CIRCUIT-IF-MIB

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Organization: IETF Frame Relay Service MIB Working Group

Last Updated: 2002-01-03

Category: Network Interfaces

Description: Defines managed objects for mapping circuits to interface table entries, enabling circuits defined in other MIBs to be represented as interfaces in the ifTable.

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

What Is CIRCUIT-IF-MIB?

CIRCUIT-IF-MIB is a vendor-neutral IETF standards-track MIB module that provides a generic mechanism for representing circuits defined in other technology-specific MIBs (such as ATM, Frame Relay, or SONET circuit MIBs) as entries in the standard Interfaces MIB's ifTable. Rather than defining new sensor or performance data of its own, it acts as a structural mapping layer so circuit-layer entities can be managed uniformly alongside physical and logical interfaces. In monitoring terms it is used to confirm that provisioned circuits have a corresponding ifTable entry and to check that entry's operational and administrative status, indirectly reflecting circuit connectivity and provisioning correctness rather than CPU or temperature-type metrics. It has an explicit and central dependency on the IETF IF-MIB (ifTable/ifXTable, RFC 2863), since its entire purpose is inserting circuit entities into that table. It is used within any managed network device — router, switch, or specialized circuit-oriented equipment — that provisions circuits such as ATM PVCs, Frame Relay DLCIs, or SONET paths needing ifTable representation for consistent management tooling. Engineers implementing or auditing this functionality typically reference the CIRCUIT-IF-MIB RFC/standard documentation for the authoritative specification.

IPNetwork Monitor allows you to monitor SNMP objects defined in CIRCUIT-IF-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 IETF MIB, not tied to a specific manufacturer
routers/switches provisioning ATM, Frame Relay, or SONET circuits

Monitoring Examples

No sample objects were provided for this MIB; per the module description ("allow insertion of selected circuit into the ifTable"), a network management system would, after provisioning a circuit defined in another MIB (e.g., an ATM PVC or Frame Relay DLCI table), look for that circuit's corresponding ifIndex entry to confirm it is represented with a normal ifOperStatus, verifying the circuit is properly exposed for uniform status polling alongside other interfaces.

What Can Be Monitored

circuit-to-ifIndex mapping presence
circuit operational status (via ifOperStatus)
circuit administrative status (via ifAdminStatus)

Imported Objects

From IF-MIB

InterfaceIndex
ifIndex	OBJECT-TYPE

From SNMPv2-CONF

MODULE-COMPLIANCE
OBJECT-GROUP

From SNMPv2-SMI

Gauge32
MODULE-IDENTITY
OBJECT-TYPE
mib-2

From SNMPv2-TC

RowPointer
RowStatus
StorageType
TEXTUAL-CONVENTION
TimeStamp

How to Use in IPNetwork Monitor

Example using ciIfNumActive OID:

Select a Routers/switches provisioning ATM, Frame Relay, or SONET circuit 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 ciIfNumActive into the Find box to locate it in the OID tree, then select it and click OK. The number of active rows in ciCircuitTable. 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 Gauge32-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

