APS-MIB

MIB Reference — IPNetwork Monitor · Updated October 05, 2026

All MIBs › APS-MIB

Organization: IETF AToMMIB Working Group

Last Updated: 2003-02-28

Category: Network Interfaces, Optical and WDM

Description: Defines managed objects for SONET Linear Automatic Protection Switching (APS), supporting 1+1 and 1:n protection architectures for redundant optical network paths.

IPNetwork Monitor uses several OIDs from this MIB in network discovery and polling the applicable devices. Start monitoring APS-MIB with a free 30-day trial of IPNetwork Monitor.

What Is APS-MIB?

APS-MIB is an IETF standards-based MIB (RFC 3592) for SONET/SDH linear Automatic Protection Switching, supporting 1+1 and 1:n redundant optical path protection groups. It defines protection group configuration (mode, revert behavior, direction, extra traffic), threshold configuration (signal-degrade/signal-fail BER thresholds, wait-to-restore timer), and notifications for switchover events. It is central to monitoring optical transport hardware faults: it reveals whether the working or protection line is active, whether BER thresholds have been crossed to trigger an automatic protection switch, and generates traps whenever a switchover occurs. It is derived from Telcordia GR-253-CORE and is consistent with ITU-T G.783 Multiplex Section Protection, so it is typically deployed alongside SONET/SDH physical-layer MIBs. It is used on SONET/SDH optical transport equipment (ADMs, transponders) in carrier networks requiring redundant path protection, as defined in the APS-MIB RFC (RFC 3592).

IPNetwork Monitor allows you to monitor SNMP objects defined in APS-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 MIB
  • SONET/SDH optical transport equipment

Monitoring Examples

An admin monitors apsConfigTable/apsConfigEntry objects such as apsConfigSdBerThreshold and apsConfigSfBerThreshold to see the bit-error-rate levels that will trigger a protection switch. apsConfigWaitToRestore together with apsMIBNotifications traps show when a switchover to the protection line occurred and whether it later reverted, indicating a working-line fault was detected and resolved. apsConfigExtraTraffic reveals whether best-effort extra traffic is currently being carried on the protection path.

What Can Be Monitored

  • protection group mode/configuration
  • signal degrade/fail BER thresholds
  • wait-to-restore timer
  • extra traffic status
  • protection switchover events
Imported Objects

From IF-MIB

InterfaceIndex
ifIndexOBJECT-TYPE

From SNMP-FRAMEWORK-MIB

SnmpAdminString

From SNMPv2-CONF

MODULE-COMPLIANCE
NOTIFICATION-GROUP
OBJECT-GROUP

From SNMPv2-SMI

Counter32
Gauge32
Integer32
MODULE-IDENTITY
NOTIFICATION-TYPE
OBJECT-TYPE
transmission

From SNMPv2-TC

RowStatus
StorageType
TEXTUAL-CONVENTION
TimeStamp

How to Use in IPNetwork Monitor

Example using apsStatusModeMismatches OID:

Select an SONET/SDH optical transport equipment (linear APS) 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 apsStatusModeMismatches into the Find box to locate it in the OID tree, selecting the specific row/instance you want to monitor since this is a table column, then select it and click OK. It reports a count of Mode Mismatch conditions. Discontinuities in the value of this counter can occur at re-initialization of the management system, and at other times as indicated by the value of apsStatusDiscontinuityTime. 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

Manages SONET linear Automatic Protection Switching (APS) groups and Multiplex Section Protection (MSP) protocol configuration.

Start monitoring SONET/SDH optical transport equipment (linear APS) 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 APS-MIB