IEEE8021-AS-MIB

MIB Reference — IPNetwork Monitor · Updated October 05, 2026

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Organization: IEEE 802.1 Working Group

Last Updated: 2012-12-12

Category: Standard: IEEE 802, Technology: Time Synchronization

Description: IEEE 802.1 MIB for 802.1AS (generalized Precision Time Protocol) timing and synchronization management in bridged networks.

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What Is IEEE8021-AS-MIB?

IEEE8021-AS-MIB is a vendor-neutral, standards-based IEEE 802.1 MIB for managing IEEE 802.1AS, the generalized Precision Time Protocol (gPTP) used for time synchronization across bridged Ethernet networks. It exposes default dataset objects describing the local clock's identity, class, accuracy, priority values, grandmaster capability, and UTC offset/leap-second handling. Its monitoring value is centered on software/clock-health status: an administrator can check whether a bridge or end station believes it is grandmaster-capable, what clock class and accuracy it is advertising, and whether its UTC offset is currently valid, which together reveal time-sync problems that can cascade into TSN (time-sensitive networking) application faults. It is a companion MIB to the broader IEEE 802.1 bridge/TSN MIB family and assumes an 802.1AS-capable device stack. It is deployed on any 802.1AS/gPTP-capable bridge, switch, or end station in time-sensitive networking environments such as industrial automation, automotive, and pro-audio/video networks. Engineers implementing or auditing this functionality typically reference the IEEE8021-AS-MIB RFC/standard documentation for the authoritative specification.

IPNetwork Monitor allows you to monitor SNMP objects defined in IEEE8021-AS-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, standards-based IEEE 802.1AS MIB, applicable to any gPTP-capable bridge, switch, or end station

Monitoring Examples

An administrator would poll ieee8021AsDefaultDSClockIdentity and ieee8021AsDefaultDSClockClass to confirm a device's advertised clock identity and quality class match expectations for its role in the gPTP domain. Checking ieee8021AsDefaultDSGmCapable and ieee8021AsDefaultDSPriority1/Priority2 reveals whether the device is eligible and prioritized to become grandmaster. Watching ieee8021AsDefaultDSCurrentUTCOffsetValid go false, or ieee8021AsDefaultDSLeap59/Leap61 flags flip unexpectedly, would indicate the time base has lost synchronization or a leap-second event is pending.

What Can Be Monitored

  • clock identity
  • clock class and accuracy
  • grandmaster capability
  • clock priority values
  • current UTC offset validity
  • leap-second flags
Imported Objects

From IEEE8021-TC-MIB

IEEE8021BridgePortNumber

From IF-MIB

InterfaceIndexOrZero
ifGeneralInformationGroupOBJECT-GROUP

From SNMPv2-CONF

MODULE-COMPLIANCE
OBJECT-GROUP

From SNMPv2-SMI

Counter32
Integer32
MODULE-IDENTITY
OBJECT-TYPE
Unsigned32

From SNMPv2-TC

RowStatus
TEXTUAL-CONVENTION
TimeStamp
TruthValue

How to Use in IPNetwork Monitor

Example using ieee8021AsCurrentDSGmChangeCount OID:

Select a device implementing IEEE8021-AS-MIB as the target host to create a monitor — the SNMP service should be up and running on it. Click New Monitor, then check SNMP Custom on the Favorites tab, click Next, and confirm the host. On the next page, click Select... to open the built-in SNMP MIB Browser and type ieee8021AsCurrentDSGmChangeCount into the Find box to locate it in the OID tree, then select it and click OK. This statistics counter tracks the number of times the grandmaster has changed in a gPTP domain. On the monitor's Main parameters page you can set the target's SNMP port (default 161), credentials, polling interval, and other settings — see the SNMP Monitor help for details. On the State conditions and Alerting tabs, configure when the monitor should change state and trigger an alert; since this is a Counter32-type OID, Value bounds is the most useful condition here — trigger an alert if the counter increases sharply between polls relative to its normal baseline, since an unexpected spike often reflects a real change in traffic or activity. Click Finish to create the monitor; you can adjust any parameter later.
OIDs

RFC description

IEEE 802.1AS time synchronization and precision timing protocol management MIB.

Start monitoring Vendor-neutral IEEE 802.1AS standard (gPTP-capable bridge/switch/end station) 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.

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