OID symbolic	OID numeric	Type	Access	Description
circuitIfMIB	1.3.6.1.2.1.94			The MIB module to allow insertion of selected circuit into the ifTable.
ciObjects	1.3.6.1.2.1.94.1
ciCircuitTable	1.3.6.1.2.1.94.1.1		not-accessible	The Circuit Interface Circuit Table.
ciCircuitEntry	1.3.6.1.2.1.94.1.1.1		not-accessible	An entry in the Circuit Interface Circuit Table.
NUM ciCircuitObject	1.3.6.1.2.1.94.1.1.1.1	RowPointer	not-accessible	This value contains the RowPointer that uniquely describes the circuit that is to be added to this table. Any RowPointer that will force the size of OBJECT IDENTIFIER of the row to grow beyond the legal limit MUST be rejected. The purpose of this object is to point a network manager to the table in which the circuit was created as well as define the circuit on which the interface is defined. Valid tables for this object include the frCircuitTable from the Frame Relay DTE MIB(FRAME-RELAY-DTE-MIB), the frPVCEndptTable from the Frame Relay Service MIB (FRNETSERV-MIB), and the aal5VccTable from the ATM MIB (ATM MIB). However, including circuits from other MIB tables IS NOT prohibited.
CIF ciCircuitFlow	1.3.6.1.2.1.94.1.1.1.2	CiFlowDirection	not-accessible	The direction of data flow through the circuit for which the virtual interface is defined. The following define the information that the virtual interface will report. transmit(1) - Only transmitted frames receive(2) - Only received frames both(3) - Both transmitted and received frames. It is recommended that the ifDescr of the circuit interfaces that are not both(3) SHOULD have text warning the operators that the particular interface represents only half the traffic on the circuit.
ROW ciCircuitStatus	1.3.6.1.2.1.94.1.1.1.3	RowStatus	read-create	The status of the current row. This object is used to add, delete, and disable rows in this table. When the status changes to active(1), a row will also be added to the interface map table below and a row will be added to the ifTable. These rows SHOULD not be removed until the status is changed from active(1). The value of ifIndex for the row that is added to the ifTable is determined by the agent and MUST follow the rules of the ifTable. The value of ifType for that interface will be frDlciEndPt(193) for a frame relay circuit, atmVciEndPt(194) for an ATM circuit, or another ifType defining the circuit type for any other circuit. When this object is set to destroy(6), the associated row in the interface map table will be removed and the ifIndex will be removed from the ifTable. Removing the ifIndex MAY initiate a chain of events that causes changes to other tables as well. The rows added to this table MUST have a valid object identifier for ciCircuitObject. This means that the referenced object must exist and it must be in a table that supports circuits. The object referenced by ciCircuitObject MUST exist prior to transitioning a row to active(1). If at any point the object referenced by ciCircuitObject does not exist or the row containing it is not in the active(1) state, the status SHOULD either age out the row or report notReady(3). The effects transitioning from active(1) to notReady(3) are the same as those caused by setting the status to destroy(6). Each row in this table relies on information from other MIB modules. The rules persistence of data SHOULD follow the same rules as those of the underlying MIB module. For example, if the circuit defined by ciCircuitObject would normally be stored in non-volatile memory, then the row SHOULD also be non-volatile.
NUM ciCircuitIfIndex	1.3.6.1.2.1.94.1.1.1.4	InterfaceIndex	read-only	The ifIndex that the agent assigns to this row.
TIM ciCircuitCreateTime	1.3.6.1.2.1.94.1.1.1.5	TimeStamp	read-only	This object returns the value of sysUpTime at the time the value of ciCircuitStatus last transitioned to active(1). If ciCircuitStatus has never been active(1), this object SHOULD return 0.
STO ciCircuitStorageType	1.3.6.1.2.1.94.1.1.1.6	StorageType	read-create	The storage type used for this row.
ciIfMapTable	1.3.6.1.2.1.94.1.2		not-accessible	The Circuit Interface Map Table.
ciIfMapEntry	1.3.6.1.2.1.94.1.2.1		not-accessible	An entry in the Circuit Interface Map Table.
NUM ciIfMapObject	1.3.6.1.2.1.94.1.2.1.1	RowPointer	read-only	This value contains the value of RowPointer that corresponds to the current ifIndex.
CIF ciIfMapFlow	1.3.6.1.2.1.94.1.2.1.2	CiFlowDirection	read-only	The value contains the value of ciCircuitFlow that corresponds to the current ifIndex.
TIM ciIfLastChange	1.3.6.1.2.1.94.1.3	TimeStamp	read-only	The value of sysUpTime at the most recent change to ciCircuitStatus for any row in ciCircuitTable.
G32 ciIfNumActiveEx	1.3.6.1.2.1.94.1.4	Gauge32	read-only	The number of active rows in ciCircuitTable.
ciCapabilities	1.3.6.1.2.1.94.2
ciConformance	1.3.6.1.2.1.94.3
ciMIBGroups	1.3.6.1.2.1.94.3.1
ciCircuitGroup	1.3.6.1.2.1.94.3.1.1			A collection of required objects providing information from the circuit table.
ciIfMapGroup	1.3.6.1.2.1.94.3.1.2			A collection of required objects providing information from the interface map table.
ciStatsGroup	1.3.6.1.2.1.94.3.1.3			A collection of statistical metrics used to help manage the ciCircuitTable.
ciMIBCompliances	1.3.6.1.2.1.94.3.2
ciCompliance	1.3.6.1.2.1.94.3.2.1			The compliance statement for SNMP entities which support of the Circuit Interfaces MIB module. This group defines the minimum level of support required for compliance.

RFC description

Allows insertion of selected circuits into the interface table for frame relay and circuit management.

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