CISCOSB-SpecialBpdu-MIB

Description: Configures handling of special BPDU frames and proprietary spanning tree messages on Cisco Small Business switches.

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This MIB is part of Cisco's Small Business managed switch family and governs how the switch handles special/non-standard Bridge Protocol Data Units (BPDUs) used by proprietary or legacy spanning-tree-like protocols. It exposes configuration data such as a table of special BPDU rules keyed by destination MAC address and encapsulation/protocol ID, along with the action to take (peer, tunnel, or discard) and per-hardware-table overrides. Rather than performance counters, it is primarily a configuration/control-plane MIB, though its RowStatus columns let a management station monitor whether specific BPDU handling rules are active, pending, or have failed to apply. It builds conceptually on standard bridge/spanning-tree semantics (IEEE 802.1D) even though it doesn't formally import from a standard bridge MIB. It is typically deployed on Cisco Small Business (Sx300/Sx500 series) switches in networks that interoperate with third-party equipment sending non-standard BPDUs, such as legacy PVST+ or other vendors' proprietary spanning tree variants. Engineers can download the CISCOSB-SpecialBpdu-MIB file directly to load it into their MIB browser.

An administrator polling rlSpecialBpduTable can see each rlSpecialBpduEntry keyed by rlSpecialBpduMacAddr, rlSpecialBpduEncap, and rlSpecialBpduProtId, along with the configured rlSpecialBpduAction for that special BPDU type. Checking rlSpecialBpduRowStatus reveals whether a rule is active or notInService, which would explain unexpected flooding of proprietary BPDUs if a rule failed to activate. The companion rlSpecialBpduHwTable/rlSpecialBpduHwAction exposes the hardware-level enforcement of the same rules, useful for verifying that software configuration was actually pushed to the switch ASIC.

Cisco Small Business private MIB defining special BPDU configuration and traffic segmentation settings.