CISCO-UDLDP-MIB

All MIBs › CISCO-UDLDP-MIB

Organization: Cisco Systems, Inc.

Last Updated: 2009-11-09

Category: Cisco Devices, Network Interfaces

Description: Manages UDLD (Unidirectional Link Detection Protocol) for detecting and disabling unidirectional Ethernet links.

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What Is CISCO-UDLDP-MIB?

CISCO-UDLDP-MIB is a Cisco vendor module for UDLD (UniDirectional Link Detection Protocol), a Layer 2 protocol that detects Ethernet links where traffic flows in only one direction -- a fault condition that standard link-state detection can miss -- and shuts the affected port down to prevent loops or blackholed traffic. It exposes global UDLD configuration (enable state, hello interval, mode, fast-hello variants) as well as per-interface operational data (enable state, operational status, aggressive mode, admin mode). Its monitoring value is squarely in detecting a specific hardware/link-layer fault: a unidirectional fiber or copper link caused by a bad transceiver, miswired fiber pair, or one-way cable fault, which UDLD surfaces via cudldpInterfaceOperStatus and related notifications rather than through simple link-up/down status. It complements standard interface (IF-MIB) and spanning-tree monitoring, since a UDLD-detected fault often explains an otherwise-unexplained loop or blackhole that STP alone wouldn't catch. It's deployed on Cisco switches, especially at fiber-optic aggregation points, where a one-way link failure could otherwise cause a silent network loop or traffic black hole. Engineers can download the CISCO-UDLDP-MIB file directly to load it into their MIB browser.

IPNetwork Monitor allows you to monitor SNMP objects defined in CISCO-UDLDP-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

Cisco switches (fiber-optic uplinks/aggregation)

Monitoring Examples

An operator would check cudldpInterfaceTable/cudldpInterfaceEntry, keyed per interface, for cudldpInterfaceEnable and cudldpInterfaceOperStatus to confirm UDLD is active and the link is bidirectionally healthy. If cudldpInterfaceAggressiveMode is enabled and cudldpFastHelloLinkFailRptNotifEnable/cudldpFastHelloStatusChangeNotifEnable traps fire, that signals UDLD detected a one-way link (often from a bad transceiver or a fiber pair swapped/miswired) and likely err-disabled the port to prevent a bridging loop.

What Can Be Monitored

UDLD global enable state and hello interval
per-interface UDLD operational status
aggressive mode setting
link failure / status-change notifications

