Definitions of Managed Objects for Bridges with Traffic Classes, Multicast Filtering and Virtual LAN Extensions
obsoleted by
- rfc-4363 — Definitions of Managed Objects for Bridges with Traffic Classes, Multicast Filtering, and Virtual LAN Extensions
Extracted elements (25)
dot1dTpPortOverflowTable exposes the most-significant 32 bits of port statistics counters as a separate table, enabling SNMPv1 managers to reconstruct 64-bit counts. The description explicitly warns that separately sampling high and low words risks missing an overflow between polls.
The original BRIDGE-MIB (RFC 1493) is maintained unchanged for backwards compatibility. This document adds two new MIB modules (P-BRIDGE-MIB and Q-BRIDGE-MIB) on top of it rather than modifying the existing module.
VLANs instantiated in dot1qVlanCurrentTable by management or GVRP are explicitly NOT also represented as entries in ifTable. Higher-layer protocol entities (e.g., IP interfaces) that communicate over a VLAN should appear in ifTable as type propVirtual(53), not as protocol-specific types such as l3ipxvlan(137).
Devices that implement Extended Filtering Services (IEEE 802.1D) but do not implement VLANs should implement dot1qTpGroupTable, dot1qForwardAllTable, and dot1qForwardUnregisteredTable with a fixed value of 1 for dot1qFdbId or dot1qVlanIndex.
In devices supporting multiple Filtering Databases, dot1dTpFdbTable must report MAC addresses learned on each port regardless of which FDB they were learned in. If an address appears in multiple databases on a single port, it is reported only once.
The ifStackTable cannot represent the full capability of IEEE 802.1Q VLAN bridging because it assumes a symmetrical transmit/receive binding, whereas 802.1Q distinguishes VLAN membership on ingress versus egress from a port. This asymmetry makes ifStackTable an imperfect representation for VLAN connectivity.
A translated SMIv1 MIB must be semantically equivalent to the SMIv2 original, except where objects are omitted because no translation is possible (e.g., Counter64). Loss of machine-readable information during translation is not considered to change the semantics of the MIB.
Both pBridgeHCPortGroup (64-bit counters) and pBridgePortOverflowGroup (MSB overflow counters) are mandatory for bridge ports whose corresponding ifSpeed exceeds 650,000,000 bits per second.
In devices supporting multiple Forwarding Databases, dot1dStaticTable should be implemented as read-only; write access for static unicast and multicast entries must instead be provided through dot1qStaticUnicastTable and dot1qStaticMulticastTable.
dot1dDeviceCapabilities is a BITS object indicating optional IEEE 802.1D/Q features implemented by the device, including: dot1dExtendedFilteringServices, dot1dTrafficClasses, dot1qStaticEntryIndividualPort, dot1qIVLCapable, dot1qSVLCapable, dot1qHybridCapable, dot1qConfigurablePvidTagging, and dot1dLocalVlanCapable.
dot1dPortCapabilities is a per-port BITS object indicating optional 802.1D/Q per-port features: dot1qDot1qTagging (supports 802.1Q tagging and GVRP), dot1qConfigurableAcceptableFrameTypes, and dot1qIngressFiltering (discarding frames whose VLAN does not include the receiving port).
dot1dPortGarpTable holds per-port GARP timer objects: dot1dPortGarpJoinTime (default 20 cs), dot1dPortGarpLeaveTime (default 60 cs), and dot1dPortGarpLeaveAllTime (default 1000 cs), all expressed as TimeInterval in centiseconds.
dot1dPortGmrpTable provides per-port GMRP control and status: dot1dPortGmrpStatus (enabled/disabled), dot1dPortGmrpFailedRegistrations (Counter32), and dot1dPortGmrpLastPduOrigin (MacAddress of last received GMRP PDU). GMRP takes effect only when both device-level dot1dGmrpStatus and port-level status are enabled.
dot1dTpHCPortTable provides 64-bit (Counter64) versions of transparent bridging port statistics: dot1dTpHCPortInFrames, dot1dTpHCPortOutFrames, and dot1dTpHCPortInDiscards, for use on high-capacity interfaces where 32-bit counters are insufficient.
dot1dTrafficClassTable maps evaluated User Priority (0–7) to a Traffic Class (0..dot1dPortNumTrafficClasses-1) on a per-port basis. dot1dTrafficClassesEnabled (device-level TruthValue) controls whether the bridge operates with multiple priority queues or a single level.
dot1dUserPriorityRegenTable provides a per-port mapping of incoming User Priority (0–7) to a Regenerated User Priority (0–7), applicable only to media that support native User Priority. Default regenerated values equal the incoming values.
dot1qForwardAllTable and dot1qForwardUnregisteredTable provide per-VLAN per-FDB control of multicast flooding: each has writable static port sets and forbidden port sets that constrain which ports receive all multicast or unregistered multicast frames respectively.
dot1qLearningConstraintsTable controls IVL/SVL learning constraints per VLAN and constraint set, using dot1qConstraintType (independent or shared) and dot1qConstraintStatus (RowStatus). dot1qConstraintSetDefault and dot1qConstraintTypeDefault provide device-wide defaults.
dot1qPortVlanTable provides per-port VLAN configuration: dot1qPvid (Port VLAN Identifier), dot1qPortAcceptableFrameTypes (admit-only-vlan-tagged or admit-all), dot1qPortIngressFiltering (TruthValue), and GVRP status/statistics per port.
dot1qTpFdbTable is an alternative to dot1dTpFdbTable for devices with multiple Filtering Databases. It is indexed by dot1qFdbId and MacAddress, providing dot1qTpFdbPort and dot1qTpFdbStatus (other/invalid/learned/self/mgmt) per unicast address per FDB.
dot1qVlanCurrentTable is indexed by TimeFilter (from RMON2-MIB) and VlanIndex, providing current VLAN state including dot1qVlanFdbId, dot1qVlanCurrentEgressPorts (PortList), dot1qVlanCurrentUntaggedPorts (PortList), dot1qVlanStatus, and dot1qVlanCreationTime.
Several objects in P-BRIDGE-MIB and Q-BRIDGE-MIB have read-write or read-create access, including VLAN membership (dot1qVlanStaticTable), port VLAN assignments (dot1qPortVlanTable), and static filtering entries. Unauthorized write access to these objects could disrupt VLAN segmentation and traffic forwarding. Implementations should apply SNMP access control (e.g., SNMPv3 USM/VACM) to protect writable objects.
dot1qTpFdbStatus defines five states for a unicast FDB entry: other(1) — determined by another mechanism; invalid(2) — aged out but not yet flushed; learned(3) — dynamically learned and active; self(4) — one of the device's own addresses; mgmt(5) — matches a dot1qStaticUnicastTable entry.
PortList is an OCTET STRING where each octet encodes eight ports: the first octet covers ports 1–8, the second ports 9–16, etc. Within each octet the most significant bit represents the lowest-numbered port; a bit value of '1' means the port is included in the set.
VlanId is a 12-bit INTEGER restricted to the range 1–4094, representing an IEEE 802.1Q VLAN tag ID. VlanIndex extends this as an Unsigned32 where values 1–4094 are global 802.1Q VLAN IDs, values above 4095 denote agent-local VLANs without a global ID, and 0 and 4095 are not permitted.