRIDGEMIB] should be represented for devices which implement the extensions: some of the old objects are less useful in such devices but must still be implemented for reasons of backwards compatibility. Note that formal conformance statements for that MIB module do not exist since it is defined in SMIv1.3.4.3.1. The dot1dBase Group
This mandatory group contains the objects which are applicable to all types of bridges. Interpretation of this group is unchanged.
3.4.3.2. The dot1dStp Group
This group contains the objects that denote the bridge's state with respect to the Spanning Tree Protocol. Interpretation of this group is unchanged.3.4.3.3. The dot1dTp Group
This group contains objects that describe the entity's state with respect to transparent bridging. In a device operating with a single Filtering Database, interpretation of this group is unchanged. In a device supporting multiple Filtering Databases, this group is interpreted as follows: dot1dTpLearnedEntryDiscards The number of times that *any* of the FDBs became full. dot1dTpAgingTime This applies to all Filtering Databases. dot1dTpFdbTable Report MAC addresses learned on each port, regardless of which Filtering Database they have been learnt in. If an address has been learnt in multiple databases on a single port, report it only once. If an address has been learnt in multiple databases on more than one port, report the entry on any one of the valid ports. dot1dTpPortTable This table is port-based and is not affected by multiple Filtering Databases or multiple VLANs. The counters should include frames received or transmitted for all VLANs. Note that equivalent 64-bit port statistics counters, as well as other objects to represent the upper 32 bits of these counters, are defined in this document for high capacity network interfaces. These have confromance statements to indicate for which speeds of interface they are required.3.4.3.4. The dot1dStatic Group
This optional group contains objects that describe the configuration of destination-address filtering. In a device operating with a single Filtering Database, interpretation of this group is unchanged.
In a device supporting multiple Filtering Databases, this group is
interpreted as follows:
dot1dStaticTable
Entries read from this table include all static entries from all
of the Filtering Databases. Entries for the same MAC address
and receive port in more than one Filtering Database must appear
only once since these are the indices of this table. This table
should be implemented as read-only in devices that support
multiple Forwarding Databases - instead, write access should be
provided through dot1qStaticUnicastTable and
dot1qStaticMulticastTable, as defined in this document.
3.4.3.5. Additions to the Original Bridge MIB
In addition to the objects in the original bridge MIB [BRIDGEMIB],
this document contains:
(1) support for multiple traffic classes and dynamic multicast
filtering as per IEEE 802.1D-1998 [802.1D].
(2) support for bridged Virtual LANs as per IEEE 802.1Q-1998
[802.1Q].
(3) support for 64-bit versions of original bridge MIB [BRIDGEMIB]
port counters.
(page 18 continued on part 2)