Imported Objects

From CISCO-SMI

ciscoMgmt

OBJECT-IDENTITY

From IF-MIB

ifIndex	OBJECT-TYPE
ifName	OBJECT-TYPE

From SNMPv2-CONF

MODULE-COMPLIANCE
NOTIFICATION-GROUP
OBJECT-GROUP

From SNMPv2-SMI

MODULE-IDENTITY
NOTIFICATION-TYPE
OBJECT-TYPE
Unsigned32

From SNMPv2-TC

TruthValue

OIDs

OID symbolic	OID numeric	Type	Access	Description
ciscoUdldpMIB	1.3.6.1.4.1.9.9.118			Cisco Uni Direction Link Detection Protocol MIB
ciscoUdldpMIBNotifs	1.3.6.1.4.1.9.9.118.0
NTF cudldpFastHelloLinkFailRptNotification	1.3.6.1.4.1.9.9.118.0.1			This notification is generated when UDLDP detects a link failure on a fast hello UDLD link and the value of cudldpFastHelloErrorReportEnable is 'true'. ifName identifies the interface where the link failure is detected.
NTF cudldpFastHelloStatusChangeNotification	1.3.6.1.4.1.9.9.118.0.2			This notification is generated when there is a change in the value of cudldpIfFastHelloOperStatus object. cudldpHelloInterval provides the hello interval configured at the device level. cudldpIfFastHelloInterval provides the fast hello interval configured at the interface level. cudldpIfOperHelloInterval indicates the hello interval that is currently operational at this interface. cudldpIfFastHelloOperStatus indicates the operational status of UDLD fast hello at this interface. ifName identifies the interface that trigger the generation of this notification.
ciscoUdldpMIBObjects	1.3.6.1.4.1.9.9.118.1
cudldpGlobal	1.3.6.1.4.1.9.9.118.1.1
T/F cudldpGlobalEnable	1.3.6.1.4.1.9.9.118.1.1.1	TruthValue	read-write	This variable is used to enable(true)/disable(false) Uni Direction Link Detection Protocol on the device. cudldpGlobalEnable is deprecated and replaced with cudldpGlobalMode.
INT cudldpHelloInterval	1.3.6.1.4.1.9.9.118.1.1.2	INTEGER	read-write	Indicates interval in seconds at which each port sends a hello packet to all of its neighbors at steady state when the link has been identified as bidirectional. For platforms which support cudldpHelloIntervalExt, when cudldpHelloIntervalExt reports a value less than the minimum value reportable by cudldpHelloInterval, then cudldpHelloInterval should report its minimum value of 7.
INT cudldpGlobalMode	1.3.6.1.4.1.9.9.118.1.1.3	INTEGER	read-write	Indicates the mode of UDLDP feature on the device. enable -- Uni Direction Link Detection Protocol is enabled on the device. disable -- Uni Directional Link Detection Protocol is disabled on the device. aggresive -- Uni Directional Link Detection protocol is enabled in aggressive mode on the device.
U32 cudldpHelloIntervalExt	1.3.6.1.4.1.9.9.118.1.1.4	Unsigned32	read-write	Indicates interval in seconds at which each port sends a hello packet to all of its neighbors at steady state when the link has been identified as bidirectional.
T/F cudldpFastHelloLinkFailRptNotifEnable	1.3.6.1.4.1.9.9.118.1.1.5	TruthValue	read-write	This object specifies whether cudldpFastHelloLinkFailRptNotification is generated by the system. Setting this object value to 'true' will enable generation of cudldpFastHelloLinkFailRptNotification. Seting this object value to 'false' will disable generation of cudldpFastHelloLinkFailRptNotification.
T/F cudldpFastHelloStatusChangeNotifEnable	1.3.6.1.4.1.9.9.118.1.1.6	TruthValue	read-write	This object specifies whether cudldpFastHelloStatusChangeNotification is generated by the system. Setting this object value to 'true' will enable generation of cudldpFastHelloStatusChangeNotification. Seting this object value to 'false' will disable generation of cudldpFastHelloStatusChangeNotification.
cudldpInterface	1.3.6.1.4.1.9.9.118.1.2
cudldpInterfaceTable	1.3.6.1.4.1.9.9.118.1.2.1		not-accessible	The (conceptual) table containing the status of UDLDP on the device's interfaces.
cudldpInterfaceEntry	1.3.6.1.4.1.9.9.118.1.2.1.1		not-accessible	A conceptual row of cudldpInterfaceTable. An entry exists for each interface that supports UDLDP.
T/F cudldpInterfaceEnable	1.3.6.1.4.1.9.9.118.1.2.1.1.1	TruthValue	read-write	This variable is used to enable UDLDP on this interface. If cudldpGlobalEnable is set to 'false' then this variable has no effect. cudldpInterfaceEnable is deprecated and replaced with cudldpInterfaceAdminMode.
INT cudldpInterfaceOperStatus	1.3.6.1.4.1.9.9.118.1.2.1.1.2	INTEGER	read-only	This mib object contains the following values, which has the meaning as: 'shutdown' - An Uni-Direction link has been detected and the port has been disabled. 'indeterminant' - Uni-Direction Link Detection protocol has not collected enough information to determine if the link is bi directional or not. 'biDirectional' - A bi directional link has been detected. 'notApplicable' - Uni-Direction Link Detection Protocol is disabled.
T/F cudldpInterfaceAggressiveMode	1.3.6.1.4.1.9.9.118.1.2.1.1.3	TruthValue	read-write	An indication of whether the UDLDP aggressive mode is enabled on this interface. If the aggressive mode is set to 'true', an active port may be shutdown in case of the abrupt loss of its neighbor(s) because the loss of communication (heartbeat) with the neighbor(s) is assumed to be caused by a fault; thus, the cudldpInterfaceOperStatus of the active port will be 'shutdown'. Instead, when the aggressive mode is set to 'false', and if there is a loss of communication with the neighbor(s), then the cudldpInterfaceOperStatus of the active port will be 'indeterminant'. Therefore, this mode is recommended only for links that don't use hubs, media converters or similar devices, and where the unexpected loss of the port's neighbor is not an admissible condition. cudldpInterfaceAggressiveMode is deprecated and replaced with cudldpInterfaceAdminMode.
