IEEE8021-Preemption-MIB

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Organization: IEEE 802.1 Working Group

Last Updated: 2018-06-21

Category: Quality of Service, Standard: IEEE 802

Description: IEEE 802.1 MIB for Frame Preemption (802.1Qbu) managing the preemption of lower-priority Ethernet frames for time-sensitive traffic.

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What Is IEEE8021-Preemption-MIB?

This is a vendor-neutral IEEE 802.1Qbu standards MIB for Frame Preemption, a Time-Sensitive Networking feature letting express (time-critical) frames interrupt transmission of lower-priority frames on the same link. It exposes per-priority preemption parameter/configuration tables covering administrative status, hold/release advance timing, and whether preemption is currently active for a given priority. Monitoring this MIB reveals the operational state of frame preemption on a link: whether the active state matches the administratively configured status, and whether hold/release timing is functioning, which affects latency guarantees for express traffic. As part of the 802.1Q TSN suite it is designed to interoperate with time-aware scheduling (802.1Qbv) and other TSN mechanisms on the same bridge. It is typically deployed on TSN-capable industrial automation or automotive Ethernet switches where deterministic low latency for control traffic is required. Engineers implementing or auditing this functionality typically reference the IEEE8021-Preemption-MIB RFC/standard documentation for the authoritative specification.

IPNetwork Monitor allows you to monitor SNMP objects defined in IEEE8021-Preemption-MIB. Use the built-in SNMP Monitoring Browser to explore available variables, view their current values and descriptions, and select the objects you want to monitor. You can then create SNMP monitors, configure thresholds, and receive alerts when monitored values change.

Supported Devices

vendor-neutral, IEEE 802.1Qbu standards-based MIB, not tied to a specific manufacturer
TSN-capable Ethernet bridge or switch

Monitoring Examples

An operator would check ieee8021PreemptionParameterTable (keyed by ieee8021PreemptionPriority) to confirm ieee8021FramePreemptionAdminStatus is enabled for the priorities carrying express traffic, then cross-check ieee8021FramePreemptionActive in ieee8021PreemptionConfigTable to verify preemption is actually operating on the port. If ieee8021FramePreemptionHoldRequest is asserted but ieee8021FramePreemptionActive never becomes true, that indicates a negotiation failure with the link partner over frame preemption support, explaining unexpected latency spikes for time-critical traffic.

What Can Be Monitored

per-priority preemption admin status
preemption active state
hold/release advance timing
hold request status

Imported Objects

From IEEE8021-BRIDGE-MIB

ieee8021BridgeBaseComponentId	OBJECT-TYPE
ieee8021BridgeBasePort	OBJECT-TYPE

From IEEE8021-TC-MIB

IEEE8021PriorityValue
ieee802dot1mibs	OBJECT-IDENTITY

From SNMPv2-CONF

MODULE-COMPLIANCE
OBJECT-GROUP

From SNMPv2-SMI

MODULE-IDENTITY
OBJECT-TYPE
Unsigned32

OIDs

OID symbolic	OID numeric	Type	Access	Description
ieee8021PreemptionMib	1.3.111.2.802.1.1.29			The Bridge MIB module for managing devices that support the frame preemption enhancements for IEEE 802.1Q Bridges. Unless otherwise indicated, the references in this MIB module are to IEEE Std 802.1Q. Copyright (C) IEEE (2018). This version of this MIB module is part of IEEE Std 802.1Q; see the draft itself for full legal notices.
ieee8021PreemptionNotifications	1.3.111.2.802.1.1.29.0
ieee8021PreemptionObjects	1.3.111.2.802.1.1.29.1
ieee8021PreemptionParameters	1.3.111.2.802.1.1.29.1.1
ieee8021PreemptionParameterTable	1.3.111.2.802.1.1.29.1.1.1		not-accessible	A table containing a set of frame preemption parameters, one for each priority value. All writeable objects in this table must be persistent over power up restart/reboot.
ieee8021PreemptionParameterEntry	1.3.111.2.802.1.1.29.1.1.1.1		not-accessible	A list of objects containing preemption parameters for each priority value.
IEE ieee8021PreemptionPriority	1.3.111.2.802.1.1.29.1.1.1.1.1	IEEE8021PriorityValue	not-accessible	The priority number associated with the row of the table. A row in this table is created for each priority value.
INT ieee8021FramePreemptionAdminStatus	1.3.111.2.802.1.1.29.1.1.1.1.2	INTEGER	read-write	The value of the framePreemptionAdminStatus parameter for the traffic class. The default value of the framePreemptionAdminStatus parameter is express (1). The value of this object MUST be retained across reinitializations of the management system.
ieee8021PreemptionConfigTable	1.3.111.2.802.1.1.29.1.1.2		not-accessible	A table containing a set of frame preemption parameters, one for each Port. All writeable objects in this table must be persistent over power up restart/reboot.
ieee8021PreemptionConfigEntry	1.3.111.2.802.1.1.29.1.1.2.1		not-accessible	A list of objects containing preemption parameters for each Port.
U32 ieee8021FramePreemptionHoldAdvance	1.3.111.2.802.1.1.29.1.1.2.1.1	Unsigned32	read-only	The value of the holdAdvance parameter for the Port in nanoseconds. There is no default value; the holdAdvance is a property of the underlying MAC.
U32 ieee8021FramePreemptionReleaseAdvance	1.3.111.2.802.1.1.29.1.1.2.1.2	Unsigned32	read-only	The value of the releaseAdvance parameter for the Port in nanoseconds. There is no default value; the releaseAdvance is a property of the underlying MAC.
INT ieee8021FramePreemptionActive	1.3.111.2.802.1.1.29.1.1.2.1.3	INTEGER	read-only	The value is active (2) when preemption is operationally active for the Port, and idle (1) otherwise.
INT ieee8021FramePreemptionHoldRequest	1.3.111.2.802.1.1.29.1.1.2.1.4	INTEGER	read-only	The value is hold (1) when the sequence of gate operations for the Port has executed a Set-And-Hold-MAC operation, and release (2) when the sequence of gate operations has executed a Set-And-Release-MAC operation. The value of this object is release (2) on system initialization.
ieee8021PreemptionConformance	1.3.111.2.802.1.1.29.2
ieee8021PreemptionCompliances	1.3.111.2.802.1.1.29.2.1
ieee8021PreemptionCompliance	1.3.111.2.802.1.1.29.2.1.1			The compliance statement for devices supporting frame preemption. Support of the objects defined in this MIB module also requires support of the IEEE8021-BRIDGE-MIB; the provisions of 17.3.2 apply to implementations claiming support of this MIB.
ieee8021PreemptionGroups	1.3.111.2.802.1.1.29.2.2
ieee8021PreemptionGroup	1.3.111.2.802.1.1.29.2.2.1			Objects that allow management of frame preemption.

RFC description

IEEE 802.1Q Bridge frame preemption MIB for managing frame preemption enhancements in 802.1Q bridges.

Start monitoring Vendor-neutral IEEE 802.1Qbu standard (TSN-capable Ethernet bridge or switch, frame preemption) with a free 30-day trial of IPNetwork Monitor. Import MIBs, browse SNMP OIDs, create custom SNMP monitors, configure alerts, and monitor any SNMP-enabled network device from a single console.

Download IEEE8021-Preemption-MIB

What Is IEEE8021-Preemption-MIB?

Supported Devices

Monitoring Examples

What Can Be Monitored

This MIB depends on

Related MIBs

RFC description