INT cudldpInterfaceAdminMode	1.3.6.1.4.1.9.9.118.1.2.1.1.4	INTEGER	read-write	Indicates the Administrative mode of Uni Direction Link Detection Protocol Feature configured on this interface. enable -- Uni Direction Link Detection Protocol is enabled on this interface. disable -- Uni Direction Link Detection Protocol is disabled on this interface. aggressive -- Uni Direction Link Detection protocol is enabled in aggressive mode on this interface. default -- Whether the Uni Directiona Link Detection protocol is enabled or not on this interface depends on the object value of cudldpGlobalMode.
INT cudldpInterfaceOperMode	1.3.6.1.4.1.9.9.118.1.2.1.1.5	INTEGER	read-only	Indicates the operational mode of Uni Direction Link Detection Protocol Feature on this interface.
U32 cudldpIfFastHelloInterval	1.3.6.1.4.1.9.9.118.1.2.1.1.6	Unsigned32	read-write	This object specifies the fast hello interval at which each port sends a hello packet to all of its neighbors at steady state. By setting this object to a positive value, this interface is enabled to send UDLD hello packet at a fast interval as specified by this object value. Setting this object to zero value, this interface is disabled to send UDLD hello packet at fast interval. Instead, the interface will send the UDLD hello packet at the interval as specified by cudldpHelloInterval object (or cudldpHelloIntervalExt if a platform supports cudldpHelloIntervalExt).
U32 cudldpIfOperHelloInterval	1.3.6.1.4.1.9.9.118.1.2.1.1.7	Unsigned32	read-only	This object indicates the operational interval value at which each port sends a hello packet to all of its neighbors at steady state.
INT cudldpIfFastHelloOperStatus	1.3.6.1.4.1.9.9.118.1.2.1.1.8	INTEGER	read-only	This object indicates the operational status of fast hello UDLD at this interface.
cudldpFastHello	1.3.6.1.4.1.9.9.118.1.3
T/F cudldpFastHelloErrorReportEnable	1.3.6.1.4.1.9.9.118.1.3.1	TruthValue	read-write	This object specifies whether error reporting is enabled or disabled when a fast hello UDLD link error is detected. 'true' specifies that when a fast hello UDLD link error is detected, the link remains in its current state and a cudldpFastHelloLinkFailRptNotification event will be triggered. 'false' specifies that when a fast hello UDLD link error is detected, the link will be automatically put in error-disable state and no error report will be generated.
U32 cudldpFastHelloMaxPorts	1.3.6.1.4.1.9.9.118.1.3.2	Unsigned32	read-only	This object indicates the maximum number of interfaces that fast hello UDLD can be enabled to run. When the value of cudldpFastHelloConfigPorts reaches this object value, enabling of fast hello UDLDP on additional interface will fail.
U32 cudldpFastHelloConfigPorts	1.3.6.1.4.1.9.9.118.1.3.3	Unsigned32	read-only	This object indicates the total number of interfaces that fast hello UDLD is currently enabled.
U32 cudldpFastHelloOperationalPorts	1.3.6.1.4.1.9.9.118.1.3.4	Unsigned32	read-only	This object indicates the number of interfaces that fast hello UDLD is currently enabled and in operational state.
ciscoUdldpMIBConformance	1.3.6.1.4.1.9.9.118.3
ciscoUdldpMIBCompliances	1.3.6.1.4.1.9.9.118.3.1
ciscoUdldpMIBCompliance	1.3.6.1.4.1.9.9.118.3.1.1			The compliance statement for the CISCO-UDLDP-MIB.
ciscoUdldpMIBComplianceRev1	1.3.6.1.4.1.9.9.118.3.1.2			The compliance statement for the CISCO-UDLDP-MIB.
ciscoUdldpMIBComplianceRev2	1.3.6.1.4.1.9.9.118.3.1.3			The compliance statement for the CISCO-UDLDP-MIB.
ciscoUdldpMIBComplianceRev3	1.3.6.1.4.1.9.9.118.3.1.4			The compliance statement for the CISCO-UDLDP-MIB. This compliance statement is deprecated and superceded by ciscoUdldpMIBComplianceRev4.
ciscoUdldpMIBComplianceRev4	1.3.6.1.4.1.9.9.118.3.1.5			The compliance statement for the CISCO-UDLDP-MIB.
ciscoUdldpMIBGroups	1.3.6.1.4.1.9.9.118.3.2
ciscoUdldpMIBGroup	1.3.6.1.4.1.9.9.118.3.2.1			A collection of objects for use with the Uni Direction Link Detection Protocol.
ciscoUdldpAggreModeOptionalGroup	1.3.6.1.4.1.9.9.118.3.2.2			A collection of optional objects providing UDLDP aggressive mode configuration information.
ciscoUdldpMIBGroup2	1.3.6.1.4.1.9.9.118.3.2.3			A collection of objects providing Uni Direction Link Detection Protocol information.
ciscoUdldpMIBGroup3	1.3.6.1.4.1.9.9.118.3.2.4			A collection of objects providing Uni Direction Link Detection Protocol information.
ciscoUdldpFastHelloGroup	1.3.6.1.4.1.9.9.118.3.2.5			A collection of objects which provides fast hello UDLD information in the device.
ciscoUdldpFastHelloNotificationGroup	1.3.6.1.4.1.9.9.118.3.2.6			A collection of notifications which provides fast hello UDLD notifications support in the device.

RFC description

Cisco Unidirectional Link Detection Protocol MIB for detecting and managing unidirectional links on network interfaces.

Start monitoring Cisco switches (fiber-optic uplinks/aggregation, UDLD) 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 CISCO-UDLDP-MIB

What Is CISCO-UDLDP-MIB?

Supported Devices

Monitoring Examples

What Can Be Monitored

This MIB depends on

Related MIBs

RFC description